RajDatta

I removed the ISV and tried jumping #1 and #3 pins and it made a slight sound for split second and that was it. Is this how an ISV is supposed to react? I srayed some WD40 in the meantime in case its jammed. Will do some research on how to test it next.

RajDatta

Update:
Did some reading and found pin#2 is the hot pin on the ISV and you can ground either #1 or #3 since the dme cycles between them. Tested the ISV while out of the car. Made a small sound with each side jumped.

Put everything back together and started the car. It started by hunting again, smoothed out for about 30 secs and then all of a sudden, it started hunting again, crap!

As per a few listers recommendation, I capped off the throttlebody hardpipe connector to ISV and the intake port to the ISV. Started the car, idle is solid!! YES!!!!!!

So, its either the ISV or the circuit. The harness has less than 500 miles, since I purchased a brand new 968 turbo S harness from Porsche Motorsports. The cables are all soft so I doubt it is the harness. Ironically, the harness came with 2 connectors that have the same 3 pin setup and they are both the same length and can fit on the ISV, thanks Porsche Motorsports!!

I have been using the gray connector, the other connector is black. Next logical step would be to check the connectors to see which of the 2 gets juice when the car is idling. This should atleast narrow it down to which connector to use. All my previous pictures show the gray connector, which is why I reused it.

Could it be the DME? Highly unlikely, since I did not have this problem prior to engine removal. I did remove the ISV and its connectors and it sat around for a while. I have heard of it gunking over time, so who knows.

In either case, atleast I know where to focus now. Thank you all for support and suggestions. I will keep this thread updated as I determine the cause of the problem.

More to follow..

Scott H

Cover one port of the ICV with your hand, blow into the other inlet with your mouth. Does air leak out? If so, you can fix the leaks with some strategically applied JB Weld.

RajDatta

Scott, I can see through from one port of the ISV to the other. There are spaces where I could see through. Is the valve supposed to be shut closed when not in action?

Ski

How will the car idle if you just remove it, the ISV? sorry, been out of the game for a while, I know we covered this before. This is what I will do, cover the ports when I get home to check mine as well. Thanks for the update.

adrial

The car will idle just fine without the ISV ... you will loose the high rpm cold idle and the idle will be very very low with the A/C on. You may need to reset the idle screw if you delete the ISV.

As I recall, the idle stabilizer is half open when unpowered.

Again, from memory ... if you have the key in the run position (engine off), you should be able to feel some small vibrations when you put your hand on the idle stabilizer. Easy test to determine if it is powered.

RajDatta

Thanks Adrial. Only issue is, what if the unit is bad and is not responsive to power? I would not feel any vibration in that case. I rechecked my old pics and I do have the correct ISV connector on.

I will remove the ISV, but based on what you are saying, that is the correct position it was in. In the meantime a friend is sending a good unit over to test with.

Regards,

RajDatta

Update: 3/22/2013

Finally had a chance to put in the spare ISV. The car started out with the same symptoms but eventually smoothed out. Same thing happens everytime I blip the throttle. Idle fluctuates and then smoothes out. So, things did get better with a different ISV.

Now I am scratching my head. Is is ISV and something else...

The honking sound I mentioned sounds like something trying to suck very strongly, like a vacuum and then eventually the sound goes away. Not sure how much time I will have to troubleshoot between now and sunday. Need to bleed brakes and clutch to finally take the car for a drive.

Will keep everyone posted on how things progress.

RajDatta

Finally had a chance to take the car out for a spin. Car is running good, boost is coming on better than before but I am keeping the revs low for now.

Interestingly, the guage in the cluster shows no difference to boost whatsoever, totally dead! Wondering if the intake manifold port is blocked somehow and not giving any reading to the klr.

Very odd that there is boost but no display. More to follow...

Laust Pedersen

Ed, thanks for drawing attention to this.

I have had the exact same cold idle hunting/fluctuations/oscillations for a very long time and when stabbing the throttle (hot or cold) the OE boost gauge oscillates as if there is an attenuation resistor missing in the KLR. When hot the idle is stable, but sometimes creeps up to 1100 rpm.

Maybe it is time to try my spare KLR and look for flaky solder joints on the installed one.

Laust

Crazy Eddie

Hi Laust
I have to admit it was one of the most frustrating issues to deal with on this car.
It took over 10 months to finally figure out what might/was be causing it ...
Truly, "A needle in a haystack" ...
And I must add, thank God for Tom ...
Who not only supplied me with a known working KLR, but then fixed the broken one with the flaking solder joints ... (that alone, saved me 300- 400 dollars, as I didn't have to send it to the ECU doctor for repair)
It would be a smart idea to swap out your KLR with a know working one and see what happens ... Best of luck
Regards
Ed

RajDatta

Ed, I must say it is definitely worth a try. Especially seeing that my boost guage is showing no output, even when I turn the ignition on, has me thinking the KLR might be toast.

Any volunteers with a good KLR they can lend?? Ofcourse, I would be happy to pay for shipping.

Regards.

Tom M'Guinn

10 months! That's libelous! It would have been 10 hours except (a) you took half a year off to reseal the oil pan, and (b) we had to negotiate for days about the quality of the microfiber lining to use on the tools needed to test stuff. (It was a sneaky one though, made very difficult to track because it was intermittent. Key was figuring out when the problem was happening even when the idle wasn't bouncing around via the wideband).

Crazy Eddie

Commoonnn ...
I changed out 1/2 the parts in the car looking for that damn surging ...
OK.... so maybe I took a detour here and a detour there ...
Yes, there was a interesting telltale sign .. After the car had warmed up, the idle fluctuating would stop, but the AFR would have to watched carefully, as when the KLR contacts were not making the correct connections, it would run rich, according the the wide band read out ...
It would go down to like 13.5 etc...

Ski

Well I tried a few things yesterday, no go, so I put the car up until I get home. It has been a PITA since I bought it back!! I'll sort it out but @#%$&*! Chased a miss for months, then found the boost line to the KLR almost off, got it running good and all I did was change plugs the other day and now this $hit.

I did manage to get the track car motor on the stand, head off, bell housing/clutch/flywheel off, drained the oil pan again, remove the crossover and start to pull the pan and oil pump, get the rods disconnected and pull the girdle. Then get all the new parts organized and old parts/bags organized; have to leave for a meeting in Houston and then out to work for two weeks but then three weeks off.