Bizarre electrical gremlin

This has never stumped and I've been scouring all forums, all sites.

2011 SR5 CM 5.7 ffv
143k

Just got back from a trip, 2400 round trip to Florida. On the way down truck died on I75, just cranked wouldn't fire, towed to svc station and fuel pump was replaced, oem pump assy. $1600 installed, that stung on vacation, but oh well. Got it back and drove it around but
down there it threw a code for Maf. Replaced that. Ran like a top and drove home 1200 mi no problem. Got home Monday. Friday afternoon, having drove it to work every day, it stalled backing out the driveway. Wouldn't fire again, just crank. Same symptom as "the fuel pump crisis" when it stranded us on the highway. Something tells me there's another issue.

Now after doing a little troubleshooting:
Blown efi1 fuse
Blown fuel pump fuse.
Replaced both but now it's weird..
Key to ON, not even start, the starter just runs, doesn't start. I can take the key out even and it doesn't stop. I have to pull the starter relay or disconnect battery.

Say I leave starter relay in and pull the efi1 fuse, it'll act as it should meaning it only engages starter when key is turned to start and starter stops when in ON position. Say I leave efi1 fuse in and remove starter relay, the pump continuously runs and there's buzzing in the engine bay.

There were no codes before but now it has the following:

============1==============
P0335
Raw code: 0335
ECU: Engine control unit #1
Status: Confirmed
OBDII: Crankshaft position (CKP) sensor - circuit malfunction
Toyota: Crankshaft Position Sensor Malfunction

============2==============
C1201
Raw code: 5201
ECU: ABS control unit #2
Status: Confirmed
Toyota: Engine Control System Malfunction (VCS lamp ON-RX3) or ECM/TCM malfunction / 51

I haven't done anything else to avoid just throwing parts at it. Besides the starter running with key off thing doesn't really translate well to crank sensor, however the ecm malf is highly suspect!q

Key notes
Battery is fully charged yellow top optima, did the removal a few hours thing already.
No rain exposure in weeks.
Tapped all the relays, swapped a few to verify function.
Cleared trouble codes
Flashing 4lo and Trac control light on
Gas is fine

Guys I'm stumped, I'm trying to avoid towing to the dealer 40 mi away from me esp after that $1600 pump but I really think it's going that way. Consider this at least a documented event and when this is resolved I'll certainly report the corrective action, in all my searches here and elsewhere I found way too often the threads just go cold! I had to guess or go off feels but this really seems like it's pointing at a bad ecu issue

 

EWDs are here if you want to try chasing out the wiring from the fuses
https://www.tundras.com/threads/ultimate-wiring-diagrams-collection.81448/

You might also check all your ground points and look for damage or loose connections. It’s not uncommon for a bad ground to cause random inconsistent issues

 

Curious if disconnecting the battery (ECU reset) may have temporarily helped the issues and the real problem wasn't the fuel pump or the MAF sensor. not very likely they are all failing one after another but it's possible.
Did you by any chance disconnect the battery before the fuel pump fix? Most likely not. How did they diagnose the fuel pump issues?

CKP sensor would be the one to research and also the ECU issues if any. Also wiring and ground issues as mentioned is a good idea but not very easy.

 

Inside the left frame rail, above the rear axle is the fuel pump control module. It’s powered by the fuel pump fuse and relay, and by the ECU, which among others, is powered by the EFI1 fuse.

I’d be looking at it and the wiring harness, as I suspect a short between circuits feeing back causing the unwanted cranking. You could even unplug the fuel pump control module and see if the cranking issue changes.

 

This is good stuff guys. Busy 4th weekend not in a good way either. Septic pump died on me so been digging for what seems like an eternity. Back to the truck, I pulled the connectors on the fuel pump module. Same effect. I did find a broken ground strap, the bare braided one down by the transmission tunnel under the passenger side floor. Repaired that. No change.

I've cleaned battery terminals and the posts. Removed any aftermarket connections (winch, light bar, sub). No change

I've had the integration relay out and took it apart to check it out internally but looks good.

