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View Full Version : Advice Please, car is severely misfiring, kinda stuck...



ryan roopnarine
01-21-2007, 10:10 AM
car is 7/91 1992 525i M50, non vanos, automatic transmission.

OK, will start off by following up from my post yesterday. my car was severely bucking, running rough, hard to get over 40 mph. i found that the FPR was broken internally, and changed it out. slight improvement, but the problem still persists. i listen to each coilpack, and note that no 1 is clicking loudly enough to be mistaken for a tappet. i take out no 1, and note that the boot now has an almost 1 1/2 inch tear along the bottom. i replace it with a spare that i have on hand. my idle improves a decent bit. at this point, i say, f' it, and start pulling out coilpack connectors (the ones at the bottom, not the connector at the plug itself) and looking for which ones can be disconnected without changing the idle. i suspect that two are doing this, and swap out what few parts/boots i have...the idle is a little better, but one can still see a little bit of white in the exhaust.
by now, i've taken the cover off of the fuel injector connector "box" and started probing. all 6 injectors come back with running voltages of .26-.40, pulsing--as much as one can observe pulsing on a multimeter. the spec--by bentley is .3-1.0v, but i chock this up to my multimeter being $4 from harbor freight on sale. i check the ohmage of each injector, each comes back at precisely 16.8 ohms, within spec. i check the resistances of each of the coils, all within spec--.8ohms--by bentley. the CPS checks at about 596 ohms, within spec. the car "feels" like a classic, but very mild, disconnected plug wire, or mixed up plug wire misfire. admittedly, the car has been running a little rich for a while now, but it never did anything like produce smoke at acceleration. is it possible that leaking injectors could be doing this? when i took the rail out to get to the FPR, i didn't notice any of them dribbling, though i was too much of a dumb @ss to think to try them out at key-on pressure while the rail was out of the intake manifold. any, ANY suggestions?

Interceptor
01-21-2007, 10:57 AM
OK, will start off by following up from my post yesterday. my car was severely bucking, running rough, hard to get over 40 mph. i found that the FPR was broken internally, and changed it out. slight improvement, but the problem still persists. i listen to each coilpack, and note that no 1 is clicking loudly enough to be mistaken for a tappet. i take out no 1, and note that the boot now has an almost 1 1/2 inch tear along the bottom. i replace it with a spare that i have on hand. my idle improves a decent bit. at this point, i say, f' it, and start pulling out coilpack connectors (the ones at the bottom, not the connector at the plug itself) and looking for which ones can be disconnected without changing the idle. i suspect that two are doing this, and swap out what few parts/boots i have...the idle is a little better, but one can still see a little bit of white in the exhaust.
by now, i've taken the cover off of the fuel injector connector "box" and started probing. all 6 injectors come back with running voltages of .26-.40, pulsing--as much as one can observe pulsing on a multimeter. the spec--by bentley is .3-1.0v, but i chock this up to my multimeter being $4 from harbor freight on sale. i check the ohmage of each injector, each comes back at precisely 16.8 ohms, within spec. i check the resistances of each of the coils, all within spec--.8ohms--by bentley. the CPS checks at about 596 ohms, within spec. the car "feels" like a classic, but very mild, disconnected plug wire, or mixed up plug wire misfire. admittedly, the car has been running a little rich for a while now, but it never did anything like produce smoke at acceleration. is it possible that leaking injectors could be doing this? when i took the rail out to get to the FPR, i didn't notice any of them dribbling, though i was too much of a dumb @ss to think to try them out at key-on pressure while the rail was out of the intake manifold. any, ANY suggestions?

Dribbling injectors might very well be the cause of it - epecially if you had problems with running rich lately, like you've said already.

Also, it's never a bad idea to check the spark plugs - they might have carbon deposits on them due to running rich for some time.

mitchc
01-21-2007, 11:10 AM
Ryan, not to suggest something real bad, but have you done a compression test? I see your mention of white smoke, which to me indicates leak in the head gasket (when I think of a motor running rich I think black smoke, and grey when the rings a fried) allowing water into one of the cylinders...

