Green93

After all the time and money I've put into this truck, it's really depressing to have to make this thread. The truck in question is the one in my sig.

Friday morning I was almost to work and the truck stalled at a light. I started it back up and continued to work. It sounded different but I crawled under and found an exhaust leak. After work started up the truck and she drove fine except for the louder exhaust. Three quarters of the way home I stopped at the drive through for a coffee and she died again. This time not restarting. I pushed it to a parking spot and let it sit. She sputtered a few times after that but never fired up again. The truck was towed home and I've done a bunch of tests so far. The truck cranks over just like it did before but theres no firing at all now.

I have followed the FSM for testing the following:

-Jumpered the diagnostic ports to check for codes. No codes.

-Tested for fuel. There is plenty of pressure and fuel is getting to the cylinders.

-Tested for spark. Removed a plug wire and she has spark.

-Tested the coil and ignitor. They both passed but I removed and cleaned grounds anyways.

-Tested the distributer. Air gap and resistances are in spec.

-Tested the VAFM. Passed both on and off vehicle tests. Removed the top cover and cleaned the contacts. Resistances were more constant but otherwise made no difference.

-Removed #1 plug and rotated until piston was at TDC. Rotor points right at the #1 plug wire.

-Checked all the under hood fuses and they are good.


I am at a loss now. Anyone know what to check next? I have no idea what else would cause these symptoms.

Thanks,
Jason

toyota4x4907

When was the last time you had the timing belt replaced?

Green93

I did the timing belt in November. At the same time I had the head rebuilt. I know that the belt is still intact because the rotor turns when I turn the engine with the crank bolt. And it hasn't jumped a tooth since the rotor lines up when I'm at TDC. I guess the passenger side cam could have jumped a tooth on the belt. But wouldn't the engine still at least sputter and try and fire since the drivers side cam is still correct? I get nothing when I turn it over.

The more ideas the better, keep 'em coming.

Jason

TNRabbit

If you've tested all those components, the only thing I know to do next is started checking sections of the wiring harness. You should have gotten SOME kind of ECU code if that is the case, though.....?

woodsguy

do you still have the stock intake? cause the silencer portion may have a leak in it. i know the 3.0L's wont run if there is any air leaking on the IS portion.

Guardian_Saint

Best thing to clarify if the belt is still in shape. You need to take a deeper look into it cause mine was stripped and the rotor still rolled.

Green93

In the morning I'll be doing some more tests. Starting with the Efi relay and other small stuff. Ill open the timong belt cover to check the belt. If that checks out then next is the computer itself. Then on to the wiring.

Does anyone have any other ideas? Would the computer throw any codes if the wiring was faulty?

projectX4runner

I having the kinda same issue with mine. I had to drop it off at a shop hopefully they could figure it out. But mines starts up but dies at anything more than half throttle. So far ive changed ecu, plugs, wires, cap, rotor, air filter, fuel filter, maf, checked tps, checked fuel pressure, checked timing, checked fpr, vaccuum lines, it all checked ok good. so next they are gonna check out the injectors and then the timing belt might of jumped teeth or something. Hopefully we both get our rigs back up and running soon

Green93

Well it was another fun day with the multimeter. Started by testing the efi relay. It's fine. Rigged up a gauge to the fuel rail. Pressure was 46psi. Pulled the ECM out so we could run the tests in the FSM. It only failed one, and pointed to the VAFM. Re-tested that and it's fine. We then tested the resistance in the wiring harness between the ECM and VAFM. It's fine. So now I'm thinking it's the ECM itself. But wouldn't there be a code if the ECM was faulty? If I jumper the terminals the engine light just blinks steady just like normal?

So if I need to swap out ECM's which ones will swap in? do I need the exact year and model? Not sure if I need one for a 4wd and auto or not.

Jason

Green93

Ok this thing is still stumping me. Talked to a Toyota tech and he figured it was just flooded. Told me I was looking too far into it. So I changed the plugs today and put everything back the way it was. Still the same. It turns over fine with no codes but it doesn't even try to fire.

