Chevy & GMC Vans

First of all, I’ve been a member here for a over 4 years now, I haven’t had to post a lot because I can find most of the answers by searching this site. But now I have a serious problem that I can’t figure out..

I have a 1992 Safari XT with MFI, and it has stopped running. Let me give you a short history of my van, when I got it, it had a blown head gasket. When I replaced the gasket, I also replace the fuel injectors, map sensor, water pump, radiator, heater core, plugs, etc… Just about everything I could but the TPS. (Also torsion bars, shocks, Idler arms, etc.. and stuffed some 235/75/R15 LT mud and snows under it.) I was just getting ready to upgrade the brakes; I have the parts list and numbers from this site. .

The van has had a couple issues with it, but nothing I thought was serious. My van always started right up in the mornings, but if I drove it for a little while and parked it for over a half an hour, it had trouble restarting, I had to mash the foot feed to the floor to get it to start quicker, but it always started. I did seem to buck sometimes while driving when you gave it more gas.

I think also that I was having problems with the TPS because it seemed like you could press on the gas to go a little faster and nothing would happen, so I would press more and more, then suddenly it would all of a sudden take off really fast. Twice while this was going on, instead of taking of, it stalled out but started right back up. After the stalling incidents it seems like the van ran better than before for a couple days, the go back to this problem..

About 3 weeks ago it stopped running, I checked the spark and fuel pump out and I couldn’t hear the pump running so I checked to see if I had pressure at the fuel rail, NONE.. After checking the fuel rail, I turned the key and heard the pump activate. I started it up and it ran fine, for 2 days, and quit again. I checked again and the fuel pump would not activate and I had no pressure in the fuel rail and still had spark.

I went ahead and replaced the fuel pump, filter sock , inline filter and fuel pump relay. Well, this pump works fine, it pumps right up and has plenty of pressure, but the van will not start. At first it seems like it starts, but only for a second or two, then nothing.. It’s getting fuel and spark, but doesn’t want to run.

I’m hoping someone can steer me in the right direction with this problem…

your not getting an SES light or any codes?

No.. No lights, no codes.. It doesn't have a security system either. This has me baffled..

You didn't mention the coil...other than it has spark. Coils are a common problem on these vans. It may be in self destruct mode. Remove the motor cover and watch the coil and spark plug wires at night. If you see any stray arcing you have found your problem.

There is no arcing, it is getting excellent spark. Could the TPS cause this problem?

I was going to suggest the coil as well. How long since wires, plugs, cap and/or rotor were last replaced?

Sounds like your spark and fuel system are good, another possibility might be the ignition switch? I also had a similar problem caused by an aftermarket tach (the rev limiter would for some reason cut the spark after driving, causing the car to not start). Best of luck chasing down the gremlin.

I would check for melted wires in a harness that run right across the top of the right cylinder head. I have seen and heard of this on a few of the early 90's vans. The wire harness comes from the ECM in the lower right kick panel and goes through the firewall near the doghouse cover. Best bet is remove the doghouse cover and inspect the harness.

What brand name fuel pump did you put in there??. Cleaned all the grounds for the pump??.

I haven't been able to work on it for a couple of days now, I will try all your suggestions and go from there. Thanks for all the replies and I will hopefully update you with good news. I know once I get it figured out it'll be an easy fix..

I borrowed a fuel pressure tester from a friend of a friend. It gave me a reading of 17 psi, this pump was not the one I needed for the CMFI system that I had asked for, I was given one for TBI and carbureted systems. Well, after pulling the 27 gallon tank out for the second time and replacing the pump with the one that was for my van, it runs great…

I had gone in to Advance Auto Parts with the correct parts number for the pump, after checking and finding out that they didn’t have that part, the man at the parts counter checked and said they had a different brand, but it was the one I needed. I asked him to make sure it was for CMFI system and he said it was. I will be talking to his boss tomorrow..

I want to thank everyone for helping me here, I feel stupid that it was the fuel pump all along. It seemed that it had plenty of pressure, but I guess without a pressure gauge, there’s no real way to tell..

After this, I’m driving the extra mile and a half to NAPA, the heck with these other parts places.. They had the pump I needed and even gave me a discount because of the trouble I had because the other store gave me the wrong part..

Glad its all figured out!