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The mkiv Supra Owners Club

Cam sensor resistance checks


Mike M

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Hi Folks,

 

In the ongoing hunt for my misfire / popping at idle and just above idle I decided to check out both cam position sensors.

What a total PITA of a job trying not to drop the bolts and i've still got the rear one to remove. The middle one was gunked up and the rear sensor connector was full of oil making me think i'd found the culprit but cleaning didnt help. Going to try removing this tomorrow.

 

Anyway the point in this thread is to check what resistance is normal on these things and i'm guessing they should be both the same.

 

Mine were:-

Middle sensor = 1381ohms

Rear sensor = 1476ohms

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Thanks mate, I'll be checking the crank sensor next and cleaning it up. If that doesnt help then i'm going to try and ignore it till the stem seals are done.

 

How does your misfire compare to mine in the vid?

Mine has been slowly getting worse and never seems to go away. It does drive well though.

 

http://smg.photobucket.com/albums/v640/mikemajorek/?action=view&current=MOV00393.flv

 

Cheers

 

Mike

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Thanks mate, I'll be checking the crank sensor next and cleaning it up. If that doesn't help then i'm going to try and ignore it till the stem seals are done.

 

How does your misfire compare to mine in the vid?

Mine has been slowly getting worse and never seems to go away. It does drive well though.

 

http://smg.photobucket.com/albums/v640/mikemajorek/?action=view&current=MOV00393.flv

 

Cheers

 

Mike

 

Pretty much the same, does yours also only start as its warming up IE before it drops into closed loop? mine also seems a bit variable, but in general its getting very slightly worse:(

does yours pop on the overrun?

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Pretty much the same, does yours also only start as its warming up IE before it drops into closed loop? mine also seems a bit variable, but in general its getting very slightly worse:(

does yours pop on the overrun?

 

Yeah sounds like we have very similar issues.:(

Its rock steady from cold but after a few minutes it starts off popping and missing.

Also pops on the over run.

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Must be some kind of Supra virus;) at and least we can bounce ideas off each other, Silversoop also has similar problems.

 

Absolutely, hopefully we can get to the bottom of this pesky problem.:)

 

This is a list of what i've done so far and got no joy.

i'm in TTC BTW but had the misfire beforehand.

 

Known issues:- the stem seals are needing changed, I get smoke on start up after its sat for more than two days.

 

Replaced spark plugs starting her up after fitting each plug in case one was dodgy.

 

Stripped down each coil pack clip and tightened up the metal connector. Again started engine after each one.

 

Replaced coil packs one by one with a good spare, started engine after each change.

 

Cleaned up idle control valve.

 

Replaced O2 sensor.

 

Tested O2 sensor, getting 0.7 - 0.8 volts. Slightly rich.

 

Checked for fault codes, none present.

 

Now checking cam sensors and then crank.

 

Oh and i did a compression test a while back and most were above 180PSI, lowest was 175 or 170.

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Mine is a single, checked all that you have, no known issues, no codes, at the same stage, in that I'm going to recheck the cam sensors, and then crank sensor.

I was convinced that it was an exhaust leak for a while, but not now, my only other check will be trying another EMU just in case,

must admit I'm baffled! as it doesn't seem to conform to any of the usual culprits.

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Did you remove the cam sensors? I've just removed and cleaned up the rearmost one, cleaned up the connector and tested 1392ohms which ties in better with the other one.

 

Fired it up, sounded smooth on cold start, revs dropped after a few min and the stuttering started but smoothed out gradually.

The idle was different, rock solid at 500revs you then blip the throttle and the misfire would come back as the revs settled then rock solid again.

So i've annoyed something, i'll need to try it out over a few days and see if its repeatable.

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