Fuching DJet issues *SOLVED*, Running out of things to try |
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Fuching DJet issues *SOLVED*, Running out of things to try |
rjames |
Jun 12 2019, 12:19 AM
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#1
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I'm made of metal Group: Members Posts: 3,918 Joined: 24-July 05 From: Shoreline, WA Member No.: 4,467 Region Association: Pacific Northwest |
Last summer all of a sudden my car wouldn’t stay running. If I could get it started the idle would hunt and the car would die unless I kept on the gas. Lack of power at times. All somewhat erratic.
Found that the MPS wouldn’t hold vacuum. Replaced the bad mps with a known good one. Car idles high when cold (higher than I think it should ~1600 rpm) so AAR is good, then when it warms up idle hunts from ~900rpm to the point where it almost dies unless I open the throttle body bleed screw quite a bit and turn the ECU knob just a few clicks away from full clockwise. So I did the following hoping to fix the issue: Replaced all vac hoses including intake runner to plenum hoses. New intakecrunner gaskets Verified plenum isn’t leaking New throttle body gasket Installed NOS throttle body Rebuilt the distributor New condenser Rebuilt injectors and flow tested New fuel lines Fuel pump is less than 2 years old Set timing and dwell with advance disconnected New CHT (resistance reads 1.7 w/engine off @70 degrees in the garage) Calibrated the TPS, even unplugged it to take it out of the equation, didn’t change anything. ECU matches the MPS (both correct part #s for a ‘75 2.0) Tried a known good ECU from a ‘74, no change. Feels like the MPS needs to be calibrated...but then again, these are all the same symptoms I had with the old bad mps. Replacement mps is from a Jeff B and was tested, but I haven’t retested it to see if it’s holding vacuum. (Don’t have the necessary tool, but maybe that’s the next step) Help! What am I missing? |
rjames |
Jul 5 2019, 07:21 PM
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#2
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I'm made of metal Group: Members Posts: 3,918 Joined: 24-July 05 From: Shoreline, WA Member No.: 4,467 Region Association: Pacific Northwest |
Updates and new info:
Installed new coil and 123 ignition distributor. Install was cake thanks to posts by others here. Homemade smoke machine revealed 2 vacuum leaks which have been taken care of. Current situation: I am able to get the car to idle at a steady 1200/1300 rpms. AFR is ~13. The only way I can get the idle lower is if I move the TPS counter clockwise, but as soon as I do that, the idle drops to almost 0 and maybe comes back up a bit once or twice and then the engine dies as the rpms drop again. Calibrating the TPS puts the idle at 1200/1300. The ECU knob will change the enrichment when the tps is adjusted to iallow a steady idle at 1200rpm. When it’s at 1200 rpm the throttle body idle screw won’t bring the rpms down any further. No vacuum leaks under the butterfly. If I take the air cleaner off and cap all lines, I can easily get the car to die by closing the bleed screw, indicating no vacuum leaks. So could my TPS be bad? Is there a condition by which it could not allow a correct idle? Was thinking maybe I tweaked one of the contact arms when I cleaned the board. Looks ok though and the board is in good shape. Or am I in MPS adjustment territory now? |
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