balky 944

porsche newbie · porsche newbie's Garage

My 1985 944 starts and runs fine until the cooling fan engages and then it just bogs down and runs real rough. The battery and the alternator have been replaced recently. Any help or suggestins would be appreciated.

Dave Colangelo · Dave Colangelo's Garage

are you running the stock ECU/chip or has the car been chipped, it could be a fuel map issue if it has been chipped.

Regards
Dave

POPS 83 944 · POPS 83 944's Garage

Check the ground and clean

rick13 · rick13's Garage

i'm not positive, but i think there is a switch that kicks the rpm's up when there is additional electrical load.

matty89 · matty89's Garage

Quote:

Originally Posted by rick13

i'm not positive, but i think there is a switch that kicks the rpm's up when there is additional electrical load.

whats ur normal Rpm when hot at ? and if u put the A/c on How much does it drop ?

porsche newbie · porsche newbie's Garage

my normal rpm when hot is about 11-1200 rpm. I still have the original chip, nothing has been modified that way. I will check all of the grounds again but they looked okay when I checked it but I will double check that I didn't miss anything. I have read that it could possibly be the idle speed valve going bad but that was just a guess on my part and I really don't want to just start throwing parts at it and hope that something works.

mytrplseven · mytrplseven's Garage

Does the A/C work? Does the problem go away when the A/C is switched off? Are you sure that the A/C compressor actually goes off and on? My thinking here that the compressor may be near seizing and putting an enormous load on the engine. The fans will come on as the compressor comes on.

porsche newbie · porsche newbie's Garage

the ac works fine. Only the one fan comes on when I have the problem.The ac is not starting at all. It is just the one fan that starts and the engine bogs down.

porsche newbie · porsche newbie's Garage

Update:::I went and checked all of the grond points and cleaned everything real good and tried again. Same result. Well at this point I was really at a loss for what to try next. As a last resort I pulled the battery out of my other car and put it in the porsche and tried that and lo and behold:

roblem solved. the battery that was in the porsche is only 6 months old and should be good. I took it to an Advance Auto and had them check the battery and find out that there is a dead cell and any strain on the battery was just draining it to low to keep up with the demand. lesson learned-- don't believe everything that is new is without flaws. Anyway, Thank you to everyone that offered help. It was really appreciated

ernie9944 · ernie9944's Garage

[QUOTE=porsche newbie;6688627]my normal rpm when hot is about 11-1200 rpm.

If everything in tip top shape engine wise the engine RPM should be between 9k & 1000k RPM at normal temp in either early & late 944. 11/12K RPM is a little higth.

ex -83-944

- 93-968