astrarally

Rally car on GEMS ECU ... could this be the cause of my mystery misfire ??? Car runs 100% fine for around 30-40 mins at a time, then starts to misfire v badly. All the obvious causes have been checked, plugs replaced, etc ... anybody offer any advise on whether this is actual "damage" or just a used component ??? Thanks

astrarally

JDM_Stig

iTrader: (3)

Sounds like a CTS issue tbf

astrarally

GEMs seems to ignore a lot of the stock sensors - MAF (uses MAP instead) and O2 in manifold i was told it doesn't use ... but CTS i'm not sure but i will give it a try thanks

Shane

iTrader: (6)

Those 2 resistors and the capacitor have been replaced by hand at some point, possibly by Gems when the unit was tested but the soldering is poor and they should really have cleaned the flux off the board after they were done. Unless they are the wrong values then I don't see why they should cause a misfire unless the soldering is that bad the connection is breaking down when it gets hot, it looks like it has flow through on the plated through hole though so highly unlikely.

sparrowdclxvi

That board has been repaired by hand at some point. Repair looks solid, so I don't think that's the cause of the problem

As all of the components are through hole, it would mark that as quite an old ECU, so it could just be age related. The answer to this is probably no, but do you have a spare you could swap out to eliminate the problem?

astrarally

Interesting ... thanks for the info much appreciated

I haven't got a spare, if anyone has one i could borrow/hire please can you get in touch

GEMS can do a full test/recon but not in time for rally Yorkshire next Saturday :-( :-(

astrarally

I think you are my guardian angel !!!

CTS swapped over and the problem hasn't resurfaced after 2 fairly long test runs. I'm heading out during the day tomorrow and if all is well we will be back on for Trackrod Rally Yorkshire this Saturday and a massive thanks to your advise

Could the CTS function okay for 20-30 mins and then fail ? anyone else had this, runs fine cold and hot but then fails after a prolonged period of time running hot ....