The maf is what I thought killed the truck in Florida because it had stumbled a bit on starts and it did something similar to me before about 2 years ago but I cleaned it and problem went away. Also when the truck had sat a bit before it went into the shop down there it started up after they took it off the rollback, a little groggy but it cleaned up and sat there idling for a bit. I think the fuel pump swap was likely in vain and masked a bigger issue. They didn't seem like the place that would have techstream or any real diagnostic equipment. When I changed the maf in FL the starts were now crisp, throttle response seemed to have improved and even got 1.5mpg better on the way back.

I think the maf wasn't really tied to this issue just a separate maintenance item that needed addressed but this start thing is new. The start circuit on this truck is confusing, I'm a mechanical guy and weak on electronics troubleshooting but I've studied the start circuit and it's not really your typical Ignition switch->starter relay->start solenoid->starter motor. It's like compounding relays of starter and integration relay to ecu and then whatever goes on in the ecu.

I'm dreading taking to a dealer in this car sales climate, they'd love to have an issue like this roll in for that bill. I'd almost prefer to go against my aimlessly throwing parts at it policy and get a known good ecu but it seems you HAVE to take it to a dealer to rewrite to the truck. And there's $800 for the ecu right there...nevermind there's loads of em for $100-$150 available on the used market.

I think before that I'll at least get a crank position sensor. Will check and test if possible before though. Will report back

 

There’s a previous video on there too but it’s a short and won’t embed..here’s the longer version.



back to diggin!

 

Little update. Dash and column all tore apart chasing wires, junction connectors etc

So I'm working backwards a bit to see where this starter circuit is being energized.

The starter relay has 12v at the coil with the key ON. Hence it is being called to start at ON position. Going backward, at the fuse box red wire in the DA2 white connector it also has 12v of course. Going back to the ecm it has 12v at pin 46(STA) red wire, output. So the call is made from ecm to start..in ON position, not START as it should be. Going back further the 2 blue wires at ecm pins 16(STAR) and 120 (NSW) are also 12v.
For a little test I unplugged the park selector switch plug and that interrupted the call to start. It had 0v at relay red wire to start. Put a jumper across blue and red on the plug and then back to 12v in ON position. This is peculiar and I should look into it further.
Ok the other direction. The reason I ended to check here is because I checked at the diode(tested ok) and connector A40 by the right kick panel and the brown wire coming from ignition switch ST2 position is 0V. This proves out when I turn the key to start position that wire goes to 12v. So I'm still at a loss on where this infernal Red wire to the relay is energized to 12V in the ON position. It's like a mile of wiring to comb through from the key to the damn relay. I reckon I need to go the other way and chase the IG2 position to try to find where there could be a cross of a hot wire and this blasted red relay energizer wire which is a zillion more connections since it dang near powers the whole truck.

I will update again as things progress or devolve into further madness

 

Well nobody can question your dedication at least. I am the same way, I will pull every nut and bolt out of that truck before I pay a 40 mile tow bill to Toyota.

I spent over an hour now looking at this and have a theory. I pulled up a color diagram of the starting circuit (posted below) and was trying to identify the abbreviations used for the wires going into the Engine Control Module (ECM) in doing so I stumbled across this which explains more of the operation of the circuit.

Cranking Holding Function Circuit
The cranking holding control system keeps energizing the ST relay after the ECM detects the starter signal (STSW signal) from the main body ECU until the ECM performs a judgment of "Engine started". Furthermore, the ECM outputs an accessory cut signal (ACCR signal) to the ACC relay during cranking to prevent flickering of the combination meter, clock, audio system, and so on.

When the ECM detects the STSW signal, the ECM outputs the starter relay drive signal (STAR signal) to the starter relay through the clutch start switch or park / neutral position switch, and then, the engine is cranked. When the ECM receives a stable engine speed signal (NE signal), more specifically, when the NE signal reaches a predetermined value, the ECM stops outputting the STAR signal. Also, the ECM monitors the ST relay operating conditions based on the STA terminal voltage status.

