7mgte no start condition

[Wade T]

Car: 90 Supra

Went to start the car Tues and when the starter engaged there was a shutter and a sizable backfire out through the AFM. After that cranking would only give an occasional back fire. It sounded like timing

It's getting spark and plenty of gas.
No codes.

Took off the timing cover tonight spun the crank around till the marks all lined up. Belt tension was in spec. I removed the oil fill cap and the lope was pointing at a ~45 deg angle - it should be pointing straight up. Spun the crank around till the lobe was straight up and the cam gear marks were off by 5 teeth!

So, what could this be, a sheared crank pulley key?

Thanks.

 

[kingofyo1]

sounds like you've done your homework sir

 

[kotu100]

its possible, however i think if the timing belt jumped, it could have caused the problem.

 

[Wade T]

Well, it runs again!

Did some testing.

The T belt was replaced at 15k miles ago and looked perfect.

Removed the #6 spark plug and put a rod down the spark plug hole - didn't want to remove the coil pack cover for #1(lol). Spun the the crank past 0 a few times to check piston TDC and the rod stayed at it's peak hight - TDC on the compression stroke with all marks at 0 (whew!).

The cam lobe thing had and still has me scratching my head. Both cam gear guide pins were on the center hole yet, while comparing it to the 85(7mgte) the 90's lobe seems off - appearing to point at the #1 cylinder. Perhaps it's 165k miles wore down the lobe?

Anyways, as a last resort I swapped in a spare CPS and she fired right up! What a relief!

 

[Wade T]

sounds like you've done your homework sir

haha, thanks. With 10 years of playing with these motors there's always something new!

 

[sogi99]

wiggling the cps connection did the trick for mine. Of course, after that the car never did that again.