Pelican Parts Forums - 944S sluggish/buggy

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Any progress with your car?

Well I haven't had any time to get under the hood BUT I did discover something interesting.

I thought if a test I could do while driving to see if it was becoming flooded. While coasting in gear down a long hill on the freeway I stepped on the gas to verify that it was doing the problem, and as expected there was no responce from accelerator. So I quickly bliped the ignition key into the off position for a split second and the problem instantly went away. I tried it several times and it cleared the problem each time. Even if I click the ignition after coasting on gear for a while and THEN step on the gas immediately after, the car will respond as if I has not been coasting all that time.
So it seems the problem is not vacuum sucking in fuel and flooding, and it seems that the DME is getting confused and doing something stupid after coasting in gear.

if the car is running and you turn the key to off and then back to the on position quickly enough it will try to shut off but then catch itself and fire normally again.

perhaps there are capacitors between the power source and the actual DME circuitry so it has a second of juice after power cut?

Sounds more likely to be a TPS issue to me. Multimeter test time to confirm no dead spots on the range of motion. This is easier to test and confirm than the AFM.

Quote:

Originally Posted by Lapkritis (Post 8310414)

Sounds more likely to be a TPS issue to me. Multimeter test time to confirm no dead spots on the range of motion. This is easier to test and confirm than the AFM.

TPS in a 944 does not mean "throttle position sensor", it's a "throttle position switch".
It switches one switch to on at idle, and one to on for WOT. Anywhere in between is just open. Probably the most useless "sensor" on the 944.
I'd suggest checking the AFM for dead spots. Carefully pop the cap off and take a peak inside.

0280120308 is listed as a switch. I'd still recommend testing as it can throw your air to fuel off if faulty.

Quote:

Originally Posted by xero (Post 8310134)

I thought if a test I could do while driving to see if it was becoming flooded. While coasting in gear down a long hill on the freeway I stepped on the gas to verify that it was doing the problem, and as expected there was no responce from accelerator. So I quickly bliped the ignition key into the off position for a split second and the problem instantly went away. I tried it several times and it cleared the problem each time. Even if I click the ignition after coasting on gear for a while and THEN step on the gas immediately after, the car will respond as if I has not been coasting all that time.
So it seems the problem is not vacuum sucking in fuel and flooding, and it seems that the DME is getting confused and doing something stupid after coasting in gear.

Check the idle-switch in the TPS. Make sure it's not stuck ON when the throttle is open.

Also check the WOT-switch in the TPS as well. Test at the DME harness itself to test the wiring in between the TPS and DME.

V2rocket: no capacitor, I'm doing this while the car is in gear on the freeway coasting downhill, so the engine actually shuts off for a split second but keeps spinning because I'm in gear, then when they key is turned back on it basically bump starts itself.

Everyone else: Yeah, TPS seems like an easy and logical place to start looking, I'll test at the DME harness with my multimeter.