Alot to unpack there, I had to read it several times. But basically it is saying to me that once you turn the key to start, the ECM keeps the starter engaged until it sees that the engine is running from the NE signal. The NE signal comes from the Crankshaft Sensor and you have a Crankshaft Sensor Code. So what are the chances the ECM is hung in a loop running the starter until its sees a say 400-500 RPM signal from the crank sensor (which never comes)? This to me would honestly make alot of sense. When the key comes back ON, power goes back to the ECM and its still in the loop (from before) looking for the NE signal so it just starts going on its own.

In removing the EFI fuse you are cutting main power to the ECM so it no longer hangs open keeping power going down the STAR wire because its not even awake.

So what if you just have a bad Crank Sensor and the ECM is not getting an signal from it ever?

 

A few more thoughts on how to really test this.

I think monitoring the output voltage on the STAR wire is key here.

Can you unhook the battery or do something to reset the ECM out of the loop so when you turn the key ON for the first time the STAR wire has 0V?
Have you been able to "reset" the truck from cutting power so the first turn of the key to start is normal and then from there it hangs and is always running the starter in the ON position?

If you can get to this point, the STAR wire should be 0V out of the ECM initially, then I would turn the key to the Start position and verify that the STAR wire goes high to 12v. If my assumption is correct it will now stay high at 12V with the key ON (all the time). I do not think the STAR wire will drop back down to 0V until the ECM sees a signal from the Crank Position Sensor.

You could try to "replicate" a crank signal into the ECM to verify the STAR wire does drop back down to 0v. Or double check connections/tap on the Crank Sensor and maybe get a little more life out of it. Assuming it really has failed.

 

Older post I just found from another Tundra Website

 

By any chance, did you get an ECM flash with your new fuel pump?? I do believe there was a recall on the FFVs which offered a new pump and a flash so the ECM would read correctly.. Just wondering if the svc station was a regular mechanic or the stealership..

 

First off guys thank you for your input. I truly appreciate your insights. These are good things I hadn’t thought much into as far as diagnostics. I did pull the crank sensor to check it out, it seems clean but I wiped it off for good measure and reinstalled it. I have yet to throw any parts at it though.

Yes the hold to start function is something I never even noticed as I always started my truck like you would most cars. Good to know just a bump to ST2 is all it takes...normally! I’m afraid though the issue is before it even reaches ST2. I’ve now not even bothered much with trying to figure out things with ignition at ST2 as the truck starter is engaged in IG2 and continues even after turning it off and taking the key out. Pulling starter relay stops continuous crank and I can immediately put it back in and it resets the process to where the starter does not start running immediately, only after going back in the cab, put key in, turn to IG2 and boom rinse and repeat. Starter sounds healthy. With the key in ACC, I can take the starter relay cap off and at will engage the starter manually by pushing the armature in the relay to make the circuit, let go of it and it stops. Something is keeping that relay energized prematurely

Also, to answer the question I did do the reset with the battery out on a charger for a few hours to rule that out. Cleaned the terminals and the battery posts as well as disconnected any aftermarket stuff I had on there. After that no change observed. The start relay is energized immediately and starter running in the ON position having never been cranked to ST2 position so yes the blue STAR wire is hot before it should be. The “why” is still TBD
No ecu flash after fuel pump install. However it did run ok after swapping and it was a bit of a shade tree garage in FL. Nice, cordial guys, but they for sure didn’t have techstream I can tell you that much.

I can’t for the life of me find out why after the kick panel junction connector brown ignition wire is 0V at IG2 position but the blue wires at the junction box in front of the ECU are hot 12V at IG2. Tracing those only leads to ecu and park selector switch. The red has 2 connections, 1 to ECU and 1 to gear selector switch. I already bypassed the switch by jumping the blue and red essentially simplifying the circuit with a straight path and yep, 12V and continued starter running in IG2 position. Gah!

Again, much appreciated responses gentlemen. I will report back with some more poking around after work. We still got our Avalon to get around, but it’s bike weather here in Indiana so I can at least be thankful this didn’t happen in January and I can use other transportation modes lol!

