No compression at all, apparantley

[Chrisso]

Yep, cam timing on the exhaust cam was out. Shifted it around and there's compression now. Unfortunately still no broom broom action at this station. My MS was playing sillybuggers reading the distributor. A bit (3hrs) of stuffing around and it seems to be reading but the battery is low. So, hopefully get some starting action before the end of today.

If any of you megasquirt people have an answer, my question is: Why are the revs reading so low flatish battery ~40-90rpm?

How fast does a 4age usually crank? I would have thought 150-200 as a guess.

[oldcorollas]

the reluctor pickup may not be providing enough voltage for a reliable signal?

also, if you have a flatish battery, it might only be cranking at half usual speed....

[Kyosho]

Edit; Forget it... I didn't see the other 2 posts above as they didn't appear until posting...

[Kyosho]

if their battery was low and cranking speed low, then that can also assist with high compression.. due to more time to fill cylinders, larger throttle opening relative to the engine speed etc etc..
but big overlap should reduce that measured amount.. unless engine speed is slow...

Low battery actually ends up yielding a lower compression reading in all of my experience...

Was testing my cars comp with a shit battery... By the time we got to cyl 4, battery was half dead, cranking at half speed, compression was reading down near 80-90PSi... Put the jumper pack on it, and it instantly span up to 155PSi

[frostyadonis]

glad you found the cam timing problem

you got any spark. on mine i left the ignition on by mistake,causing coil failure

[Chrisso]

I charged the battery while posting and had another crack. The MS was a bit on and off with registering the dissy signal but it was trying to start. Playing with the timing got it pretty close, but now I need to adjust the fueling. Time to double check the required fuel calculations and adjust the cranking pulsewidths.

Thanks for your help guys.