Author Topic: Maybe an easy fix... (Read 2990 times)

nigel · « **on:** March 09, 2009, 02:26:09 PM »

I just got my engine put together after buying it in pieces. It fires up and will keep going if I tap the throttle, but dies at idle...
While I was putting it back together I did the hose delete thing, so maybe it's a vacuum problem?

xwill112x · « **Reply #1 on:** March 09, 2009, 04:10:54 PM »

sounds like a vaccum leak to me.

vonkamp · « **Reply #2 on:** March 09, 2009, 05:43:27 PM »

check to make sure your intake manifold nuts/bolts are tight.

nigel · « **Reply #3 on:** March 10, 2009, 11:15:53 AM »

thanks for the suggestions, guys... I've been toying with it...
can't find any vacuum leaks, but there are 2 nuts missing from the intake array (others are tight). I cranked up the idle speed to see if it might keep idleing at a higher rpm, but it just bounced back and forth between a high idle and almost stalling...
also, the PO installed a new fuel pump, but it hasn't run since that was done, so maybe that's an issue, too?

B318M42W · « **Reply #4 on:** March 10, 2009, 06:50:02 PM »

did you check the "mess under the intake thread"

might give you ideas

good luck!

nigel · « **Reply #5 on:** March 11, 2009, 08:09:12 AM »

Yeah, I've already done the hose delete thing and have been quadruple checking the diagrams to make sure I didn't forget anything... as far as I can tell, everything is kosher.
I was thinking it might be the ICV... just a guess, really. Is there any way that would get dirty/clogged/inoperable?

doitover · « **Reply #6 on:** March 11, 2009, 08:41:42 AM »

Yes it can. If I remember correctly it should have 500 ohms between the pins. It can also just get dirty. You can clean it with throttle body cleaner. That's the short answer, there are threads here with better detail.

Also, did you say that you have a couple of missing bolts on the intake manifold? You would definitely want to fix that.

In my humble opinion, you really want the correct range torque wrench to work on this engine. It's is remarkably easy to strip threads.

Quote from: nigel;68091

Yeah, I've already done the hose delete thing and have been quadruple checking the diagrams to make sure I didn't forget anything... as far as I can tell, everything is kosher.
I was thinking it might be the ICV... just a guess, really. Is there any way that would get dirty/clogged/inoperable?

nigel · « **Reply #7 on:** March 11, 2009, 09:56:34 AM »

I have about 8 ohms there... and it's rusty inside.
Are these valves a fairly universal design? could I grab one from any car at a junk yard? sure, the connections would be different, but it still performs the same function, right?

doitover · « **Reply #8 on:** March 11, 2009, 11:20:52 AM »

http://www.m42club.com/forums/showthread.php?p=61770

You might want to read through some of the other threads before tossing it. This one suggests putting 12 volts across the ICV to see if it opens cleanly.

I'm not sure how much faith I'd put in my memory of 500 ohms being correct but 8 does seem to be pretty low for something driven directly by the Motronic.

I think there are two different types of ICVs electricly. The real trick is finding one that is physically compatible. Many are bolted directly to the throttle body and don't have hose fittings.

nigel · « **Reply #9 on:** March 11, 2009, 02:49:44 PM »

Ok, so it was an easy fix after all...
the ICV was fine (hooked it up to 12v and it did what it does).
I replaced the missing nut on the throttle body and it idles now. not perfect, and it still stalls if I let it drop from a higher RPM, so I figure there's some other little leak somewhere. Definetly makin progress, though. thanks guys!