Car running rough, smells like gas, gas mileage terrible [Archive] - DFWstangs Forums

: Car running rough, smells like gas, gas mileage terrible


mustvid
05-11-2009, 06:17 PM
1992 5.0 H/C/I No emissions accept for EGR.

Okay, car was running perfectly fine yesterday. When I started car this morning I noticed it was running rough (unusual for this car). Half way to work I stopped and checked plug wires (did tune up a week ago) and one was really loose. Started car and the same condition exsited. At work I disconnected the battery to reset computer (set for 4 hours). No change. On the way home car blue smoked and smell like gas (I could tell people behind me could smell gas too). Gas mileage is terrible. Got the car home and ran codes. The KOEO code was 85 and the KOER code was 92. This car has new fuel pump and after market FPR.

My Haynes manual says the
85 code is canister purge circuit or transmission shift control circuit and the 92 code fuel mixture rich, fuel pressure high.

I checked all vacuum hoses and don't see or hear a vacuum leak. I don't hear the fuel pump turn on but this is an after market fuel pump and I don't remember hearing. Obviously the pump is on but it seems like it is not working properly or the fuel pump relay switch is stuck open.

Does this sound like a fuel pump relay? Or does it sound like the fuel pump is stuck on?

Any suggestions from more skilled mechanics than I? I want to replace the fuel pump relay. I have replaced this relay twice since I've had the car (6-7 years). The WOT relay is only in play if the AC is on and just shuts off the AC right? The Haynes manual is garbage for troubl shooting and I'm not a technician.

bonestk87
05-11-2009, 06:28 PM
i don't think it's a relay problem at all. i would check your fuel pressure first. might be the fpr took a shit?? is it a 5sp?

mustvid
05-11-2009, 06:32 PM
Yeah it is a 5 speed. Fuel pressure looks normal on the guage.

blackedv
05-11-2009, 07:28 PM
if your fuel pressure is fine then you might have a leaking injector,possible maf out of calibration, something is causing the rich condition
the code 82 references the air pump but if you took that off it wont have an effect on the running of the car

greenbullitt
05-12-2009, 06:33 PM
try cleaning the maf first marty since the fp is ok. whats tp voltage base at? timing verified?

mustvid
05-12-2009, 07:49 PM
I just cleaned the MAF (didn't look dirty at all) no change to runs rough and smells like gas. I just replaced the TPS. I probably need to set it to .95 but I'm waiting on the computer to reset. I have not messed with the timing yet. The strong smell of gas and horrendous gas mileage leads me to believe it is fuel system related. Could a dirty or clogged fuel filter cause these symptoms?

greenbullitt
05-12-2009, 07:53 PM
i dont see a filter having anything to do with it. if no vac leaks, im leaning toward a possible inj prob...try swapping the bap sensor but i dont see that fail very often. if you need a donor bap, i prolly have one to try

dee
05-12-2009, 07:57 PM
Na if the fuel filter was clogged you would be lean.What was fuel pressure and are injectors stock?

mustvid
05-12-2009, 08:14 PM
Yeah, the TPS didn't change anything. I did put RXP in my car the other day. This is the third time i've done this with no problem. Could be coincedence I guess. The injectors (24lb) have less than 30k on them and I bought them new. I guess one could have failed. It is really bizarre because they day before the car was running great and the next day this. Virtually everything motor wise has been replaced. How do you determine if a FRP is bad? Fuel pressure hasn't change, it drops when the car is turned of like always. It's like the computer is compensating for a lean condition by increasing the fuel mixture. The car smells like gas and is backfiring through the exhaust. Could the bad ECM cause these symptoms? I'm sure based on the gas mileage the cylinders are being flooded with gas.

dee
05-12-2009, 08:21 PM
It could be ecm but I would pull plugs to check injectors.

bwild
05-12-2009, 10:00 PM
When you did tune up, what type of plug wires did you use? Hope you did not use those cheap autozone wires. Also pull plugs to see which ones are fuel fouled, those would be your problem cylinders.