 

The ECM is holding the continuous 12v out the STAR no matter what the ST2 switch is doing. You verified this by removing the EFI fuse which cuts power to your ECM.

To me it really feels like the ECM is stuck in a start loop as soon as it gets power (key on). My research shows it’s because it’s not seeing a signal from the crank position sensor.

Do you still have the crank sensor trouble code?

Why is the engine not full starting? Starter is engaged, key is on, ECM has power, fuel pump is running. Does it not know the crank location so no spark? You have every input needed to make it run yet it just turns over and never starts. This is odd to me and evidence is more than a shorted wire in the starter circuit.

One guy mentioned unplugging and replugging in all the coil pack connectors. He said a loose/bad coil connection was messing up the crank sensor. Worth a try.

The first part I would buy and throw at it would be a new crank sensor. Worth the $100 gamble even if it just a chain auto parts one.

I see no evidence in the starter circuit wiring that would cause it to hang like it is. You ECM is stuck in a loop because it’s not happy about somthing. Getting the trouble codes in the ECM fixed and cleared is a great start.

The park neutral switch is just a block between the STAR wire and the starter relay. If the truck is not in P or N the switch just blocks the power flow. It doesn’t generate a power signal, bypassing it won’t do much. Signal is generated by ECM STAR pin, park switch will just block it when you are in R or D

 

Short update, I only got to work on the truck today after a few days being too busy elsewhere. I have a couple variables here. I reset everything again with the battery disconnected. I also pulled out the main body ecu down by the driver kick panel really to inspect the wiring, plugs etc in there. I changed the crank sensor and I pulled each coil plug and put them back. So the truck starter still engages with key at IG2 position. However now it will actually turn off when I turn back to the OFF position but it continues to run in ACC and when I do go to OFF it hangs for a second. It doesn’t stop instantly.
I will get another video put up. Fuel pump continues to run constant, not just prime and shut off. Not sure yet if the ACC cut relay controls this or the fuel control module. I honesty haven’t looked at that end much. I half way split the fuse box to see if anything is crossed underneath all the relays and fuses. It’s a pain to do but didn’t see anything surprising there. I put it up for the day to take a break and take the fam to the co fair, can’t be all work and no play. Back to checking things tomorrow.
I haven’t found a single burn, discoloration, frayed tape, scrapes wires, broken grounds etc but it doesn’t mean it’s not there. I’ll give it to Toyota they made a very robust wiring harness. I’m about to just put the dash all back together and send this mf to the dealership.
It’s gonna kill me to find it’s something stupid but I’m coming up on 8 days down!

 

Have you tried to read trouble codes again?

The engine ECU is where I would really be looking also. It’s on the firewall passenger side. Worth the few minutes to pull the connector off it and maybe remove it full for inspection. Does it smell burnt, have black spots on the case ect.

Even unplugging and replugging it back in could “reset” it.

Any chance the fuel pump circuit or module is crossed up making the engine ECM freak out. I think you said you unplugged all the fuel pump wiring?

The fact the truck doesn’t actually start while cranking is still a little odd to me.

Did you put a voltmeter on the STAR wire coming out of the ECM to make sure it is in fact staying high at 12v keeping the starter going. I would do this sooner than later to make forsure something internally in the ECM is keeping the starter going.

 

I pulled the pcm a bit ago for a sniff and visual inspection but also to be double sure of the PN on mine. Looks normal, clean, no smell.

Yes I put my DMM and observe 12V on STAR wire right at the junction box pin 7 in front of the pcm connector D73, yes confirmed orientation. As soon as I turn to IG2 it hits right to same as battery voltage. I'm just not finding where it is being supplied this voltage. It has to be between D73 pcm proximity junction box and A40 by the passenger kick panel since I've verified brown key switch wire at A40 is 0V key at IG2. Maybe I should look ar the bulkhead grommet to see if there's any chafing of the wire bundle

The only thing I unplugged for the fuel system was the fuel control module inside the driver side rear wheel fuel rail. I checked the connectors, looked ok. I haven't dropped the tank. I suppose I could but I'd prefer not to yet, it's a 46gal steel tank so kinda cumbersome in gravel. Tomorrow I'm going to really focus between the junction box D73 and the passenger kick panel A40. Somewhere between those ends it's picking up the 12V.

