Three years ago we had the engine in our 1997 GMC Safari Van replaced. Ever since then we have had one problem after another with it, preventing us from using it for anything other than local driving. Long story short I found that the previous shops made a lot of careless electrical and mechanical mistakes which took me months to resolve. After going through all of the electrical connectors, performing oxidation remediation, I added ground straps between the engine and the frame, the frame and the body, and from the engine to the body. I cleaned the positive wire from the alternator and the negative wire from the battery to the engine block. I pulled the starter motor, cleaned all of the contacts, and added a heat shield to the starter solenoid. All of this improved the electrical response of the controls/gauges/headlights, etc. Now the biggest issue I have with the van is it being hesitant to start when the engine is hot. We bought the van new 23 years ago, and the original engine started in half of a turn hot or cold no matter the temperature up until the point the engine died. The Jasper replacement engine starts just the same cold, or after the engine has sat at least six hours after being previously run. Starting when hot is another story. As long as the engine has run that day, a minute or an hour, the engine will be hesitant to restart. Sometimes this entails two additional seconds of cranking, sometimes an additional ten seconds of cranking is required. Cycling the ignition to run the fuel pump, or holding the accelerator down during hot starts does not change anything. I tested the alternator and battery individually, both seven years old, and both are working perfectly. I finally bought a genuine Kent-Moore fuel pressure gauge. I hooked the gauge up to the fuel rail on the engine and it reads 58psi initially, dropping down to 55psi of fuel pressure with the ignition on - engine off, and 45-50 psi (usually 48psi) of fuel pressure with the engine running. I finally caught the hesitant hot start on video with the fuel pressure gauge and tiny-tach showing rpm. You can clearly see that fuel pressure is not low or dropping during the start up process. I have let the van sit off for over two hours and the fuel pressure in the rail does not drop more than 2 psi. I am starting to think that this issue that I am having has to do with the distributor cap, or with whatever is plugged into the distributor. I bought a brand new Delco distributor when the engine was replaced. It only has 591 hours and 24,000 miles on it. This engine has the updated spider injector in it. Since fuel pressure is not dropping when the engine is off I believe the injectors are fine. The engine is not throwing any codes. The hesitation simply bothers me. I want to use the van again for long distance trips. My last trip with it, four weeks ago was 940 miles, with 3800lbs of iron in it for four hundred miles. It averaged 15.2mpg. I recently had the exhaust completely off the engine as the shop never bolted the collector to the manifolds. I took this opportunity to inspect the catalytic converter and oxygen sensors. Everything is surprisingly clean. I appreciate your thoughts on this issue.
I am sorry about the ringing in the video, I should have taped the open door sensor down.
Chris
I am sorry about the ringing in the video, I should have taped the open door sensor down.
Chris