AJP8 No Start after Top End Rebuild
Discussion
Engine turns over at the appropriate speed, definitely fueling (airbox/hoses off), then occasionally firing back through the intake.
Double checked plug lead connections, but need to confirm the following wiring loom arrangement:
Loom with Odd TP has connections for Odd bank plugs and EVEN bank Coil Pack, similarly Even bank loom has connections for even bank plugs and TP but ODD bank Coil Pack - correct?
CPS is new, if faulty would injectors fire?
Flywheel has been off but care was taken to replace with dowel in correct place.
Not checked compression, but why is it firing back through the intake?
Double checked plug lead connections, but need to confirm the following wiring loom arrangement:
Loom with Odd TP has connections for Odd bank plugs and EVEN bank Coil Pack, similarly Even bank loom has connections for even bank plugs and TP but ODD bank Coil Pack - correct?
CPS is new, if faulty would injectors fire?
Flywheel has been off but care was taken to replace with dowel in correct place.
Not checked compression, but why is it firing back through the intake?
Paul, your wiring seems correct. Have you checked you're definitely getting a decent spark on all plugs?
I recently had a couple of problems with mine caused by a poor connection at the engine bulkhead connector (mine's an early Cerb with the bulkhead connector under the expansion tank), the fuel injectors on 1 bank weren't getting the full 12v on 1 side, and the TPs werent able to send a signal to the ECU, when I put the laptop on the TP readings remained at 9.5% regardless of throttle position. Not surprisingly the engine turned over fine but didn't fire. Interestingly the coolant temp, air temp and pressure read fine so the ECU didn't put the radiator fans on, which would have been a dead giveaway that there was a problem with the bulkhead plug. Maybe worth a look?
I recently had a couple of problems with mine caused by a poor connection at the engine bulkhead connector (mine's an early Cerb with the bulkhead connector under the expansion tank), the fuel injectors on 1 bank weren't getting the full 12v on 1 side, and the TPs werent able to send a signal to the ECU, when I put the laptop on the TP readings remained at 9.5% regardless of throttle position. Not surprisingly the engine turned over fine but didn't fire. Interestingly the coolant temp, air temp and pressure read fine so the ECU didn't put the radiator fans on, which would have been a dead giveaway that there was a problem with the bulkhead plug. Maybe worth a look?
CerbWill said:
Paul, your wiring seems correct. Have you checked you're definitely getting a decent spark on all plugs?
I recently had a couple of problems with mine caused by a poor connection at the engine bulkhead connector
Many thanks, I did remove the engine earth lead in order to put the new heat shield sleeve on the battery earth cable. I will check it again as well as put the Diags on later today.I recently had a couple of problems with mine caused by a poor connection at the engine bulkhead connector
jamieduff1981 said:
Last time I had mine apart I checked, checked again and still somehow had the HT leads plugged in 90deg out around the coil packs.
I would have thought that firing back through the inlets is a timing issue. Ive had this on older cars with the dizzy/cap 180 deg out, so plug lead order makes sense.jammy_basturd said:
Also double check the crank sensor? Though I'd imagine that would show up on the diags.
It is new, and shows as good on the Diags, as well as Crank Wiring, whatever that is.Will try swapping back the old one just in case.
Edited by ukkid35 on Monday 28th September 16:13
I used a simple light bulb spark checker on cylinder 1 and 2, all good. I did a compression test on cylinder 1 and 2, both were 230.
I checked the plug leads again, for about the forth time and they are as below.
I did find that a couple of leads were not seated properly in the coil packs and thought I'd cracked it, but no - the firing through the intake became even more enthusiastic.
What on earth have I done wrong?
I checked the plug leads again, for about the forth time and they are as below.
I did find that a couple of leads were not seated properly in the coil packs and thought I'd cracked it, but no - the firing through the intake became even more enthusiastic.
What on earth have I done wrong?
I had exactly this problem but only on one bank. One bank ran fine and the other was spitting back through the intake, this was after a valve clearance and timing check.. It took me ages to sort and even swapped my valve timing by 180 deg before I spotted it, I then had to correct the timing back to what it was as it wasn't the valve timing. If you are certain on the valve timing I'd go with the ignition, mine turned out to be one coil was back to front. Note the wiring connection on the side of the coil, the coils should be installed facing opposite directions with the low voltage wiring on opposite side to each other. I put mine back with both on the same side which switched the firing order around by 180 deg.
If you have already checked this then it may be worth just swapping it all around and giving it a try.
If you have already checked this then it may be worth just swapping it all around and giving it a try.
Shanksy87 said:
My experience similar to these symptoms was the result of a bad coil pack dropping spark on two cylinders.
There was no hint of ignition problems before the strip down, so I didn't even consider replacing the coil packs, but since you can now pick them up for £14 inc delivery perhaps I should have done.Gassing Station | Cerbera | Top of Page | What's New | My Stuff