vt951

Hello, I think this is probably my first post... I just got an 86 951 with 106,000 miles in December, and have some questions about a few minor (I hope) problems it has. Yes, I did search extensively for answers!

First, it is running cold. It will warm up to the first line (about 1/3 from cold) after idling for 10 minutes or so. When I drive it on the highway (in cold weather), it is not able to stay warm, cools down to near the cold line. Driving in stop and go traffic, I've seen it get up close to the 2/3 mark. I suspected the thermostat was stuck open, so I replaced it today. Before I pulled it out, I noticed that it was loose, and the o-ring was missing. I guess it wasn't stuck open, but coolant was just flowing around it. Anyway, after replacing it with a 71C thermostat, I took it for a short drive today, and observed virtually identical behavior. Could it be the temp sensor? One thing that seems a little strange is that it will blow warm air in the cabing when the temp gauge shows cold. I don't think this could be related, but the front defogger does not seem to work.

Second, compression might be low. After I got the car, I took it straight to a private porsche mechanic for a full check out. He did a compression test and found all 4 at 120-125 psi. I know it was supposed to be 155 psi when new, and from my searches I read that many factor can affect compression test results. The mechanic said he thought it was fine, but I'm just looking for a second opinion.

Third, boost gauge shows 2 bar at full throttle. When I do get the car warmed up, I take advantage of it with some full throttle sprints, and have noticed that the boost gauge reads 2 bar. I've read that 1.72 bar or so is about the maximum I should expect. I'm wondering if the car might have a chip in it. Would that explain the high boost numbers, or is it more likely the inaccuracy of the sensor or gauge? Note that the ecu was recently replaced with a used one from Long Island, NY (a lot of modified 951's there right?)

Fourth, I've noticed the oil pressure usually is pegged at around 5 when I drive. If I let it idle for a while after driving, it will slowly go down to about 2.5 or 3. As soon as I start driving again, it will peg at 5. From what I've read, this is not normal oil pressure. Maybe the oil pressure sender is bad?

Now, the good news is that the car was given to me for free by the "seller." I was shopping for a while, and was very close to buying a non-turbo (due to lower maintenance cost). But I came across a turbo in my area listed on cars.com for $6200. I went to see it, and they told me up front they were having problems starting it and keeping it running. I checked out the service records, and the last 3 years had over $6000 in receipts for work done at the dealer, including belts at 100k. The dealer also threw all kinds of new parts into it when trying to troubleshoot the starting problem. I told them I wanted to get it checked out by a private mechanic, and mentioned that their price seemed fair even with the starting problem. When I called them back to make arrangements, they offered to give me the car! They didn't feel comfortable selling it to anyone with the problems it had. At first I said I couldn't accept it, and offered them some money. But they insisted that they had gotten what they wanted out of it, and hoped that it would go to someone who would get it running and have fun with it. I stopped arguing and accepted it. Had it towed to a mechanic, and he found that the ecu and knock sensor boxes were bad. Total cost to replace: $1100. So, I'm only about $1500 into this car all told so far (including towing and taking the previous owners out for a nice dinner). Pretty incredible, eh? Allright, now focus... I need some help here!

chris951

That's crazy!, If you have 110-115psi you have good compression for a car with over 100k miles on it, so don't be worried unless one cylinder is more than 5psi different. Having the oil pressure gauge pegged when it is cold is normal unless it does not fall when warm. Do you have any mods done to the car?

OriginalSterm

good deal!

the 2 bar you see on the boost gauge at full throttle may or may not be correct. some people have seen this gauge off by a few psi.

mods951

If u live in the northeast as i do. My car does the same thing with the tempature. As far as i know and according to my mechanic this is completely normal in winter driving. My water pump, thermostat, radiator and coolant were replaced within the past year or so. Also my temp sensor was checked recently so if i were i wouldnt be worried about it.

vt951

No mods that I know of. I am considering looking inside the ecu to see if it is chipped, though. Thanks for your help on the compression and oil pressure... sounds like I don't need to worry about it.

sweanders

Congratulations!

vt951

Do you drive it hard even though the temp gauge is showing cold? I'm just wondering if I need to continue taking it easy on the boost...

sweanders

Put a boost gauge in the car so that you can see if it boosts more than 1 Bar (14.6 psi). Check to see what kind fo chips are in the boxes.

mods951

I might get on it a little bit but nothing extreme. I dont get on it until I have been driving it for a good 15 minutes. All cars run cooler on the highway from my experience. In the summer on the highway it reaches 1/4 mark but thats just because of the tempature change.

schadenfreude

Yes, be careful with the boost - the highest the stock gauge reads is 2 bar absolute, so you might actually be running greater than 2 bar absolute...

Zero10

The stock gauge is pretty much worthless. Mine reads 2bar at ~8psi of boost. I have a seperate boost gauge that I used to verify this.
Install a seperate boost gauge so you know what your boost is really at.
As for the heating issue, a 71*C thermostat is far too low. IIRC the stock thermostats are ~80-85*C. This will help with how warm the car runs.

I bought my 951 in NYC, and drove it back to Calgary during January. I had 1800km of -35*C weather, all highway. The needle stayed exactly in the middle of the gauge, and the heat from the vents was so hot we were cooking sandwiches with it (no lie).

I wish I was lucky enough to get a 951 for free. I am in ~18k (US) on mine, and it's still far from done.

Jerad

Alan, glad to see you finally posted the story! Take it easy on the boost until the oil pressure drops to ~3 bar on idle. I know its tough sometimes, but take it easy until the engine warms up. Regarding the boost you're seeing, a chip alone will not increase the boost. There must be some kind of boost controller to increase the boost. The Autothority chip kit included a jetted banjo bolt that increased the boost as well as the Performance Products chips that were in my car when I bought it. I then switched over to Guru chips with the reliaboost and a stock banjo bolt. If you want, I have a new boost gauge (I think its Autometer) that I never installed. If you want I will sell it to you for $30 shipped, I think it was ~$50 new from SFR. I also have the Perm. Products chips I'll send those for free because I messed up the pins when I removed them. Some of the pins are bent but they are all there and you could probably straighten them out.

reno808

Hey if you need help with your 951 i can help you out no problem no charge lol. I only live 30 min away from NYC. Just pm with you number and i call you or somthing. And we can meet up or somthing. I do have LOTS of TOOLS...

EdC

Check your owners manual to see what those temp marks mean. It sounds like you are at normal operating temps.

vt951

Hey really appreciate the offer, but I live out in Indiana. Just bought the ecu from Long Island online. Would have liked to see that Shelby Mustang you have listed...