Best of luck

Mitch

ryan roopnarine
01-21-2007, 11:55 AM
Ryan, not to suggest something real bad, but have you done a compression test? I see your mention of white smoke, which to me indicates leak in the head gasket (when I think of a motor running rich I think black smoke, and grey when the rings a fried) allowing water into one of the cylinders...

Best of luck

Mitch

it hasn't lost any water compared to yesterday morning (i usually check these things on saturday morning), and the "smoke" smells of running rich, rather than percolator water, antifreeze, or burning oil. the oil is probably full of gasoline at this point, so i'm not too worried if it starts combusting oil temporarily.

ryan roopnarine
01-21-2007, 03:05 PM
update.
took the fuel rail out, and put a little bottle cap under each fuel injector. tried the key-on pressure. none leaked into the caps. though, i did observe some fuel drip off of injector 6 when i pulled it out of the intake manifold. i'm currently wrapping all 6 coils and their boots in strapping tape (to prevent any spark jump from tired coilpacks) and am going to swap out injectors 4 and 6, both of which i think are suspect.

Ferret
01-21-2007, 03:13 PM
If it's disappearing coolant suddenly and misfiring - pull spark plugs 2 and 3 and compare.

If three's covered in crap or different in a big way, there could be trouble ahead.

EDIT : Apologies I misread that and thought you'd said it /was/ disappearing coolant.

ryan roopnarine
01-21-2007, 03:18 PM
oh, forgot to mention.

plugs are less than 1000 miles/1600km old. i pulled them yesterday, they all look fine. also, looking down into the cylinders (with them out) none of the pistons looked steam cleaned. oil is fine, water is fine. its not white, more grey smoke, and it smoked this color the last time that the dme died and started dumping gas into cyls 1 and 6. it isn't coolant coming out of the tailpipe.

ryan roopnarine
01-21-2007, 04:38 PM
of the south, 'cause i'm the king of the south.
if you are ever in the metropolitan gainesville/ocala area, and need someone with a strong pimp hand, or someone to construct a brick $hiathouse for you, contact ryan's m50 emporium.

alls i had to do was fix it was:
change the fuel pressure regulator
wrap all 6 coils in strapping tape
spray brake parts cleaner inside/upside two spare fuel injectors laying around
replace fuel injectors with spares
spray brake parts cleaner (i was pissed off, and was out of contact cleaner) into the underhood dme plug next to the service plug
disconnect the dme
disconnect the battery

sigh:(

oh well, i didn't have to go to a mechanic, that's always good.
i think i might buy some new coils and pick up a fuel rail from somebody's salvage car, and have those injectors professionally cleaned, then swap them into my car.

i'm content--and i smell like gas-o-lin-a

ryan roopnarine
01-21-2007, 09:40 PM
57 miles and a bunch of WOTs later, and it looks like it is fixed, for now at least. perfesser roopnarine turned his head after pulling out #6 fuel injector,and a good couple of ounces of gasoline spilled right under the cabin air intake, i guess i'll need to pour a couple of glasses of water down there if i don't want my car to smell like a poorly maintained boat after turning the a/c on.:(

at any rate, i appreciate all of the people on this board who post comments saying "air, spark, and fuel" and leave people to figure things out themselves (as jerk-ish as they might intend it.). really helpful in fixing this problem in a couple of hours rather than borrowing somebody's car and stretching the repairs out over a week. i didn't waste time cleaning my throttle body or looking for intake leaks (admittedly i did spend a can of carb cleaner spraying over any gasketed joint or possible leak site, but once that was done with...) when my idle speed wasn't affected. i didn't spend all day playing with fuel injectors when the car was exhibiting classic ignition symptoms, and was able to quickly get to the root of the problem. this place has been really helpful for developing "mechanic's" intuition about things for me. i could tell by feel that 4 and 6 were acting up, but pulled the coils just to be sure. i certainly couldn't do that a couple of years ago.

BillionPa
01-21-2007, 10:21 PM
shorting coil packs can cause DME damage, so its best to catch it as soon as possible.