Ok so every thing is swapped over but still I have weak or no spark.

Heres what I have checked so far.
Fuel pressure is perfect, 33psi at start up.

Compression is ~145 PSI across all 6 cylinders, I know its low but the motor has just 600 miles on it so I figure its just not broken in yet and it hasen't run in a several months. Any thoughts?

All Ignition coils are good.

Camshaft position sensor is good. Ground is good their too.

Crankshaft REF sensor is good. Ground is good their too.

Crankshaft POS is troubling me. My 98 sensor is different than the 96. The 98 magnetic pick up surrounded with plastic, the 96 magnetic pick up is not surrounded and has more magnetic surface exposed. My 98 passed the test in the Haynes Manual for functionality, the 96 failed. Both sensors came of of running cars? This leaves me with a few questions.

Could their be a difference in the trigger wheel between the 96 & 98? The 96 looks like it fits the 98 motor perfectly?

Are the sensors different?

Anybody got some helpfull advice to offer?

 

when you swapped the motor, did you swap the wiring harness also? when you checked those sensors, you checked the resistance of the sensor? or you checked the circuit? I had a prob once with a short in the wiring harness causing a cranking/no start condition.

 

just throw the engine in the garbage.

 

I'm using my original harness, it was working before I un hooked it?

Checked the sensors with a DVM per the Haynes manual. I'll check the circuits back to the ECM tonight.

Nick, I would if I could but its way too heavy!

 

Low compression hmm. Are you sure thats not normal for that engine. I mean did they build it with lower compression so you can run more boost.
Check all the wires man. I mean I'm sure you have already done so but do it again, and again after that. You may have overlooked an unhooked cable or something.
Even with a little spark it should start it might run like crap at idle but spark + fuel= combustion. You may also wanna try check the spark plug wires themselves. Are those new or the old ones. One thing you may wanna try that might work. Put some gas in like an old spray bottle or something. Spray the gas into the intake hosing, supercharger whatever. This might help it to fire up. This produces more of a gasous air mixture better for starting conditions. Well its just some ideas. I'll try to some up with some more.

 

hmm ok...
-no spark wires in the VQ
-too much fuel will cause a rich condition = worst no start.
-with a weak spark the air coming in will blow out the spark/flame

it has nothing to do with the ignition per se..it's getting a bad signal of WHEN to light it. it sounds like the crank angle sensor. check if the harness/wiring going to it is producing the right power or resistance.
then bite the bullet and buy a new 96 sensor and see if that works (last resort). make sure the connections are clean. since you're getting a weak spark it might be something loose or wiring/harness is corroded. if you're brave while someone is cranking get a small stick and wiggle the wire (crank angle sensor) and see if it gets better or worst or no change.

 

Thanks guys, I'll be giving it a go again tonight.

Any one else?

 

You might want to confirm if the wire to the coil is sending a singal to the coil to fire. Or have you checked that already?

 

Well, the compression is almost at the LOWEST acceptable (142psi is minumum - 185 is peak or normal), the variance between all cylinders should be no more than 14psi. If the engine is NEW, the compression would be higher than 145 for sure. Check all the variances. If low, add a little oil to the cylinder, then re-check. If it gets better, the rings are not seated right, or could be bad. If compression stays low (even) could be a stuck valve. ** If you have the two adjacent cylinders low also, the head gasket could be bad.

For the timing, try this:

tighten the crank until mark is about 60-66 degrees (about 12:30 / 1 o'clock position MAX)...Then install the cam position sensor (PHASE) then the REF/POS.

Its hard to tell these things sometimes. You just have to keep going over your work. Are you using the ECU for that motor? Harness?

Good Luck!!

Don