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Friends,
Our 1994 945 NA (California car with EGR) with about 260,000 miles started running rough after 2-3 hours of highway driving in heavy rain. When we stopped, it also had a rough idle. It started to run better after we checked for loose wires (we didn't find any) but then got worse again when the rain got heavy again.
Background:
Our 945 has had a few performance issues over the last winter and this spring we have been working on getting it to run better, especially before a long trip out of town.
First, we cleaned out the throttle body, replaced the EGR and the oil trap, checked vacuum hoses, replaced on spark plug wire, etc. Cleaning the throttle body made a dramatic improvement!
After doing that work, we found there was a hot-start problem (which I think developed independently). To deal with the hot-start problem, we tried replacing the FI relay, the radio suppression relay, the engine coolant temp sensor, and the power stage. We wanted to replace the coolant sensor anyway because the car seems to run rich when just a little bit cold in the winter.
These did not fix the problem, so we then had our mechanic replace the RPM sensor, which fixed the hot-start problem.
By the way, the kickdown cable needs to be replaced--right now it is splinted right where it attaches to the throttle but even with the splint it does not shift as quickly as normal. I don't see how this would affect the idle.
The trip went quite well, but on the way back in heavy rain we got the rough running. The car has been home for a couple of days, but it still runs roughly.
I'm wondering if the rain could have caused the problem. We did not see water dripping on the distributor (or the rest of the engine). I'm wondering about the wire connections to the fuel pump under the car.
We are thinking of replacing the fuel pump and the fuel filter as part of a larger program of preventative maintenance, but I wonder if the fuel pump wiring could be affected by water. I'm also wondering about the main ground wire from the engine to the battery--it seems tight, but I have not taken it off to check the connection.
Any suggestions for tests would be appreciated.
Thanks,
Paul
Baltimore MD
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