I've had my 951 3 months and 1000 miles (maybe).

If I crank up the boost much above .8 bar, I get a sound that I initially diagnosed as pinging/knocking. I have never experienced it before (never had forced induction before), and don't know anyone that has experienced it before. I'm just a long time auto enthusiast that has read alot. I've been led to believe by rennlisters that it is indeed pinging/knocking according to my description of the sound - full boost, hard acceleration, sound appears to come from wastegate location. Imagine taking a can, and placing 10-15 tiny ball bearings in it, and shaking it frantically. If I could isolate ONE sound, I would say it almost sounds like a spark. Except there are 50 sparks, and they have no rhythm. Really hard to describe - hope I make sense.

I had also thought I had a possible exhaust leak around the wastegate, except I checked the exhaust - it all looks really good and tight. Next I checked for an intake leak - I tightened all hoses, and was unable to detect a leak by ear. The only hissing I hear is from the intercooler which I would think is normal. I checked all my vacuum hoses and connections - there was actually one cut in half. I replaced it thinking I had found my problem - nope!

So next I changed my fuel filter. Again, no difference. I wanted to get in touch with Huntley to buy an AFPR with a fuel pressure gauge to mount to my fuel rail since they are the only ones I have seen that have the small VDO gauges for sale. I wanted to check my fuel pressure, and if necessary, crank it up a bit with the AFPR. Huntley apparently doesn't care about my business so I guess I'll be looking elsewhere.

I get horrible mileage ~15mpg, so I may have a bad O2 sensor too, although usually a bad O2 sensor will make a car run rich if I am not mistaken, explaining the bad mileage.

Next on the to do list is to pull the injectors and get them cleaned and flow tested. I assume anyone local will work just fine for that.

I also thought that maybe the stock BOV is bad, although visually it looks ok, and appears to hold pressure. I thought that might cause an intake leak, in turn causing pinging, so I was probably going to order a forge BOV - maybe today or tomorrow. I figure even if it doesn't fix the problem, it will be a worthwhile investment, and I can always sell it on ebay for probably 70% of what I paid when I get a MAF and hard pipes (somewhere down the road once I get everything else fixed). Down the road I was thinking of buying the SFR level 3. And then the Kokeln turbo. <a href="http://www.speedforceracing.com/massflow.html" target="_blank">http://www.speedforceracing.com/massflow.html</a>

Right now I'm pretty frustrated since I'm feeling I made a mistake buying a porsche. If it wasn't for the price, I would have bought a 95 supra TT. I could afford it, but I really like payments in the $200 range rather than the $400 range.

That's pretty much my story - I don't think I've left anything out.

Right now I just want to get my car running properly...

Any and all advice you have is much appreciated.
I don't really have any questions but I welcome any input.

I really want to love my car like some of you do, but it's frustrating!

MJ <img src="graemlins/soapbox.gif" border="0" alt="[soapbox]" />

 

Alright, I have kinda of felt that my car pings sometimes, it is hard to describe. Danno suggested on another post that when I get a 3" exhaust I may want to try a 3 bar 944S2 FPR, like 40 bucks from paragon he said, call them, not on the website. That is cheaper than AFPR. Intake leaks would really only help you b/c at boost the positive pressure would let you run more rich as you lost air. Forge BOV's are dope, but I don't think intake leaks could cause pings, esp. b/c the leak in the bov or intercooler piping would be downstream of the AFM and you would be losing already metered air and have excess fuel.

An O2 sensor would maybe help the mileage, get the universal part from napa that was recently discussed on the board.

I would run some techron fuel injector cleaner and then maybe try some higher octane gas, either a few gallons of 110 mixed in or a can of octane booster. note that some of those products are listed as not safe for catalysts and o2 sensors, read the box to find a safe one. flow testing the injector could also help/save this step.

I took my car to let my mechanic check out the sound last year after a new turbo (old one was shot), we drove around for awhile and he thought it could be the cv's clicking when the car squatted on boost. They were kinda shot anyway, so we replaced the axles, but the sound was still there!!

When I ran the octane boost it seemed to help some, but the most help came from me driving differently.

I have APEII chips and the lbe and nology wires, those are the only mods to the engine. I can get the car to full boost at only part throttle, I noticed that this was when most of the pinging started. I could also associate this "noise" with a goodly cloud of blackness behind the car, more so than just the car running rich I think.

Anyway, my solution was to make sure that as the boost was rising and I wanted to hit 15#'s, I FLOORED the pedal, all the way. That way I know I am putting in as much fuel as I need and can give it for the max boost. I have seldom heard the pings since I started doing this. I also get around 23 mpg.

Also, could the TPS in your car lead to the car not knowing the throttle was fully opened and thus leaning the mix? I hope some others will comment based on my story/solution.....?!?!

BTW, do you hang with the florida crown pca guys, they are all really nice, I hope to do their DE in sept. at Roebling, they have a fun time down there.

Jason

 

Thanks for your input Jason. I just ordered my BOV, so we'll see how that goes. Tonight I'm going to pull the injectors, and tomorrow I will drop them off at a local place to be cleaned and tested. I've never been a believer in additives to fix a problem, although I may try some toluene (sp?) to increase the octane. The last octane booster I tried was supposed to make it 107, but it didn't help any. I have since heard that they are all worthless. I suppose the TPS could be a factor, but I heard they are kind of expensive to just "try", unless you (or anyone else knows of a way to test a TPS).

As far as the florida crown pca guys, what's a DE, where's Roebling, and how can I get in touch with them?

Thanks again.

MJ

 

There is a test procedure for the TPS, probably search the archives, I know the haynes manual has one. Although if the tps were bad the car may have some other drivability problems, like on adrial's bucking thread. I will probably go with a 3 bar FPR that I mentioned when I replaced my fuel lines later this summer, kinda getting paranoid of flames. Can anyone else comment?!?! Let us know what the injectors say.

Roebling Road Raceway is a 2 mile 9 turn road course near savannah, ga. the fl crown pca guys check<a href="http://www.pcafcr.org" target="_blank"> here</a> often have Driver educations there (DE). drive your car on a track kind of thing. If you join pca, and you should (as well as rennlist), this would be your home region where you could attend the meetings and events, etc. I live in Charleston, so Roebling is my home track it's safe and fun, with good runoff.

Jason

 

Cool!! Where do I sign up!!??

 

<a href="http://www.pca.org" target="_blank">www.pca.org</a> they have a join page or something

join rennlist here:
<a href="https://rennlist.com/members.htm" target="_blank">https://rennlist.com/members.htm</a>

Most DE's are a very good value for the amount of track time and instruction you get as you come up through the ranks. If anything people can run cars on the track instead of the street where average driving IQ is much lower.

Jason

 

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