Looking like new ECU time FIXED

I think I’m about tapped out of ideas on what next to check with this truck.

Trying to fix a crank no start situation.

I have a thread over in the build forum of all my trouble shooting.

https://www.tundras.com/threads/the-journey.119538/

unless any of you more seasoned Tundra techs have any other suggestions of what to test or trouble shoot, I think my next step is purchasing an ECU.

Any thoughts or suggestions are welcome. TIA

 

I'm posting over here just "because". Don't want to clog up your build thread.

That one coil pack is suspect as hell with how wet and corroded it was, and leaves me wondering about stuff. Have you at least done a basic compression test on the engine? (sorry if I missed that)

This is maybe a stupid question because it's turning over, but have you tried turning the engine over manually to make sure there's no considerable resistance throughout?

Have you tested the MAF yet, just to see what the ECU is seeing as far as air intake goes?

Finally, I realize this is medieval, but it works: You've confirmed you have spark. Have you tried the basic, no-computer, no-bullshit method of giving it some ether/starting fluid to see if it turns over? If it has spark, it WILL turn over with ether. Just a small shot, either directly into the intake, or hit each plug hole with it if they're out and you should get fire.

Sounds like you've confirmed the big three: Fuel spray out of injectors during turnover. Spark at coil pack during turnover. I assume you've verified the plugs, that they're not some bullshit counterfeits someone bought off scAmazon (b/c that actually happens more than it should). But third, you surely have air coming in, but you've tested the MAF to figure out what the ECU is seeing, right? You checked for rodents in the air filter, and there's no debris on the MAF sensor, and it has correct impedance? (actually, just searched MAF in your post - looks like you checked it, but I didn't confirm the values in the FSM).

I dunno if it helps, but here's a couple of fuel/start troubleshooting videos, just important to note: There's a bit of misinformation in the fuel one, the fuel pump in these trucks only runs when the key is in the crank position OR the crank position sensor notifies the ECU the engine is running. The latter is why the crank position sensor is important. Link: https://www.tundras.com/threads/2005-ac-wont-start-fuel-system-problem.113385/#post-2921783

I also assume you've tested both fuel-related relays, checked the EFI fuses, etc.

To boot, here's the fuel pump circuitry if you want to understand how the fuel system works.

More info may be gleaned here, along with diagrams if the above didn't help.

 

Oh and last bit - did you check the ECU for water damage, by separating its clamshell?

Did you check the integration relay (in-cab fuse panel) for water damage? (I know, it's a bitch to remove)

And you checked both temp sensors to confirm they're both OK?

What is your ECU part number? Someone may have a spare laying around ... It's printed on the sticker of your ECU.

 

Shifty, first off thank you for the response.

I forgot to do the compression test, I can do that later this week, the wife won’t give up her garage when them temps are in the single digits

Yes I’m able to turn the engine over with a 12” long 1/2” ratchet and socket( no cheaters) only expected resistance.

MAF ohm tested within spec but haven’t had a chance to test air movement while ohm’ing it.

I replaced all 8 coils with Denso coils from rock auto, new Denso plugs from rock auto also. Once replace I’m getting good spark from each coil.

3 short sprays of starter fluid/ether was shot into butterfly valve of the intake with no hint of combustion, which is seriously confusing to me. I might have to try putting some in each plug port.

what is the best test to see what data is coming from the MAF via the ECU?

MAF ohm results 2.38. Range 2.19-2.67

I have swapped relays and tested both, missed that also when transposing my notes

I believe everything is working on the fuel system, but now that I go over the FSM, I didn’t jumper bypass the fuel resistor, I have added that to my list of things to do.

Can’t count how many times I have checked all the fuses.

The cab shows no sign of any water leaks, I have opened the ECU, no signs of water, heat or smell of hot or burnt electronics.

I haven’t unbolted and removed the integrated relay and fuses but have contorted my self into many pretzel shapes to inspect as much as possible.

