Crank no start

I have a 2003 Toyota tundra with the 4.7 in it. It has been setting for about 1 year before I got it. It has a crank no start problem. I have been doing more throwing parts at it due to not having enough time to really dig in and do proper diag but I am still trying to do some here and there with it. So far I have replaced the spark plugs, coil packs, crank position sensor, cam position sensor, PCM/ECM, tested fuel pressure (51PSI), and verified that the timing belts aren’t broke. I did verify I am getting power to the PCM/ECM and I did check the wiring harness off the crank position sensor to verify no wires had been rubbed through and that I am in fact getting spark to the plugs. As of right now I dont really know what to do next. And really want to get this truck running and driving again because it has a lot of sentimental value to me. If anybody has any ideas on what to do it really help me out.
Thanks

 

If you are getting spark your ecm and sensors are working.

you have a fuel problem.

 

Do the simple test of checking for fuel pressure. You need to confirm you’re getting fuel to the rail, and the pressure is consistently above 30psi.

Did you check for rodent damage on the wires on top of the tank? It’s one of two places they love to nest on these trucks and you said the truck has been sitting… you wouldn’t be the first person to find wiring damage there.

 

Thanks for the info. I have not checked for rodent damage on any wiring except for the engine harness. I do have fuel getting to the rail because that’s where I checked fuel pressure at. I did look into the fuel pressure being considerably higher than the recommended fuel pressure. But what I found was 38-42 psi is what was desired at the rail and my only concern with it having 51psi is that it could be flooding the plugs. Which in my opinion would lead to a regulator problem, but I will definitely check the harness coming out of the fuel pump and going to the engine to check for any rubbed wires.
Thanks

 

Ok, just to confirm:

• Are there any codes logged in the ECU that may give us an extra clue here?
• Did you take a 10mm socket to loosen the timing cover to make sure the timing belt is intact?

And a question: You said the truck sat for a year. Was it suffering from this same problem, which is why it sat for a year? Or is this a case of "It ran before, so this is a surprise!"

If you have fuel pressure, the fuel pump is certainly lighting up at some point. If yours is like my '06, it has two fueld delivery modes: high and low. IIRC, switching between high and low is toggled at the relay, via two pins. One pin runs directly to the pump, the other pin runs through the fuel resistor, which is a flat finned thing mounted to the top of the fender, either under the brake MC or next to the power steering resrvoir depending on your year. Easy to get confused, there's a similar finned thing for headlights nearby.

You could try bypassing the fuel resistor to see if that's the issue, though. And it may be a good idea just to try.

But generally, IMHO, if you have confirmed spark, you have confirmed fuel delivery, there's no way you don't have air getting into the engine, and you know timing belt is intact, things start to look electrical and/or computer for me.

I do remember a similar case from another member: https://www.tundras.com/threads/time-to-ask-for-help-truck-wont-fire.108227/

I also remember one person had a case of either no-crank, or no-crank-no-start because the coolant temp sender the ECU uses (there's two, one for your dash gauge, one for ECU) was malfunctioning or not wired. On the '04 and earlier it was located here, the green sensor specifically (Grey is for the idiot gauge).

 

Mine is a 2003, but from I was told is that it was parked because it was overheating and they didn’t have the money to replace the water pump which is what the mechanic had diagnosed. I have not really looked at that side of the problem because it isn’t running for me to diagnose. I have verified the timing belts are still intact, they aren’t in the best shape but they are there and they have tension on them. I will definitely look into the high/low fuel pump mode because this is the first time hearing about it to be honest. I have looked into that finned relay you are talking about on other forums but since I was getting fuel pressure I didn’t think I had to worry about but I will also look into that as well. I won’t be able to work on it until tomorrow, but if y’all have anything else for me to check I will continue to check this thread throughout the rest of today to see if there is anything else I need to do.
Thanks

 

There are also no codes in the ECU I have recently checked those to see if it would lead me in any directions.
Thanks

 

Not all that up on fuel injection but could clogged injectors cause high rail pressure
Vehicle sat for a year ,,, not good with ethanol
just a thought

 

Do you have a can of starter fluid? You said you verified spark IIRC. In theory, if you are getting spark and you shoot starter fluid in the TB (or hell, in each cylinder even), you should get at least 5-10 seconds of runtime. But that's only gonna happen if you're really getting spark. If you fire off with that, again, that would just mail home you've got a fuel delivery issue.

Anyway, here's the fuel circuit and operation. It may help.

 

I'm not trying to be a jerk but since you mentioned timing belts twice I'll mention that there's only one timing belt, visible on each side of the engine by removing the plastic cam gear covers (10 mm bolts as mentioned above).

Have you checked compression? That will confirm a key element for combustion.

Also, spray some starting fluid in the airbox to see if it fires. That will point out an injector problem even though you have fuel pressure (edit: what shifty said).

That's what I've got. Here's hoping you get it running.

 

@jimf909 im glad you mentioned that. I meant to close out my post with “compression test”. Especially after what most recent big thread came through.

 

You may find this thread useful also; some great input from @BubbaW there: https://www.tundras.com/threads/2006-double-cab-fuel-pump-no-power.36822/

 

I’ve done some digging today on it and tried using some liquid courage on it. Still nothing. So I pulled another plug and coil
And had no spark. So out of curiosity I disconnected battery and let set for an hour or so and reconnected battery and tested spark again and had it. So from what I tried today something is telling it to cut spark. Still not sure what could be telling it to cut spark but it is doing it. Another thought I had today was that if it got parked because it was overheating could the temp sensor going to the ECM be trying to go out and after it got parked it just finally killed it. I know it’s a long shot because normally sensors usually work or don’t but it worth mentioning in my opinion. I had been thinking about doing a compression test on it just to see and since y’all mentioned it I am going to try to get that done sometime this week around my work schedule, but if I can’t that will have to be a next weekend thing.
Again thanks for all the help.

 

And you replaced the ECM already, and the crank position sensor. Did I already mention the coolant sensor? There are two, one for the ECM, one for the dash gauge. One for the ECM will cause no-start situation. Both are to the passenger side of the throttle body, one is green and larger (for ECM) the other is smaller and grey. Green one is closest to the TB. We had two other people on here in the 4yrs I’ve been on here who had issues starting when their sensor went bad.

But yes, I’d do a compression test also, at some point, to be sure. Bad compression won’t lend to no spark though, while no spark will totally lend to no fire.