I just checked my book. It looks like they started the MAF sensor in 96. I have a 95 so I don't have one.

 

DaveG_01 Did you replace the pulsator when you replaced the fuel pump? GM sent out a tsb to owners about 1-2 years ago, to do so when changing pumps.

 

I had a truck years ago that did that. It turned out to be a round piece of plastic ( the cutout on top of the tank for the float) When they built the truck the cutout fell into the tank and would suck up on the screen now and then. Took me awhile to find it. I have a question... do the fuel pump relays stay on constant or are they momentary? Could be a relay going bad if they are constant. ?????

 

If any of those sensors were bad enough to make it run that bad they would throw a code and the service engine light would come on for sure.

 

Update.

I double checked my work on the CPI install and found a problem. One of the fuel lines was not all the way in and it was slowly leaking. I oiled (really helped) the lines up real good and made sure it was all the way in this time.

I gas fouled all the plugs so I have to change the plugs before I can let you guys know if that fixed it. Also, it is still bleeding off pressure with the key off. It has been going all the way down to 10psi.

My current guess is it is the pulsator since it was never replaced. From what I understand this might not cause problems after the van has been started.

I will try and change the plugs before work tomorrow and let you guys know . I might not get finished because it is not the easiest job on that van.

 

congrats you now have a new rig

 

Just my 2 cent!!!!

Just a couple of weeks i worked on a 95 chevy pickup, same problems you are having. We found the problem to be a temp sensor. What it was causing it to do was go into basically a choke mode, It ran like the choke was on all the time, the temp sensor tells the computer, Hey where cold,run choke mode.

 

as far as the fuel pres being in spec, I would seriously hope that you used an oem fuel pump, if that engine is anything like my old gasser, 96 5.7 vortec, then the pressure has to be there or the injectors will not pop. I had learned the hard way, cheapo parts store brand fuel pump wasn't quite cuttin it. switched to oem and bam not a problem since. sure it cost more but havin a truck run is the whole point.

 

Hey 12v chevydually did that truck with the bad temp sensor throw a code or make the check engine or service soon light come on.

 

no we have a Snap-on scanner and it did not throw a code,it just made the engine think it was cold, so no code was thrown.

 

I finally got it fixed. I suspect it was the pulsator.
I ended up dropping the tank and replacing the pump, threw out the pulsator and replaced with fuel line, replaced the main gasket and a missing o-ring on one of the fuel lines to the tank. I am not sure if the o-ring was lost when I dropped the tank or some other time.

It runs great now. Thank you guys so much for all you help and suggestions!!!!!