Slow Carrera - what's wrong
 

I have an 81 Euro SC, and my father has an 88 Targa Carrera. I spend quite a bit of time in my SC which has no AC, no Sunroof, aftermarket seats and a few other weight savings. My fathers Carrera has all of the standard US comforts like AC, power seats... While driving his car the other day in 93 degree temps, I noticed that it is VERY sluggish. I know that the Carrera has a higher power band, and is quite a bit heavier, but I didn't think that this should have made it feel as sluggish as it was. My SC snaps your head back from a stoplight, while the carrera feels just SLOW. I think that there is something wrong with it. Where do I start? I did notice that the oil temp gague made it to about 2/3 of the way up the gague which seems pretty hot. On a similar day, my SC gague (Euro brass tube oil cooler) doesn't make it even to 1/3 of the way up. I would think timing was off, but it cannot be adjusted in the Carreras. Both cars are bone stock, and I would expect performance to be about equal with the two. The Carrera has had a valve adjustment w/i the last 6000, oil change, new plug wires ($$$ ouch), plugs, dizzy cap and rotor. What do you think the problem could be?

Hang on a minute, your SC oil temp doesn't make it to the first mark, (1/3 of the way up, 90deg.C/194deg.F), on a 93deg. day?? There is something wrong w/ your guage or sending unit. I have the same cooler, it is THE BEST, but still the guage could make it to half way up, (~220F), on a 93deg. day. Before, with trombone cooler, it would have been ~30deg. hotter. http://www.pelicanparts.com/support/...amingdevil.gif

As for the Carrera, you need to diagnose it systematically. On this board, there is a popular game known as, "pin the tail on the Carrera/SC/turbo/etc.", which consists of everyone guessing what might not be right w/ your car. Sometimes this is based on real experience, which may or may not be your answer, sometimes it is just bored people on a Sat. afternoon. I will throw the first dart and guess that you have a bad cylinder head temp sensor(?), a common bugaboo on Carreras that will cause the motor to run rich, (I think), all the time and perform like a pig.

I do not mean to discount the help available here, it is phenomenal, but ALL good mechanics diagnose things systematically, (go down the list, eliminating everything less expensive), even if they "think that they know what's wrong". Unless something is really obvious, like a banana in your tailpipe or wheels missing, it is just a guess. Have it checked out or do it yourself, but go down the whole list under the hood, ie. ignition issues, fuel issues, etc. by the book. You have a book, right? :)

Thanks for the info, very helpfull. First, I already suspected the head temp senson, and have already purchased one but have not replaced it yet. I suspected it because the car runs very rich at startup but runs ok when warm. I didn't know that could make the car run poorly when warm also though. I am on my way to the garage to replace that immediately and see what happens.

My SC never makes it quite to half way. I was a little optimistic when I said 1/3 of the way up. On a very hot day, it will make it almost half way, but never above that. on a cool day, never above 1/3 of the wya. I really need to backdate that gague and sender to have the real numbers on there. the sc temp gague is just terrible. there are only two marks on it and it is very vague.

As far as books, I have the bentley, and a haynes (worthless). Thanks for the help.

My 77 911S (2.7) seems to hover between 80 and 90 (C) under normal driving conditions [ 100C is the halfway mark], and on a really hot day with 2-3 hours of driving, around 100 to a max of about 103-105C [212-220 F].

As for the Carrera... it should be at least as fast, if not faster than your SC.

-MAS

Casey, It sounds like your dad's car is running hot, also, and this of course can be caused by the fuel mixture being off in either direction , I just learned this recently from Tyson S. I always knew that a lean mixture or retarded timing= run hot, but rich on our cars will cause the unburned fuel to combust in the exhaust or cat and make for quite a furnace under the heads. Not good, to say the least.

