DANdeMAN

Hey guys, I'm in the Ottawa area, I need to borrow a known working ignition distributor for an 84 928 to confirm / infirm that my distributor is or isn't the cause of a recurring misfire. Will pay for shipping if out of the area and give you any guarantee of return that you request. Thank you. Daniel

Adamant1971

Have you changed the CPS yet? Sorry I don't have any 4.5 or 4.7 distributors.

You could test the unit for resistance with a multi meter and the plug wires as well, to rule them out.

Good luck

DANdeMAN

Adamant, don't know what a CPS is. What resistance am I looking at to check the wires?

Some additional info. Maybe someone will have a "AHA" moment from reading this. Thanks.

Here is the short of it : New injectors, plugs(the old ones looked good), rotor(cap looks good) and connectors. All donne last week. Coil, wires, both coolant bridge sensor in 2008/9 when I did water pump timing belt job but low milage since. For whatever reason, some time after that the misfire started. Had the alternator rebuilt, no change. Started a thread and checked all that was suggested and after some time playing with this and that, I said f*ck it and drove it as is but it wasn't as bad as now.

Here are the 3 WTF symptoms that may help you help me.
1) No misfire during the engine cold running cycle. After the cycle, about 2 minutes, the engine revs go down and misfire starts.
2) Often after changing the timing (advance or retard) the problem goes away for that day but the next time ( can be a day, a week or whatever) its back. When the alternator was rebuilt and nothing changed, I went back to the shop. The tech came outside, turned the distributor and the car ran perfect but you know the story... The cat came back.
3) Misfire are at idle and low RPM only. There is no starvation or miss when pulling hard... For now.

So you can see how baffling it can be. I was so pissed off, I went to an import garage who seems to know 928s for some help pinpointing the problem. He(the owner) confirmed my suspicion about the distributor and said : "if it is a high milage car(my car as 250,000KM) the bearings may be worn inside and the play from that may be the cause for the misfire".

Now, I have checked the play and it is very small. But from what he said, it does not have to be big. Is it that, is it not that? May be may be not, but I'm getting desperate and will try about anything except trowing more money at it. I just spent $700 and 15/H doing the injector/connectors/plugs.

Daniel

Imo000

Stop throwing anymore parts at it! Have the problem properly diagnosed be someone that knows 16V 928s. I have a spare '84 distributor but I'm not 100% sure if it prefectly good, I think it. I can send it to you and you can try it. If nothing changes, the the problem is 't the distributor or the bearing in it. I have a reeling you have a sesor or ground calbe problem.

DANdeMAN

Yeah, finding a good 928 tech is like drilling for unobtanium in your backyard
There may be one not to far from here but the first and only time I went there, he soiled my carpet with dirty boots. So not to keen on returning to is shop. Didn't like is personality either.
As for the dizzy, Wayne in Caledon as one. He is going to check it and if it's presumed good, he will send it to me. If for some reason I can't get it, I will give you a shout. Thanks

Ground points are the only thing I did not do yet. I even cleaned the fuse/relay board.
Will work on the ground while waiting on a dizzy...

Adamant1971

Oh yes do the grounds, and change the ground strap at the battery.

But I agree don't throw any more parts at it, till it's diagnosed properly.