Dodge Techs: RamVan=FailVan '02 no spark.

Posted By: CrAlt

Dodge Techs: RamVan=FailVan '02 no spark. - 07/29/10 09:34 PM

My brothers failvan strikes again. This is the 5th time its been towed home in as many years.

It tossed a rod at 50k and is on its 2nd motor. It eats electronic senors for lunch. Anyways..

Now we have no spark.

This is what we have done.

Replaced:
Coil (new)
Crank Sensor (new)
Swapped cam sensor with a known good one.
I have 5 volts at both sensors.
When I turn the key on I get voltage to the coil for a few seconds. But its not enuff to fire the coil.
*injectors and fuel pump are going.

I hooked a MSD to a points dist and spun it with a drill. Plugged the MSD coil in to the dist on the motor and the thing ran with my external spark source. I know i got fuel. The injectors are going. It will just not fire the coil.

No codes.

Any ideas?

Posted By: Blown71X

Re: Dodge Techs: RamVan=FailVan '02 no spark. - 07/29/10 11:16 PM

Just a couple of thoughts:

IF.....and I mean IF you really have correct injector pulse then you have both proper cam and crank signals (injectors will NOT fire without both), key on voltage at the coil should only last a couple of seconds, it will turn on the asd once it sees crank pulse.

The simple fact that the PCM is cycling the asd relay on "key on" at least indicated that it is powering up

The coil feed (green with orange) is also the injector feed so it you have correct voltage there it eliminates an ASD relay problem

The coil return to the JTEC is gray and will go to connector C1 which is black (sorry I don`t remember the pin number and i`m not where I can look it up but I think it may be pin 7) which is the right most connector looking AT the module (they number C1 thru 3 right to left with them facing you) personally in a perfect world I would use a scan tool to actuate the coil output and see if the module is capable of switching the output...but with lack of a scan tool your only choice at this point is to ohm out the return and make sure it is intact and also not shorted to ground somewhere.

If all that is intact then it is a good possibility that the coil driver failed and it is time for a new "box"

Disclaimer: This all assumes that it really does have correct cam and crank
Rick

Posted By: CrAlt

Re: Dodge Techs: RamVan=FailVan '02 no spark. - 07/30/10 01:02 AM

OK i will ohm out the coil wires. Thats one thing I did not do. Thanks.

Like I said in my original post... If I give it spark it runs fine. As long as the drill is running she runs strong..cam and crank must be working. We are able to drive it around the yard. Everything in my mind is now pointing to that computer which you are reaffirming.. The computer which dodge says is $927

Thanks

Posted By: CrAlt

Re: Dodge Techs: RamVan=FailVan '02 no spark. - 07/30/10 03:58 PM

Checked the coil wiring. A7 and C12 IIRC. All good.

I get the 12 volts on the coil/injectors when cranking but the computer is not pulsing the ground on the other side of the computer.

I opended up the ECM to look for a power transistor or something but its filled with epoxy.

Posted By: kevin69bman

Re: Dodge Techs: RamVan=FailVan '02 no spark. - 07/30/10 10:40 PM

Your power to the asd and feul pump relay is mising look for a bad wire as said green wire is power by asd and its fed by a red wire from 30 amp fues.If you need a wire diagram let me know.

Its not the ECM if you have injeter pulse which you do!!

Posted By: Skeptic

Re: Dodge Techs: RamVan=FailVan '02 no spark. - 07/31/10 01:15 AM

Remember, shorted coil windings=failed coil driver, spring for a new O.E. coil. The box should be available Reman.

Posted By: TMCCuda

Re: Dodge Techs: RamVan=FailVan '02 no spark. - 07/31/10 02:57 AM

If you really think it is the ECM then try ebay for a used computer. Seriously, $150- $200. Much better than $900.

Posted By: 383man

383man - 07/31/10 05:32 AM

Quote:

Just a couple of thoughts:

IF.....and I mean IF you really have correct injector pulse then you have both proper cam and crank signals (injectors will NOT fire without both), key on voltage at the coil should only last a couple of seconds, it will turn on the asd once it sees crank pulse.

The simple fact that the PCM is cycling the asd relay on "key on" at least indicated that it is powering up

The coil feed (green with orange) is also the injector feed so it you have correct voltage there it eliminates an ASD relay problem

The coil return to the JTEC is gray and will go to connector C1 which is black (sorry I don`t remember the pin number and i`m not where I can look it up but I think it may be pin 7) which is the right most connector looking AT the module (they number C1 thru 3 right to left with them facing you) personally in a perfect world I would use a scan tool to actuate the coil output and see if the module is capable of switching the output...but with lack of a scan tool your only choice at this point is to ohm out the return and make sure it is intact and also not shorted to ground somewhere.

If all that is intact then it is a good possibility that the coil driver failed and it is time for a new "box"

Disclaimer: This all assumes that it really does have correct cam and crank
Rick

Amen as this man knows what he is talking about. Oh how nice it is to have the right scanner and actuate the coil so you can check the coil driver circuit in a push of the DRB button.

Ron

Posted By: CrAlt

Re: Dodge Techs: RamVan=FailVan '02 no spark. - 07/31/10 09:15 AM

Quote:

Your power to the asd and feul pump relay is mising look for a bad wire as said green wire is power by asd and its fed by a red wire from 30 amp fues.If you need a wire diagram let me know.

Its not the ECM if you have injeter pulse which you do!!

I jumped 12 volts to the green wire early in my testing stage.
The ECU is not pulsing ground. I think the power transistor in the ecu is cooked.

It thinks its firing the coil but nothing is happening.

The injectors and fuel pump are running. It will run forever with my external spark source.

Posted By: CrAlt

Re: Dodge Techs: RamVan=FailVan '02 no spark. - 07/31/10 09:18 AM

Quote:

Remember, shorted coil windings=failed coil driver, spring for a new O.E. coil. The box should be available Reman.

The motor before this one had a failed coil then my brother put a autozone china coil in. I wouldn't be surprized if one of those weakened the driver in the ecu.