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2000 rpm idle!! (repost on correct forum)

pietrzj

Well-known member
Joined
19 Mar 2014
Messages
309
Hi, I have been driving and maintaining this car for 5yrs and today I got a new problem.
Started her up after a few days sitting in its normal location. Outside temperature about 10 degrees as per the last few days. However...

Really rough fire up then settled at around 2000 rpm. I got out, checked the throttle hadn't stuck, poked around at a few vacuum hoses but no change. Dabbed the throttle (at pedal and inlet) - it revved but settled back at 2000 rpm. Throttle was against the idle stop at the inlet.
Switched her off. Started again and it was fine. Drove to work ok.

Started it lunch time, same problem, so off and on and again "fixed". Started after lunch - no problem - so it's not happening every time.

Started at end of work, same problem, but I ignored it and it settled to normal after a couple hundred yards of driving.

Any ideas?

I can't see the ISV having such a dramatic affect and I clean it regularly.

I can't see it being a vacuum pipe, as it wouldn't resolve itself in that way.

Is it a switch somewhere or something to do with the choke?

I will take a look at the ISV tonight, but I am not hopeful.

It's not a turbo and there is no cruise control. It's pre-

I hope there are some good ideas out there.

Jan
 
ISV would have been my guess. :dont know:

Good luck.
 
Hi

My money on ISV also. I would clean the connector, or at the very least reseat a few times having had a good look at the pins.

Another possibility is the MAF. I used to have an Alfa that would exhibit this behaviour, and it was the MAF (check connector also). MAF's can be cleaned by the way).

Best of luck

Berni
 
My vote is also isv perhaps it's beyond redemption. Worth checking crap around the throttle pedal hinge, "Oh that's where that mint went"
 
Thanks guys. I will check the ISV out even though I cleaned it last year.

I was just surprised tht it could have such a dramatic effect - I thought it was a minor balance of gases. However there are lots of threads that explain how it works and it could well be that.
 
Well, I took the ISV off. I was not excessively sooty but with the tip of my finger I could tell it was a. It stiff, so it could have been jamming.

Soaked it for about 2 minutes in white spirits, but lifting it out there was no indication that was dissolving the soot, so I dried it off and used aerosol brake cleaner.

That worked a treat and I also threaded a rag through and with a wire hook covered with a rag delicately scraped in the cylinder recesses top and bottom, through both ends.

Pleased with result I dried it out and re-fitted.

Tried starting a few times and no racing idle. Fixed!

I had cleaned it last 15 months ago, but as the ISV is on the clean side of the filter and it was still sooty, I will probably ditch the K&N filter and go back to paper filters.

I tested the resistance of the coils while the ISV was off:
Pin 1-2 was 10.4 ohms
Pin 2-3 was 11.7 ohms
So no open circuit, which was good.
Pin 1-3 was 22 ohms (pretty obvious really)

So fingers crossed.

Time: less than 10min to remove and replace.
 
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These are before it was cleaned.
 

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Unfortunately, for my ISV, cleaning it out only kept it going for a few months.


Managed to get one eBay cheaply, combined with a 20% off deal for £116.

Still the same Bosch part number but a very slightly different design. Old one on the left.
 

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