running really rich!

dookie · Apr 28th, 2003, 12:34 AM

my motor is running very rich. there is smoke coming from the tailpipe. when i start the car soot shoots from the tailpipe. there is lots of soot on the pipe and some on the back bumper. i pulled the plugs to do a compression test, thought it was burning oil, and all four of them were black from the soot. fuel consumption is very high. i have had a CEL on for about a month for the EGR valve but i just started getting smoke from the exhaust a few days ago. i replaced the oxygen sensor last summer. i checked the maf sensor voltage and its fine. i just replaced plug wires, rotor, and cap in January. if my it is an injector problem i would think one cylinder would run rich instead of all four. compression is fine on all four cylinders. the car drives fine, it just bogs a little under part throttle.

insanestvtop · Apr 28th, 2003, 10:07 PM

I have the exact same problem with my 94 le sentra. It runs really rich, i just had to replace the EGR chip or something, my CEL was on for bout a mouth cause of that. It smokes during startup and high revs, I was wondering what all you have done to your car so we could compair what our problem is. Recently I replaced my plugs with split titaniums and i think my wires are in good condition. So those arent causing it. How much milage do you have on your car?

If anyone can help, i bet both of us would appreciate it.

Stovetop

dookie · Apr 29th, 2003, 01:57 AM

i have a hotshot CAI, hotshot header, 2" crush bent cat-back exhaust (it's no stromung), ACT clutch and pp, ground control coilovers, AGX shocks/struts, courtesy front and rear stb's, and i'm looking for the cheapest way to get some AD22VF brakes.

i know half of the stuff i listed has nothing to do with me running rich but i just wanted to tell everyone what i have.

javierb14 · Apr 29th, 2003, 03:12 AM

whats ur fuel pressure set @? sometimes the fpr's can go bad and cause this problem.

Apr 29th, 2003, 08:05 AM

EGR chip???

I have the exact same problem with my 94 le sentra. It runs really rich, i just had to replace the EGR chip or something, my CEL was on for bout a mouth cause of that.

sunnysentra · Apr 29th, 2003, 11:58 AM

you need a new fuel pressure regulator, they are expensive, so go to a junk yard and get one from there. the reason is too high pressure is pushing fuel into the cylinders if all 4 plugs are fouled. Check the spark too. That causes alot of issues. For some reason high mileage and Nissan coils are not lasting long. I got a new one for mine also. we should take a poll for who replaced the coils and what mileage at. Those are your 2 things to check. Easy enough to fix, go the the yard and get both, chekc the coil first and see what happens and then replace the fuel pressure regulator.
Chris 92 classic

dookie · Apr 30th, 2003, 01:48 AM

is there anything else i should check to make sure that i'm getting the optimal a/f ratio? like the AIV, EGR, O2 sensor, MAF. my car has always felt/seemed weaker than other GA16DE cars i have driven/raced, especially considering the mods i have done. when i checked the MAF voltage, according to the haynes manual, the voltage at idle was fine but when revved to 4k rpm the voltage was around 2.8 instead of 4.0. i figured if anything this would give me a lean mixture. but i want my MAF working correctly anyway. can i do anything to salvage my MAF? maybe clean the hotwire with something?

dookie · Apr 30th, 2003, 01:52 AM

i just thought of something else that maybe affected by my motor running extremely rich, the cat. can my cat be damaged and how soon can it be damaged and how will i know if it's damaged? sorry about all of the questions but i want to make sure my cat is ruined before i punch it. if it's fine i don't see the point in ruining a perfectly fine cat. if it's ruined, what do i have to lose, i'm already grossly polluting the air, might as well make the best of it.

