running problem help!

Well I've got a weird running problem.

Take it out for a drive and it's ok, then give the full beans and its fine til probably about 5000 rpm then all power drops, and a big backfire then have to drive it like a nun to get it anywhere, popping and banging if you try to accelerate at all hard.

First I thought it was fuel so I changed the high pressure pump. No difference.

Any ideas, before I head back the the rolling road place.

Pops/bangs usually means over fuelling, or by virtue under-ignition (sic)

Check your alternator is charging (14.5 volts min at the battery whilst running)... had exactly same symptoms with mine recently, turned out to be a burnt diode pack on the alternator.

I initially thought about the overboost protection, but this will run OK as soon as the boost drops.

I did have a problem some years ago with a new Bremi (Italy) brand distributor cap that after a few months has this sort of siliconnny conductive ooze coming out on the inside and this didn't want to be removed with the normal solvents. Only shifted it with thinners and even then it took time, only for it to reoccur after a couple of months.

I seen this same problem with 4 of these caps on other cars. Just buy the Bosch one for a mid 80s big BMW 6 to save dramas.

The above problem caused my car to miss, but only on boost. Also the seal where the distributor shaft goes into the head can fail causing the cap to fill with engine oil, which usually doesn't help.

Rupert has a 24v atmo, his turbo is long gone.
Not sure what ignition system you are running Rupert, but sounds like it has got confused somehow or does not know where TDC is after the back fire. What happens if the Nun stops and restarts the car, which often resets all sorts of ignition componants?
Maybe a carb linkage has popped off and full fuel is being fed in constantly.... til it back fires?

Pops/bangs usually means over fuelling, or by virtue under-ignition (sic)

Check your alternator is charging (14.5 volts min at the battery whilst running)... had exactly same symptoms with mine recently, turned out to be a burnt diode pack on the alternator.

rupert definately check this out you mentioned seperate connections to the alternator recently I hadj similar problems popping banging althouh christine would.not.run below 3000 rpm still worrh.checking all connection.to eliminate I it; it worked for me. Looks likely all the attempts to restart have charred the solenoid contacts and now.the starter wont kick in

Worth.ad look though especialy those seperate connections at the alternator.

si21

Just to throw another thing to think about into this - it sounds a bit like the A610 known issue, where the car goes into limp-home mode. I think there's still some discussion (and probably variation) as to what the cause is but two that I know of that have resolved this are

- injectors
- ECU overheating.

Of course, this could be completely unrelated but it sounds like something's causing the ECU to lose its mind. Does switching the engine off and re-starting cure anything?

Rupert has a 24v atmo, his turbo is long gone.

Not sure if he has an ECU ???

Rupert has a 24v atmo, his turbo is long gone.

Not sure if he has an ECU ???

Emerald ECU