mustvid
05-14-2009, 07:59 PM
I'm using MSD wires and cap. Six of the eight plugs look fouled. Swapped the BAP and sensor and no change. This is driving me crazy. I wish I knew a systematic way of narrowing this down. You would think the codes would tell me something or at least where to look. I hate buying parts as a way of figuring this out.

dee
05-14-2009, 08:23 PM
Whats feul pressure

joes01bullitt
05-14-2009, 08:31 PM
not sure if this will help you but had a similar problem with mine.

check your injectors to see if one is maybe stuck open.
and while you have them out, check the seals. one might be tore.


hope you get it fixed.

i almost guarantee its an injector problem.

mustvid
05-14-2009, 08:47 PM
Fuel pressure is at 39 with the vacuum line on which is where it was when the car ran great. The injectors are new (less then 30k miles since I replaced them). I've cleaned the MAF and unplugged and nothing changed. Swapped BAP still no change. I sprayed carb cleaner arounf the manifold and vacuum lines and nothing so I don't think it is a vacuum leak either. I pulled the plugs and six looked fouled and smelled like gas. I replaced the air charge temp sensor and the engine coolant sensor and the O2 sensor are new (all have less than 30k miles) on them. THe EGR was replaced around the same time. The TFI has been replaced as well. Now, that does not mean that an AZ part didn't fail so I'm trying to find the volts each sensor is supposed to be at to check to see if one failed. I have a shop manual (slowly following apart) that has information like this is it I just haven't found it yet because I the table of contents and index is gone.

dee
05-14-2009, 08:51 PM
What kind of o2 sensors did you put in?

mustvid
05-14-2009, 09:06 PM
Bosch

dee
05-14-2009, 09:10 PM
Thats very possible your problem I've never had good luck with bosch but it sounds more like fpr. Make sure your getting a good vacum to the regulator and there are no holes in the regulator vacum line.

blackedv
05-14-2009, 10:04 PM
just because parts are new doesnt mean they cant be bad

greenbullitt
05-14-2009, 10:04 PM
just because parts are new doesnt mean they cant be bad


he stated that earlier...

donnie90stang
05-14-2009, 10:48 PM
Temp sending unit bad? Can make the computer read cool, so it adds fuel to heat up the engine. This may be where your flooding is coming from.

mustvid
05-15-2009, 05:20 PM
Temp sending unit bad? Can make the computer read cool, so it adds fuel to heat up the engine. This may be where your flooding is coming from.

Are you talking about the air charge temp sensor?

dee
05-15-2009, 05:52 PM
No he is talking about the engine coolant temp sensor

mustvid
05-15-2009, 06:22 PM
Okay, well both have been replace but I guess I can replace again. I would like to find out what the voltage should be for each before I throw money at a problem. However, I've just about eliminated everything else accept a short and the PCM.

dee
05-15-2009, 07:04 PM
Okay, well both have been replace but I guess I can replace again. I would like to find out what the voltage should be for each before I throw money at a problem. However, I've just about eliminated everything else accept a short and the PCM.

Voltage constantly changes with the temp resistance changes

blackedv
05-15-2009, 07:09 PM
tap into the 02 sensor wire and see what its seeing. its suppose to switch between 0 and 1 volt when heated up. closer to 0 volts is lean and closer to 1 volt is rich.just for shits and giggles have you checked base timing?

mustvid
05-17-2009, 08:42 PM
Okay, I did check the timing and it is at 14 degrees. I've replaced the fuel relay switch, ECT, TPS and swapped BAP, unplugged the MAF and 02 sensors and condition stays the same. Actually, I think it is getting worse. Unspent fuel is leaking out of the h-pipe and blowing out of the tailpipes. I have listened to 6 of the 8 injectors and it sounds like they are working.

I'm not positive unplugging the 02 sensors proves anything but read where that eliminates the MAF from the equation. I'm ready to pull the hair out of me head. I get only the code 92 which is the left side 02 sensor telling me that the system is running rich which probably means it is actually lean so the PCM is compensating. Fuel pressure does not seem to be an issue as I can start the car but the vacuum lines smells like gas which I read could mean gas is getting into the intake.