I put my scanner on a little but ago and pulled the codes. Same faults as before, the crank and ecm malfunction but this time added a P1340 cam sensor fault. Cleared them and they came back immediately. Poked around the cam sensors thinking maybe I unplugged something in the fray, not seeing anything out of the ordinary.

Yes even though it cranks it just does not fire, not even a sputter.

 

As long as the STAR wire is hot with 12v it will back flow 12v out the D73 junction connector back to the diode toward A40

Unplug the junction connector fully and then verify that the Pin 7A coming in from A40 is only going to 12v when you turn the key to start. I think it should be operating correctly.

It really seems the ECM is energizing you’re STAR wire from a different internal source. Pulling the EFI1 fuse cuts main power to the ECM and makes it stop doing this. With the ECM dead the starter is acting normally sending 12v from A40 through Pin7A of the junction connector and to the starter. You can see this in your video, with the ECM dead (no fuse) the starter is working normally.

The ECM is stuck in the auto help start mode and is sending 12v out the STAR wire continuously. It is getting this power source internally from a short on another sensor or somthing.

I think what I would do next is try to remove the STAR wire Pin 7B from the D73 junction connector. Unpin it or somthing. Removing this should break contact that keeps the starter running without having to kill all the power to the ECM. Disabling the auto help start feature for now.

Once the ECM has power but the STAR is unhooked at the junction. You should be able to turn it over like normally but the ECM still be on. Go look for reasons why it’s not starting. I assume no ingition. Make sure it has fuel at the rail. Check for spark. Pull each CAM sensor one by one clean and reinstall. If you figure out what’s keeping it from starting (sparking) you probably find what’s sending bad signals to your ECM making it operate in weird ways.

A lot of reading last night showed the crank sensor is sometimes a false code. Really seems somthing else has failed, and is sending bad signals into your ECM making it do weird things.

Put the OEM crank sensor back in just in case. Some people said this actually helped

 

The blown EFI1 and fuel pump fuse from day one are still odd to me. Somthing happened in the power circuit to the ECM or fuel pump to overload and blow these fuses.

 

OK the saga continues. I did exactly as you described man, I even pulled the wire free of the loom straight from PCM pin 16 to where the crimped end goes into B73 and sure enough, we'll call it STAR 7/16 is 12V at IG2.

This should be an input signal that feeds 12V to the PCM, correct? Meaning this wire is energized by the ST2 circuit only when certain conditions (ie ST2 position only!) are met then start command is sent out to the red wire to relay but it seems it's constant 12V with PCM power regardless of the circuit conditions. These cam and crank sensor issues are brand new with all of this happening so I haven't done much beyond what was mentioned and focused my efforts mainly on the premature starting issue.

I did verify also that 5 and 6 are indeed 0V at IG2 and both go to 12V when key is bumped to ST2. This was checked with 7 removed from the connector.

I guess from here there's something
internally wrong in the ECU CB to ground this line to power when the PCM is powered. The trail kinda cold from here unless you got any other ideas. Dude I appreciate your working with me on this headache!

I'm uploading 2 videos but I basically described here what is happening in those.

 

No read my post #8 again carefully. Also look at the purple arrows and text I added.

The STAR wire is the output to the starter from the ECM. The power comes out the STAR through the neutral switch and to the relay. This is the “auto start” help feature and it just merges with the key start signal at the junction connector.

With the ECM fuse pulled the starter still worked because the key signal came in through 7A into the junction then out 5B to the neutral switch. These ECM auto start just keeps this going with the STAR wire and junction. Hope this makes sense.

The brown STSW on bottom is the input trigger wire to the ECM for the “auto start” It is tied to the key, when key goes to start position, STSW switch goes 12v which tells the ECM to energize the STAR wire out to the starter. This begins the “auto start feature”

The red STA wire is just a voltage monitor wire for the ECM, not the starter power wire.