As for your SC, now it sounds just like mine, temp-wise. That cooler is THE BEST factory cooler ever, particularly in slow traffic, (doesn't rely on air movement as much as radiator style). Not sure that I agree about the guage, though, it is actually very accurate and calibrated, you just can't see the #s. Middle of first slash is exactly 90deg.C,(194F), second slash(white stripe) is exactly 120degC,(250F), and beginning of red is 150C, or 300deg.F. OUCH, OUCH! http://www.pelicanparts.com/support/smileys/devil.gif

9 o'clock on our guage would be 220-225deg.F, which is a perfectly acceptable oil temp on a 911, a little less is great as well, of course. Good luck! :cool:

There may be nothing wrong with the Carrera. If your SC has a 7:31 ring and pinion, it will waaaaay out-torque a later Carrera. The Carrera has taller gearing which, unfortunately makes it feel quite sluggish by comparison, especially pulling away from a light. I believe they went to the taller final ratio to meet EPA requirements. Our tax dollars hard at work!

The good news is that his Carrera should pull like a banchee above 4000 rpm.

Well, I think that is what I am experiencing. I replaced the head temp sensor, and no difference, except for better start up. I think it is just the difference that I am not used to. It is amazing to me how much of a personallity difference there is between two cars. His car does pull like crazy above 4000. It's almost like turning on a switch. On the highway, there is nothing like it.

What about the oil temp. Is it normal for a Carrera to be in the upper 2/3 area of hte gague? I didn't get near the red area, but it was above the upper white line. Could this be a sign that the vavles are out of adjustment? I adjusted the vavles about 500 miles ago, and they had been done about 6000 miles before that at a shop. This was my fist attempt at adjusting valves on a 911 so I will be the first to admit that I could have done it wrong. I do konw the proper feel though having done it on VW engines.

I'm not so sure anything is wrong with the Carrera. Your SC is lighter and not that much less powerful. The 88 Targa's G0 is also geared lower than your SC. My '88 Targa has lost every stoplight grand prix run against my neighbor's '83 SC, and it's not real close, either. But on the freeway, I can walk away from him.

You may want to feel the front oil lines to make sure that oil is getting to the cooler. If the engine is hot, but the lines are not, you could have a bad thermostat. On hot days at the track my temp will run in the same area. There is an oil cooler fan that should come on around the temp you are describing. Does it ever go higher? Might want to make sure his fan is working.

Nope, a 3.2 shouldn't run that hot. Mine seems to run between 200 and 225. If you get stuck in traffic and sit and idle for a long time the temp will hit the second mark, but that should be the only time (assuming you aren't on the track)

Speaking from my own experience with oil temps....Even in the most demanding LA stop and go traffic, my 3.2 barely got close to the 3/4 line once on the oil temp guage. Most often its dead in the middle or just a hair above.

Poor low end performance and higher than usual engine temps is what I have experienced with an air flow meter that was adjusted too rich which seems to be a common problem with the 3.2's.

Best to deal with it as soon as possible since rich running Carreras have been implicated to have caused premature valve guide wear according to BA.

Cheers,

Joe Garcia
86 Carrera

How do you test the AFM to see if it's bad?

Have the CO checked before the cat.

Joe

Bad news: Your Carrera definately seems to be running way hot

Good news: Low compression Carrera's are all sluggish. So there is probably nothing wrong with it aside from being too hot.

Slow Carrera? What's wrong? Nothing, that's just the way they are. Muwahahahahahaha ;)

Casey,

The 3.2 in my 77 has the numbered gauge and on a 90 degree day on a spirited drive it will see 215-230 max. Also it has no external fender cooler, lines or thermostat so your running hottter than normal. I did the blower motor control fix so I can use that for a little extra engine cooling. Try running and feeling the lines like suggested above and keep us posted.

Not mine, at least, until I got my air flow meter set right!

I dialed in so much low end torque that taking off in second or even third gear is no problem...and that's without smoking my clutch.

I couldn't do that with my 79 SC.

That explains why some 3.2s are blazing fast while others are just plain slugs off the line.

Cheers,

Joe Garcia
86 Carrera
Redwood PCA since 1976

That Carerra is running hot. Mine will just barely get above the second white line, not even close to half way. Hard to say if that is the reason it is running sluggish, or just another symptom of what is really wrong. Somethings up though, be happy to compare side by side with mine. Available all day today.

