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95 Lumina APV 3.8L No start, cranks fine

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Old 10-14-2012, 11:57 PM
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Default 95 Lumina APV 3.8L No start, cranks fine

The van turns over fine, but does not start. Exhaust smells rich. Don't have a fuel pressure tester, but couldn't hear the fuel pump running so it was replaced along with the fuel filter and air filter.

Now I can hear the pump fine when the vehicle is keyed 'on'. Pulled a plug
on cylinder 1 before replacing the pump. Plenty of spark, but the plug was very sooty and the gap measured out at .090. Replaced plugs and wires but there is no change in the problem. Thinking that it may be the fuel pressure regulator or maybe a bad TPS or other sensor. Checked across the coils and they all ohmed out fine according to my Haynes manual. Any ideas? This has me totally stumped . Thanks in advance. My wife and I are sharing my truck until I can get this fixed. Please help.
Old 10-15-2012, 06:49 AM
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the crank position sensor controls timing so you could have spark and not the right time. i would hook up the scanner and see if you rpm while cranking. the easiest way to check stuff with a scanner to see if you have throttle position through the pcm so you arent lead down the wrong path. also cant really assume the fuel pressure is good they could have given you a bad one. the parts stores will rent you a gauge for free.
Old 10-19-2012, 10:30 PM
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jw, thanks for your reply. It is my understanding that on the 3.8L GM motors like this that if you are getting any spark at all, then both the crank and cam sensors are functioning. It is the computer that adjusts the timing based on inputs from the knock and other sensors. I'm certainly not claiming any expertise here, the last car I had to did in this far for was an '83 Trans Am 305. This is a whole different animal and that'* off topic anyway.

Unfortunately, I do not have a scanner. The van has hook-ups for an OBD 1 connection, but the 'B' pin is missing from the connection to allow any sort of diagnostic to be read thru the 'check engine' light. I guess that was common on GM'* from 1995 during the transition to the ODB 2 standard.

I did go ahead a buy a fuel pressure gauge to see what I was pulling. At the rail I have about 40 psi (haynes calls out for 41 to 47 but I would think that 40 would be close enough). I have left the gauge on just to see what kind of a drop I get over time. 2 days later the rail is showing 20. Because I am not losing pressure very fast and the rail is not way over pressurized, I'm thinking that the regulator is doing what it is supposed to. Do you, or anyone else reading this, agree?

I need to do a little more digging and test a couple of the sensors to see if I have a reference voltage. The TPS and MAF sensors are the easiest to get to so I will probably check those first. At this point I am thinking either a bad ECM or a plugged cat converter.
Old 10-20-2012, 08:13 AM
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so its a 95 not a 05. that does make things more difficult. i guess it would run with that pressure. they do have diagnostic but it is quite a bit more for the scanner. you can test the tps. i wouldnt think the cat could make it not start. the crank sensor has been known to not make the spark good for power and timing. the maf you can unplug and if it runs thats your problem
there are test procedures for the various sensors
Trouble shooting + Test Procedures - GM Forum - Buick, Cadillac, Chev, Olds, GMC & Pontiac chat
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