Q running rough,almost like a bad gas issue.whatt next???

[jmorasch]

been having what seems like fuel Issues with 91Q.got a fuel pump from goody one that was known to be good and then grounded the fpcu,and its still running with a miss like sputter.theres really no specialty shops around here,or Id ride like the haitian really soon. Im wondering if Ive got a clogged injector? would it be of any harm to run some BG through the tank? Im also wondering if the quality of gas here in the midwest is dropping because the misses Q done the exact same thing going to work one morning and stopped soon after it started.I went and got some injector cleaner and ran it through and it quit on the way home. I dont want to mess this motor up driving it to see if BG clears it up though.IM gonna check the injectors see what kinda reading Im getting. does grounding the fpcu definatly let you know if the units good or bad?

[Raxephon]

Have you checked your fuel hoses? A leaky fuel hose will cause a ''miss-like" sputter or slight vibration like the motor is missing on a cylinder.

Have you checked your fuel pressure?

[Q45tech]

The amount of fuel consumed idling is 1/50 of that at peak power and 1/15th that cruising steady at 60 mph. SO

Idle fuel pressure while helpful cannot replace fuel pressure measurement at 6,000 rpm on the road.

[Haitian_King]

been having what seems like fuel Issues with 91Q.got a fuel pump from goody one that was known to be good and then grounded the fpcu,and its still running with a miss like sputter.theres really no specialty shops around here,or Id ride like the haitian really soon. Im wondering if Ive got a clogged injector? would it be of any harm to run some BG through the tank? Im also wondering if the quality of gas here in the midwest is dropping because the misses Q done the exact same thing going to work one morning and stopped soon after it started.I went and got some injector cleaner and ran it through and it quit on the way home. I dont want to mess this motor up driving it to see if BG clears it up though.IM gonna check the injectors see what kinda reading Im getting. does grounding the fpcu definatly let you know if the units good or bad?

If it's not clogged, it could just be the injector giving out.

Since you checked the FP and the FPCU, maybe we can rule them out. Let's move on to MAF, EGR, IAC, TB, and injectors. Ohm the injectors, or even just go to a regular shop and have a powerbalance test done. (Those can be done anywhere right?)

The PB test will show the engine speeds and the RPM drop for each cylinder. I think my #6 dropped to 25 RPM after it was warmed up and failed the PB Test.

I asked Keith about running a can of BG in there and he said that he really didn't think it would help as it wasn't a "dirt" problem, but more of an electrical one. He said that back at the dealership, he and the other techs would be replacing at least 1 set (All 8) a week. It was a fairly common issue on the 90-93's apparently. I'm considering just getting a 94 fuel rail and injectors to eliminate the chronic injector failure. Around this time last year, I replaced my #8.

[maxnix]

Try some ISO-Heet also as I bet you are in an ethanol area.

[jmorasch]

Try some ISO-Heet also as I bet you are in an ethanol area.

tried some iso already,Ive been womdering the same thing???There was a thread on the states required to mark the pumps by the feds awhile back and kansas and Mo. were the only ones not required if I remember right....anywayze,Im off to pick up some lectra-clean crc and hit the maf,check things out from there. WILL IT HURT THE VH TO RUN IT LIKE THIS WITH SOME BG INJECTOR CLEANER TRYIN SEE IF MAYBE WE ARE DEALING WITH A DIRT ISSUE ??????after I get the maf cleaned out.

[maxnix]

I would run both ISOHeet and BG44K and see if that makes a difference.

[jmorasch]

un-plugged the MAF and it died,researched this and one of wes's posts he'd said the car should idle w/the MAF unplugged.I got the MAF cleaned really good,cleaned the plug....good clean connection and its the same thing.drove it around the block and it seems to some what run smoother once you get up to about 30mph but its not running any diffrently. Theres buzzing from the fuel pump again too,granted I got a used FP from goody but I dont think there was anything wrong w/it.its almost like Ive still got the FPCU grounded out????? THE GREMLINS AT IT AGAIN....could the FPCU be bad even though I grounded it,and ran the car??? I know I need to do a F.P. check,thats next on the list. Im kinda lost as to where to start backtracking.....