sunnysentra · Apr 30th, 2003, 07:12 AM

If you have a weak coil, then you should replace this. it may be the root of the problem. Try a good one first. I guess you have a 1995 so its in the distributor. You can run the consult first to determine the real issue, this will diagnose any voltage issue or will tell you if the injectors are bad or not also, check the fuel pressure after the regulator to see if that is bad. You are running rich because of 2 things and its either weak spark, or too much fuel pressure. You better take care of this now, or the CAT will clog and fail too. Do you have OBD2? Has the light come on at all yet??
Chris 92 classic

SRV1 · Apr 30th, 2003, 10:37 PM

well first off, you mentioned an EGR code. did you fix that problem? if not, find out if the EGR is sticking. It will cause a rich condition. How about a cold start injector? Does yours have one? I cant remember if they do or not. Bad coolant temp can do it as well as low coolant in the engine. I can go on and on, but you need to check the basics first. See if the fuel pressure regulator is holding vacuum. Make sure the MAF door moves freely. Check all connections. Check to see where you put the Intake Air Temperature sensor if you added a CAI. Is it disconnected? Go from there.

James

dookie · May 1st, 2003, 02:47 AM

IAT sensor is correctly installed in the CAI. as far as i know i don't have a MAF sensor door or a cold start plug. i don't have low coolant in the engine but the resevoir never seems to get low, as if the overflow always stays full. i replaced the cap a few weeks ago. how do i check the coolant temp sensor? my temp guage in the cluster reads fine. and since the igniton coil is integrated into the distibutor, don't i have to replace everything, meaning a lot of $$$. how can i check the coil?

oh and by the way everything seemed to start messing up after i cleaned the engine bay with some engine brite and a water hose. i also changed the valve cover to the metal b13, on the same day. i put the original plastic b14 valve cover back on since then, just in case. oh and i just cleaned the PCV valve and it's fine. hell, once i replace all of this shit the car should run better than ever.

SRV1 · May 4th, 2003, 01:09 PM

Quote:

Originally posted by dookie
IAT sensor is correctly installed in the CAI. as far as i know i don't have a MAF sensor door or a cold start plug. i don't have low coolant in the engine but the resevoir never seems to get low, as if the overflow always stays full. i replaced the cap a few weeks ago. how do i check the coolant temp sensor? my temp guage in the cluster reads fine. and since the igniton coil is integrated into the distibutor, don't i have to replace everything, meaning a lot of $$$. how can i check the coil?

oh and by the way everything seemed to start messing up after i cleaned the engine bay with some engine brite and a water hose. i also changed the valve cover to the metal b13, on the same day. i put the original plastic b14 valve cover back on since then, just in case. oh and i just cleaned the PCV valve and it's fine. hell, once i replace all of this shit the car should run better than ever.

You should have a vane style air meter and it will have a door. As for you washing the engine, maybe you got some water in a connector. check them all again. You changing the valve covers wouldnt make it run rich.

Question. Is it misfiring also? Does the car run fine or does it spit and sputter? If so, take off your distributor cap and plug wires to see if they got wet.

James

dookie · May 4th, 2003, 11:25 PM

i took the throttle body and fuel pressure regulator off and cleaned them. the tb and intake manifold had lots of carbon deposits possibly clogging the vacuum line that goes to the fuel pressure regulator. when i pulled off the old b13 valve cover the seal that separates the airway for the pcv valve from the oil, crumbled in my hand. that would cause me to burn oil, if it gets sucked in by the pcv valve, therefore making it smoke more. i pulled off the cap and checked for any water, i didn't find any. i blew through the fuel return line, the one that goes from the fuel pressure regulator back to the fuel tank. the line wasn't clogged. after putting everything back together, the car ran fine with very little smoke. a friend driving behind me told me that when i downshift and floor it, there is black smoke. i ordered a new fuel pressure regulator anyway, it is coming in tomorrow. i'll see if that clears up the rest of the smoke. i can't even tell from the driver's seat if there is smoke coming out of my tailpipe. that is much better than it was before.

Mervic · May 5th, 2003, 12:03 AM

Check your hoses for vacuum leaks. It might need replacing.