I will have the garage back Wednesday to be able to do more testing.

Will read up on the links you gave me. I have the full electrical manual, and FSM

I think I answered all your questions

Thank you again for your assistance and time

 

This might not help much and you may know already but the mass air flow meter has 2 sensors associated with it. One is used for IAT(input air temp) and the other senses air flow volume.

Those ohm results indicate that the IAT circuitry, E2-THA(pin 1 and 2 respectfully) signals are within tolerance at 68 deg F

To check the air flow volume, the below procedure can be followed. On my 04 using test below, the voltage VG-E2G was .6vdc. While blowing air into MAF meter, voltage fluctuated .6vdc - 2vdc

This might not help but if I unplug my MAF, the engine will at least produce a short burst of combustion(vroom) but shut down within 1 -2 seconds.
I reckon my point is even if MAF was bad, when you sprayed ether into butterfly valve of the intake, you should have had combustion. Yeah I know, not much help.

 

This is the confusing part for me also.

If the engine has ether in any cylinder (or all cylinders) and it's not frozen up, and it gets a spark in the cylinder with the ether, there's no way in hell it's not igniting. If @Dctoner73 removes any coil pack, pulls the plug for that cylinder, sticks it into the still-wired coil pack and confirms the plug sparks at turnover, in theory he should be able to shoot some ether in that cylinder, reinstall the plug, reinstall the coil pack, and get at least a coupleof fires out of the engine.

That's even true if the throttle isn't opening. Ether is hyper-flammable. All it needs is a container (cylinder) and ignition (spark) and you've got combustion.

@Dctoner73 I saw in the other thread you tested for spark. Did you only test for visible spark on the coil pack, or with the spark plug attached to the coil pack, or via other test method?

 

@BubbaW , I plan on doing the air flow test tomorrow. It’s good to be thorough.

@shifty` I tested each coil pack with the spark plug in the coil, grounding it to the engine hoist hook. I will see if I can get a good pick off some video or post a video of it.

also on my list tomorrow is compression test and ether in a plug or two.

will also pull some fuel out and test it’s flammable

 

Should not make a difference but what happens if you remove vacuum line of brake booster that goes to intake and while spraying ether/starter fluid into the booster line, have someone attempt to crank !

On a side note regarding your build thread relating to problem, all gnd readings you checked "GROUND TESTING from ECU WIRING" checked out with the 2000 EWD schematics.

 

I had a similar problem on another vehicle and it turned out the ground to the coils was bad, and they still fired weak (found a ground through the ECU). Once I fixed the ground one of the coils didn’t fire and replacing the ECU fixed it. Not saying that’s what’s happening but that was my experience.

Have you checked out ScannerDanner on YouTube? He’s got the best videos on diagnosing crank no starts. He follows the scientific method and proves everything so you don’t miss anything.

 

@BubbaW i will try the starter fluid in the vacuum line also, more out of curiosity

Thank you for validating the grounding for me.

@SnowB0und according the the electrical schematics I have cleaned all the grounds with the exception of the ones inside the door panels of the AC doors. I will look up ScannerDanner’s vids. Thanks

 

Did you happen to look on the side of your ECU to get the Toyota p/n? Should be in general format of 10 characters, hyphenated, like XXXXX-XXXXX

 

Reporting back,

The Good

Fuel has no issues, lights up easily, no boiling or sizzling sounds so I don’t believe there is any water or other contaminants.

No signs of moisture in or around the in dash fuse panel.

MAF air test, I was able to get the voltage to change when blowing air from a heat gun, but the voltage change was in millivolts, it wasn’t much air but I didn’t want to get the gun too close.

I was working alone so I couldn’t get the spark test pics.

The BAD

Starter fluid in the spark plug port yielded no results

Compression test failed miserably
55-75 PSI the acceptable range is 145-174 PSI

There is no way this thing will fire up with that low of compression.

