After around 25000 flawless KM of driving, now my '87 328 has developed an issue which i think is ignition related. While driving, sometimes it starts misfiring on one but i expect on more cilinders. Some bangs of petrol igniting in the exhaust. And then after some time ( read, minutes) , it run normal again. Sometimes this issue occures right from the start, sometime after driving for an hour. As normal maintenance was due anyway, i replaced the plugs, caps and rotors but this was without any change. I tested the ignition modules by running the engine on one cilinderbank only. On one bank it ran reasonable ( as expected)_ on the other t ran crap. So i thought it was the module was at fault and i changed them both to the other bank, just to confirm. However at this test both banks ran the same ( reasonably good) As the ssues seems not constant, it still could an ignition module but it's not conclusive. What else could be causing ths issue? Has Somebody a similar experience, and cure?
Very rare for a transistor module to be intermittent. More likely a connection issue. I have seen cases of incorrect plug wires causing RF interference in the ignition system and be very intermittent. The Microplex system is very sensitive to RF and it has some very effective antennas running close the the secondary ignition components to pick it up. I have cured a few gremlins by replacing with known good, correct plug wires when all else failed.
Along Brian's thought -- did you measure the resistance per foot of each wire from the metal contact inside the cap to the metal fitting at the end of the extender (and from the center button to the metal fitting for the coils) when you replaced the caps (and I assume you trimmed off ~5mm and did a fresh piercing for each wire)? Were the values reasonable and consistent?
You did not say anything about the plug extenders. Those low quality ones have caused a ton of trouble and do not last very long.
I experienced RF interference in my '87 GTS a number of years ago but the symptom was different and very perplexing. Took Rifledriver's advice and replaced original ignition wires. Problem went away immediately and never returned. I always wiggle the wires when I check them for resistance looking for fluctuations in readings. They are not sitting still when driving.
As noted, the plug extenders can be the problem, they can also not seat as tight as necessary, and can cause intermittent misses.
Replace all the plug extenders, wires, and the two caps and rotors, and while your at it, the spark plugs. Just my opinion Thank you Good luck Sir
I also found that even a small excess spark gap can cause some rough idle, and misses as higher rpm, so yes as noted check the plug gaps. The distributor caps after 25,000km could also have some deposits on the contacts. You can just clean the contacts, and perhaps replace the top carbon button in the cap which is available separately, the caps are expensive and not throw away items like in regular cars and can be serviced. The rotor is surprising small in size, but from my observations its the cap contacts that seem to need a periodic clean up. Caps, rotors, and wires/extenders are expensive and so don't replaced as often as in regular cars. Try checking some of the easy to reach plug gaps first (or just replace, the conventional NGK's are cheap and that is why your tool role has the spark plug socket), and makes sure the wires affix snuggly, that's the cheapest and easiest thing to do first.
First thing to check is if the coil packs are breaking down. With the engine cold, start it up and drive around until it starts to misfire, with the engine still running put your hands on both coils and see if one is warmer than the other. The warmer one is the problem. As it starts to break down it runs warmer. If the above does not help then next thing to check is the fuel distributor head, have you noticed the level of the sump increasing or a smell of fuel on the dipstick- if the seals are gone then it will misfuel different cylinders with excess fuel or no fuel. Unburnt fuel can pass the piston in to the sump oil. You can get a repair kit on e bay as the k tronic system used on other cars like volvo. About £50 for the kit and an easy diy job.
Ok guys, Thanks for all advise and suggestions. i ordered new leads and extenders so let's see where this brings me. I will keep you posted.
oke replaced the leads and the extenders today. Not the nicest job as reaching the front bank s pretty bad. Anyway, all work done but with NO result whatsoever. If i did not do anything... So replaced now are the plugs, the leads, the extenders, the caps and the rotors. Somebody some more advice?
You should go back to doing some diagnosis. My comments finished by saying "when all else failed". Throwing parts at a problem can be justified but typically only when you are out of options. I don't think you are. You were getting some results by trading parts from bank to bank. I'd be doing that. I also suggested a possible problem with connections. I'd peruse that too.
You are right sir but most of the work was due anyway so i hoped it would be the cure along the way. As I now start to be done with regular maintenance I will focus more on all connections. But there seems to be only a limited amount, right? I already checked the ECU earlier thinking it might be wet and looked at the connector but this one seems oke. I also checked both flywheel sensor connectors and they look clean as well. what more are there?
no real difference there but i kind identified on which bank thre problem is so i will swop the coils tomorrow
New plugs, new wires, new extenders, new caps and new rotors. OK, not much left. I once had an ignition problem on my 328 because the two little connectors at the left of the engine bay that feed the two TDC sensor signals to the main engine harness. The connector was not tight all the way and it caused misfiring constantly. Your problem is more intermittent. Perhaps one of the two TDC sensors is on its way out. I think you need an oscilloscope to look at that signal though. At this point, I think you need a scope to start proper troubleshooting.
When i had a problem with my coils, i was starting to get a misfire after the car had been running for a few miles. Started up fine and got worse the longer the engine was running. Dealer told me to drive it until i got the misfire, then jump out and feel for a difference in coil temp- the difference is not much but it is noticeable. They are either the same temp or not. Any history of the fuel distributor head being fitted with a repair kit as that is the next possability
I have. The problem was a bad ground connection. A couple other posters have suggested diag and a scope; I think you need to start testing circuits and get some hard data.
Was just going to say this. I lost a bank on my 85. No spark on any cylinder. The consensus here was replace the crank sensor. After properly diagnosing the problem with a scope and impedance measurements I found a carbon track in the rotor. $12 later and the cars runs perfectly.
that is true, the problem is with electronics i never am very good in testing. No real clue where to start. i did some: It seemed at some point two days back that i identified which bank was the one with an issue. Today i was out for a short spin to confirm my earlier findings and with the plan to swop out the coils. Starting went fine, the first haf mile too and than the issue accured again. This time however much worse so i hardly made it back home. So my plan to swop faied before i started. I did start to explore and cleanup all connections i could find. I will contine with this a little tomorrow I did feel both coils immidiately after got home but there was really no temp difference between them.
Not sure if this will be of much help, but I was experiencing a somewhat similar issue with GTSi , so not quite the same as your 328, however , mine would randomly drop an entire bank and never do it while I was able to have the engine cover open to enable me to determine which bank it was that was dropping out. I was convinced it was obviously spark related as it would usually backfire when the bank cut back in. I visually checked all electrical connections and cleaned as best as possible with no success. I was also pretty confident it wasn’t a cap/rotor/extender issue as the fault wasn’t engine load related. Long story short I found a post on here somewhere suggesting using deoxit followed by a product called stabilant22 on electrical connections. I did this to all my connections / plugs and happy to report about 400km later not a single cough or splutter. So my problem appears to have been a poor electrical connection ( my suspicion was to one of the coils) that visually looked ok but wasn’t Hope that info may be of some help Sent from my iPhone using FerrariChat
Do you have a multimeter you can connect up to the 12 volt coil feed terminals, 2 meters if u can borrow one. Run the wires into the car and get someone in the passenger seat and go for a run, see if the voltage is steady or drops when your trouble starts. When it starts playing up do you start getting misfires ?
As some small part where on the way, only today i did some work again. And contrary to the common believe that the ignition modules either work or do not work, my intermittent issue clearly showed different. I changed out both for new ( Bosch 0227 100 137) ones and the car now runs flawless again. Thanks all for the support!