BigTim
10-05-2004, 10:51 PM
Hey everyone, I PM'd this to Mark D'Sylva (thanks for the quick reply too Mark) and he suggested I put it up on the board for you guys to consider as well. Any input greatly appreciated!
Firstly, mine is a fairly early 1989 Euro 535i with no cat (leaded fuel map). It's been sitting in my mechanic's workshop for about 5 months now (I am in withdrawal)
The head on my car has been rebuilt and a new slightly warmer cam has been put in (stage one if this means anything to you). The computer is unchanged. The car starts fine and runs great until it warms up - then it starts idling like a rotary engine (large pauses in between firings) and apparently consumes large amounts of fuel, running rich (there was no problem with the old cam, besides the fact it was completely stuffed.)
My mechanic has all the latest Bosche gear and tells me that the problem is with the computer - or more specifically, my computer doesn't like this particular cam. He has tried installing a different computer with similar results. I spoke with him today and I think he is stumped - I have to wait for some Bosche guru from Australia to arrive next week to have a look at it (with some replacement computer in tow at mega $$).
What is interesting is that he plugged his Bosche unit into the computer and ran the car fine for half an hour (problem disappeared). As soon as he disconnected it the car went back to it's sick state. He explained that the Bosche unit took over running the engine while connected, and that my car's computer couldn't do the job. Hmm.
He also tells me that the old computer has had a chip upgrade at some stage, and that his Bosche gear can't read the parameters of this chip.
What I was wanting to ask was - is this crap, or can the computer's performance be affected by a cam upgrade (to this degree)
He tells me that my computer is fairly crude and takes input from only a few sources. Is the computer inflexible in that it can't adjust to the cam upgrade? Or is this where a performance chip like the EAT chip takes over?
Any other suggestions - perhaps a faulty sensor that might cause this engine condition? He mentioned the Bosche unit indicated a fault with the crank position sensor, then told me that the E34 doesn't have one of these anyway? I'm confused.
Thanks everyone.
Tim
Firstly, mine is a fairly early 1989 Euro 535i with no cat (leaded fuel map). It's been sitting in my mechanic's workshop for about 5 months now (I am in withdrawal)
The head on my car has been rebuilt and a new slightly warmer cam has been put in (stage one if this means anything to you). The computer is unchanged. The car starts fine and runs great until it warms up - then it starts idling like a rotary engine (large pauses in between firings) and apparently consumes large amounts of fuel, running rich (there was no problem with the old cam, besides the fact it was completely stuffed.)
My mechanic has all the latest Bosche gear and tells me that the problem is with the computer - or more specifically, my computer doesn't like this particular cam. He has tried installing a different computer with similar results. I spoke with him today and I think he is stumped - I have to wait for some Bosche guru from Australia to arrive next week to have a look at it (with some replacement computer in tow at mega $$).
What is interesting is that he plugged his Bosche unit into the computer and ran the car fine for half an hour (problem disappeared). As soon as he disconnected it the car went back to it's sick state. He explained that the Bosche unit took over running the engine while connected, and that my car's computer couldn't do the job. Hmm.
He also tells me that the old computer has had a chip upgrade at some stage, and that his Bosche gear can't read the parameters of this chip.
What I was wanting to ask was - is this crap, or can the computer's performance be affected by a cam upgrade (to this degree)
He tells me that my computer is fairly crude and takes input from only a few sources. Is the computer inflexible in that it can't adjust to the cam upgrade? Or is this where a performance chip like the EAT chip takes over?
Any other suggestions - perhaps a faulty sensor that might cause this engine condition? He mentioned the Bosche unit indicated a fault with the crank position sensor, then told me that the E34 doesn't have one of these anyway? I'm confused.
Thanks everyone.
Tim