924Board.org

undrprzur · Joined: 27 Apr 2003 Posts: 18 Location: Eastern Washington

My car ran great, I parked it at the end of September. Went to start it this weekend ran great, until I was ready to go for a drive. The temp gauge showed that all was normal, pulled out and lost power. The engine just would not pull, the turbo gauge showed thatI had 10 lbs boost but no power. Limped the car back to the house, engine idling very low and rough. I opened the hood while it was running the exhaust manifold was red hot, really red. Idled the engine till the exhaust manifold cooled down and then shut it down. After the car was stone cold, I started it up and it idled fine and drove great 10lbs boost for about a mile. The temp came up to normal then it lost power again!

I have owned this car since it was a baby (1981), for the last 10 yrs I have done all the work to it. Rebuilt the engine, turbo, head and cam 3 times. This car has 185000 miles and has been my daily driver in the summer.

Need wisdom! Any help and advise would be appreciated.
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81 931 Always on Boost.

Smoothie · Posted: Tue Nov 08, 2005 2:22 am Post subject:

Maybe the fuel has gone partly bad - lost some octane? Try disconnecting the unpluggable wire that runs over the front-left wheel well inside the engine compartment. That'll retard the spark some and should have it running better if low octane fuel is the problem. If so, obviously fill up with high octane.

Also go over the ignition parts. Check plug, plug wires, dist cap, rotor, etc. You can scrape any oxidation off the rotor and dist cap copper parts with a small sharp flat blade screwdriver.

Check vacuum lines, vacuum line Tees and intake path boots, connections and o-rings for leaks. One possible scenario is a cracked T - they can be closed and sealed when cold, then open up and leak vacuum when warm.
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"..it's made in Germany. You know the Germans always make good stuff."

'82 924T, US version, dark green metallic, 5 speed Audi 016G gearbox

undrprzur · Joined: 27 Apr 2003 Posts: 18 Location: Eastern Washington

Thanks for the response, I'll check all. The car has New gas. I replaced the exhaust manifold 10K ago, while doing that redone all the vac hoses, put a 1 Bar spring in the wastegate with new diagphram, new plugs wires, rotor and cap. I have always stored this car at the end of September, and drive it begining of April it has never done this.
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81 931 Always on Boost.

Smoothie · Posted: Tue Nov 08, 2005 3:54 am Post subject:

Check your voltage? I have a cigarette lighter adapter that the leads from my multimeter can connect to. Something like that comes in handy. -I'm thinking maybe the alternator isn't charging the battery - you run good for a while, then as it discharges, there's not enough juice to fully power the ignition system..

Another possibility is the larger elect. connector on the DITC box below-behind the radio. Humidity or bumpy roads can affect the connection. Usual symptoms though, are misfires, backfires and the tach needle flops around.

Rodents might be another possibility - chewing on wires and vacuum lines.
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"..it's made in Germany. You know the Germans always make good stuff."

'82 924T, US version, dark green metallic, 5 speed Audi 016G gearbox

Tigger937

Paul · Posted: Tue Nov 08, 2005 9:36 am Post subject:

Check your timing belt before starting the car again.
_________________
White 87 924S "Ghost"
Silver 98 986 3.6l 320 HP "Frank N Stein"
White 01 986 "Christine"
Polar Silver 02 996TT. "Turbo"
Owned and repaired 924s since 1977
Porsche: It's not driving, it's therapy.

numbbers · Posted: Tue Nov 08, 2005 1:50 pm Post subject:

You have a plugged exhaust. Now you just have to find out where.
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1980 924 Turbo

undrprzur · Joined: 27 Apr 2003 Posts: 18 Location: Eastern Washington

Thanks All, wish you were all here and having a beer with me as I do all that has been suggested.

I'll check the voltage. I thought about a plugged exhaust, started the car tonight just idled the car, 15 minutes, very good exhaust pressure even when it started to run rough.

More symptoms: 1.rad fan came on indicating nornal temp achieved.
2. Vacuum droped from normal to 5hg.
3. pressed on gas vacuum droped to 0hg no increase in RPM. I can hear the turbo whine.
4. tried to move the car, slight incline on my driveway, almost stalled, Vac/turbo guage showed 5lbs boost but no power. pushed it back into the garge.
5. Open the hood the Exhaust manifold dull color of red not as red as it was this weekend.

Just driving me crazy! Thanks for the input.
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81 931 Always on Boost.

Racing · Joined: 27 Apr 2004 Posts: 374

Timing problem.
The red hot man is a dead give away.
Check EVERYTHING in sight as far as timing and ignition goes.

john h · Posted: Wed Nov 09, 2005 9:35 am Post subject:

Check teh pressure lines around the motor and to the control unit if it's a digital control unit. If the lines have a leak then the timing gets advanced - could cause your red manifold.
Mine did that lasty ear while racing but we noticed it before any lasting damage done to the motor.
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Remember a Porsche is not just for Christmas,

if you take it to pieces slowly it can provide anguish all year long!

undrprzur · Joined: 27 Apr 2003 Posts: 18 Location: Eastern Washington

Checked all hoses, replaced what need to. I hooked up a timing light and started the car. Timing is good till it reaches normal temp, then it retards. BTW the car is a 1981. it has new gas, plugs cap, and rotor. I took out the ditc control box behind the radio, looked very clean, cleaned the ignition igniter(module by the front left headlight), timing belt is good and on it's marks. Just can't figure it out. To remind what is going on, start the car all good, when it reaches the normal temp, no power, red hot exhuast manifold, exhuast is not blocked, great pressure out of tail pipe. Anymore Ideas. Spring is coming and would love to drive the car.
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81 931 Always on Boost.

Paul · Posted: Sun Feb 05, 2006 3:24 am Post subject:

We need to determine what's retarding the timing. Do you have a spare DITC? Have you checked the temp sensor in the intake manifold? (unplug it, remove it from the manifold, plug the hole with something that will not get sucked in or blown out, reconnect the connector and secure the sensor in the coolest spot you can find.)
_________________
White 87 924S "Ghost"
Silver 98 986 3.6l 320 HP "Frank N Stein"
White 01 986 "Christine"
Polar Silver 02 996TT. "Turbo"
Owned and repaired 924s since 1977
Porsche: It's not driving, it's therapy.

Smoothie · Posted: Sun Feb 05, 2006 4:50 am Post subject:

Also check that wire that runs over the left-front wheel well. If the connector there's unplugged or the connection just isn't good, the timing will be retarded by 7 degrees.
_________________
"..it's made in Germany. You know the Germans always make good stuff."

'82 924T, US version, dark green metallic, 5 speed Audi 016G gearbox

Joes924Racer · Posted: Sun Feb 05, 2006 5:53 am Post subject:

The board in action, undrprzur these guys
really know there porsches. They can source
any prob. just about.

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1979 porsche 924 Na
1980 porsche Turbo 931GT Replica
Have u ever driven a turbo.

Tigger937 · Posted: Sun Feb 05, 2006 7:06 am Post subject:

Just a guess, but it almost sounds like the fuel pump is dying or plugged as it warms up. Get down behind the right rear wheel well and listen to the pumps as the car is warming up and listen for a change in pitch when the car begins to run bad, especially the external pump. If the pump slows down or runs erratically as it warms up, this could cause a lean mixture leading to your hot exhaust manifold and retarded timing.
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1981 931 (Concours)
1982 931 (Daily Driver)

"Think outside the box"