ETA stumbling hesitating not running right

[metalix1021]

^^ I told Tony to do this!

[MysterE30]

yes chris. yes you did. lol. and i also unplugged the O2 sensor and it ran better than ever. the best since ive had the car actually. im guessing the wire is the problem seeing as how it looks pretty melty. by the way chris, do you happen to have the wire that runs from the O2 sensor up to the engine bay?? lol. preferably one thats not muffed up?

anywho when i drove it after the unplugged O2 sensor, it ran great BUT it still feels like it should be giving more to it and it still backfires through the intake...any ideas? possibly the intake boot still? anyone wanna buy a half assed running e30?

[Camarok]

My post on bimmer forums
UPDATE 2

Alright, just to make sure the new o2 sensor was for sure working on this car, we unplugged it, sure enough, significatly better running, even a operating temp...

so I followed that intermediary cable that goes from the enginebay to the o2 sensor, looks like it's past experience was laying on the exhaust system about halfway down. melted and all sorts of goey fun.

so I'm off to search for that cable an see if it runs even better with an o2 signal.


I assume it should clean up a bit even more when it's getting an o2 signal from the sensor because it is still running open loop which could cause some of the misfiring... maybe. I say get the intermediary wire that runs between the o2 sensor and engine bay and see how it likes it. Should get even better still seeing at after 4000 rpm it cleans up almost perfectly because it goes into WOT mode without hesitation even before we pulled the o2 wire off.

Proper signal from this should help alot, then it's just chasing some small vacuum leaks and you should be good to go bro!

Get some plates on it and sell the train!

[Yogawrench]

The suggestion about getting a new intake is sound. My car ran like crap after warm-up and the intake boot looked shiny and new on top..... BUT, the underside of the intake boot had 2 1/4 slits from rubbing against all the crap underneath. Once I replaced it the car ran like a dream and the surging idle and misfiring were history.

[MysterE30]

yes indeed my intake boot is pretty janky. i'll have to score a new one with for sure no leaks and electrical tape. haha. that plus the cable to the O2 sensor should do the job.

[netcsk]

Did you actually check the cable for the O2 sensor? A multimeter will do the trick to check the resistance in the wire. The signal wire is the only one you are worried about (the one pin that is different on each end of the wire than the other two).

It ran better without the sensor plugged in because the engine runs slightly richer, meaning that you helped balance out some of that non-metered air first.

I'm telling you, focus on the obvious first. Your car will NEVER run right without the intake leaks fixed. If it still doesn't run perfectly after the intake leaks are fixed, then move on to the less likely things like some resistance in the O2 wire.

I promise, I'm speaking from experience (surging with an ETA, unplugging the O2 makes it not as noticeable -- still stumbles at the same spots but not as hard).

Just trying to save you $$ and time.

[Camarok]

Well we know the o2 cable is bad, I will still check, theres about a foot worth where all the shielding in the individual wires are all touching and the outter most jacket for the 3 wires have melted and sorta froze all 3 together.....

TONY BUY A NEW INTAKE BOOOOOT!!!!!!!!!!!!!

pelican please :)

[MysterE30]

buy it for me for my birfday ;)

also worked up the balls to take the ole girl on the road. took plates from another car and put them on the e30 with an unpaid parking ticket and a freshly expired license. lets hope i dont get pulled over! lol.

wow im retarded..

[Need4Speed1299]

It was fun though.

[Camarok]

Nick?

[Need4Speed1299]

Yup hi!

[Camarok]

Ok here's an update.... ignition parts new ( cap, rotor ) I want to say the the only thing left is vacuum.... NOW here's a shot in the dark.... would a bad EGR valve cause a proble like this? Is there even an EGR valve on these cars? Can't seem to see anything like it

[Restoman]

Ok here's an update.... ignition parts new ( cap, rotor ) I want to say the the only thing left is vacuum.... NOW here's a shot in the dark.... would a bad EGR valve cause a proble like this? Is there even an EGR valve on these cars? Can't seem to see anything like it

Really? Everyone on here has suggested you fix the obvious intake leaks. Fix this and you will run right. An intake boot is $5 new.

[Camarok]

The obvoius intake leaks have all been accounted for... SEEMS to be accounted for...

When the car gets to operating temprature, give it any gas and it just falls apart.... I will double and tripple check all hoses.... :(

[Camarok]

added to the "new" list, intake boot and hose that runs under the intake manifold from Valve cover to TB....

I was told coolant temp sensor could be a culprit... but which one?

http://www.realoem.com/bmw/showparts.do?model=1254&mospid=47308&btnr=11_0759&hg=11&fg=35

also, did some reading

from this thread

http://www.r3vlimited.com/board/showthread.php?t=156827

this post

http://www.r3vlimited.com/board/showpost.php?p=1791587&postcount=4

and this post

http://www.r3vlimited.com/board/showpost.php?p=1795011&postcount=8

relating to electrical issues... does it sound far fetched?