View Single Post
  #6  
Old 12-16-2007, 07:25 PM
grasshappa grasshappa is offline
AF Newbie
Thread starter
 
Join Date: Dec 2007
Posts: 10
Thanks: 0
Thanked 0 Times in 0 Posts
Re: 87 Cherokee Laredo 4WD Manual 4.0L cranks, but won't fire.

Ok, so here's my sensor results -

TPS seems perfectly fine - 5.0V supply and .85V output

MAP sensor supply is perfect 5.0V, but backprobe output is 3.5V (suggested cold range is 4-5V) How bad is this, if bad at all?

CPS seems borderline - resistance is 165ohm (should be 200 +/- 75), cranking voltage is .45VAC (should be .5-.8VAC) How bad is this, if bad at all? If you can't tell, I'm really hoping that this isn't the problem, so that I don't have to try to replace it. Perhaps I will try the "tonk the mount" procedure to get this in range. I know, I know, I should change it anyway...

Stator gave strange results, and I'm going to have to retest and make sure I am backprobing the correct wires. The blue B connection to engine block ground gave 7.25V (spec is 7.1V). The blue B to the black A ground gave 2.25V (should also be 7.1V, yeah?). The blue B to gray C gave 0V (should be 5V). <Implies sensor is bad! The DCV seemed to be fluctuating on the digital readout when cranked, so that seems to imply that the sensor is good! I will try to check these again soon, because now I'm not sure about those connections. 7.25V - 2.25V = 5.00V (proper B to C backprobe V) which is why I think I need to verify these numbers!

So, I guess the Stator seems like the biggest suspect now, but I suppose I haven't ruled out the CPS or the MAP. Like I said, I will test the stator again, and then do the continuity tests for the three wires involved.

So, if it turns out that all of these sensors seem acceptable, then I guess I'll have to see if I can borrow a vacuum tester? Any other idears?
Reply With Quote