[Kiven422]

With the MAF unplugged... It will idle in PARK but if its in DRIVE it will die unless you hold the revs with the gas. Don't know if you already knew that.

Replacing the FP--chances are you will have to replace the FPCU.. You didn't say you replaced that, just grounded it... Its already grounded by the metal pieces that screw on to the car. I read somewhere it corrodes or burns out after the FP goes bad... So the question is... did you also replace the FPCU? My car finally ran after I replaced the FP without replacing the FPCU... then died in one week-no start.

My replaced fuel pump also buzzes full time.. but it runs great throughout all the revs.

What are the highest revs you can achieve until the sputtering starts when in DRIVE? in NEUTRAL? Can you be a little more specific on what it does exactly when it sputters? Different things cause different sputters.

[jmorasch]

NO,I havent replaced the FPCU. when in nuetral with the car running at idle,you wouldnt really know theres a miss or sputter unless you listen close at the rear of the car.It does have dual exhaust system on it from the previous owner. you can puy your hand on the top of the engine and feel a slight jitter to ie.otherwise you wouldnt really know until you put it itno drive.the its almost like it got a bad motor mount,but the shutters not as radical.It shudders on take off,its a strange shudder,miss kinda deal???its really frusterating.....at about 2k on the Rs,it seems to smooth out until it shifts.then it goes through the same cycle again.(Ive got 1st gear start TCU) ID like to put some BG injector cleaner into it and drive it back and forth to work,but Im not big on the autozone type quick fixes so to speak.I want to know what the problem is and resolve it !!! I grounded the FPCU after I put this other pump in...and it still ran the same.after I grounded it out,I pulled it out of the garage and parked it.gave myself a break. disconnected the wire from the fpcu and plugged it back in.next day I pulled it back in and did the O2 sensor,and though I couldnt believe the color of the cleaner after it came off the O2 it was brownish black,there was no diffrence in things when I fired it back up??? the sputters not a spitting,nor sputter through the exhaust as far as I can tell,though like I said you can hear the slight miss at the exhaust.almost like an old 350 chevy with a mild cam in it would be my best example kind of a shutter type miss within the engine??? its consistant too,theres really no changes other then when the Rs reach a certain point it seems to fade somewhat until it shifts again.

[Haitian_King]

NO,I havent replaced the FPCU. when in nuetral with the car running at idle,you wouldnt really know theres a miss or sputter unless you listen close at the rear of the car.It does have dual exhaust system on it from the previous owner. you can puy your hand on the top of the engine and feel a slight jitter to ie.otherwise you wouldnt really know until you put it itno drive.the its almost like it got a bad motor mount,but the shutters not as radical.It shudders on take off,its a strange shudder,miss kinda deal???its really frusterating.....at about 2k on the Rs,it seems to smooth out until it shifts.then it goes through the same cycle again.(Ive got 1st gear start TCU) ID like to put some BG injector cleaner into it and drive it back and forth to work,but Im not big on the autozone type quick fixes so to speak.I want to know what the problem is and resolve it !!! I grounded the FPCU after I put this other pump in...and it still ran the same.after I grounded it out,I pulled it out of the garage and parked it.gave myself a break. disconnected the wire from the fpcu and plugged it back in.next day I pulled it back in and did the O2 sensor,and though I couldnt believe the color of the cleaner after it came off the O2 it was brownish black,there was no diffrence in things when I fired it back up???

BG 44K isn't an "Autozone Quick Fix".

You know what? I was getting a wicked shudder on take offs. I thought it was transmission/suspension related. All sorts of acceleration issues. I changed my spark plugs and now most of the are gone. Weird eh?

I never would have guessed it was under the hood. Given what you said about the color of the cleaner coming out of the MAF, you don't have anything to lose using the BG.

