M90 low idle and sluggish

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mcibmw533
Posts: 14
Joined: Tue Jan 06, 2009 9:55 am
Location: Seattle, Washington

M90 low idle and sluggish

Post by mcibmw533 »

My m90 (can somebody tell me how to verify that it is infact a euro vs us 3.5?) doesn't want to idle. I have to keep the foot on the gas to keep the motor running and when driving, 1st gear feels like im driving in 3rd gear - totally lugging. When shifting I have to heal-toe just to keep the motor running.

When I bought the car (less than 3 months ago) it ran great but now I can't hardly get it to run. It does sit outside (= getting cold here in the NW) and the one time I had it sitting in the garage for about 6 hours, it was about 10 degress warmer than outside and started up and idled just fine. All of the injector plugs are loose and I found one to be disconnected. When I reconnected it was when it ran great, but apparently it didn't solve the issue. When I tried to drive to work this morning, when floored in 2nd gear it would radomly decide to run correctly & break the back tires loose (not fun on a wet, uphill road with oncoming traffic).

Any suggestions on what could be the issue?

Also, what is the best resource for early e24 discussion boards as that is supposedly what this motor came out of?

Thanks in advance,

Micah
T.Hanson
Posts: 1696
Joined: Wed Jul 26, 2006 7:39 am

Post by T.Hanson »

I have a euro 635 and have used the same adjust, tuning procedures as on the 2.8's.

You can Google search here or just go down old posts and find answers to any questions you have, rather than waiting for replies. Or, read the FAQ's.

Start with the basics: Check over all the brown wires (grounds), clean and tight. The big braided one from the negative battery terminal. Check all vacuum tubes, secure, no leaks. Dip stick in all the way.

Read the timing FAQ and do it, just as written. Not hard. After that, the throttle body FAQ.

Leaks, loose wires, dirty, crunchy, out of adjustment or old worn out parts. Your patience and motivation, or the shop's. Your's is cheaper.
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Mike W.
Posts: 2889
Joined: Wed Aug 30, 2006 12:12 am
Location: Sonoma County

Post by Mike W. »

Timing is what comes to mind first on being sluggish with a low idle.

As to what it originally came out of, what year is the block, what is the serial number, does it have the water jacket on the side of the block that looks like an E12 block or the later US B34 block and does it say 3.5 on the side of the block?
Mike W.



02 525ita. Wife's, aka grocery getter
02 530i. New to the fleet, 3 pedals.
03 QX4, AKA the Datsun. Finally got the 4WD vacationmoble to stop smoking.
07 Xterra. Still on the DL, a purchase from hell.
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