The tests I ran on the ECM the other day are on page EG-185 of the FSM. Obviously I couldn't do any of the tests that require the engine to be running. The only test it failed was in the #3 section:

VC-E2 measuring plate closed I get 5v (spec is 4.5-5.5)
VC-E2 measuring plate open I get 5v (spec is 0.2-0.5)
VS-E2 measuring plate closed I get 5v (spec is 4.5-5.5)
VS-E2 measuring plate open I get 5v (spec is 0.2-0.5)

Like I said before the VAFM passed all tests. I tested all wiring between the ECM and the VAFM and it's fine. Does this problem point to a faulty ECM or to another sensor? Would this cause a no-fire situation? Hopefully there is someone out there more familiar than I am. Any and all help is appreciated. I need this fixed so I can move onto the next problem.

Jason

Green93

Well today I got ahold of another ECM. Swapped it in and turned the key with my fingers crossed. Still the same, ECM made no difference. Basically I'm bumping this thread up to see if anyone has any ideas today.


Thanks,
Jason

Green93

Tonight I finally got off my ass and did a compression test. Mostly since now I need the truck. Compression test was horrible.

#5 0 #6 100
#3 0 #4 100
#1 100 #2 70

Well at least now I know it's something mechanical. That's much easier than chasing electrical gremlins. And to those of you that suggested checking the compression right off the bat, I should have listened.

Jason

rocketguy13

could be low compression cause the cylinders are washed out with fuel. my 90 4runner was doing the same thing one day to me and i found on the driver side of the engine a wiring harness was laying on the manifold and burnt the wires.

rocketguy13

but i wouldnt rule out a jumped timing belt.. it does happen. and it would cause compression reading that look like that too. but i would think it would pop and backfire and stuff

Green93

When I try to start it sometimes it gives a small puff or sputter but it doesn't keep trying. Just a little puff and then just cranks and cranks. When I pulled off the air intake to do the compression test there was a faint smoke coming out of the throttle body. And there is fuel getting to the cylinders for sure. Depending on how good the hockey game is tomorrow I'll be making some more progress.

Jason

Green93

Well Friday after work I decided to rip into the engine. Pulled off the plenum and valve covers. Nothing out of place so while I was still motivated I pulled off the front to take a look at the timing belt. When I pulled the timing cover the bolt head for the passenger side cam gear falls out. Cam gear is worn on the back from riding on the camshaft. The knock pin is worn down almost flush with the end of the camshaft. I'll have to extract that as well as the end of the cam gear bolt.

So why did it break in the first place? I put a wrench on the camshaft and it's seized solid. Valves still move up and down when I press them down so I guess it's seized in one of the journals. Soooo....is there any way to fix the journals without pulling the head? And I guess I'm going to have to check on my oil pressure to make sure that isn't what caused the failure.

I'm tired of working on the engine. Can't wait to start on the suspension.

JAson

Wrenchinjoe

Sorry to read about your trouble Green93. Looking at your pics, you have done a lot of good things to this motor, and your diagnostic efforts in this situation have also been solid. I think you know way more about the 3vze than I do, hence any advice from me is like the pupil advising the teacher.

That being said, I think you are already planning to pull the passenger side cam to see what damage has been done to the journals. Since the cam has seized, I'm thinking the damage will likely be enough to require you to get a new head. I don't know of a way to replace the journal but maybe a machine shop could. Also, I'm not sure you should trust the stressed head to hold up long term anyway. Hopefully you can build up a used head to match the setup on the drivers side and get her back on the road fairly inexpensively.

Good luck.

Green93

I removed the cam a few minutes ago. I had to use a brass drift to release it from the front two cam journals. The head is toast. The cam looks rough too. I'll have to take it to Colt Cams to see if Geoff can salvage it. If not I need to have a new one ground. Plus machining the oversized valves in a new head. New headgaskets and headbolts, the parts list is getting scary. I can't believe I'm doing this again.

rocketguy13

you should just do a 3.4