[elwesso]

OK there is a LOT of guessing without actual testing...

If its just a rough idle (not unstable), in other words the RPMs are steady but it shakes then its probably an injector. If grounding the FPCU makes no difference its may not be a pump issue. Still havent seen any fuel pressure data, but if its not stalling just running really rough then its probably not fuel pressure related, but its ALWAYS A GOOD IDEA TO CHECK IT.

you checked the MAF, another good place to go. Just because the connection is good doesnt mean the MAF is good...Still, most often the car will run good and then randomly buck and jerk and/or stall with a bad MAF. Can be misleading to a bad fuel pump as well, which is why i tell people to ignore MAF problems until we check fuel pressure.

Get yourself a VOM and check the injectors. BG44k is NOT MEANT to CLEAN DIRTY INJECTORS, it can only keep clean injectors clean. Not a terrible idea but the easiest/most effective way to clean injectors is to get a rail flush, no real substitute for that.

[goody90q45]

the sputters not a spitting,nor sputter through the exhaust as far as I can tell,though like I said you can hear the slight miss ......theres really no changes other then when the Rs reach a certain point it seems to fade somewhat until it shifts again.

It sounds like you may have a plugged injeector or two. What's the history of your injectors/fuel rail/engine. Had it/they been sitting in a salvage yard for a while?

I'm having the exact issue where it idles rough but sort of smooths out above 40mph. PO installed a fuel rail from a salvage yard and 2 of the injectors were still plugged even after a BG flush at a shop. I've replaced one (#8) and am waiting on a 2nd injector to arrive. All of the injectors were ohming in range BTW.

If you don't have a consult cable and scan program on your laptop to do a power balance test (good investment for $135), the best way to check for a dead cylinder is to unplug one coil at a time and see (feel) which shows the least change in RPM. All this is assuming you've ohmed your injectors and they're all good, and you've verified spark and compression to each cylinder. Open a door to measure the amount of miss as you unplug each coil. Watch the top edge of the door and look for increased movement.

Try the manual power balance test, ohm the injectors, and let us know what you find. Good luck.

[jmorasch]

I agree....Im doing alot of guessing here,without any facts,FP and checking the injectors is something I need to do next!!!! this car sat for about 3 yrs before I bought it.this is the Q that was suppose to have a broken chain. anyhow im gonna check the FP and ohme the injectors this weekend and go from there. If an injector doesnt ohme properly does that mean its plugged or bad??? wes described the charactoristics of how the engines running,IM going to start on things this weekend.....thanks for the help,feedback and parts.hoods struts worked out great!!!!

[maxnix]

If you haven't inspected the guides, then you don't know if the timing is on or not.

[Issac]

Mine has been running rough and I did some beginner stuff that was safe. But then it started smelliing like raw gas. this happened fairly close to when I did fuel pump, so I assumed I missed something or leak, etc.Checked and checked.

Turns out the extra pressure was enough to make a seperate fuel line leak. it was the hardest hose clamp to reach I could have imagined.

Took almost 2 hours. I finally decided to pull the intake (plenum I guess its called) and it was down deep in there.

Tightened up, stopped bubbling, and my rough idle leaving was the added bonus!

Every since clamp got loose on my old car. I know- everything must go. Save the lectures.

[Haitian_King]

I agree....Im doing alot of guessing here,without any facts,FP and checking the injectors is something I need to do next!!!! this car sat for about 3 yrs before I bought it.this is the Q that was suppose to have a broken chain. anyhow im gonna check the FP and ohme the injectors this weekend and go from there. If an injector doesnt ohme properly does that mean its plugged or bad??? wes described the charactoristics of how the engines running,IM going to start on things this weekend.....thanks for the help,feedback and parts.hoods struts worked out great!!!!

Your Q had a broken chain? Timing chain? Did it run better before and this problem just come about? Or has it been a slight nuisance that's become worse?