E36 Horrible Idle and Bad Hesitation

[E36Ray]

Hey guys this is where I have resorted to after trying multiple fixes on this troublesome angel. The Car is a 1992 E36 325iS. On cold Start up car idles somewhat slightly higher than it should. As it begins to warm up it bounces up and down from about 500-1300 RPMs. Once warm its constantly bounces idle from 500-1500 RPMS and in some cases has jumped from 1500 straight down to 0 ( Stall ). When moving off from a stop when cold car moves somewhat normal but when I'm taking off from a stop when car is warm I have a horrible hesitation / surge like a loss of power then its just jerks until i reach a certain speed or it takes off as if I popped the clutch. It gives symptoms as if i'm learning to drive manual ex: bucking / jerking / hesistation / surging. It is absolutely horrible on gas I get about 10 MPGS not even exaggerating. Sometimes on really cold days the car doesnt want to even go over a certain speed or it will do something like as if it begins misfiring when I get to certain speeds.
What I've tried.
Disconnected MAF still idles horrible but I dont get the misfiring as bad at certain speeds but its still there.
Removed and Cleaned Idle Air Control Valve ( ICV ) and problem still remains.

Whatever input you guys have will help significantly and I can already feel my rear bushings going bad from all the stress being put on them daily as the car is always basically jerking and launching itself.

[E36Ray]

Bump

[E36Ray]

Sos

[MIKYZZ4]

Check for intake leaks. Inspect the rubber intake boots and all hoses and intake connections for cracks.
A smoke test can more easily confirm and locate the presence of intake leaks.
Check fuel pressure at fuel rail with fuel pressure gauge if you have one available.

[E36Ray]

check for intake leaks. Inspect the rubber intake boots and all hoses and intake connections for cracks.
A smoke test can more easily confirm and locate the presence of intake leaks.
Check fuel pressure at fuel rail with fuel pressure gauge if you have one available.

will do

[Eric93se]

Vacuum leaks
Check/replace spark plugs. If you find oil on them then the valve cover gasket needs replacing.
Run a bottle of CRC 1 tank cleaner to help clean the injectors.
Replace your oxygen senor.

[flyfishvt]

Do you have a CEL? That bouncing idle and rough running is symptoms of a bad o2 sensor.

[E36Ray]

I do have a CEL . Got the Code pulled only MAF came up ???

[MIKYZZ4]

Post up the actual code #'s, not just your interpretation of them.
It is very common to show fault codes for MAF and oxygen sensors, when you have a scan performed at an AutoZone with a generic scan tool.
Once all intake leaks have been resolved, Only then can we turn our attention to other possible causes, such as defective components or sensors.

[Andrewk79]

Create your own smoke test kit and do a smoke test on your intake. Youtube has some videos on said kit and it will only cost you $10-15 and is not bulky to store. I found leaks in places I never expected, and now do a smoke test once a year as part of my annual diy checks on the car.

Second, use the carb cleaner test. Google and youtube for that. Identify vacuum leaks.

Fix all vacuum leaks once identified. Sometimes they can be securely patched, other times you'll have to replace the piece entirely.

If the rough and hunting idle persists, you'll have to do the disconnect test on your drivability sensors to identify the bad sensor that's causing this issue. That is if the stomp test is not helpful here.

- - - Updated - - -

Run a bottle of CRC 1 tank cleaner to help clean the injectors.

Nothing can clean your injectors on the car through the gas tank. Most fuel injector cleaners are glorified octane boosters...the engine feels peppier for awhile and you think something must have happened.

Injectors don't get dirty - they get microdirt dirt trapped in them (usually because the fuel filter was not changed for too long), and that can't be dissolved away by anything that wouldn't harm the plastic, metal and hoses found in the fuel system. After all, the particles are not dissolving in fuel despite exposure at high pressure and heat.

The injector will have to be removed, backflushed, ultrasonically massaged, etc, to fix that. Even then it might not work, and there might be issues with the microsolenoid in each injector. Cheaper and smarter to just buy a good used one ($5-$8) or a good used remanned one ($10-$15, and comes with a warranty) with new O rings and call it a day.

[E36Ray]

Create your own smoke test kit and do a smoke test on your intake. Youtube has some videos on said kit and it will only cost you $10-15 and is not bulky to store. I found leaks in places I never expected, and now do a smoke test once a year as part of my annual diy checks on the car.

Second, use the carb cleaner test. Google and youtube for that. Identify vacuum leaks.

Fix all vacuum leaks once identified. Sometimes they can be securely patched, other times you'll have to replace the piece entirely.

If the rough and hunting idle persists, you'll have to do the disconnect test on your drivability sensors to identify the bad sensor that's causing this issue. That is if the stomp test is not helpful here.

- - - Updated - - -



Nothing can clean your injectors on the car through the gas tank. Most fuel injector cleaners are glorified octane boosters...the engine feels peppier for awhile and you think something must have happened.

Injectors don't get dirty - they get microdirt dirt trapped in them (usually because the fuel filter was not changed for too long), and that can't be dissolved away by anything that wouldn't harm the plastic, metal and hoses found in the fuel system. After all, the particles are not dissolving in fuel despite exposure at high pressure and heat.

The injector will have to be removed, backflushed, ultrasonically massaged, etc, to fix that. Even then it might not work, and there might be issues with the microsolenoid in each injector. Cheaper and smarter to just buy a good used one ($5-$8) or a good used remanned one ($10-$15, and comes with a warranty) with new O rings and call it a day.

Thanks i will look into the diy smoke test kit

[FiberFast]

Vacuum leak, icv, fuel pumps, fuel regulator, crank/cam sensor, dme. In order of most likely culprits. You most likely have a vacuum leak or a fucked off icv.

[Franky goes]

What was the issue in the end ?
Thanks