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: 3,910 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 |
Jun 20 2019, 08:34 PM
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#2
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I'm made of metal Group: Members Posts: 3,910 Joined: 24-July 05 From: Shoreline, WA Member No.: 4,467 Region Association: Pacific Northwest |
Okay, problem remains after replacing the fuel filter and verifying the fuel pump is doing its job.
Some new info though that I can’t believe I didn’t notice before: I verified the timing (again). It was slightly off. Vacuum line was disconnected and plugged. After setting timing and with the vacuum line still plugged, it idled steady at ~1800 rpm. No fluctuations in idle. As soon as I plug the vacuum line back into the distributor vacuum canister, the idle drops to 1000 and fluctuated between 1000 and almost dying. Remove and plug the vac line and it’s back up to a steady 1800 or so. No amount of adjusting the throttle body screw will bring it down to 1000 with the vac line connected. I can get the idle higher, but not lower. The ecu knob is effective at only keeping the rpm stable at idle (as it should). AFR reading reads a steady 13.4 when I the vac line is disconnected and plugged. Does this mean it’s my distributor that’s the prob? I know the canister leaks, but shouldn’t it still idle around 1000 even with the dist vacuum line off and plugged? Does that point to an mps that is bad or needs adjusting? |
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