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Matt's '88 780

Alright, so some more interesting:

Yesterday afternoon it was about 25*C and I just about immediately threw a 4-flash code - the car was running for maybe 45 seconds from dead cold and I got the code the first time the engine went above 2500 RPM. It flashed until I got to the first set of traffic lights where I shut it off and restarted it to reset the code, and the very next time I got it above 2500 it happened again, and I restarted it again to reset. I kept it below 2500 for a while and it didn't flash a single code. About 4 or 5 times that drive, I'd restart it and rev it above 2500 (WOT or neutral, didn't matter) and it would flash the 4 at me.

After leaving the pub the temperature outside had cooled off to maybe 19 or 20*C, and I took the long way home. It flashed the odd knock code but no matter what I did, I couldn't get it to flash and hold a 4 again.

The other day I started it up from cold to go get lunch and got a 4 flash as I left the office, and after I ran in to grab some lunch & came back out, it ran flawlessly on the way back to the office.

I'm thinking that it's a heat issue with the ICU. It's obviously not related to engine temperature or load, but one of the characteristics of this car is that in hotter weather it would ALWAYS run crappy, so it seems to be strongly related to ambient temperature. Being that the A/C has never been hooked up, the temperature inside the car is always =/> the temperature outside the car. The times when it's done it during warmup and then not on the way home could have been from the interior cooling off with the windows open - it's hot enough to make it happen at first but cools down enough with the windows open so that it doesn't happen again.

ICU swap happening soon.
 
That's the thinking I was getting, not so much that it was getting abnormally hot and needed modification like that, but that there was a cold solder joint or some component that was being affected by heat.

Anyway, the damn thing threw me a curveball this morning: I had to run my boss over to a tire shop and my car threw the code immediately. It was still cool out and it was cool in the interior, and the engine was practically up to operating temperature.

The monitoring continues!
 
Well I don't want to speak too soon (sort of like I have whenever ELSE I speak on this latest subject :lol:) but I think you might have called it earlier, Boosted: The last time it happened I popped the hood and reset the bulkhead connectors, and I haven't gotten a code (or a knock light) since. I haven't been able to replicate the CIRCUMSTANCES under which I was getting the failure code before, so we'll have to wait and see.

Sure does run nice when there's no code set, though. :)
 
awesome! lets keep our fingers crossed that it dosent re occur. if it dose and you do the connectors again and it fixes it for a while i sugest replacing the connectors with weather pac or some other good connector
 
SFSG, not a code since, and barely a knock event that I've seen. Car runs like a top, I just have a couple things to fix up and I can enjoy it for the summer.
 
Nope, no aftermarket ignition in it yet. I've never run one, not sure what the benefit would be in an otherwise completely stock motor? If I need a BTM for whatever reason ( :blah: ) I'd be looking towards an all-in-one system, though.

A fleeting thought is along the lines of the Buchkas' wasted-spark EZK mod, though... AFTER the more pressing matter of ditching the automatic.
 
it wakes it up some. and i saw an improvement in gasmilage too. went from 19mpg to 21 all day long. just open the plugs up another .005. i alway ran platnums too. all the other plugs i tried prior to droppin the cash on em didnt run as smooth
 
Matt Dupuis said:
Interesting read so far, I'm not finished yet though.
Click to expand...
Definitely - one year long issue solving has to be interesting :)
Matt Dupuis said:
The first thing I saw wrong was that he got TWO flashes. Two flashes mean faulty ECT signal, according to the EZK ignition greenbook. One flash means knock.
Click to expand...
In fact, it was two single flashes - two knocks.
Matt Dupuis said:
I am also getting a series of single flashes rather infrequently while I drive. It does seem to be between 2000 and 3000 RPM, but it's only under certain load values. I don't think it's anything unusual, really, just a product of having a knock sensor based ignition and a slow-burning engine.
Click to expand...
It depends what gas do you have in your tank. B280F requires N91 or better, B280E requires N95 or better (RON). But if you fulfill the requirement, there should be no knock at all. Knock sensors are used as the last protection against engine damage, not as something that should adjust your timing every day.
Matt Dupuis said:
The "four flash" error I got was DEFINITELY an error code.
Click to expand...
Ok, I am glad that the ignition diagnostic helped you. When I saw the rpm range you've got the knock, I immediately thought - whow, another one :-D but this seems just as a poor contact in the KS connector.
 
I think that's correct - that my only issue was a poor contact in the KS circuit. Since correcting it, I've seen maybe 1 or 2 flashes total in the last tank of gas, but it hasn't been very hot out since correcting it...

Anyway, thanks for the links to the diagnostic light and to the test methods, guys.
 
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