Help - Djet running way too rich |
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Help - Djet running way too rich |
Halfnelson |
Jul 23 2021, 06:51 AM
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#1
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Newbie Group: Members Posts: 46 Joined: 31-July 17 From: Cornwall Member No.: 21,303 Region Association: England |
Help - my new to me 1973 1.7 Djet came running really sweet, but almost immediately developed the 'hunting tick-over' of lean running / air leak. We replaced all the vacuum pipes, found one of the inlet gaskets had a very slight leak. Seems somewhere along the line things have been tweaked to compensate for the leaks so that now they're cured, the car is running super rich. Having had a L-jet for years the Djet is new to me so any advice on where to start first would be much appreciated. Thanks Chris
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rjames |
Aug 20 2021, 09:35 AM
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#2
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I'm made of metal Group: Members Posts: 3,955 Joined: 24-July 05 From: Shoreline, WA Member No.: 4,467 Region Association: Pacific Northwest |
I had a similar situation and it turned out to be a bad ECU. After 15-30 minutes of driving, the car would run super rich.
I still question your rebuilt MPS. You said you tested it, but just verifying that it holds vacuum isn't enough. You need the tools to adjust it (tangerine racing) and an AFR meter to dial it in. If the rich running your experiencing is intermittent, than you can probably check the MPS off of your list. But if it's always rich and swapping the ECU out doesn't change anything, then I suspect your MPS needs calibrating. QUOTE Quote jrmdir @jrmdir At the very least you need the tools to adjust the MPS and and an AFR meter to set the MPS correctly.In rebuilding the MPS, reestablishing the height of the center plunger involves an imprecise measurement. So this could be the issue. There is mention of uncovering the adjustment screw and then calibrating the MPS. But Mr Anders says this requires special equipment. It seems like this adjustment could easily impact the rich/lean situation. Has anyone tackled this calibration without test equipment? |
Halfnelson |
Aug 20 2021, 09:54 AM
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#3
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Newbie Group: Members Posts: 46 Joined: 31-July 17 From: Cornwall Member No.: 21,303 Region Association: England |
I had a similar situation and it turned out to be a bad ECU. After 15-30 minutes of driving, the car would run super rich. I still question your rebuilt MPS. You said you tested it, but just verifying that it holds vacuum isn't enough. You need the tools to adjust it (tangerine racing) and an AFR meter to dial it in. If the rich running your experiencing is intermittent, than you can probably check the MPS off of your list. But if it's always rich and swapping the ECU out doesn't change anything, then I suspect your MPS needs calibrating. Thanks Robert - the MPS hasn't been rebuilt, still the original and holds vacuum - or at least was. Will double back and recheck. How did you diagnose that it was the ECU? There seem to so many potential culprits and I had hoped these were already ticked off the list. |
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