I have a '97 Hyundai Elantra (That has been turned in to a Dirt Race Car) anyway the car will idol for an hour fine. When we take it on the track it will run 4 or 5 laps fine then we take it in the pits shut it off for an hour and then go back on the track and on the 2nd lap it will quit and will not start it will crank but their in no spark also the dash lights no longer work. After the cars sits for a couple hours it will start back up and idol fine. We have replaced the ECU/ECM relay as we thought that was the problem but the symptoms remain the same. We have checked fuses and don’t seem to find a problem our next step is to replace the ECM but wanted to know if anyone has any suggestions for this problem
All I can say is DO NOT replace the module just yet.
The engine control module is very rarely the cause of problems
MANY modules get needless replaced
Because proper AND complete diagnosis has not been performed
No offense, but it sounds like you haven’t actually done a lot of diagnosis yet.
Other than agreeing completely with db4690, I might ask if you’ve been on this forum at some point in the distant past as this complaint sounds somewhat familiar.
No spark and no dash lights (which I assume to be warning lights) could point to a faulty ignition switch but that’s just a WAG.
We have also checked all grounds and fuses. I have not been on this forum before so possibly someone else asked the same question
If there are no codes, etc then it still comes back to me as a possible ignition switch problem or a power source problem to the switch. That could mean a poor connection on a fuse link, etc. Sorry I can’t be more precise.
ECMs do fail sometimes but it’s very rare and should not affect the warning lights.
Why did you replace the ECU/ECM relay? Did you use your DVM and found it wasn’t operating when it should? The fact that the dash lights don’t work is a major clue. I’d use that fact and go from there.
From what I see for the instrument panel lights on a 97 elantra sedan w/l4-1.8 engine, there’s a 10 A fuse in the dash fuse box that should be hot in “on” and “start”, check there first. If there’s no power at the input to that fuse, it is either the ignition switch or possibly some relay malfunctioning. To find which relay, work backwards from there, consulting the wiring diagram. If not that, i.e. the fuse is powered up and is passing current, it looks like there are several grounds involved which complete the circuits, so it could be any of them, but check ground 1 and ground 3, those are likely candidates affecting the dash lights.
May have found the problem. A fuseable link (I think that’s what they are called big plastic fuse like things under the hood) was blown but still making a slight connection so it worked till it got vibrated apart but then when things cooled down it touches again. Will find out for sure tomorrow night
If it turns out to be the fusible link, me, I’d put the old ECU/ECM relay back in. The replacement part – unless your purchased an OEM version meeting 100% of the OEM specs – is probably not as reliable as what you had in there originally. You’ll likely save yourself future grief by putting the old one back in, even if you can’t return the new one.