Author Topic: [SOLVED] running rich & mind of it's own.. (Read 4376 times)

E36-italia · « **on:** February 08, 2012, 04:32:16 PM »

since a few months my '93 coupe is having some wierd issues.
It started with bogging down in about 1 min. after startup, not enough to stall but surely enough to come to a near halt.. giving a little more gas made it worse, until you'd hit full throttle and it was ran fine-ish.
First check was removing the vacuum hose to the fuel pressure regulater, it looked like it solved it, I replaced it with a new one.. it ran fine for a few days... and cleaned the ICV.

the week after that it started again, I swapped out the AFM - no change.
Then I jacked up the car, unplugged the lambda and the connector was full of fluid.. cleaned it - no change.
changed the Lambda - no change.

2 weeks ago I swapped out the injectors for a known rail (from my italian car, what was working fine)
it was joy for about 130km... then the shitty running came back.
But now it only starts to run bad after � 20km drive...

Tonight I went to my girlfriend's place.. that same �20km from my house/drive... And at the trafficlights i noticed a 1200rpm idle.
While driving home, startup fine.. but nearing the 20km mark and it started to do something new.. while coasting down the exit from a highway..around 80km/h and with the throttle closed it felt like it was accellerating with little blips, like a very gentle breeze on the accel-pedal, not enough to make the car go, but the engine makes a few rpm more.
at the end of the exit, high idle.. few km later for a round about back into running overly rich idle, nearly stalling.

So far I have replaced with no change:
AFM
Lambda/O2
injectors

With today's new symtomes i will replace the TPS.. Or what else could cause these problems?

Geoff · « **Reply #1 on:** February 08, 2012, 06:24:25 PM »

how do you determine its an overly rich idle? symptoms sound like a possible vacuum leak, which might cause a lean condition with some of the same symtoms you mention. just a thought..
Geoff

gearheadE30 · « **Reply #2 on:** February 08, 2012, 07:23:27 PM »

Check your coolant sensors. If they are bad, then the car will think the engine is too cold and run a higher idle, retarded ignition timing, and will run richer.

E36-italia · « **Reply #3 on:** February 11, 2012, 12:30:16 PM »

Quote from: Geoff;110115

how do you determine its an overly rich idle? symptoms sound like a possible vacuum leak, which might cause a lean condition with some of the same symtoms you mention. just a thought..
Geoff

The lambda was covered in black soot.
And with a vacuum leak it should also run bad at high rpm... which it didn't.

I checked the tempsensor and i found a loose connector, re-attached it and went for a drive.. it seems to be running fine now.
That leaves me with a t-stat to replace, it's getting sticky...but that I do when the temps go over into positive numbers... even she ran a bit weird for the last few weeks, at least she started at -20!! (can't say that from my girlfiends volkswagen polo '05

)

So for now she seems to be fixxed, so herewith a thanks to gearheadE30.

DesktopDave · « **Reply #4 on:** February 11, 2012, 03:07:30 PM »

I hope it stays fixed. Definitely sounded like a closed loop problem...both wide-open throttle and cold starting run open loop...basically only the temp sensors and the AFM are monitored. Once the car heats up, all the rest of the sensors come into play.

E36-italia · « **Reply #5 on:** February 18, 2012, 07:15:23 AM »

hmmz... it started to act up again.. but removing and re-connecting the temp switch made it run fine again.. pressumably for another 150km... that about the range i get before it starts to act up everytime.

Is there a way to test the temp sensor (without the need to remove it) .. or is it something else? -fault codes in the DME?
I tried the stomp test.. but I don't seem to be able to get it switched on.. and on start-up/turning key to start I see no CEL in the dashboard lights...

E36-italia · « **Reply #6 on:** May 01, 2012, 04:51:32 PM »

replacing the exhaust manifold + removing the 'racecar' lambda, refitting the daily lambda seems to have cured the drowning in fuel problem.
plus it runs a lot quieter now

(racecar must make noise.. right at the limit xD )

I've also refitted the original AFM.. now it pulls again.. yey!
Is there a difference between a '93 and a '94 AFM? (with a 94 AFM it didn't pull that strong)