autocomman

Well I did have another thread but it was very old and messy so Im starting a new one.

86' 951, stock..clean 90k miles and not abused. Got the usual limp mode .2bar boost. here is what ive done

Pinched the wastegate hose, it will make plenty of boost with no problem.
Replaced the CV with a new one, same result.
Ohmed out the knock sensor at the KLR 300k ohms, same reading at the knock sensor, so the wiring is very doubtful as a problem.
No blink codes. If i yank the TPS, i get blink codes.
The vacuum/pressure signal at the KLR is good

Now where do I go next, some people say KLR, but i dont want to go through the trouble if finding a KLR and paying for one without knowing that will fix it. Some people have said inj/knock harness, but the knock ohms out, yes it could have an intermittent open, but i should get a fault though ya?

What i am going to do is jump the klr pins 9 and 16 and drive the car, basically as if it had no knock and see if it runs the same, if it does i guess i have a bad knock sensor, even though its within spec. and as i write this im not convincing myself.

And I need to check to see if the CV clicks when the AFM opens over 65% engine running. Im pretty sure i checked that in teh past and it does click. If it does click, then WTF? Then it gonna be a bad KLR. if it doesnt....then ill go further in the elec system

Im in socal, ill be wiling to drive a little if there is someone whos got a klr I can try. A $250 shot in the dark isnt an option, and the car is staying stock, so an MBC isnt an option. I know there are guys in socal who can help me out here, pleeeeeese

Mark

autocomman

Another update.....The CV will cycle if you rev the motor. Still only .2 bar, also i noticed while down at the KLR, 3 wires have been rubbed through in the KLR harness. Pins 3 green, 18 white, and 20 brown, have grounded at some point. Looking at the diagram, 3 goes to the LED pin in the test socket, pin 18 goes to B in the test socket and the DME, this is for idle setting. I dont think thats an issue as this is normally grounded for the base idle and CO adjustment. and it may explain the occasional idle inconsistency. And pin 20 is ground anyway, so that doesn't matter. I popped open the KLR and looked carefullt at the upper board, unclipped it and there were small bits of corrosion at the very edge where it slips into the plastic connector....but it dosnt look like there are any traces of water or anything that may have gone farther down the board, and i didnt remove the lower board, but it all seems to look ok inside. Im woried that if the LED wire was grounded for a long period of time it may have done something to the KLR.

Whats really weird is the KLR will cycle the CV and it still wont make boost, and if i pinch the waste gate hose it will boost, so the KLR is prolly bad. Now ive got to try and find one to try before buying it

Mark

JohnKoaWood

Sounds to me like a vacuum line problem... as if the CV is opening the WG to atmosphere...

Have you tried to pull vacuum on the line to the J Boot...

If it is good to the J boot, try pulling vacuum through the CV to teh J Boot and the WG (by tripping the CV)...

Just a thought... my thinking is if the CV is tripping with throttle, the KLR is doing its job...

autocomman

Ya know I thought that, but it looks as thought everything is connected properly. Ive followed all the lines. The center goes to the pressure side..the banjo bolt fitting in the intercooler pipe. The right one goes to the j-boot and the left one to the waste gate, just like the vacuum diagrams says. And ive got to be getting pressure there somehow cause the WG opens like it should, at .2 bar. The CV vents pressure to atmosphere to keep the gate closed or to close it down. Unless the vent line to the j-boot is plugged, then it wont be able to vent the pressure keeping pressure at the wastegate....and keeping it open, dropping the boost. But im damn sure Ive checked that to make sure its open...ill check again tomarrow, ill disconnect the vent side of the CV, the right side to the j-boot. if it starts to boost the vent is plugged and ive got to see where. I was thinkin about that eariler....ill repost with an update.

Does anyone know if the duty cycle of the CV is fixed? or is it variable?

Mark

autocomman

Well, i pulled off the vent line from the CV back to the j-boot....drove it to the valley, 12 miles on the freeway....it suprisingly hit .4 bar boost but it was slightly unsteady...I let the car sit for about 30 minutes and drove back....no boost, like maybe .1bar boost. I also noticed the last few days of driving it there was a rattle at the same point in boost .1ish bar, RPM and vehicle speed did not matter, only load....prolly the waste gate falling apart....cause that is im sure what it was.

So hopefully this week ill have some time to yank it to find prolly a broken spring or somthing

Mark

autocomman

FIXED!! Took the wastegate out and apart completly....no problems there. I drove it another few miles wastegate hose unhooked...got my foot in it a few times, carefully as not to overboost, to my suprise....boost wasnt imeadiate...slowly it would creep up, slowly, very slowly holding it at WOT nonetheless. If I had a boost leak, id hear it and it would idle off to have that much of a leak....

I did a few WOT passes to see how it reacted. Got home and went WTF, its got to be clogged exhaust, thats all thats left....but what, cat plugged? the car has never been abused...its an 86 yes but i unno....i got out engien running to put my hand behind the muffler and to my suprise I see this...



It was 6' of fiberglass hair coming outa the muffler. This is balled up of course. And as my hand was itchy a minute later, it was definatly fiberglass! This is crappy cause that muffler is only 4 or 5 years old and it was an ansa direct replacement.

SO went to the muffler shop and had a magnaflow straight through oval put on. Still nice and quiet and its the stock size (still grandmas car) and bam! The car now runs as it should. Hard accereation is smooth and firm yet again.

Mark

Tom M'Guinn

That's exactly what I was going to guess -- fiberglass hairball in exhaust....

Glad you found it !!!

JohnKoaWood

made me laugh...