Definitely feeling a little defeated here.

PO is more of a mechanic than I am, but still swears he didn’t know. I call BS, the truck had less than half power and smoked like a train. I’m mostly to blame because I rushed the purchase and didn’t insist on checking the truck out more.

no I need to start figuring out what to do with it. I don’t have to tools or experience to rebuild it let alone get the motor out of the truck for someone else to do. Real tempted just to part it out.

 

All 8 of them were in that range?

 

Yes, I even rented a second tester because I didn’t believe the first results

 

Respectfully ask....all coil packs and plugs removed, good strong battery and RPM was over 200+ when cranking !
Bummed and grasping for straws !

Edit....Yes, I'm grasping
Had a hmmm moment in thought. I have always done a comp test after engine was fully warm....Dad-in-Law taught me years ago. Even the FSM mentions that. Others more knowledgeable would have to answer. Can someone receive accurate comp test when Eng is not fully warm sitting in a cold environment like Idaho below freezing temps(oil would be thick) ?

 

@BubbaW yes all spark plugs were out, good battery 12.65 volts when started testing. Testing was done with battery charger connected to help maintain voltage. The RPM gauge doesn’t move when cranking on this truck, and I didn’t have my scanner connected to view the live data.

I agree cold temps will play a roll in a lower compression number but that low? It was in the teens last night and my garage was barely above freezing.

I just watched the below video thanks @SnowB0und

He states that most fuel injected vehicles you don’t need to perform the compression test while opening the throttle wide open, but in the video the car he was working on had an IAC that was plugged causing an air restriction requiring the throttle to be wide open to get a more accurate compression reading.
These trucks don’t have an IAC so I’m not sure that will make a difference, but I will try it tonight.

the car in this video sounds exactly like my truck

https://youtu.be/hJQ6qnhTgdg

 

Video is busted. But anyway...

There's a reason the first troubleshooting sentence I posted on this page is "did you do a compression test". Your build thread indicated you had spark, air, fuel. When I saw that one coil pack and how barfed-up on it looked, first thing that struck my gut was, "motor's blown". But I'm not saying I'm right and I also think it's weird to get the same mid-range compression on all 8 cylinders necessarily. You sure you confirmed all timing is in order?

For easy sanity check and/or S&G, have you inspected the fluids, oil and coolant, just to see if any mixture has happened? Oil floats on water, so it's as easy as barely cracking the drain plug for oil to look for water in the first cup or so, then lifting off the rad cap to look for froth/floaters.

Part-out's an option if the motor ends up truly being blown. Depending how much into it you are, it shouldn't be too difficult to find a '00-'04 used engine with the same drivetrain and still get it wrapped up at a shop for $2.5k - 3.5k.

 

Tad bit more troubleshooting
Oil looks Redish Purple, I think royal purple is this color but I’m not seeing any water/antifreeze in it.



I did have to add more antifreeze in it, but I had topped it off over 3 weeks ago, no floaters, I also drained some out of the bottoms and it looks ok also



This thing gets more and more confusing the more I dig into it. Zero soot or oil in the tail pipe. Wouldn’t this be black if the motor was blown. This truck is giving me a permanent headache



Temps are a little warmer tonight, truck has been in the garage since last night, coolant temp was 46*
performed another compression test, all spark plugs out, fuel pump relay removed. For good measure I unbolted the header from the CAT and stuck a screwdrivers between them to make sure I was getting enough air out and pulled the hose off the intake. This should ensure I’m getting enough air in and out for this test.
PSI range was 70-90 and it topped out at 185 RPM while cranking. Battery was on a trickle charge since last night. Batt voltage started at 12.75. All tests were done with throttle wide open, but I did do one with no throttle and the test result didn’t change.

is there anything in the intake that can block air from going in besides the valves?

next step may be to pull the intake and see if I can see any bent valves

@shifty` timing pics

 

Maybe invest in a modest priced inspection tool?

