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| solex |
Aug 23 2020, 09:16 AM
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#1
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Senior Member ![]() ![]() ![]() Group: Members Posts: 789 Joined: 12-January 05 From: Long Island, NY Member No.: 3,439 Region Association: North East States |
On my past few drives the car has been stumbling when I accelerate specifically when warm and in every gear except first, in my 2.0L D-Jet in a 75'
A few of things to note: - Ground strap at transmission has been cleaned - Installed a second ground at battery ground point to the engine fan - New spark plugs Bosch W175T2 - Engine compression 134-145 all cylinders - Fuel pressure set to 28 psi - spark plug new wires - 123 Ignition curve 2 with vacuum advance attached, 10 degrees advance at idle - Injectors have been rebuilt by Mr. Injector - All vacuum hoses have been replaced - AAR is in working order and has been oiled Not really sure where else to look, the engine idles < 1000 but is not smooth at times jumping +/- ~ 200 RPM Any advice would be appreciated. |
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| solex |
Sep 7 2020, 01:12 PM
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#2
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Senior Member ![]() ![]() ![]() Group: Members Posts: 789 Joined: 12-January 05 From: Long Island, NY Member No.: 3,439 Region Association: North East States |
Got everything installed new with new boots between the intake runners and the plenum. I added very little Loctite gasket maker underneath the TB gasket just incase it was not perfectly level
Adjusting the TPS was curious; I adjusted it on the bench measure resistance but it would always read a resistance until (1) the middle wiper was past the gap and on the next trace on the lower part of the board OR (2) I got past the gap and would turn the TPS CCW The contacts on the plastic arm are in contact with the post which will always measure a resistance. I also tried the continuity adjustment measuring continuity until there is not and backing off 1 hash mark. This got be close but it was not until I adjusted the TPS by hand making sure that from idle I was able to mash the pedal with no bogging through the pedal range. I guessing that we are all adjusting the TPS until the middle wiper is on the gap between the traces, I had to turn mine about 1 hash mark CW so the engine would rev smoothly when masking the pedal. I set the timing to 10 degrees static timing at idle, measured the CHT 2.62kOhms at 75 degrees. The engine idles between 920 and 980 when HOT. The drivability is night and day to what it was, I now see that for the most part most of the past 6 months debugging was chasing the vacuum leak at the plenum and the TB. The car now accelerates smoothly although there is a very slight hesitation at 2800 & 3200 when I mash the gas pedal in 3rd and 4th but I can live with this as I generally do not drive like I stole the car. I would be interest to know what advance curves on the 123 distributor you are all using particularly those with a 75-76 ECU. Thank you all for your help |
solex Debugging stumble on acceleration when warm Aug 23 2020, 09:16 AM
wndsrfr Clean the contact strips on the TPS... Aug 23 2020, 09:25 AM
rjames Have you tried adjusting the fuel mixture with the... Aug 24 2020, 11:04 AM
BeatNavy
Have you tried adjusting the fuel mixture with th... Aug 26 2020, 09:22 AM
windforfun I had a similar problem. I found a new TPS & ... Aug 24 2020, 11:11 AM
solex Thank you everyone. I just removed the TPS, which... Aug 25 2020, 10:35 AM
PCH Looks like the board is worn out. 914 Rubber has n... Aug 25 2020, 11:12 AM
PCH DP Aug 25 2020, 11:14 AM
solex I saw the new board, looks great and will order on... Aug 25 2020, 01:23 PM
solex I reinstalled the TPS and it was still stumbling, ... Aug 26 2020, 06:28 AM
solex Hey Rob,
I think I may have overstated the huntin... Aug 26 2020, 09:30 AM
solex I go the new boards on Friday, 914Rubber has some ... Aug 30 2020, 07:53 AM
sechszylinder Hi,
did you checked the trigger contacts which a... Aug 30 2020, 08:35 AM
solex
Hi,
did you checked the trigger contacts which ... Aug 30 2020, 09:40 AM
sechszylinder
[quote name='sechszylinder' post='2847084' date='... Aug 30 2020, 01:28 PM
rjames Fuel pressure maybe too low, AFR could be too lean... Aug 30 2020, 10:16 AM
solex This evening I did several things in attempt to fu... Sep 1 2020, 04:37 PM
rjames
This evening I did several things in attempt to f... Sep 2 2020, 01:54 AM
DRPHIL914
Thank you everyone. I just removed the TPS, whic... Sep 3 2020, 06:47 AM
solex I removed the plenum and located a crack on the to... Sep 5 2020, 03:57 PM
porschetub :idea: looks like your throttle body gasket isn... Sep 5 2020, 10:30 PM
solex The crack exposed... :D
and hopefully repaire... Sep 6 2020, 10:18 AM
porschetub
The crack exposed... :D
and hopefully repair... Sep 6 2020, 10:10 PM
porschetub
Got everything installed new with new boots betwe... Sep 8 2020, 07:39 PM
solex
Excellent result,my experience with injection al... Sep 9 2020, 09:20 AM![]() ![]() |
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