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Hey you guys, i have this annoying problem with my GS.
It started the other day stumbling like it wasent getting any fuel, would jerk and cut out above 4k rpm.
Next time i started it, the same only would jerk and cut out above 2k rpm and now it will hardly start or keep running

The distributor is new and due to the fact that is was getting worse fast and it acted like there was no fuel in the tank, i figured the pump was bad or the filter was clogged, wasent the case! Now im beginning to think it might be the distributor anyway allthough its new!

Have a question though, tried cranking the engine with a plug on the lead holding it 5-10mm from the manifold and im getting a yellow spark, not tiny but a nice long yellow spark. Manual says "strong blue spark" So if the spark is yellow, is it too weak for normal combustion??

Maybe the coil is bad on the distributor, havent measured it yet at this time.

Any help or input on this would be greatly appreciated.

If you have a spare distributor to try out, that is a good place to start. Even new units are often garbage out of the box.

DJsMX-3 wrote:Hey you guys, i have this annoying problem with my GS.
It started the other day stumbling like it wasent getting any fuel, would jerk and cut out above 4k rpm.
Next time i started it, the same only would jerk and cut out above 2k rpm and now it will hardly start or keep running

The distributor is new and due to the fact that is was getting worse fast and it acted like there was no fuel in the tank, i figured the pump was bad or the filter was clogged, wasent the case! Now im beginning to think it might be the distributor anyway allthough its new!

Have a question though, tried cranking the engine with a plug on the lead holding it 5-10mm from the manifold and im getting a yellow spark, not tiny but a nice long yellow spark. Manual says "strong blue spark" So if the spark is yellow, is it too weak for normal combustion??

Maybe the coil is bad on the distributor, havent measured it yet at this time.

Any help or input on this would be greatly appreciated.

Sounds just like mine, waiting on a new distributor cap to finish the HEI mod and stop worrying about those distributors. Even if after doing the mod the car still does not start I know down the line I have improved reliability. My spark is also not a good one, which I think is due to a poor distributor cap mod by myself; however I ahd no spark before the mod. If you pull the distributor you can check the resistance in the coils, in my original distributor they were well off.

Well i pulled the plugs today and they were black and all smelled of fuel, so im not missing fuel, rather more the spark is weak or missing, causing the carbon build up and drowning the engine. Please correct me if my logic is wrong.

So i cleaned the plugs and put them back in, hoping it would improve spark enough to get the car running again, disconnected the fuelpump to keep it from flooding while i would perform a new sparktest "to see if the spark had improved with clean plugs" now theres no spark! By the way ignition leads are as new as the dirsty and plugs.

I then checked the coils assuming they were bad, but both coils are within specs, primary 0,7ohm and secondary 13,73kohms

Ill have to check grounds and supply to the dirsty tomorrow, maybe the ignition switch is bad, voltage to low to get a good spark but good enough to open the fuel relay, just an idea.

And ill try to check if the ignitionpulses get to the dirsty allso.

Anything else i could check for? If the NE1 or G signal was missing from the dirsty it should throw a code.

Just think it is really wierd the way the fault evolved, and so quickly, weakening coil would be obvious, but since theye within specs and i have no code it has to be something else that deteriorated quickly

By the way i dont have another dirsty to swap to.

Did you check the intake hose going into the throttle body? They are prone to tearing causing air leaks. Also VAF you can test that with meter also. Spark &I gas also need air right.

Okay i tested everything today, still no sign of a spark, completely dead!
All the grounds are there at the dirsty and allso the 12v supplys. 12v is there both in on position and when cranking, tested it to be sure.
Allso i tested the 1G at the ecu and its 0v in the on position and putting out 2,5v pulses when cranking "manual says below 1v in both on position and at idle" but i dont see this as a fault since its rotating slowly enough when cranking that the multimeter can "see" the voltage, at idle it would be putting out so many pulses at a fast rate that the multimeter would measure lower.

