86 951 Driver

I just noticed that while driving my car is hovering almost right above the 12 not really in the middle its a little too close to the 12. What could be causing that? This could be the cause of my other problems as well.

pontifex4

Again, this is exactly like mine.

Cleaning all the grounds caused the volt gauge to jump to 13V for about an hour of running, but now I'm back down to between 12.5 and 12V. Almost all of my hesitation has cleared up since doing the grounds, though.

I wish I had the solution: today, I thoroughly cleaned the other bell housing ground stud / connections and there wasn't much change to the voltage reading on the dash. I'm starting to suspect the alternator (which, on mine could either be slipping or overheating since I'm running it without the shroud on my AC delete bracket).

86 951 Driver

UPDATE:
I just had a VW mechanic help me out and he started to look at it. We saw that at one point the fuel pressure was around 2 bar while idling. Then after I blipped the throttle a few times the pressure shot up to over 100 PSI. He told me to shut it down. Does this sound like FPR now?

He took out the Recirc valve and blew into and it had no resistance either way. He said he saw that all the time on the 1.8 Turbo's. Most people just replace them with a blow off valve. He said thats why its not running that well. Replace this or get a blow off valve I guess?



Now we also found was a vacuum line blown off one of the sensors under the intake manifold. (Picture 2) Look at pictures.

Tom M'Guinn

You don't want to use a true blow off valve. Once the air has been measured by the air flow meter, it needs to stay in the system or else you will throw off the air-fuel ratio and have a grumpy motor.

The hose missing on the second picture is part of the evap recovery system. Good for the planet to fix it. If the hose if unplugged, a wee bit of extra unfiltered, unmetered air will get in, but not really enough to notice.

You might keep looking for a mechanic more familiar with these cars.

86 951 Driver

So would the diverter valve when its bad cause a huge vacuum leak. I would like to know as I need to get this fixed asap. Also what about the FPR 100 psi is too much pressure at the rail correct?

User 41221

pm sent on KCWS. Sorry I am late to the party.

Paulyy

i know these hold up to 100 psi, but it shouldnt be that much for stock psi.
atleast the FPR works.

when he took the by pass valve out, was the vacuum hose dissconected and the engine off, or he blew in it while the engine was running with the vaccum dissconected. not saying your mechanic is an idiot but theres some out there.

& if it had no restriction, you car wouldnt boost past 1-2 psi

86 951 Driver

BTW the mechanic isn't someone who claimed to know anything about Porsche he was trying to help me out with checking the fuel pressure.

I'm pretty sure the FPR is bad and this is why. With the pressure gauge hooked up the car at idle would be at like say 30-32 psi. I revved it up a little bit and let the car warm up and then the fuel pressure pegged the gauge at 100 psi and it stayed there until we shut the car off and release the pressure in the rail.

The fuel pump is noisy as well after the car has been driven for a while.

User 41221

All the things you are listing are consistent with having a bad FPR (Bosch part # 0 280 160 277). I can get you a new one through Banger and have it to you by Thursday if you want. I'll call you tomorrow.

Common list of FPR problems (borrowed from Clarks):
Engine runs rough
Engine stumbles or sputters
Engine runs very rich - black smoke from the exhaust
Engine will not start
Engine starts but stalls shortly after startup
Noisy fuel pump
Noticeable decrease in fuel mileage

DivineE

This is the Forge 007p in black, an excellent replacement which looks standard and I've used it on an audi S3 running 1.85bar (for 2 weeks until the gearbox failed). It's a far better replacement than the usual 993 turbo item with the metal internals and is cheap to buy/comes with interchangeable springs for different boost levels. I highly recommend it.

86 951 Driver

Sounds good. I am looking for something that will help my car out. I thought it was the FPR, but wanted to make sure. I bought a set of wires that I most likely didn't need. Wanted to keep me buying random parts to a minimum.

86 951 Driver

That looks like something I saw on ebay for really cheap. Has anyone used the Ebay ones?

User 41221

FWIW, you likely won't regret the plug wire purchase.

86 951 Driver

I will take the FPR. I would be willing to pick it up if you are in KC.

User 41221

I've got the order in and it will be here tomorrow. Once I have it in hand, I'll give you a call and we'll arrange how we will get it to you.

Price is $69.35 total, btw, for the OEM Bosch part# 0 280 160 277 .