meanmaroon951

Coming back from a long trip, 951 loses power goin about 70mph.. first thought: Damn DME relay (HopelfulllY since i was 4.5 hours away from home) Pulled over and pulled the hood up I found shreds of a timing belt . Luckily I was being followed by some friends so I was able to ride home with them. Next day come back to pick up the car, Uhaul wouldnt rent me a car dolley, " The 944 turbo sir will not work on the car dolly". Rented a trailer and brought her home with my fathers f250.


Meat and potatoes of the post:

Got the head back from the machine shop, did $263 worth of damage, not including (my) labor. 4 obviously bent intake valves, though the pistons had impressions fromt the exhaust too. This morning I completed reinstalling the head and it runs very roughly and donesnt rev freely. The engine is timed correctly, it acts like its running on 2-3 cylinders. Any ideas guys? I'm going to ohm out my plug wires tonight after work and make sure each plug is firing.


Josh
(Disgruntled 86 944 Turbo owner)

Also I can only blame my stupid self for this t-belt failure. The t-belt had not been checked since I put it on (30k ago) much less replaced.

Tom M'Guinn

Have you pulled the plug wires and/or injector connectors, one at a time, to see if it really is running on 2 or 3 cylinders?


Did you check all the intake/vacuum connections... i/c couplers, throttle body, etc. Check that the wires are on the right plugs? All the electrical connectors well seated -- all injectors, TPS, AFM?

michael2e

I'd recheck the timing and consider a compression check because of those exhaust valves first. also could be running rough from Balance Shaft belt out of alignment

good luck

meanmaroon951

Well, all plugs have good fire. Next test injector wire test, the center two injectors are not firing. When I unplug them it makes no difference in running; However, disconnect #1 or #4 injector the engine immediately dies. Any idears.... run an ohm test from the injector plug in, to the dme plug.

jgporsche

i can atest to the 944 turbo BARELY being able to fir on a uhaul car dolly. When I bought my turbo, it was 6 hours away. i just wanted to tow it home. the car dolly's "towing" was too close for comfort. So i drove it the 6 hours.

meanmaroon951

I was to the point that I would have drug it home if the cops wouldnt have cared lol

Does anyone have the wiring diagram for the injectors to DME? I lost my copy of the shop manuall

gregeast

My guess would be a vacuum leak at the intake manifold. Did you remember to change the orientation of the intake gasket on cylinder #1? I also had some issues getting the intake manifold to seat properly on the slot that it rests on on the driver's side, which meant that the runners didn't line up correctly on the intake gaskets.

HTH and best of luck.

Rock

Are you positive the injectors arent firing? That sounds fashy.

If you unplug them, and it does not change the engine tone, that doesnt mean that the injectors arent firing. That might mean those cylinders arent properly operating.

Chris Prack

If the exhaust valves left impressions in the pistons then they are most likely bent. Those valves are fragile and won't take any contact. Do a leakdown on the motor and see what you get.

meanmaroon951

#1 and #4 cylinder compression tests 130-140 #2 and 3 90 maybe 100.. called the head guy said he checked all the valves. I'm think my headgasket? the car ran great before the bending

Dal Heger

Wait a minute? You didn't get a new headgasket when you put the head back on? Those are only one time use.

If you did, then do a leakdown test, that will tell you where you're losing compression. You'll hear the air escaping through the intake (if intake valves aren't seated well), through the exhuast (if the exhaust valves aren't seated, or through the oil filler (rings).

That's your next step.

Dal.

meanmaroon951

Well Dal thats a funny story..

I had a redneck friend convice me that I could save 50 bucks by spraying the old one down with this "copper spray" they offer from advance. I'm sure this is the culprit after the tests. I have much confidence in my head guy. As of now the head is almost back off, and I should have a new gasket here by Monday. I'm just trying to figure out how to get the exhaust header off withough unbolting it from the Xover pipe . Because I did just buy 2 new (17 bucks a piece) exhaust sealing rings. I hear there one time use too. It could be worse

SD Porsche Fan

For only $25 more you can upgrade to the full auto trasport. I drove 5 hours each way and had it back at U-Haul that night. I was leary of what the dolly would do to the rear end.

Tom M'Guinn

The headers bolt directly to the cross-over, so you cannot remove the headers without unbolting from the x-over first. (That's not to say you might not be able to get the head off without removing the headers from the car -- never tried that.) If you order a head gasket set, it comes with the exhaust rings (and intake/exhaust/coolant gaskets, etc.). You are probably causing yourself more headaches than good trying to take short-cuts, and the HG set does not cost much more than the HG alone. Call 944online.com before 3 and you can have the exhaust rings (and HG) on your porch in the morning. See my HG R&R write-up in the link below if helpful.