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Discussion Starter #1
I have a 2002 v8tt that just died while I was driving! It cranks over no problem, has communication with the ecu, but no spark and no rpm reading!
There are no codes in the ecu. I have checked the crank and cam sensors, all wiring from sensors to ecu(ran continuity check from ecu to sensors) all fuses and relays, and am now pulling out my hair! I was wondering if the imobilizer was cutting the ignition, and also would that account for no rpm while cranking? Any help would be appreciated.:shrug:
 

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When you turn the ignition on but before you crank, do you hear the fuel pump running for the first several seconds before shutting off? If not, the start by pushing the plunger on the top of the inertia switch in the right front area of the engine compartment. On my car I had the inertia switch partially tripped and it needed to be fully reset.

Knut
 

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Fuel pumps are fine, checked pressure just in case, and it is at 60psi. Like I said I have no spark and no rpm signal when cranking. I also tried my buddies ecu(he also has a 2002 v8).
 

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Discussion Starter #5
Checked continuity of harness from sensor connector to ecu connector and checked crank sensor resistance--660 ohms.
 

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this may not apply to the V8... but on the 4cyl (similar wasted spark system to the V8) the ECU does not have full control of spark advance until the rpm gets above 700. Before 700rpm the ignition module (back plate of the coil packs) monitor the crank sensor for the sync-pulse and then send that signal to the ECU. The ignition module must see that sync-pulse and then a flywheel signal in order for the engine to start.

So I'm guessing you may have bad wiring to the coil packs, bad coil packs, or an injector driver circuit issue (one that doesn't throw a check engine light)...

Have you verified that the check engine light turns on as you try to start the car? Otherwise, maybe there is a code stored and the dash bulb is burnt out???
 

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Discussion Starter #11
Well, found out what happened! I was not getting an rpm signal cause the passenger cams are not turning! Tearing down the top of the motor tonight to see what went wrong.
 

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Discussion Starter #13
well.....passenger cam belt has stripped teeth at the intermediate shaft! Sooo...what are the chaces that I did not hurt the heads? Or should I just pull the motor and remove the heads for inspection????
 

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The chances of the cam stopping at a position where you would not hit valves with pistons is very low. One way to proceed is to get a belt on and do a compression test. If you still can get good compression you can assume you did not bend valves. Otherwise you should just pull the head. Figure on doing BOTH belts and probably the tensioners too.
David Teitelbaum
 

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I would pull the cams out and check the valve stem heights. If you bent valves they would probably be hanging open. Easy to do a leak down test with all the valves, hopefully, closed. Like Dave said chances are not good, this is an interference motor.
 

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If it died while driving, it's almost guaranteed you bent valve. The crank would have made at least a dozen full rotations with some of the valves down into the cylinders.
 

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You could use a videoscope/inspection camera to inspect the chambers thru the spark plug holes. I have ordered one. (7mm head or smaller). Recommended to me by Guy after my engine blew recently.
 

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well.....passenger cam belt has stripped teeth at the intermediate shaft! Sooo...what are the chaces that I did not hurt the heads? Or should I just pull the motor and remove the heads for inspection????
Remember that this is an interference engine.....so.....

If I am understanding your previous posts correctly, you cranked this engine over several times ---- while the passenger side cams were not turning (in retrospect) due to the broken / stripped cam belt. ????

If true, the chances that pistons did NOT hit valves on that side are.....well....zero :( They would have had to make contact --- only question is how hard and how much damage. You really need to pull that cylinder head in order to properly assess this ---- hopefully, the pistons will be only dinged and are still useable, but I highly suspect that you will find at least a few bent valves :(.
 
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