3VZE 3.0 Starts then dies
 

Hey all, my dad and brother picked up a 92 4Runner with the 3.0, original owner, perfect maintenance and all the records 400K miles. He and my brother drove it home 140 miles after picking it up today and drove it to my work to show me. They stopped in the parking lot, and I came out, and he started it to show me how good it ran (it ran amazing by the way, couldn’t believe how quiet and smooth it ran), and then shut it off. When they went to leave about five-ten minutes later, it would start and run for anywhere from 1-20 seconds before shutting off. Guy at work told me he is 99% sure it is the primary fuel pressure regulator, we jumped two pins on the diag port (I believe it was pins FP and B+) and it ran again until we pulled the paperclip. He said this confirmed his suspicion. While I want to believe him, it doesn't make any sense to me that bypassing the fuel pump relay fixed the broken diaphragm in the regulator? He's been a mechanic for 20 some odd years and has owned quite literally millions of 4Runners, so he knows his stuff. I already have a regulator coming in at NAPA, but I'm curious what this thread brings for answers before I pull the trigger.

Upon my own research it could be a COR issue, or something with the air volume sensor? My co-worker told me in his years of being a mechanic, he's seen it a bunch of times, he said the regulator just randomly breaks, and you get the start, run, die issue. I will check the small vacuum line on the regulator and see if there i fuel in there tomorrow, and update if so. I would appreciate any help or ideas. I do have a code 14 that I am able to pull from the ECU, if that makes a difference, but I think it's had that code for a while, and they drove home with it.
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Here is an excellent troubleshooting guide for your problem.

My truck runs a few seconds and then quits ... - YotaTech Forums

Update: As of today, this has become a crank, no start issue, it is no longer a crank, start, die issue. I can not even get it to start. So now it will not work when it is hot or cold if that helps anyone. I pulled the little vacuum line on the regulator and confirmed there is no fuel in there, so regulator is not bad. I pulled EFI Relay and let computer reset, and checked the EFI fuse, all seems good, I think I heard the fuel pump run, but I am not quite sure when I should be listening, so I will read up on that. However, I did smell fuel while trying to get engine to start, I imagine the fuel pump works, however I will diagnose for sure tomorrow. A friend of mine said it is common for fuel pumps to just die after sitting for a long time, it happened to him, so that is something that is on my radar. I still can't get it to fire while jumping FP and B+, which also makes me wonder if the EFI Relay has gone bad?

Game plan for tomorrow is to take my multimeter and determine if this is an electrical problem. It is 100% not getting fuel, so I will be checking resistance and voltage on every possible issue in the various circuits that pertain to fuel and starting.

@Justthemechanic thanks for the reply, that is going to help my troubleshooting and diagnosis tomorrow. Article contains a lot of helpful information.

Bad alternator?