If you still don’t fully understand this let me know and I will layout a diagram.

With the STAR wire unhooked from the junction does the truck turn over normally with the key. With the fuse and ECM powered up it should. As I mentioned unhooking the STAR wire just disables the “auto start” feature.

Now that it’s turned off why is the truck not starting still. Do you have spark and fuel?

 

This is the starter circuit with no ECM or "auto start" feature involved. Essentially what you are doing in your video when you pull the EFI1 Fuse cutting all power to the ECM. Power comes through the key out ST2 all the way down and around, straight through the junction, then through the P/N switch, finally to the Start Relay.

 

This is when you add the "Auto Start" feature back in from the ECM. When the Key goes to ST2 it sends a signal through the smaller junction connector down the brown wire that comes in the bottom of the ECM. This is the STSW wire which is the signal to begin the "Auto Start" process. When the ECM gets this signal is send 12V out the STAR wire which goes right to the junction connector (red line with arrow), then through the P/N switch and to the starter relay. This new "Auto Start" signal just merges with the Key Start signal from above in the junction connector.

The STA red wire is just a way for the ECM to monitor how much voltage is being sent out to the Starter relay.

This is the description of the circuit directly from Toyota and from my post above. "When the ECM detects the STSW signal, the ECM outputs the starter relay drive signal (STAR signal) to the starter relay through the clutch start switch or park / neutral position switch, and then, the engine is cranked. When the ECM receives a stable engine speed signal (NE signal), more specifically, when the NE signal reaches a predetermined value, the ECM stops outputting the STAR signal. Also, the ECM monitors the ST relay operating conditions based on the STA terminal voltage status."

 

When you break the STAR wire connection either at the ECM or at the Junction connector you are disabling the "Auto Start" feature. Doing this will let you try to diagnose other issues with the engine and not having the starter run constantly. The ECM will still have power and the starter will still work off of just the Key signal as described above.

Now the truck should just start and run like normal but it isn't. As mentioned first thing I would do is verify you have spark and fuel. I have a strong feeling another sensor somewhere is dead, shorted out, something and it is sending foul signals into the ECM. It is not allowing the ECM to see the Crank Position Signal.

It could be one of the CAM sensors, it could be something else. I am not really sure. Now that its in a position where you can actually diagnose without the starter going crazy, its time to find the real problem. I have a feeling you have no ignition circuit or spark so the truck will not start and the ECM cant see the crank signal.

 

OK, I understand better now. I'm way out of my normal area so thanks for your patience, I was way off there! Yes with STAR wire removed from the circuit the ignition sequence works as it should. No hung starter. Ok so back to it, I went through and cleaned all 4 cam sensors, they looked ok, just a dab of oil on them, dielectric greased pins. Did the same for all coil connectors. Cleaned up all my engine bay grounds I could see. Probed each coil connector for continuity to ground at battery post, all good there. Swapped the crank sensor back to the original. Still no start. I dont have a way really to bench test this 3 pin sensor that I know of. I pulled a spark plug and left coil attached and grounded it. No spark when starting. I can recheck this better with my spark tester though. Seemed rude and crude just laying it there on the ground by the air filter.

 

Ok now we are getting somewhere.

Since you understand probing for continuity, I would check all wires to the crank sensor from the ECM connector to the crank sensor plug. Did you happen to look up in the hole where the crank sensor goes to make sure the teeth/pickup points were still in place so it could work correctly?

Another thing to check just to be sure, lay under the back end and unplug the connectors to the fuel pump control ecu. I know this will make fuel stop but does spark come back when doing so? What if you FL mechanics got somthing backwards. The pump and EFI fuse were blown when we started this

I am trying to think of other things that would take the ignition system down. I think we are much closer to finding the actual problem.

 

Also try a second key if you have it, just to make sure there is no bug with the security ECU and the key. I doubt it but worth the 5 mins to make sure if you have a second key.

Additionally, take a few minutes to check every fuse in the engine fuse box as well as in the body control module in the cab. A bad fuse will make you go crazy and its best to rule that out now.

