My '84 512BBi is playing up and wondered ifg anyone has any ideas? Get in to start from cold, starts perfectly, warms up fine, drive great appart from a little 'hesitation' below 3000rpm. Get into town, park the car for 20~30 mins the ngo to strat it again...and it wont. Maybe tries to catch initially then turns over and over with no start. A couple of times now, including yesterday, it got to backfiring (loud!) whilst turning it over. Eventually got it running really rough, not responding well to throttle, and it wont drive properly.....as soon as I load the engine, as in pulling away it bogs down...I have to slip the clutch etc to ge tmoving...absolutely no torque. Once past about 3000 again it seems better, and generally gets better after a while. When I got home I tried starting it again and it started, so I checked exhaust gas again, and its not far off perfect (1.5% CO) Checked ignition timing with timing light and its spot on, and advance seems to work fine' (I have MSD ignition) One odd thing; sometimes when I turn off the ignition, the car keeps running 'till I touch the brakes, then dies instantly...electrical gremlin. But was doiing that prior to this stareting problem. I was thinking an air leak, but cant see anything, nor can I put my finger on exactly what might be happening Any ideas? Thanks, Robert
Robert, Here's what we know so far: -Cold start: OK -Immediate hot start, after shut down: OK -Warm start, after off for 20-30: Hard start The first thing I would check is your fuel pressures to see if they're leaking down when you first shut off the car. These are pretty much the classic symptoms. If you find that pressure is falling quickly...and you know that the fuel pump check valves are indeed functioning correctly, I pull the injectors and inspect them for leakage. Presuming you have the curves for the WUR's, verify that they hold pressure for the specifed timelines... A loss of "hot control pressure" will cause the symptoms you describe. A vacuum leak will be seen as high CO...and 1.5% is too close to the mark to indicate such a problem. Once fuel pressures are known, we can go further. Regards, David
Hi David, Thanks for the reply, and sorry it's taken so long to get back. Fuel pressure check I can do ( I have the gauges) , but the injectors were all new recently, so doubt they are faulty. Fuel pump check valves....not sure about these...have never replaced them. However, not sure why they would cause the symptoms I have? I rebuilt the WUR's a while ago, and whilst the curves may not be perfect they were working fine. Also, I would suspect something that would affect both banks together....the has run great on one bank when fuel pump fuse has blown, so if one WUR etc was down I'd still expect the other bank to run and sustain the other. When the car does get going after a hot start, it is still driving very poorley and even backfiring, with vewry low torque and terriable throttle response.... The 1.5% co is because thats were I adjusted it, and It was adjusted after the problem was obvious, so I might have 'obfiscated' the problem by adjusting the mixtures at idle? Let me check the fuel pressures, and get back to you . Thanks again David. Robert
