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> Surging and Unsettled Idel after MPS Rebuild, '74 2.0L D-Jet
914four
post Oct 17 2016, 07:36 PM
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Running down a bucking issue and found my MPS to be leaking. After rebuilding the MPS and verifying a good seal, everything went back together okay. When I started the car, the engine surged up and down and would not idle.

The electrical connector socket on the MPS does not appear to be keyed and using the diagram below from Clay's D-Jet troubleshooting guide it seems I may have plugged in the MPS wire incorrectly. I ohmed the wires from the ECU connector to the MPS socket and made sure the wires are in the order shown in the diagram.

The wires look to be looping back from terminal 7 to 15 and 8 to 10 so that the socket could be plugged in either way and work correctly. Could plugging in the MPS wires incorrectly have damaged the ECU? If not, what should I be looking for that would cause the surging and lack of idle?

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914four   Surging and Unsettled Idel after MPS Rebuild   Oct 17 2016, 07:36 PM
Rand   It's lean. Which means vacuum leak somewhere a...   Oct 17 2016, 07:39 PM
pbanders   You can't plug the MPS in incorrectly, you did...   Oct 17 2016, 07:47 PM
914four   You can't plug the MPS in incorrectly, you di...   Oct 17 2016, 08:13 PM
Jeff Bowlsby   The MPS may be calibrated too lean for your engine...   Oct 17 2016, 10:26 PM
pbanders   The MPS may be calibrated too lean for your engin...   Oct 17 2016, 11:19 PM
Philip W.   I agree with all the above, you are running lean-...   Oct 18 2016, 06:33 AM
pbanders   Jeff Bowlsby can check your MPS and set it to th...   Oct 18 2016, 08:11 AM
Bleyseng   You are running too lean and need to use a AF mete...   Oct 18 2016, 08:07 AM
914four   Thank you all for the responses. I was able to ch...   Oct 18 2016, 11:16 AM
Racer Chris   Kelvin, You have the adjustment tools. It may take...   Oct 18 2016, 11:32 AM
914four   Kelvin, You have the adjustment tools. It may tak...   Oct 19 2016, 09:17 PM
pbanders   Thank you for the direction on the MPS. I was ab...   Oct 20 2016, 09:28 AM
zambezi   What would you recommend for a good tester to test...   Oct 20 2016, 10:39 AM
pbanders   What would you recommend for a good tester to tes...   Oct 20 2016, 02:16 PM
914four   Success! I disassembled the MPS and added t...   Oct 20 2016, 08:36 PM
914four   So far I my car has been running smother than ever...   Nov 3 2016, 06:24 PM
pbanders   So far I my car has been running smother than eve...   Nov 3 2016, 11:19 PM
914_teener   Check your fuel pressure and TPS conditions first.   Nov 3 2016, 07:08 PM
lsintampa   I chased a surge for over a year on my 2L (1975). ...   Nov 21 2016, 07:55 AM
R Shaff   I know this is an old thread, but for anyone who w...   Apr 2 2017, 05:00 PM
Rand   I know this is an old thread, but for anyone who ...   Apr 2 2017, 05:11 PM
r_towle   What kind of cigar?   Apr 2 2017, 07:04 PM
Tbrown4x4   A friend of mine built a smoke tester with a coffe...   Apr 3 2017, 07:14 AM
cary   I built one with a new paint can. Worked great to ...   Apr 3 2017, 07:53 AM


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