So my 88 XJS V12 (48,000 miles) still runs very rough and runs super rich. When cold, it idles so-so, and actually revs halfway decent, but once warmed up to 190F in about 20 minutes, it can barely hold an idle and bogs like crazy when I try to rev it. The vacuum is also super low, anywhere from 10 inHG down to 7 inHg.
I’m at a wall, not sure what to do next. I bought it 3 months ago as a project. I’m hoping some of you may be able to steer me to what to check next.
- I’ve since renewed the entire fuel system. I verified I am getting 36 psi at the fuel rail with ignition on, and I get 33 psi at idle. I’ve also just had all the fuel injectors cleaned. Injector harness is good.
Tank and fuel pump were replaced too. FPR is brand new and working.
- I found the ignition system in rather poor shape. I replaced all HE wires, spark plugs, cap, rotor, the GM part in the ignition amp, the coil, and I overhauled the distributor as instructed in the book. I also replaced a bad pickup, along with a new star wheel. I also checked my timing, got it to 10degrees BTDC at idle with vacuum advance at 800 rpm.
- I checked compression in October, and all were good, within 180-195 cold.
- Vacuum at idle and while revving it averages 10 inHg
- I changed out the CTS, checked CTS, and verified CTS wires to ECU are working. Unplugging CTS or shorting out plug to CTS with paper clip makes no difference.
Car is fouling spark plugs like crazy, and the oil is also getting quite dirty quickly.
thanks for any help, I understand it could be a million things. But I need a list of things to check one at a time, to get this car back to running.