Darren111 Posted February 23, 2009 Report Share Posted February 23, 2009 my 92 deville 4.9 just started smoking real bad,and the smell of raw gas is unreal, smoke so heavy i will get a ticket if i drive her, i had 4 gal of gas in the car when i started it up in the morning, drove out the driveway but had to turn around because of the smoke and gas smell. when i pulled in and put her in park, the engine had a roll. and the speedometer kept going up 4mph 5,6,7,8 and down with the roll of the engine(like a tachometer) but i was at a dead stop, in park... i let it idle.. it did,, but with a little miss. checked all the vacume hoses, everything obvious, reved it up, let it idle down.. i did this for about 35-40 min, smoking the neighborhood up. then it stalled and would not restart, looked at the gas gauge and it read E.. i said no way i burned up 4gal of gas... i had exactly 2 gal in a gas can for my yard equipment, so i put it in. my gauge read 2 gal. turned the key, let the pump pick it up, it started, let it run, it still smoked when i reved it up and the smell of raw gas,, did this for about 4min or so, it stalled, looked at the gauge, E out of gas again. i checked the code's and 31 was in.. checked the book, map sensor... anyone ever have a problem like this?, the speedometer going up and down confusses me. the book say's the map sensor controls the air to fuel ratio and timing, this makes sense, but could it burn that much fuel? any help would be great, thanks, Darren Link to comment Share on other sites More sharing options...
Ranger Posted February 23, 2009 Report Share Posted February 23, 2009 I just replaced the MAP on my wifes 3800, but only because the SES light was on and that was the DTC listed. It ran and idled normal. After replacing it, the SES light went out. That said it could have failed in such a way as to be telling the PCM that you are WOT and it then is delivering MAX fuel to the injectors. The other possibility is a severely ruptured FPR, but that would not set a code. I assume the "smoke" is white and smells like fuel? If so. it is not smoke, but unburned fuel vapor. Link to comment Share on other sites More sharing options...
winterset Posted February 24, 2009 Report Share Posted February 24, 2009 ditto on the FPR. just be sure & change your oil & filter whatever the problem is. if your engine is running that rich, you probably have a dip that's past full, and it's thinned out with gasoline - & ovvering very little lubrication Link to comment Share on other sites More sharing options...
ampiifire Posted February 24, 2009 Report Share Posted February 24, 2009 was there a source of the "smoke" aside from your exaust? was it steaming off of your engine or leaking from another joint, possibly where the fuel line hits the filter? if not, it sounds like your pcm caught a nasty spark or maybe have a few exposed sensor wires touching somewhere.. check the front by your fan blades and see if they caught part of your harness. im sure i'm probably wrong but even at WOT on the highway it wouldn't burn two gallons in four minutes.. the instantaneous still reads 8-10 mpg on my northstar at WOT and unless you are going like 240 mph you shouldn't burn 2 gallons in 4 minutes. it seems to me like each injector would have to be spewing max fuel nonstop in to its cylinder to cause that much of a drop in your fuel level. sounds to me like it may be confusing the input from some other sensor with the input from your speed sensor (given the speed fluctuations in park and such)... and if that's the case, god only knows what else it's confused about. i dunno i'm no technician but i'd take the PCM shroud off and check it out real good.. maybe pull the harness off the pcm input where it all ties in and check for corrosion if you don't see any obviously exposed wires. i don't know - even if i am wrong and crazy/stupid, make sure you don't drive it or idle it excessively trying to figure it out if it's sending that many unburned HC's through your cat or you will end up having to replace that and likely your o2 sensors sooner than later after you get this issue taken care of. best of luck to you and if you do get it taken care of please post back - i'd love to hear wtf can cause THIS :\ Link to comment Share on other sites More sharing options...
Darren111 Posted February 24, 2009 Author Report Share Posted February 24, 2009 there is some smoke coming out the exhaust right at the pipe at the fire wall, the pipe leaving the engine and going to the covertor, and yes the smoke is a grayish white and stinks of fuel. would the FPR dump that much fuel? and why would i get a code 31 (MAP) could the problem be throwing the ECM off that bad.. thanks to all, Darren Link to comment Share on other sites More sharing options...
ampiifire Posted February 24, 2009 Report Share Posted February 24, 2009 you can clean the map sensor with carb cleaner if you want to try that.. just give it a good blast and be careful reinstalling it so you don't rip the seal around it. to test it, you can stick a multimeter between the output lead and ground - the output the sensor is supposed to feed the pcm ranges between .5 with low vacuum (i.e. idle) and 4.5 volts at WOT. unless it was giving a much higher reading than that that i don't think it would be the actual source of your problem - just another symptom of it or another problem all together. like i said before.. in order to use that much fuel each injector has to be open the entire time the engine is running, including exaust strokes (making gas vapors come out the exaust) maybe you should try testin the injector cables with noid lights? look for a steady pulse.. if the light stays on when the engine is running or being cranked on any of the injectors, you have a problem. i think pepboys and autozone have noid lights for rent in their arsonnals. Link to comment Share on other sites More sharing options...
Ranger Posted February 24, 2009 Report Share Posted February 24, 2009 Normally a bad FPR will not dump that much fuel, but it is easy enough to check and rule out. Link to comment Share on other sites More sharing options...
JohnnyG Posted February 25, 2009 Report Share Posted February 25, 2009 You could have an injector stuck wide open too! Don't bend a rod from hydrolock..........it wouldn't be the first time!! Never underestimate the amount of a persons greed. Link to comment Share on other sites More sharing options...
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