M42 won't start

[KenC]

Only when cranking? I can hear my m20 pump when i turn the key to on... ?

I really don't remember... and mine is several miles away so I can't check :(.

[Funkmasta]

4 most common M42 no-starts in my experience

Ecu
Crank position sensor
fuel pump
intake leak

[Jordan]

I don't recall on M20 cars, but on M42 cars the fuel pump does only run in crank or run.

[Funkmasta]

Curt, try to crank it and the pull a plug... see if it's wet. OR have someone crank it and get your nose down by the tail pipe...

[Van Westervelt]

Crank

[KenC]

UPDATE:

Pulled the head tonight. Everything looked fine. Is there place I should look for warpage? Will it be obvious? The head looked perfectly straight. Bit of build-up on the cylinders, but that's 280k for ya.

Head is going to be pressure tested before it's reinstalled.

[Hick]

So? what have you found?

[KenC]

Head still hasn't been pressure tested. We need to remove the cams first. The plan is to remove them today or tomorrow and then have it tested. If it checks out alright, we'll slap the cams back in and remount them head on Wednesday. If it compression tests OK after that we're going to remount everything and try and fire it up. A long work schedule and not having the car near me has made this a slow process.

[M42Technik]

M50 swap. ;)

[318ls]

My M42 didn't start as well 3 weeks ago. After going through all sensors, I did find out the CPS have gone hell. Do a simple check with your DMM, it should read about 560 Ohm or so. Mine actually read over 1500kOhm...

[KenC]

My M42 didn't start as well 3 weeks ago. After going through all sensors, I did find out the CPS have gone hell. Do a simple check with your DMM, it should read about 560 Ohm or so. Mine actually read over 1500kOhm...

Both crank and cam sensors read well within spec. I also replaced them with known working ones.

[KenC]

I should get the diagnosis on the pressure test of the head this afternoon.

[Funkmasta]

Aluminum head rebuilders says: exhaust valves not seating, due to carbon buildup. Fairly common with the M42s they said. The flash carbon buildup was probably due to a minor overheat...

hmmm

[Simon S]

update ?

.

[KenC]

update ?

.

Ran like a champ once the head was popped back on.

Now to fix the leak from the thermostat housing :/