 

OK man lots to report back with..

I'll cut to the chase though. The truck is running! I had a few hiccups since I'm a dummy and left the front passenger cyl coil unplugged during all the and I was like wtf it's running like crap. Well, that was why.

As for fuses I feel like I ran the world tour on the fuses in the truck at least 3x thinking my eyes were deceiving me but yes they were all OK. Never blew a fuse since the initial EFI1 and F/pump at the beginning.

After repeatedly chasing the crank and camshaft position sensor I turned to that fuel module for a change of scenery I suppose. So I crawled under and for about the 3rd time checked the module plugs and pulled it off the frame rail but this 3rd time I used a small brass brush and touched up the contact pins on the module and hit the pigtail pins with some dielectric grease. I keyed it on and didn't hear the pump this time, I noticed it had only clicked on after bumping to ST2, it didn't prime at IG2 like it usually does or continuous run. I don't know if during all this chaos I smoked the relay but I swapped it with another I had. Truck fired up, ran like crap, dash was a christmas tree but after fixing the disconnected coil plug I went through clearing all the codes and no lights on the dash. So with all this I had crankshaft position, camshaft position, I even got a MAF fault and that ECM fault code. I can report it has all original parts in it, I only bought the crank sensor but put the OE one back in. I taped the PCM harness back up, had a whole mess of stuff taken out to put back. Once everything was back to status quo at least electical, I tried putting pin 7 STAR wire back in D73 and starter hit at IG2 again so I shut it off real quick and pulled the start relay. Pulled the pin again, taped it over and set it aside inside the PCM junction box. Drove it up the street, ran fine! I still want to address this bizarre STAR wire issue. I at least can get it to a shop to look for this. I've had my fill and can at least get it somewhere on its own legs.

I really can't tell what was the catalyst to all this, maybe age? Corrosion? I never found a broken wire, burned terminal, short etc. That's frustrating because now I'm worried about what's next. I will keep on this one to see what the issue is with this continuous start because as far as I can tell it's still an open case. Jeff I can't thank you enough for helping keep me on the right trail!

 

I re-read. I should clarify I did the relay before the R&R on the module. I checked the plugs and put them back, then it seems cleaning the contacts is what really made the difference. I heard the pump but still no start at the time. I try to try just 1 thing at a time, perform test, then move to the next to keep the variables down to 1 for each attempt

 

Great news!

Just to clarify does it still have trouble codes in the ECM. I would drive it the next few days but not further than you can tow it back home. Maybe just let it sit and idle in the driveway for a while.


I wonder if your fuel pump control ecu could be in the way out the door. The shop only replaced the pump right? Not the ecu also?

Where any of the wires going to the fuel pump control ecu modified or spliced? Or was it all factory wiring still? If you want lay under there again and snap some photos. Just to be safe and verify the right wire is on the right pin ect.

You might keep playing the game of trying to unhook the battery and reset the ecu to try to fix the STAR wire problem. Getting all the codes out of the ECM and not returning would be my first goal.

I really thought once it was running the STAR wire issue would have fixed itself. Small concern the full pump control issue could have damaged this circuit in the ECM. Good news is you don’t have to have it to drive if you just leave the STAR wire unplugged.

If you keep messing with it or take it to a shop report back findings. Really curious as to what the real issue is now with the STAR wire.

 

Little update after a few days. I've finally got everything put back up, taped up the harness, etc. That's correct, no codes. We'll sort of. I've cleared codes but it appears it has stored permanent inactive codes for crankshaft position sensor and camshaft position sensor. It pulls them again after clearing and recheck.

It idled nice and smooth for a good hour while I assembled the dash and cleaned everything inside. You'd be amazed how much junk gets under the kick panels and sills. Drove it to work yesterday, no issues. During all of this I found my vacuum lines for the ACIS were broken. Fixed those. Seemed to run even smoother than before. Probably not because loss of acis functjon but more so the manifold vacuum leak. Still no dice on the STAR wire. I'm going to have to take it to the shop for that I think.