I allso checked the IG/NE1 and G wires from the ecu to the dirsty and they are allso okay!

Tried measuring the rpm at the diagnose box, but couldnt get a decent signal, probertly to low rpm for the meter to detect it, i did however hook up a LED between IG- and 12v and got a vague flickering, so the igniter is fireing but maybo it isnt grounding the coil hard enough to induce a spark

I allso pulled the cap to make sure that the rotor rotate when cranking.
If the timingbelt slipped, wouldnt it still make sparks? Just at the wrong point in time..

So after all this measuring around i still cant say that it is one or the other for sure But since the ecu is putting out pulses and theres ground and supply AND the wires checked out okay it must be the dirsty somehow allthough its measuring out fine

Just REALLY hate that it isnt possible to say for sure, gives me the annoying feeling that maybe the car still wont run after i put in another dirsty

Anyone heard of a faulty ecu in a MX?

+1 on Wags suggestion, but it could also be fuel injector or fuel pressure regulator related and that is much harder to diagnose. Injectors really need to be bench tested to be sure, but if you find the right place having them rebuilt is cheaper than testing. The FPR is not all that cheap, but chaper than a new disty for sure. As for your spark if you get a good spark from the electrode (the tiny tip) to the curved finger the plugs are good. So rest the plug-end on the manifold and test again. You should not hold the whole thing away and see how far it can ark. It will not hurt anything to do that, it is just not the proper way to test.
AtlMX3 had a set of injectors rebuilt and the shop did a awesome job. PM him since he does not visit much and see if he remembers their name.

Im aware of injectors and fpr beeing the possible cause after checking pump and filter didnt help.
BUt then i would have two faults, im not getting any sparks at all now.
I have to get spark to the plugs again before i can search for anything injector/fpr related.

But i REALLY hope its only the dirsty!

Could faulty injectors or fpr cause the fault, evolving so quickly?
withinn 30miles it went from working normally to not working at all, on three trips it went from a harmless bogdown on hard accelerating to wont start at all! I just eased off of the gas and it went away the first time.
On my way back from work it would bogdown above 4k driving ok under.
Third trip i couldnt drive above 2k to begin with and 1,5k before i got back and it died om me twice allmost couldnt start it up again, but got it started with the speeder floored, so it was flooded allso pointing at missing or weak sparks "could be injectors flooding the car allso" Next day car wouldnt start at all, looked at it in the evening again and it fired up long enough for me to see the spark was weak, leading me to believe it had been flooded again and the fuel had evaporated during the day. But after that point it hasent started and there is no spark at all now. So im thinking the dirsty started having weak spark, so the engine flooded when i floored it, as the spark got even weaker it flooded at lover rpm and finally the spark died completely.

Checked the stealership and they wanted the equivalent to allmost 1200usd for a new dirsty
Only called them to check, because they can deliver next day but thats freaking ridiculus!!!!!

Finally got my new dirsty tody after two weeks of waiting!!!!!!
After all it was the dirsty, the only thing i couldnt measure out 100% was the igniter, everything else checked out allright.

Second time this year i had to wait two weeks for a new dirsty, so either im going to order a spare for when/if it happens again or i will buy the parts for the external igniter and coil fix, so i have the parts ready for the next time..

But earlier on it was possible to buy a dirsty-cap with a extra nipple for the high tension-lead from the external coil but now i cant find it anymore, are they still for sale somewhere??

Anyone seen theese 7nipple dirstys recently?

I see you are in Denmark, so not sure if this does you much good, but the PRD web site sells the modified distributor cap at this link.

Keep in mind the ignitor is a seperate system from the hall effect sensors that give the timing signals (therefore spark and injector) to the ECM.

external coil/ignitor only fixes half of the potential issues.

Im used to ordering parts from around the world, so thats no problem but wasent there a cap where the seventh nippel was placed just like the others?

I know Ryan but i would allso order a distributor-module, its a fairly cheap part.
Then i would have hall-sensors, igniter and coil ready to swap out