Ok, thanks in advance for the help... we're working on a 92 Accord today that is experiencing loss of spark. Initially the vehicle was running and began to intermittently die at random times. After some inspection, we found that when the vehicle would not start, there was no spark present. During our tests, we confirmed no spark; however, at times during the tests we would have sporadic moments of somewhat normal spark operation through spark plug - the vehicle would either run, or begin to fire, and then spark would disappear completely and the vehicle dies.


We have tested fuel pressure and determined that the issue is spark-related only; fuel pressure was 42psi during all tests.

Tested the distributor sensors CKP, TDC, & CYP which all had continuity and low resistance (approx 350 ohms on all) at distributor plug (unplugged). Also tested continuity of these circuits through ECU plugs & engine harness distributor plug with same results.

HOWEVER, CYP (orange), TDC (orange/blue), and CKP (blue/green) wires all have continuity to body ground (tested at ECU plugs and engine harness distributor plug). It is my understanding there should be NO continuity to body ground for these wires??

Have not tested the external coil (does anyone have a test procedure for this)? Although, we have swapped external coils and the issue is still present.

Are we correct in thinking that we have an issues with the distributor sensor wiring being shorted to ground?


Thx ;-)

 

UPDATE :: After sitting for an hour or two, we attempted to start the car and it fired right up, and continues to run! The CKP/CYP/TDC sensor wires that previously had continuity to body ground now DO NOT. This is extremely odd - we did nothing but let it sit for a while... =/ . Seems we have an intermittent short to body ground? Tried wiggling the harness around and couldn't get the car to skip a beat, seems to start up every time now... But being as we did no repairs, I'm not confident the problem is resolved...

Any ideas?? RonJ, where ya at buddy? Lol =P

 

BUMP

 

Sounds like you could have a main relay problem.

Very common, esp. when you describe how it wouldn't start and then would start a while later. The solder in the relay terminals is know to go bad over time and cause that weird intermittent start/no-start situation. Weird that it would cause it to die, usually it's a no-start situation, but maybe if the connections were really bad it might cause that....

It is located on the driver side under the dash, do a search on here for exact location, there are tons of posts about it. You can either re-solder and repair, or get a new one. I don't recommend a JY one as they go bad all the time.

 

LOL

Main relay for no spark? Ummmmm, NO!


Faulty igniter (very common)
Terminals loose at igniter (also somewhat common, unhook the terminals and squeeze them with pliers to tighten them, be gentle)
Faulty CKP/CYP/TDC (rare, but happens. Repl the distributor sub-assembly)
Check MIL operation when not firing. Make sure it operates normally. Check for injector pulse when not firing. If it is the pickup, the injectors will not be working either.

Those external coils almost never fail, the internal ones fail regularly.

 

LOL, I know right?!?! lol!

Igniter (ICM) had been replaced, no change in symptoms - will check connections, as we did not do the ICM replacement.

Tested CKP/CYP/TDC and appear to all test well. Yes we could swap distributor assemblies - however, we prefer to have a definitive diagnosis (if possible), prior to replacing parts...

MIL light functions as it should - There are no MIL codes when vehicle will not start.

Injectors pulse has been verified. The issue is solely spark related.



Thanks... any other ideas?

 

If the Igniter had failed, would it cause the distributor sensors to be shorted to ground??

 

...bump...

 

I'm not sure, I've never tested one that way.

 

We're assuming we have a wiring issue within the engine wiring harness, but that is just an assumption at this point. Would be nice to have a more definitive diagnosis...

 

Take out the ecu and open it up. Look for some burned spots in it.

 

UPDATE :: There were no noticeable burn marks on the ECU circuit board. However, we swapped in another ECU that we happened to have lying around the shop... Been just about a week now and has been running great w/o skipping a beat... Looking like our problem was ECU-related. ;-)