Shop Bmw Mirrors

hi i am hoping someone can help me. i have a 98 chevy malibu 3.1l with 168000 miles. the problem is it idles very rough. i replaced the lower intake gasket because of the coolant leak, did a tune up(fuel filter, plugs, wires, pcv valve, air filter, oil change every 3000 miles, and all other maintenance. i sprayed carb cleaner around the intake but didnt find any leaks. what else should i check.thanks for your help.

thanks i will try those suggestions. yes i have a autel scanner and it is able to show live data. i was told by a more experienced tech (bmw foreman) that it could be the mounts. i think its rough in neutral and park. but its really bad in gear. i could see the mirrors shaking. also i did have an issue with the egr valve. can it be cleaned.

well i spoke to two different techs. one tech used the TECH 2 scanner and we saw that the egr valve was open a bit at idle. so we tried to free it up by using the scanner to open and close the valve. also i sprayed carb cleaner in it and let it sit to loosen the carbon. (is that a good way to clean it?) then the bmw tech did not look at the car. i spoke to him and he said it could be a mount since it was happening when it is in gear. i dont feel anything in park but im not too sure if it is rough in park also. but in drive its kinda bad. i feel it in the seat and steering wheel and i also see the side mirrors shaking.

Hello I have had this problem for four years. The car is a 1986 bmw 325es with a 2.7L engine. The problem I have is a constant misfire or appears to be a misfire at 2800-3200 hot or cold but once I pass those rpms if I open it wot it bogs terribly but if I feather the throttle I can rev to 5k and it pulls like it should but it wont allow me to go wot. Also I watched the exhaust one night in the side rear view mirror and when it misfired I seen it in the exhaust stream. It was cold out so I could see the moisture coming out of the exhaust but right when the car misfires it had no moisture in a few strokes what i would be assuming an injector not firing or no spark. Now the list the stuff I have changed or swapped with a known normal running car.
ecu-swapped no change
afm-swapped no change
tps-swapped no change
new fuel filter-no change
car has two fuel pumps a pre pump and a high pressure pump
pulled screen from tank-full of rust, so I cleaned that but fuel filter I could not blow through, so injector screens might have rust <---have to test
new spark plugs-no change old ones were all normal color no rich or lean indications or burning oil
plug wires swapped-no change
new cap-no change
swapped rotor-no change
swapped coil-no change
new fpr-no change
new o2-no change
added another ground wire to engine-no change
checked injector pulses and they are firing at those rpms
also I had the exhaust off at the manifold down pipes and it still misfired, popping noise was present from the exhaust, which Im thinking a valve burnt
also did vacuum test and its saying that its not a clog exhaust theres more to the vacuum gauge things too which indicate rings leaking but im not sure if having the exhaust off after the cat is messing with my readings
new timing belt and water pump but is irrelevant, it had the problem prior to these parts
I did compression test and fuel test Ill post that soon but Ill see what you guys think at this point maybe im missing something. also I got a ecu temp sensor but didnt get around to put it in cause its cold out and it requires me to undo stuff I put together already. Only things i didnt get around to do is the injectors,intake gasket but did have the vacuum gauge hook up and indicated that there is no leak but if it is it might be small. thoughts and opinions are appreciated cause I giving up on it, I dont want to keep throwing money at something thats not doing anything. ask away, also I got two repair manuals on this car and no luck with them.

I have question about your fuel pressures.. You stated fuel pump 92 psi.. Is that what its rated at or is that fuel pressure reading?? Only asking since you have below,, KOEO pressure at 36 psi,, KOER at 28 psi and below specs by ten psi.. Where did you get the 92 psi reading from?? Also I would check injectors for blockage if you had rust or other contaminants in your fuel system..And make sure the connectors are are properly connected..I would also check voltage at pump to make sure you have proper voltage throughout driving speed..
Also does this engine have a timing belt or timing chain.. Either could be strecthed and cause a slight misfire..

With All that you have checked and or replaced,, i would say to check the injectors for any blockage and also ohm them to be sure they ohm correctly....It could be that since there is alot of contamination in your fuel system...Cant recall right now but did you check fuel pressure regulator... If not Check that.. Also is the fuel pump in or out of tank...If its in tank,, have you ever dropped tank and looked at it to make sure you have proper line and electrial connections...

From the description you gave, it sounds like the throttle has to be in the same place every time the problem happens. You may want to take a closer look at the throttle position sensor. If it has a dead spot, it will cut fuel when the wiper goes over the dead part of the coil in the sensor. You can check this with an ohmmeter between the input and signal terminals. Work the sensor by hand slowly as you watch the resistance change. It should be a smooth change with no sharp drop outs.
The ohmmeter will work for this, but, a trace scope is the best method if you can get your hands on one. You will be testing voltage over time if you use this method, much more accurate.

Steve

Yeah I change the entire throttle body that has the tps attached, also I verified it is getting power 5volts. Also these tps arent potentiometer styled, they have a two switch style kind. At idle it switches to idle mode and the idle control module starts to work which it starts working my idle control valve and then at wot it ignores the o2 sensor. and I checked the tps like it says in my one manual and at idle posistion your suppose to get continuity and at wot its suppose to get continuity at 8-12 degrees before wot and it does. Yeah its a mind boggler I cant seem to figure it out.

alright heres the compression numbers spec is (142-156)psi
cylinder dry wet
#1 165 psi 174 psi
#2 155 psi 180 psi
#3 145 psi 160 psi
#4 140 psi 159 psi
#5 164 psi 179 psi
#6 180 psi 190 psi

Im gonna say that number 6 seems like it has some carbon build up

I did the seafoam in the intake a while ago. And now recently I put 10oz in approx five gallons of fuel and still nothing also put 4oz in the crankcase that seem to free up the motor but didnt effect the misfire or bog. I was thinking of running more but if 10oz didnt do much, im not sure if I need more. I havent heard of deep creep yet, Ill look it up. thanks tom for your advice.

when it bogs down does it make any difference or do you notice any
difference whether you have a half tank or full tank fuel?

I havent lately put a full tank in but when I put 3/4 in the one time I did notice it relieved my hesitation from a standstill to wot throttle. also this bog is only in the upper rpm range after I pass 3200, i forgot to mention that, also all the effects of the misfire and bog are in every gear also its an automatic but I dont think its the tranny what so ever. I got to find my fuel pressure specs when I find them Ill post them aswell.