Hi all
Hope somebody can help me to get my cat back on the road. Every now and then, the engine just cuts out at speed. Sometimes if you select "N" on the gearbox, it will start again as you are still rolling, sometimes you have to stop and wait between 3-30min until it will start again. You can turn the key to start but the starter will not operate. No codes to read out, all coils are new.
Can anyone help?
Matt

 

Maybe the fuel pump is intermittent?
When you crank after the cut-out, does the tach come up to about 200-300 rpm while cranking?

 

Hi Ross
Fuel pump is new, jes the tach comes up to about 300rpm.
Matt

 

OK, so that means it IS NOT the CKPS. Maybe look for an intermittent fuel pump power issue. It takes air, fuel, and spark after the engine is already running. You are lucky in a way in that it does not immediately re-start. Figure out what you ar loosing, probably fuel, but maybe spark!

 

I was having this problem back in January of this year and I think I solved it by replacing the ECM relay. Hard to say exactly because I changed out the alternator that same week, but days after I swapped the relays and before the alternator changeout the problem seemed to be fixed. First I swapped the AC clutch relay (known to be good) with the ECM relay and I found the engine cutouts stopped and the AC was sketchy at best. That week I bought a new relay for the ECM and put the AC clutch relay back in its place. The relays are located right behind the right front headlights. The ECM relay is the right-most as I recall. The AC relay is 3rd to the left as I recall. It's worth a try.

 

Thank you all for your tips! I'll have a go at the ECM relay. That makes a lot of sens to me. @GatorJoe Do you know what the 3rd relay is for and are the relays all of the same type? maybe it would be worth changeing the all..?

 

No, I don't know the make and model of the relay; I just called the local indy garage that works on Jags, Bimmers, MBs, etc. and had them order a ECM relay. I picked it up and installed it. Cost me $19 or abouts.

I think all three relays are the same, but I as I recall the second relay was more important to keep running than the AC clutch relay given that it was winter.

 

The relays as mentioned by others is ALWAYS a good idea. One other thing to check since you seem to be intermittent. Check the two large connectors right below those relays. Wires there can corrode and lead to your symptoms, and eventually leave you completely unable to start. Just be sure to check them with the car in a safe, out of the way place. If the problem IS there, you're probably dead in the water until it's fixed, once you take them apart.

Good luck!