No, it is not fixed. Sorry that previous post was not clearer. I did not replace the injector harness connector. I reconnected it. What I meant is that after testing the injectors with the pulse box, and reconnecting everything, the engine fires right up. Now the problem is getting worse. It is bad enough that it will not start without a lot of cranking (unless I test with the pulse box). It is almost consistent now, so I should be able do some productive testing today. Also the pressure only come up to 56 of 58 PSI. I ordered an adapter for the fuel return
Testing procedure and starting: I have tested it four times since replacing the rotor with the same results. It doesn't start, so I check fuel pressure. 60 psi before cranking, 50 psi when cranking. Pull a plug wire (#8) and check spark with a spare plug. Cranking shows good spark. A couple of times I did the same with #6 - also good spark. Pull the injector harness connector. For each injector, connect the tester. Cycle ignition to get fuel pressure. Pulse it injector twice while observing the fuel pressure gauge. It drops the same amount for each injector. Reco
1997 5.7 Vortec intermittent slow start revisited. Long version: I have a 1997 5.7 Vortec with the CSFI system. It has 130k miles. This is a continuation of the problem in an earlier post. https://www.gm-trucks.com/forums/topic/238081-1997-57-vortec-intermitant-slow-start/#comments I thought I had it fixed when I replaced the rotor, but no. The symptoms are more consistent now. I suspect that's because with the new rotor it only has one problem. With the testing I do, it always takes about four or five tries to start. Injector testing causes the engi
1997 5.7 Vortec intermittent slow start revisited. Short version: I have a 1997 Express with a 5.7 Vortec and the CSFI system. It has 130k miles. It is hard to start after sitting. If I pulse each of the fuel injectors with an injector tester then it starts right up. Problem description is mostly in next post. The test procedure that makes it start is in the third post.
Status: I tested yesterday and found the rotor had broken. I replaced the rotor and it started right up. It also started right up this morning, so I think that it is fixed. I will leave it be an see how it starts after sitting for 24 hours. I bought some techron fuel injector cleaner and will use that as soon as I am sure the main problem is fixed. BTW, the 3 page diag procedure in the manual that I used is pretty smart. It divides the system in half to narrow the problem to one part. I does however tend use specialty tools when common tools would do just fine.
All right, It has no spark. I was previously testing with the timing light and that is apparently not as good of a test. The timing light still flashes occasionally, but the spark plug test shows nothing. I did the spark plug style test on a running 7.4 (almost identical ignition) and the plug had a bright steady spark. So I think we have a good idea of the problem. The manual has a 3 page diag procedure that looks pretty detailed and systematic. I will try that and give you an update.
I left the pressure gauge on for 30 minutes. Dropped for 60 psi to 58 psi. The pressure would read 50 psi consistently when the engine was running. It reads 50 psi while cranking.
There are no misfires in the history. I said that the fuel pressure stays for a long time, I meant many minutes, not hours. I left the gauge on after testing and it was down to about 10 PSI at the end of the day. Should it stay pressurized for a whole day?
Disconnected MAF. No change. The car has not started this morning (i.e. it's getting worse). The tailpipe looks normal (grayish black). I wipe my finger on the inside of it and get only a little dry grey powder. I will try fuel injector cleaner if it starts.
First, thank you all for you advice. east3021 - I have had several other people suspect the ECT besides you, so I replaced it. I haven't tried to start it cold since then, but will today. I don't think it is that, but would like to eliminate a "suspicious character". oldguy96 - All the parts are either ACDELCO GM original equipment or ACDELCO professional series except the Champion 9404 Iridium. I have had good results with these brands. I hadn't thought about the cap and rotor. I will take off and inspect the cap. I will be looking at the van again this morning.
It holds pressure for a long time after the ignition is turned off. (I edited the original post for clarity) The injectors/regulators are original. 130k miles. The ECT reads the correct temperature before starting. I haven't done much testing once the engine starts. Also I have been thinking that the injectors are good because 1) no leaks and 2) good performance after first start of the day. Is this correct?
Check for binding in the throttle with the engine off. Then disconnect the cruise control cable at the throttle body. Check for binding again. If no binding, start the engine to test. This doesn't fix anything, but might tell you some things. Good luck
Here are some possible next steps I am considering: 1) Measure the resistance of the injectors. 2) Test the injector wiring with a noid light. The manual said to use a simple unpowered 12v probe. I did and could not see anything, even with the engine working, so I will need to buy a noid light to test. 3) Check any of the many sensors: MAF, IAC, CPS, etc. Again, any help would be appreciated.
I have a 1997 5.7 Vortec with the CSFI system. It has 130k miles. Symptoms: It is sometimes hard to start when cold. The engine turns over fine, but only starts after cranking for a variable amount of time. No cel and no codes. Once it has started, it runs fine and it will start easily later that day. This was happening infrequently, but now occurs most days. Recent parts: About six months ago I gave it new plugs, wires, cap and rotor. The plugs looked old, but consistent and no oil fouling. New fuel pump and filter about four months ago. Used AC Delco parts.
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