I picked up a 91 3.1v6 with my buddy for 500 bucks. Its rough but we figured its worth it either way in scrap/parts.

We can get it to run on ether but not off the tank, we have fuel coming up from the tank but it wont run off it that's if it is making it all the way to the injectors. Injectors or regulator clogged?

Another question is that if we do the key barley any fuel comes if any at all. but if we crank it and keep cranking it does come up with decent pressure, does this engine have a mechanical pump with a lift pump in the tank?

Any insight would be appreciated

 

Why would efi have a lift pump ? That’s not right should have a high pressure pump in the tank. If it’s sat for years chances are injectors are varnished shut. Start with basics you have spark, but what’s the fuel pressure after pump prime ?

 

I was just wondering, a neighbor walked over and said something about it which didnt seem right. Fuel would only come up the line when cranking so I am assuming its either the weak pump or like you said the injectors are clogged. Any recommendation for trying to save them? or should I just get the set of them for like 50 bucks on Ebay? Ill be checking fuel pressure tomorrow hopefully and would appreciate a range of PSI i should have. Anything to watch out for on the regulator? Thanks

 

@southbay08 don’t waste $50 on junk. Goto to southbay fuel injectors but might want to replace the pump and clean the tank first.

 

https://www.southbayfuelinjectors.co...-1992-tpi.html

 

The fuel pump should run a 2-second prime cycle when the ignition is turned on, commanded by the ECM.

Measuring the standing fuel pressure will be very revealing. Below 34 PSIG running pressure (41 PSI standing) becomes a problem.

As for the injectors, they might be made to work, but be aware that they are from the range of model years when the infamous Multec injectors were factory installed. They have a pretty bad reliability and duration history. Getting another set of those would not necessarily be a step forward.

 

Hey sorry for jumping in so late. @flippedtable wanting to possibly save your stock injectors or have them cleaned and flow tested is a big mistake. They are problematic and prone to coil failure. Any respectable fuel injector shop should be honest enough to explain this to you. We will not warranty our work on the multecs if someone wants them cleaned.
We charge $22.50 per injector to clean and test. A new set of remans fully tested, cleaned, and matched is $27 per injector plus you receive a 10% discount for being a thirdgen member. It's a no brainer.
If you want to spend $10 per injector on Ebay that's your choice....however sometimes to save money...which i completely understand...... can cause more problems than you need.
Just my opinion