5speed300

OK guys, big update...well I think.

So my dad and I were fooling around with some of the lines, tightening them down and what not. We started the car and had it idling, pulled the line from the ISV to the J-boot, car died. Put it back on and started up the car, pulled the intercooler hose banjo bolt line and nothing happened. Then pulled the line from the intake banjo bolt to the KLR, nothing happened.

Then we pulled the vac. line to the FPR while the car was running. Nothing happened...I thought that was kind of strange. So we put the line back in and tapped on the FPR with a wrench a little bit, not hard, but a little tapping. The car sputtered and died, while the vac. line was plugged in mind you, so just tapping the FPR caused It would not fire up after that either.

So the FPR is toast. everything is connected up just as before, but now the car wont start because the FPR is dead.

My question is, could a dying FPR cause the rough running problems I was describing? Could the culprit have been the FPR going out and not a vacuum leak afterall?

I was about 10 minutes away from pulling the whole manifold off before this happened, so I'm hoping this is the overall issue and putting in a new FPR will fix everything.

5speed300

Installed the new FPR and the car now starts up fine, but the damn thing still is running rough.

There is a loud hissing noise coming from the area between the 1 and 2 intake runners, but I'm not sure if thats normal or not.

I think its about time to just pull the manifold again, check every hose, clamp it all down tight and hope for the best.

PorscheDoc

Good call. Also, check the nipples on the intakes between the runners (Where the ISV hose attaches, and the brake booster attaches). They can come loose from the intake, and cause a vacuum leak.

5speed300

Alright, got the intake off in like 35 minutes...getting pretty good wiht it by now haha.

Here are some pictures. I tried to get pictures of anything I think would have a remote chance of being an issue so by all means if you see something that looks fishy please point it out.

Let me know what you guys think

Also before I forget, is there any special way to connect the intake manifold banjo bolt? I just tightened it down snug, but if the hole in the bolt itself is not lined up with the fitting hole will there be an issue?

Ski

man you need a new sensor in the back. Is your oxygen sensor un hooked, round female plug at the back?

5speed300

I thought that was the O2 sensor connector, but when I pulled the manifold the first time I found it unhooked so I didn't mess with it. Damn this car has really been screwed with by the PO. I'm surprised the car ran correctly with the 02 sensor unhooked. Ill definitly make sure to plug it back together.

That other sensor with just the 3 wires you can see, basically disintegrated when I touched it. I am going to rewrap it thoroughly with electrical tape until I can get a new sensor.

PorscheDoc

That broken reference sensor plug probably isn't doing you any good for engine running.

Also, plug the holes on your AFM and turbo boots as well, things like to fall in holes when you aren't looking

5speed300

Well, I tightened everything down twice, put electrical tape on any exposed wires I saw, installed the manifold and... the car is worse than before. I have no idea what the problem is but I am just so fed up with it right now.

Its time to take the damn thing to someone who knows what to look for. Anyone of a good 951 shop around Raleigh, NC? I dont wanna take it to the dealer because they are going to want to take the boost controller and other stuff out.

just so sick of it

Luis de Prat

Are you still getting the hissing sound from underneath the manifold?

5speed300

Yep. I cant tell if its a normal noise or not because I never really got down and listened to the motor when it was running correctly.

Could a failing fuel dampener cause this issue?

I plugged the cycling valve back in instead of the MBC and the car ran the same way, so I know at least the mbc is not my problem.

Luis de Prat

If you're hearing a constant hissing sound, I think your Idle Stabilizer Valve may be leaking. Have you ever replaced it?

hosrom_951

If i were you. i would disconnect and remove all the hoses there.

Clean up that area very nicely, replace the hose for th top of the AOS with a new clamp (as well as everything else).

Then, using the diagram, hook up each vacuum line/hose one at a time.

I would then use some zip tie's to secure the vacuum lines to the thermovalve, FPR, Damper, etc.....

5speed300

Nope never replaced it, but I did take it out and clean it out real thoroughly with some carb cleaner as I've heard those are commonly a source of leakage.

Thats what I did before I reinstalled the manifold, I even took every hose out and ran air through them to check for leaks. I cut a new 90degree elbow for the AOS and used a new clamp on it. I've gone over the vacuum diagrams 100 times and tried hooking the lines up a few different ways, nothing seems to help.

How do you adjust timing on these cars? It really seems like the timing is wayyyy off or something. I just dont know anymore tahts why I'm taking it to a shop. I know I'm gonna pay out the nose for it but I need my daily driver back.

Ski

1. A decent shop should be able to do the vac lines or double check yours in less than 5 minutes.
2. If you do take it to a shop, get them to test the TPS and your AFM. If it is your AFM, many here will have one lying around, probably for shipping only or very cheap.
3. Timing is done on given maps in the computer so you can't adjust it (in stock configurations - disclaimer), however, it is possible that your timing belt could be off a tooth, maybe two.

Search "setting or finding TDC", and you'll find the how to and how to check. check out
www.clarks-garage.com - keep that site on your favorites.

The LEAST amount of splices you have, the better off you are - go for none. That reference sensor needs replacing.

Do you know if the car is on stock or aftermarket chips? How many miles on the car?

Luis de Prat

Well, if you say you've replaced all the vacuum lines the hissing you're describing sounds a lot like the attached pic.

I have a similar situation with no visible leaks other than the ISV itself so now I'm trying to see if can find the part number for it from Renault. You see, Bosch makes the same idle control valve (Bosch PN 0.280.140.501) for the Renault 19, 21, Clio and other models and here in Spain I can get it from Renault in a day instead of waiting for a special order from the Porsche dealer at a significant premium to boot.