Toyota pickup 3.o v6 manual 3vze 4x4. So I went to drop off my boyfriend for his surgery and we stopped to get gas. Hadn't driven the truck or started it in about 2 weeks which is normal for us. We filled up and went to pull out of the gas station and the truck died. Started right back up but did it a few more times on the way to the hospital. And after I pulled out and got to a stop light, it died and would not start. It finally started and I had a friend come follow me home. It ran fine and never died. We went to start it days later but it wouldn't start. It threw codes and it never had before. Codes were for VAFM, TPS, distributor, IAT. We've ruled these out and then some. After replacing the TPS it starts but dies within 10 seconds. We have jumped the fuel pump but have not done a fuel pressure test as of yet. Also put in a new TPS and fuel filter, plugs, wires, cap and rotar. My question is, could we have a failed ecu and is there a way to test the damn thing? Chasing a ghost over here. I have tried to find information on how to do this using a multimeter but couldn't find much 🙃 and I don't own a FSM. I know we would be testing the harnesses? that plug into it and not testing the actual ecu? Please for the love of all that is holy, someone help. TYIA!!!

 

Anybody? We also have checked the cold start injector, the coil and they test fine. Please has anyone solved this issue before I buy a fuel pump only to find out it's not the issue? Or an ECU??

 

How did you "rule out" the codes? "Starts and dies within 10 seconds" is the classic sign of a VAF-COR circuit problem. https://www.yotatech.com/forums/f116...-quits-312747/ It's the easiest thing on your truck to check. Use the jumper to run the fuel pump; if your symptoms clear up you've found the problem. (The VAF code is a red flag; the FC control for the VAF-COR circuit is in the same connector as the rest of the VAF; if loose, that's the first thing to happen.)

Have you checked ignition timing? If you don't have a timing light, you certainly need it before replacing any of the parts you've already touched, and they're only $30. You can use the pickup on each plug wire; if the light flashes the plug is firing.

You have not done nearly enough testing to replace a fuel pump. Checking fuel pressure takes a bit, but you can get 80% of the way there with a flow test. Replace the FPR fuel return with 6mm (1/4") clear vinyl to a suitable container. Start the pump with the jumper. There is no spec, but if you get about 1/2 liter / min your problem is unlikely to be the pump.

Last, while not impossible, it is VERY unlikely to be the ECU. Your problem is almost certainly in the switches, wiring, and sensors.

 

We did all that and then some. Testing everything you said to. TWICE. Replaced the fuel pump relay or COR and it started and ran! So we went to town with it and it died at an intersection and the check engine light came on. It started right back up and ran fine until we got it home. Went to start it again the next day, won't start, no check engine light, no codes. At a loss here. Any other suggestions? TYIA

 

Battery terminals? Especially the cheap, thin metal Toyota OEM ones. They are VERY prone to corrosion, especially the positive one. But even a "regular", heavy lead, terminal, can be prone to corrosion. So can the points where the wires bolt onto the terminal. The wires/cables themselves can develop corrosion inside the insulation, especially the positive ones.

The ground points. ALL of them, not just the battery cable's grounds.

All I can think of right off...
Pat☺

 

Check the big hose from the VAFM to the manifold for leaks?

 

2Toy is likely on the money here, not getting full 12 volts or ground somewhere in the system.
either that or you have to look at the coincidence that you had just stopped for gas and wonder if you got good fuel or if there was water or other contaminants in it.
It wouldn't be the first time that a fuel truck offloaded the wrong product into a tank at the gas station.
I have seen it twice here in Alaska, once it was a load of gasoline in the Diesel tank. It ruined a fleet of Dodge trucks when I worked at their stealership.

 

I hope your BF is recovering well.
Like Pat says above about corrosion. ask me how I know (https://www.yotatech.com/forums/f199.../#post51939319)

 

Yes Bswarm we checked it thoroughly. No leaks. Now it starts and runs but blows the efi fuse with the paper clip in it... 😂 and battery has no corrosion. Update - wrong place for the jumper wire lol so now, it starts, it runs, but it throws a code 12 again which is distributor or ecu. I'm done 😂

 

Check the AFM/Flapper and air box for mice nesting. Saw a mechanic video with a vehicle that wouldn't run had the whole air box and part of the intake jammed packed with mouse nesting material. Removed it and the vehicle started. Can't hurt to make sure the air intake path is clear.

 

We are in a rural area. I mean, we are in the serious woods. Yes the air box has had nests in the past but now we check it weekly to make sure. Thank you for the suggestion!

 

Read on an 'Ask' web page that a Code 12 is distributor related. One Toyota master mechanic says it's a short in the electronics and needs a new distributor.

 

Crazy thing is, at first it had every implication that it was a fuel problem. Then when none of that checked out, it seemed to be an electrical problem. Couldn't find that source of that problem and now it seems like a mechanical issue?? It gives none of the signs of the distributor being faulty from what I can tell.

 

Ok so the distributor tested out to FSM spec. I know little to nothing about electrical, testing the electrical and such. We put a new connector on the negative post of the battery and the code disappeared but the CEL came on and stayed on solid. Started it up a few times and we got the code 12 for distributor again. Can only assume at this point it's the wiring? Which from what we can tell looks good but I don't know how to test it. Will be looking into the magnetic pickup coil replacement. We are moving out of state, towing the truck on a flatbed but need it to run dependably when we get to our destination. It will be our only vehicle for a bit. TYVM for all the input. My boyfriend helps when he's not at work and I am certainly not a mechanic. TYIA

 

Water in the gas?