Thread: Mystery Troubles! 1992 Grand Prix SE 3.1 (VIN T)

I am currently working on a 1992 Pontiac Grand Prix SE 3.1 VIN T model and I am having some trouble diagnosing my problem.

The back story that I received (not my vehicle): The car was running and driving fine until one day he was on his way to work. Car started fine, placed into reverse, braked and car died. Started again just fine and made it to work. After work he was headed home and car would not start but would crank. This is when the car is delivered to my house. I work on cars on the side for the experience and the fun I guess.

At this point I will tell you what I have done to the car:

Installed New Plugs
Installed New Plug Wires
Installed New Fuel Filter
Installed New Crank Position Sensor
Installed New Battery

Replaced battery due to it failing test a local parts store. The plugs looked awful so I replaced them but I was getting spark on front 3 (2,4,6) when grounded to motor, did not test back 3 but replaced those as well. Replaced the crank sensor once I saw I had spark and fuel pressure, not fun but got it done. I decided to replace the fuel filter on a hunch. I pulled the old one off and tried blowing through the filter, not recommended, and was not getting near as much air flow as I was with the new one. I tried to crank motor and it would only crank with my foot pressing gas pedal all the way down then turning motor until it cranked. It idled but seemed like it was hard. I turned car off and attempted to start again, nothing, would only crank. At this point its night time, this is when I see the plug wires (not new ones yet) arcing off of the block and possibly off each other but there was definitely blue spark present. I made it to parts store just in time to pick up new plugs, store brand because it's the only set they had. Replaced wires one at a time to maintain correct plugs and wires. Attempted to crank and it started, again, idled a bit hard but ran. Tried to drive around the block and was backing out when it died again. I pushed vehicle back into driveway and looked over some things, cranked the motor again in the dark and saw arcing again if not more arcing. The motor will crank but will not start at this time. I assume it may be because plugs are wet. I tried started fluid but got no response, depressed Schrader valve and it released fuel and pressure for what seemed like 30 seconds.

Tomorrow I plan on renting fuel pump diagnostics kit and checking the fuel pressure as well as checking injectors and possibly the fuel pressure regulator. May look at the Idle Controller and clean it up just in case. Can anyone think of anything else I can try or point me in the right direction?

I forgot to mention during all of this I did rent a OBD I scanner and did not have any stored information.

Any ideas?

Do you have any replacement Coils? I have had a couple of rough runninng issues with my 94 3.1 and a new coil (different one from another Motor) made the difference. I now keep two spare coils in the trunk with a 9/32 socket and a 1/4 inche Ratchet so I can change them anywhere. It is pretty straight foreward and the same as with the spark plug wires remove only one at a time and replace it on the "new" part before moiving on to the next wire. Each Coil has two bolts holding it on to the "pLate" and then they just up plug from a clip on the plate. Do you have any Coils from other RUNNING Motors?? Start on one end and replace them one at a time. HOWEVER You must replace them with a known GOOD ONE, and hopefully at one point it will run good because you have the bad coil out and a good one in its place. I wouldn't buy any actual new ones to try this just use the ones from a running engine so you can tell if it makes a difference

I was thinking about bad coils as well. Would the plugs still have spark with a bad ignition coil? I tested 2, 4, and 6 so with the pairings on the coils themselves I was getting spark out of each coil. (1,4) (6,3) (2,5).

Is there anyway to test the resistance in the coils to see if they fall within requirements? I am a little tired of chasing this thing around but I am so damn close to have it running again.

I think I am going to return the plug wires for another set or to upgrade to a name brand from a store brand.

I am Not Sure if there is a way to test them but it seems likely that there is. My experience is ONLY with Replacing things, truthfully it is VERY Easy and would only take about 15 minutes to change them all out (at least on the 94 not sure how the 92 is set up). My bet is that the coil has not Failed Completely, but is not working correctly and failing intermittently, at least that is what mine did and it was upon accelleration so it isn't really the same thing but your description made me think of my issue so I figured it was worth a try. My personal oppinion is that the store brand is exactly as good as a name brand for this instance...it only has to transfer an electrical impulse, how can one copper wire be that much better than another copper wire??

I ran a voltmeter over the six injectors 5 of 6 read 12.5 the 6th one read 2.5. I replaced the injector and pieced everything back together. Car ran and idled but did it rough at times. Went for a test drive where it eventually died on me. I then replaced the fuel regulator on the fuel rail and I cleaned the IAC Valved and replaced some cracked vacuum tubing. Car started and when I was backing out of the driveway died again. The car was still running very rich and had what seemed to be fuel or condensation that smelled like fuel in the tailpipe. I think my next options are to test compression and coolant system pressure just to make sure we do have compression on all of the cylinders. While doing this I may try to test spark on all of the plugs just to make sure I didn't have any foul out during all of this. Any ideas?

I checked vacuum. I replaced a hose that was leading away from FPR underneath intake manfold and toward the firewall. I have suction, are there any other trouble spots to double check?

I thought it may have been a faulty Fuel Pressure Regulator and have replaced it but still having the same symptoms. I am thinking now the only option is to check for compression in all of the cylinders. The reason I was led to believe the FPR was at fault was due to the oil on the dipstick having a very strong fuel odor. Does anyone else have any ideas? Where else can I check for vacuum leaks? Is it possible for an auto shop to test the fuel rail including the regulator and the injectors? I do not have the means to test them. I have fuel and spark and it starts when everything is dry but will not drive but idles hard then dies. I am stuck, any help or ideas much appreciated.

Today I plan on looking at the knock sensor as a possible culprit and possibly running a compression check as the upper and lower intake gaskets may have given out. Anyone else have suggestions or ideas?

I removed the knock sensor and attempted to start, all it did was crank per the usual. I pulled plugs 2, 4, and 6 because of the ease in their location. They were wet but with what just smelled like gasoline. I dried them off, pulled the Fuel Pump Relay and installed only plug 2 with 4 and 6 still being pulled. I attached my spark tester and received a spark light but also the motor tried to turn over! So I replaced plugs 4 and 6 and the Fuel Pump Relay and I attempt to start but just get nothing. So I then pull the fuel pump relay again and the motor is starting but only running for a second or two. I did this a few times, then placed my foot on gas pedal as I was starting and had the motor running at about 3500-4000 RPM for almost 10 seconds albeit no fuel relay. I asked my buddy to replace the relay as I had the car idling, just as soon as he did the car dies and returns to no start condition. Repeated this a couple of times with the same outcomes.

I am not sure if it is just igniting the residual fumes in the cylinders and burning it off and then dying or what. I think the car may have some gasket leaks somewhere. Possibly the upper and lower intake or even the head gasket. If I pressure test the coolant system could this reveal a bad intake gasket? Would a compression test just show a possible bad head gasket? I do not have equipment to perform leak down test on either.

Maybe get a replacement for the Fuel Pump Relay that may be your issue. I am sorry I can't help more. I wish we could do more but it is very hard to do from here. I just wanted to resond to you so you wouldn't think we abandoned you.

Thanks. I tried using the a/c compressor relay which is the same relay with the same result. I am confused. Thanks for the help.

Any help with checking ground wire for the injectors?