FOXOLA Endoscope, Wi-Fi Industrial Borescope with 6 LED Lights, 7.9mm Type-C USB Snake Camera, Waterproof IP67 Inspection Camera for OTG Android, iPhone (11ft, USB Powered)

https://www.amazon.com/FOXOLA-Endos...=1675418991&sprefix=bore+scope,aps,120&sr=8-3

Clean fluids suggest that the head gasket is not blown. That leaves rings and valves as the suspects. I believe that you can test for rings by squirting oil in the cylinder, then testing compression again (google it). If it increases after the oil then the rings are shot. If not, it's likely the valves. Odd though that all the cylinders measure low...how can all the valves fail at once? I'm told that the frequent use of starting fluid can burn up the valves. In fact, I ruined my AC generator this way one very cold winter. Excessive carbon buildup, and other causes can burn up your valves...but all at once?! Maybe it was a chronic problem that PO just ignored until the problem got so bad it was time to dump it, and then you happened along? Dunno...

If you can narrow it down to the valves then perhaps you can pull the heads and have them reconditioned. Still not easy or cheap however.

 

Do you have an air compressor? A leak down test would answer alot of questions.

 

@w666 last night I rented a bore scope from Autozone but the camera at the end was too long wouldn’t allow me to bend the end of it enough to see anything but part of the cylinder head, none of the walls at all(even with the cylinder all the way at BDC)

I sprayed some Deep Creep down each cylinder just for the hell of it. Will try some oil tonight.

@tvpierce i will rent a leak down tester tonight.

 

Exactly. That's why I was, like, "if timing was off, or things weren't at TDC when setting the timing, I could see this happening, or remember what happened to @Brynden29 in his thread his thread recently?"

His issue ... well, see for yourself 20+ pages later and @EvilMilkshake with the deets of how/why it happened a few replies later.

Timing is important and not always as simple as looking at the belt. I'd be curious who changed the belt, and if it ever ran after. Also curious if anything else was done, since leaking camshaft seals is a problem (at least on later models) and there are clearly things a shadetree mechanic could get wrong.

 

@shifty` forgot to post this last night

 

On that same note, I've had an itch each time the "timing pics" have been shown and have wanted to post, "Please remove covers totally, turn the crankshaft clockwise until No.1 cyl is at TDC with timing marks aligned" and then post a pic.

 

Yup, what we're seeing is inadequate. And even if the marks line up, a verification of whether all was set at TDC is advised.

This is only FYI: 89661-0C361 ended up being replaced by OEM reman part 89661-0C36184. It appears 89661-0C361-84 is discontinued also, but I see fs1inc.com (which is a legit source) has refurb units with each p/n available. I'd probably run with the p/n ending 84.

*IF* you were going to go that route, at least. I'd still verify timing first. It's nagging me that this has timing written all over it.

 

I’m pointing to the timing mark

 

What are the chances that this belt could skip that many teeth? PO claims the TB was changed in October 2022, and it quit running in December

also what are my chances I correct the timing issue and the cylinders have good compression?

On top of that, no bent valves? I think I need a lot more luck

 

Is the belt tight? Could the timing belt have been replaced but not the tensioner and the tensioner went bad?

Seems like some have luck with no contact when a belt breaks or skips. It'd be great to have a look at the valves but if the tops of the pistons aren't damaged you may be in the clear.

 

Ya the belt is tight, I don’t see how it could skip unless something got in between the belt and a pulley

there is no mileage sticker for the timing belt so anything is possible, it doesn’t look new but PO looks like he did some off-roading in it so no real way to tell if the tensioner was replaced

 

The thing I'd be asking the previous owner if they're still entertaining queries is this: Did anyone touch the cams at all in the last little while? Like, were the cam seals replaced, anything touch the cams at all?

If not, I'd take it to TDC and start over with the timing belt install. If someone touched the cams, you've got a lot of work on your hands but it's do-able.