Anyome here have an FPR go bad? If so, what are the symptoms? Also, what does a bad PCM do? At this point, I think I'm down to the ACT sensor or the PCM.

Is it possible that a bad valve cover gasket could cause a crank case ventilation problem resulting in a lean condition?

greenbullitt
05-17-2009, 08:49 PM
is there fuel in the vac line to the fpr? bad pcm can do any number of things marty....

blackedv
05-17-2009, 09:05 PM
if you smell gas in the vacuum line to the fpr its possible that fuel is leaking past the diaphram and getting sucked into the intake causing your rich condition. pull the vacuum line off and plug it and see if that helps some. if it does then replace the fpr and go from there

mustvid
05-17-2009, 09:15 PM
Well, I pulled and plugged the vacuum line an no change. So, I guess that eliminates the FPR. Does unpluggin the 02 sensors eliminate the MAF system? Is this something an EGR could cause (Mine has been replaced)?

It is difficult to narrow it down with one engine code and thats coming down stream with lots of possibilities to consider. I'm not disciplined and skilled enough to know how to systemtically eliminate possible suspects and get to the root cause.

Could a leaking valve cover (bad gasket) cause a crank case ventillation issue resulting in a lean condition the PCM is reacting to?

greenbullitt
05-17-2009, 10:31 PM
cause.

Could a leaking valve cover (bad gasket) cause a crank case ventillation issue resulting in a lean condition the PCM is reacting to?


no. the leak would have to be huge and would result in lean...the pcm can only adjust parameters so wide also.

Dacotua
05-18-2009, 06:13 AM
Sounds like you have a leaking injector or one stuck wide open.

Put your old 19 pound injectors back on the car with the stock MAF.

If your problem goes away, one of your injectors is junk.

STICKMAN
05-18-2009, 09:06 AM
Been messing with same prob last week n half. been through all the injector stuff , o2sand what not . ordered a new fuel pump , dropped the tank was full all kinda crap so probly trashed the pump. call the dealership and they said i should have 90psi at the fuel rail with the key on and 35 to 45 after the cars started. had 36 psi with the key on and 32 after start.

all started a month ago when i got bad gas and had to replace the plugs and fuel filter.ran good for month then last week started this crap.

Diabolic
05-18-2009, 09:31 AM
Have you pulled your plugs to see which cylinders are fouling out the plugs? This would tell you if it's a specific injector or a universal problem to all the cylinders. If it's fouling all the plugs then I would loook to replace the computer. If you unplug the oxygen sensors it will just run off the preprogramed warm up fuel map. If the FP is good and steady then it isn't the regulator. I would look to injector failure(read the plugs) or PCM failure.

greenbullitt
05-18-2009, 09:34 AM
Been messing with same prob last week n half. been through all the injector stuff , o2sand what not . ordered a new fuel pump , dropped the tank was full all kinda crap so probly trashed the pump. call the dealership and they said i should have 90psi at the fuel rail with the key on and 35 to 45 after the cars started. had 36 psi with the key on and 32 after start.

all started a month ago when i got bad gas and had to replace the plugs and fuel filter.ran good for month then last week started this crap.

someone lied to you! 90psi! wtf?

bigsal817
05-18-2009, 11:20 PM
my buddies car was dumping fuel like crazy and it turned out it was just the diaphram. Maybe worth a try it happened twice to him
Good luck

turbostang
05-19-2009, 08:13 AM
Marty's problem is most likely a bad injector - he has ONE plug that looks like it's been spray painted black.

mustvid
05-22-2009, 06:32 PM
Brooks is correct. It turned out to be a malfunctioning injector (stuck wide open) in cylinder seven. Thanks for the help Brooks! I learned how to spit on exhaust to diagnose a problem.

turbostang
05-22-2009, 11:43 PM
Brooks is correct. It turned out to be a malfunctioning injector (stuck wide open) in cylinder seven. Thanks for the help Brooks! I learned how to spit on exhaust to diagnose a problem.

No problemo Marty!