Mine was very sluggish until I put a test pipe on( I'm still testing)
and changed the stock chip for an authority model for the 3.2.
Does your dad run premium or regular?

Keith- 87 slant nose cabriolet wide body carrera.

I can easily start mine in second without smoking the clutch.

Low Compression??

Well, after driving around this morning with the new head temp sensor the car is deffinately driving better. I didn't get as hot as it did the other day, but I was not sitting in any traffic. I am going to inspect the oil cooler next then check for dirt on the cylinder heads to see if that could be causing the problem. I will have to have the AFM checked next. Unfortunately this will all have to wait until next week since I'm out of town. Thanks a lot for all of the input. I will post with what I find as soon as i figure it out.

Hi Masraum, over here, all 3.2's from (and including) '86 onwards have low compression. Only the '84-'85 models have 231HP. VERY noticable diff.

Plugged Catalytic Converter maybe?

Im becoming somewhat of an expert with one, as I believe I just fried mine. From what I understand, a plugged Cat will significantly reduce HP in a Carerra.

Its not easy to fry one, if your engine is misfiring like mine is... fuel gets into the Cat and burns there. Now I smell some funky plastic like smell coming from the Cat, and its probably friend. Im gonna bang out the comb inside and just run it wide open like a test pipe.

Until you need to get it smogged...

Talk to me in 2 years my friend. I just had it smogged and will deal with it in 2 years when its up for smogging again. :)

Hurting the environment? Maybe...but there are studies that show that 'having' a Cat, will hurt the ozone layer...so it works both ways.

Interesting that you mention the cat. About six months ago, the car somehow tosted its dizzy rotor and was badly misfiring.
Here is what the rotor looked like when I replaced it.
No Idea what caused this, but it's been fine ever since.
[IMG] [/IMG]
I had to drive the car about 9 miles to get it home badly misfiring all the way, but still ran ok. The cat was VERY hot from burning all of the unburnt fuel off. It wasn't red hot, but it was hot enough that I could feel it from about 4 feet away. I took off the tire to keep it from cooking it. I hadn't thought of that causing any long term damage. I would think that overheating the cat would clean it out if anything. Anyone else have ideas on this. Since we do not have smog testing here in Indy, gutting the cat is an option

You drove it 9 miles w/ that rotor?? :eek:

Instead of "gutting your cat", just get the Dansk euro pre-muffler, you'll have the right amount of back-pressure and they don't cost that much. :cool:

Eurospec (RoW)was always 231
US (cat equipped models) was 207 and then rose to 217 in 87

Australia, Sweden and Switzerland had a different tune for noise and emissions. Lots have said these cars felt very different

Air Flow Meter flaps get "tired" and need to be adjusted. Also, my car was running way lean and had the on/off over 4000 rpms that you describe. Dealt with both of these and set the CO/idle, and now there is a noticable low-end torque increase.

On the temp issue, I vote for the aux cooler thermostat as noted by Mike F. I had this problem in my 87 Carrera. The T-Stat is set to open around 195 degrees or so (the marking on the T-stat in my car said 90 degrees celsius). This means that once the temp gauge moves a bit past the first mark the aux cooler should come into play and you should see an initial drop in temperature. My T-stat was not opening at the right temp so I took it apart and the pin was stuck (there is what looks like a small metal golf tee inside that pushes out and opens a valve as temp goes up). I pulled the pin out and cleaned the whole mechanism with parts cleaner. I then did some tests using boiling water to be sure the pin pushed out at above 200 degrees. It worked fine after the cleaning. The other option is buying a new T-stat, but that is pretty pricey.

Mine seems to be sticky. If I get on the road and stay at a constant speed I can drive all day and see about 215. If I get on the road until the car gets up to temp and then get stuck at a light or in traffic so the temp goes to 230 then once I get moving the temp will go back down to about 205 and stay there. Almost as if it needed the extra heat to overcome sticking.