Rebuilt engine fires then immediately backfires and dies

[Pro car crasher]

Still trying to get my rebuilt mk1 running, I’ve sorted out the spark issue with a new igniter and a setting in tuner studio which was wrong, now it’s firing but as soon it starts to go it backfires a lot and fails to start. Not sure what the problem could be.

[Pro car crasher]

https://youtube.com/shorts/4wb4XTNKKzM?si=bV-gwMSk...

The last attempt was the longest I’ve got it to run so far

[Gord1]

I would check all your basic stuff again, check base timing, check cambelt is on correctly (its easy to get it a tooth out), check the ignition leads are on correctly, no vacuum leaks from any pipes etc.

[Pro car crasher]

So I swapped it back to the stock ecu, narrowband, tps and maf sensor, and it fired up immediately! All running nicely just won’t start on the megasquirt. Only problem is my clutch won’t disengage now… tried bleeding the clutch and adjusted the pedal as far as it will go but it’s not even trying to go into gear with the car running. I’m considering swapping out the master cylinder and the slave cylinder in case they’ve gone bad but the arm appears to be moving far enough





First image is with the clutch all the way up, second is with the pedal to the floor, does this look right?

Will try and sort the megasquirt out once I’ve got the car drivable

[MKnight702]

Gord1 said:

I would check all your basic stuff again, check base timing, check cambelt is on correctly (its easy to get it a tooth out), check the ignition leads are on correctly, no vacuum leaks from any pipes etc.

I had Megajolt on my XI and I couldn't get the car to run. After much head scratching, swapping parts, triple checking wiring etc my electronics engineer mate took the actual unit apart and discovered that there was a wrong value resistor (IIRC) soldered to the motherboard. This resistor meant that everything functioned as it should, however, the signal to the coil pack wasn't strong enough to trigger a spark, without him I would never have found it in a million years.