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Full Version: Hesitation / jerking around 3200 to 3500 rpm
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914itis
The car runs great as long as I don't hit 3200-3500 rpm. Same spot on all gears and all engine temps.I mentioned 32-3500 since I know that these old gauges are not accurate.
jmill
Carbs or FI? Engine size, type and any other pertinent info would also help.
poorsche914
If FI, could be the TPS (throttle position sensor).


driving.gif
914itis
Diet 2.0 leaker , if tps I have onee on the way .
jmill
If carbs it could be transition issues or ignition problems.

FI, I'm out.
falconfp2001
I'd say the TPS. I had the same symptoms once. By the third one I was able to get it working right. I never replaced the board but always intended to.

AA sells the board for replacement.
TheCabinetmaker
Yep, the traces are worn. Sometimes you can tweek the arms just a little to make it contact better on an unmarked part of the trace.
914itis
I ordered one from Dave sprinkle last week. I had a feeling it was causing some of my issues . I should have it soon .
914itis
QUOTE(vsg914 @ Apr 21 2012, 09:02 PM) *

Yep, the traces are worn. Sometimes you can tweek the arms just a little to make it contact better on an unmarked part of the trace.

I tried that, didn't work.

Btw thanks for the dizzy seals Curt
jim_hoyland
Does the L-Jet TPS have the same problem, or is it completely different ?
euro911
Jim, they're very similar and are prone to the same problems.
trfrick
I had the same problem once and it was the rebuilt mps.
davesprinkle
QUOTE(jim_hoyland @ Apr 21 2012, 06:13 PM) *

Does the L-Jet TPS have the same problem, or is it completely different ?


Hi Jim,

I'm going to disagree with the previous poster. The Ljet TPS is substantially different from the Djet TPS. The Djet sensor detects changes in throttle angle of roughly 2º. The Ljet sensor is only used to detect idle and wide-open throttle.

-dave
euro911
I stand corrected and recant my previous post.

I did additional research and found the following post from Sean Molloy:

"the L Jet TPS is a 3 position contact switch that RARELY fails unlike the d jet 10 position 3 pole sweeper type.the unit used in the 1.8 has contacts that look like ignition points. clean them and the should work. they never fry because they are low voltage low current"

I confused it with the difference types for the 1.7L & 2.0L D-jet systems.
bulitt
Your car looks great Paul!
914itis
Thanks , I am happy with the outcome .
jim_hoyland
QUOTE(davesprinkle @ Apr 21 2012, 08:41 PM) *

QUOTE(jim_hoyland @ Apr 21 2012, 06:13 PM) *

Does the L-Jet TPS have the same problem, or is it completely different ?


Hi Jim,

I'm going to disagree with the previous poster. The Ljet TPS is substantially different from the Djet TPS. The Djet sensor detects changes in throttle angle of roughly 2º. The Ljet sensor is only used to detect idle and wide-open throttle.

-dave


Thanks Dave. Good info
underthetire
Or the mechanical advance in the dizzy is sticking. That's about where they go full advance I believe. Just a thought.
914itis
Update:

I rebilt my original dizzy using the vacum advance from another one with a broken ground, clean it up nicely, re-do timing and the issue was solved. I was able to raise the rpm on 1st 2nd and 3rd to 5000 for testing, hesitation is gone and the car sounds great. I was never able to go past 3900 before.

Thanks to all my mentors here.
ConeDodger
Pop the cover on the TPS. You will probably find it all gummed up in one spot. It does that because the RPM you are describing is right at cruise.

Take a good new pencil eraser and gently rub away the goober on the circuit board. Then cover it back up and check it out. It should be much improved. New replacement boards are available in the Member Vendor section of the World.

Edit: I see you found Mr. Sprinkle on your own... biggrin.gif
914itis
QUOTE(ConeDodger @ May 22 2012, 10:48 PM) *

Pop the cover on the TPS. You will probably find it all gummed up in one spot. It does that because the RPM you are describing is right at cruise.

Take a good new pencil eraser and gently rub away the goober on the circuit board. Then cover it back up and check it out. It should be much improved. New replacement boards are available in the Member Vendor section of the World.

Edit: I see you found Mr. Sprinkle on your own... biggrin.gif

Thanks anyway.
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