LS 24X sync loss when hot

[dustt31]

2014-04-12_18.39.44.csv

Hello! This is my first post here, 2nd MS install. Guess I've been lucky and had no problems with my first project!....
This time however, I'm having an issue that's baffling me.
Its my dads car, a 79 Malibu (ran drag week 2012 on motor with a carb and MSD) with Stroked LQ4 402 LS with a 88mm turbo, on MS3x, full sequential, low-z injectors with 2 JBperf 4-channel drivers, I built the MS and harness.
It starts and runs great, but after running and getting hot it will start to cut out, relay starts clicking on and off like crazy and will eventually not be drivable, and seems to be set off when given some RPM, and will get harder to start. Letting it cool down for a long period will make it run fine again, around an hour. The thing is, its not just hot as in operating temperature; its been driven for and hour, no issue. Last time it happened, drove about 20 minutes, got gas, and then it started right after pulling out of the station, like something heat soaked. Ive searched and have not found anything similar. Already replaced the crank sensor. Throwing sync error 68, flashes half-sync when is happens.

So, my first question is, will sync errors cause the relay to click on and off? Seems to me like it would, just want to rule out its not a power/ground or something else. I've tried different relays and ruled that out as well. Second, looking over my Composite Logger, I see 2 issues. First, the signal appears inverted, I would think this would be an issue all the time? You can see when it happens, looks like a false trigger on one of the long pulses. Is this just signal noise? Im thinking of running a new shielded wire for the crank signal, the MS3 harness had been siting in a box since around 2006. Everything else is new, MS3X was assembled end of 2013. Unfortunately I did not get a datalog when it happened. I could try to get it to happen in the garage, but haven't had any luck. This is my first issue so I really don't know where to start, any help would be awesome.

My thoughts are either a faulty component not liking heat, crank signal noise, or my inverted signal.

[racingmini_mtl]

I haven't looked at the msq or data log but you mention the 4-channel driver board and low-Z injectors. Are you using inline resistors with the injectors? If not, that's a problem because the board is not designed to drive low-Z injectors directly.

Or did you mean that you're using peak&hold driver boards? Those are different and designed to drive low-Z injectors directly.

Jean

[dustt31]

Oh yes, I meant peak and hold boards.

[chybber]

did you find the problem?
got the exactly same problem, works fine until I'll shut it of, it wont start and sync loss like crazy..
Need to wait 30-60 min for it to cool down, then it starts fine.

[dieselgeek]

Had a similar issue to this. Loaded the latest alpha firmware at James' suggestion. Problem solved for us!