Idle Problem

[91325IX]

'91 325IX Won't idle. Changed the O2 sensor and catalytic converter, no help. Went to check the on-board computer for a fault code ,can't get code ck to respond! Fuel mileage really fell off, and problem has gotten progressively worse. Any ideas?

[yob]

could be the idle control valve

[91325IX]

I believe it was replaced already. I bought the car and I think it has had this problem for some time now, because a lot of parts were changed. The Mercedes dealer just didn't tell me about it. Go figure. I just changed the valve cover gasket -vacuum! Nope, no change. Still can't get the engine check lite to give me a code. Any way of checking the Idle control valve for function?Thanks

[75stoneman]

This applies to BMW E30 3 series. Disconnect the idle control valve electrical plug. There should be 3 spade terminals in the connector on the valve. Set a multimeter for measuring ohms. Connect the multimeter to the two outer terminals. It should read around 40 Ohms of resistance. Then, check the center terminal to each of the two outer terminals. It should read around 20 Ohms between them. If you dont get close to these values, the valve is bad. Stay cool. 75

[91325IX]

Thanks, Got 38 overall and 19.8 and 18.3. Is that close enough? Seems pretty even but not sure how sensitive it is? Starting to sound like it's the DME. Can't get it to give any codes either. Sounds like you may have the same issue.

[91325IX]

Thanks, Got 38 overall and 19.8 and 18.3. Is that close enough? Seems pretty even but not sure how sensitive it is? Starting to sound like it's the DME. Can't get it to give any codes either. Sounds like you may have the same issue. 91IX

[75stoneman]

Your idle control valve should be just fine with those readings. Yeah, I have an idle control prob too, but mine is intermittent. The car runs fine for a while, then craps out. I'm also looking at vacum leaks. Check the lines going to the fuel pressure reg. If they look at all shabby or brittle, bulk vacum line at the local auto parts store is cheap. Another thing to look at is the boot that connects the intake to the intake tube out of the air box. Physically remove it from the car and work it around, making sure there are no cracks. On my car, it never throws any codes or a check engine light. Anyhow, Im going to do some more work on my car tomorrow, Ill let you know how it goes.75

[91325IX]

Mine started the same way and became more frequent and longer lasting. Going to pull the DME and plug in one that is known to be goog abd see what happens. From what I'm reading it is a common way for them to die. Check your valve cover , make sure its snug.

[regis101]

There seems to be alot of idle problems. This is the most common problem I read about. My german mechanic says that the motronic ECU's have problems with idle. Our 89 325is showed hard starts progressing to no start even though no codes come up with the stomp test or with the diagnostic port hooked up. All sensors are reading well within spec. Blah, blah, blah. had two rebuilt ECU's sent in with no luck. each made the car worse in other areas. So... I'm gonna bite the bullet for a NEW one from the stealership. Dunno what else to do. Mine uses a 380. don't want to regress by using a 173 or even a 153. Afraid to try a 526 or 527 because i dunno what that'll do.
IIRC, some earlier Motronic set-ups had a separate ingition module from the ECU. they had their own problems. Then Bosch incorporates the ignition program into the ECU with the 1.3's and there are still problems. I have gone through all the required sensor testing along with shop quality testing equipment and the only thing left is the ECU. Couple more days and we'll see. I'll try to let yins know the outcome. If this thing fires up and purrs with the new ECU, I'll shiat.

[jamesthevaliant]

I went through the same crazy idle mission with my 325is... I ended up changing the valve gasket, adjusted valves, plugs, wires, cap and rotor, a new ECU, a new airmass meter... had the mechanic clean my intake manifold, replaced all the vacuum hoses, fuel filter, new O2 sensor, new coolant temp sensor..... etc. etc..... everything that I could think of that would be causing the bad idle, to no avail. While each repair seemed to make it run better, it still idled poorly. Finally, I replaced the fuel injectors with new Bosch replacements I got on Ebay for $150 (not so hard to replace, by the way) and the car idled like a dream. By the way, I had no fault codes for the injectors, but after I replaced them, it was like night and day.

[jase007]

Search is your friend ....

E30 1990 325iX vacuum solutions

I think I mention Intake Manifold gaskets but if not .... they are another culprit.

No idle issues for 218,xxx mile .... on second ICV.

Jase

[91325IX]

Just replaced the ECU with only a slight help in the idle. Got a fault code now 1444 which means there is no faults! HA! I tink I got more than one problem. Will check the injectors next and let you know. 91325ix.

[akgustin]

I have the same problem with my 89 325i. Have checked for vacuum leak. Replaced injectors, fuel filter, fuel pressure regulator, plugs, wires only have 30k miles, cleaned ICV with carb cleaner, adjusted the throttle position switch, etc.

Nothing seems to phase it. It will barely idle. Step on the gas and will sputter and belch black smoke. Plugs get covered with black soot.

going to try the test on the DME connector specified in Bently, but am losing hope.

Maybe replace the DME.

[jase007]

AK:

Check this thread on PP E30 Board.

Have you done all of these vacuum checks?

Jase

[akgustin]

Not all of them. I will try some of the things on there next.

will post results after I try the suggestions on these other posts.

Thanks.

Ok, Jan 2008.

Came back to update this message.

I finally took it to Bemers in Houston in 2006 and found that the pulse wheel had been damaged in a wreck and it's two parts had slightly separated. I had tapped it back together after the wreck, but I suppose it had more damage than I thought. Jose put one on from another car, and presto.

1 week later a drunk driver took out the whole front end again and it is now my parts car for it's successor.

[91325IX]

I checked for vac leaks using starter fluid and it really idled smoothly and sounded great. I sprayed around all of the hoses and lines and intale manifold. Only improvement was when I sprayed it under the center of the intake menifold! Not around the gaskets? After taking the intake manifold off I found out where the leak was. Are you ready for this? It was the O-Rings on the Breather tube from the Case to the intake manofold. Trouble is you can't see it with the air intake system on. AH HA! After all the reading and checking I have not come across this. Heck I could only find the O-Rongs at the stealership. Could not even find a picture of them. So check these out because they are so well hidden. I may get this running yet , then watch out!

[Driver Ed]

I'm not sure where you mean these o-rings are located. The breather hose on my 86 325 seems to be just a simple hose with hose clamps on both ends. Can you post a picture?

[akgustin]

On the 89 325i, the breather tube is a straight metal pipe running from under the intake manifold down to the engine block right above the oil pan. It has o-rings on each end. It has a spring coiled around the outside maintaining pressure on the o-rings but allows for slight movement between the two masses. It allows excess oil from the cam shaft and rockers to drain back down to the pan.

[Driver Ed]

I understand now. It sounds like what I'd refer to as an oil return tube.

[jase007]

Here is a pic for clarification:



In the pic I have new o-rings and a zip-tie compressing the lower spring prior to IM install. Once the IM is installed, cut the zip-tie and the spring expands. Makes like much easier.

Jase