engine idle issue

[6670charger]

I just changed my timing belt last week in my E30 325i, and the car has been running great until a few minutes ago when I arrived at work.  Turned the corner to enter my workplace, and the car stalled the moment I took my foot off the gas.  Every time I start it, it revs fine, but dies as soon as I take my foot off the gas.  It was running like a top all the way in, and has been for the past week since I changed the belt, so I don't think it has anything to do with the belt or timing. 

 

I will check shortly to see if it starts and runs in neutral to verify that the torque converter isn't stuck.  If not, what else should I be checking other than the fuel filter?

[Earl]

TPS?

[B C]

TPS?

 

 

yes.

 

http://www.wibimmers.com/board/index.php?/topic/2018-m20-tps-20/

 

 

and vac leaks (check intake boot for tears) also check that the idle control valve is working 

[6670charger]

Do you still have your TPS for sale Snap?  

 

Checked the car for start in neutral, and same thing, so it isn't the torque converter.  Basically won't run unless I have my foot planted on the gas constantly.  Will check the intake boot.  Found an article from Pelican on how to test the ICV and which vacuum hoses to test or replace.  

 

Just hope I can limp her home from DePere to Appleton tomorrow morning.

[Jeff]

Look into the iacv pull it off make sure it is clean. Usually when you have to hold the gas for the car to start it is the iacv or big vac leak

[B C]

yes I do have it still.

 

if you want to test your TPS , check continuity between two of the pins on the sensor (engine does not need to be on) and check for continuity with the throttle closed, it has been a while since I have messed around with them but I believe 2 and 18 have continuity at fully closed throttle  and pins 18 and 3 have continuity at fully open throttle. 

 

There is no need to remove the intake boot if you can manipulate the test leads like chopsticks and have good dexterity, but removing the intake boot is probably a good idea if its your first time so that you can see what you are working with. 

 

Make sure you test the switch multiple times. The last tps I had had continuity 6 out of 10 times I tested it.  There is also a tiny bit of adjustability in the TPS so if the continuity test fails you may need to remove the throttle body, loosen the mounting screws, and adjust the TPS so it makes contact.

[KaiserRolls]

yes I do have it still.

 

if you want to test your TPS , check continuity between two of the pins on the sensor (engine does not need to be on) and check for continuity with the throttle closed, it has been a while since I have messed around with them but I believe 2 and 18 have continuity at fully closed throttle  and pins 18 and 3 have continuity at fully open throttle. 

 

There is no need  remove the intake boot if you can manipulate the test leads like chopsticks and have good dexterity, but removing the intake boot is probably a good idea if its your first time so that you can see what you are working with. 

 

Make sure you test the switch multiple times. The last tps I had had continuity 6 out of 10 times I tested it.  There is also a tiny bit of adjustability in the TPS so if the continuity test fails you may need to remove the throttle body, loosen the mounting screws, and adjust the TPS so it makes contact.

 

[6670charger]

OK.  I'll have to look around for the thing tomorrow after I get up and see what I can find out.  Seems odd that I'd have a sudden huge vacuum leak, unless some hose somewhere suddenly ruptured in a big way.  Will also check the IACV.  

 

Read an article on IACV cleaning.  May sound like a stupid question, but, are throttle body cleaner and carb cleaner basically the same thing?   Sounds like they're pretty similar other than that carb cleaner may be a little more potent.

[B C]

[6670charger]

I take it that they're not the same?  I should be using TB cleaner?

[B C]

My understanding is that TB Cleaner is not harsh on Teflon bushings or coated surfaces (anti-icing for throttle shafts) and carb cleaner is. I would probably use  Carb cleaner on it in a pinch. 

[Brian.]

Carb cleaner isn't as harsh as everyone thinks. That shit evaporates so damn fast

[B C]

makes it hard to huff

[KaiserRolls]

That shit evaporates so damn fast

 

so does acetone. and it makes a spectacular fire starter 

[6670charger]

Well, get this; After work I go out to start the car. Starts a little hard and runs a little rough for a few seconds, but then, straightens right out and ran fine all the way home.  Ran like normal yesterday too.  We'll see how she runs today.  Normal idle, and no problems with anything whatsoever.

 

I think I can rule out vacuum leaks and probably a clogged IACV.  Briefly considered that something might have briefly clogged the fuel filter, but, I doubt it would have started at all then.  Still wondering about the TPS, though.  Might be that it's working OK for now, but, could fail again at some point?

[Jeff]

Does your oil smell like gas?

[mkoepp]

An ICV can act up and still work fine. I would clean in as a preventative measure if anything. My M20 did the same thing. 

 

Good luck

[6670charger]

Sounds like a plan.  

 

No, my oil does not smell like gas.