Need engine help... Stumped
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Need engine help... Stumped
Since my F-150 was totaled I swapped my 351w into my wrangler. The problem im having is that it will run fine then quit for 30min to hours. It will crank but no start. It has 5 pounds to of fuel the holley carb, plentuy of air and a completly new ignition system: coil, wires, cap & rotor, ignition module and plugs. It is constantly leaving me on the side of the road and do not know what else i can do. any suggestions?
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From: Denver Metro Area, CO
When it quits, remove the air cleaner, look down the throat and open the throttle fully with your hand, you should see two strong streams of gas being injected.
Most likely that isn't your problem but it never hurts to check.
Take your ignition module to a parts store and have it tested, those things can fail due to heat-caused reasons.
The three step scenario of a failing ignition module:
1) Module overheats, engine dies. Module cools down, engine re-starts almost at once.
2) Module overheats, engine dies. Module cools down, engine re-starts in an hour or so.
3) Sooner or later, usually sooner...module overheats...BURNS OUT. Now the engine will not re-start.
Testing those things will SOMETIMES tell of a failing module; ideally, you can bring it in in a failed state.
Most likely that isn't your problem but it never hurts to check.
Take your ignition module to a parts store and have it tested, those things can fail due to heat-caused reasons.
The three step scenario of a failing ignition module:
1) Module overheats, engine dies. Module cools down, engine re-starts almost at once.
2) Module overheats, engine dies. Module cools down, engine re-starts in an hour or so.
3) Sooner or later, usually sooner...module overheats...BURNS OUT. Now the engine will not re-start.
Testing those things will SOMETIMES tell of a failing module; ideally, you can bring it in in a failed state.
Post Fiend
Joined: Dec 2007
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From: Lost
Silly question. Are running full 12V to the module, or do you have a resistor to drop the voltage a bit? Too high voltage can cause it to overheat, and an alt kicking out 14V+ can certainly be a bit too much for the circuitry.
As for o'rielly's modules, prolly a cheap "made in china" item. 90% of the non-Motorcraft modules are junk before they come outta the box. There used to be a couple decent aftermarket brands, but they've pretty much gone the way of the dodo bird.
As for o'rielly's modules, prolly a cheap "made in china" item. 90% of the non-Motorcraft modules are junk before they come outta the box. There used to be a couple decent aftermarket brands, but they've pretty much gone the way of the dodo bird.
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that is true, what kind of resistor is there that will keep it at 12v? I assume that if something does happen to the power the resistor can take 12.4v to 10.4 which is not good aswell
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From: Denver Metro Area, CO
IIRC the module gets full battery voltage only in START and drops to I believe around 7 in RUN.
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pedant
Joined: Jan 2008
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From: EXTREME southwest CT
^^^
Voltage is reduced to the coil, not the box.
See here: Duraspark II
But the resistor wire should be in the harness if you had a DSII system in it before the swap.
Ideally 1.3 Ohms resistance.
Voltage is reduced to the coil, not the box.
See here: Duraspark II
But the resistor wire should be in the harness if you had a DSII system in it before the swap.
Ideally 1.3 Ohms resistance.
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Joined: Nov 2007
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From: Denver Metro Area, CO
Thanks for the correction, Jim. 
This guy installed a 351W into a Jeep Wrangler, I have no idea if that'd have any sort of voltage reduction apparatus built in or not.
I seem to remember people here talking about some sort of externally-mounted resistor intended for use on certain 1960s or 70s Chrysler products still being available at parts stores.......?
This guy installed a 351W into a Jeep Wrangler, I have no idea if that'd have any sort of voltage reduction apparatus built in or not.
I seem to remember people here talking about some sort of externally-mounted resistor intended for use on certain 1960s or 70s Chrysler products still being available at parts stores.......?
pedant
Joined: Jan 2008
Posts: 23,576
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From: EXTREME southwest CT
Yes Chris.
The large white ceramic Mopar ballast resistors are available almost anywhere.
Jeg's, Summit, Ebay, etc...
There are two wire and four wire versions. Early points type and later electronic ignition ones.
Either one can be made to work.
http://www.tidewatermoparclub.com/TECH/ballast2.pdf
Edit: I have no idea how much of the harness he took out of his truck to put into the Jeep, but the pink(???) wire is in there.
While cranking the DS-2 box gets signal to retard the timing and reduce load on the starter motor for easier hot starts.
The large white ceramic Mopar ballast resistors are available almost anywhere.
Jeg's, Summit, Ebay, etc...
There are two wire and four wire versions. Early points type and later electronic ignition ones.
Either one can be made to work.
http://www.tidewatermoparclub.com/TECH/ballast2.pdf
Edit: I have no idea how much of the harness he took out of his truck to put into the Jeep, but the pink(???) wire is in there.
While cranking the DS-2 box gets signal to retard the timing and reduce load on the starter motor for easier hot starts.
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Ok so I traced the falure down to the coil, I do not have a ballast resistor but neither did my f-150. I have gone through 2 control modules and 3 accel coils... I am going to move the box to the cab to reduce the heat it is exposed to because it was blistering hot, smae with the coil. how would i keep the coil cool?
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Joined: Nov 2007
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From: Denver Metro Area, CO
Millions of these things are on the roads with the components located under the hood and they work just fine.
How to keep yours cool? Install the proper inline resistor to reduce the voltage to the levels at which the components were designed to operate.
Post Fiend
Joined: Dec 2007
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From: Lost
I'm thinking the main key on power to the DS2 box has a resistor wire to drop the voltage, much like the wire from the switch to the coil on the older breaker point ignitions used. It's been a while, but I read an atricle detailing upgrading an older ford to the DS2 system, and IIRC it mentioned using the resistor wire to power the box.
Also, the painless wiring DS2 harness actually incorporates the use of a ballast resistor like the old GM and mopar stuff used.
I do remember very well that the MSD built ford motorsport DS2 system called for a ballast resistor or resistor wire to be used.
Also, the painless wiring DS2 harness actually incorporates the use of a ballast resistor like the old GM and mopar stuff used.
I do remember very well that the MSD built ford motorsport DS2 system called for a ballast resistor or resistor wire to be used.