| Subject: |
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Re: Re: Mopar Ignition Troubleshooting #2 |
| Name: |
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JimmieD |
| Date Posted: |
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Aug 23, 08 - 9:42 PM |
| IP Address: |
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66.81.199.226 |
| Dodge-Link |
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http://youtube.com/watch?v=e-LOtKIIKcg |
| Message: |
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Below is outtakes from Jimmy's post, there is some "miss-info" in there so here is the right info. outakes are in " " , nothing reflecting on Jimmy himself as he is just passing info
on....
"Remember that Mopar ECU & voltage regulator must have clean bare metal ground, plus ECU requires fully charged battery for the voltage shot to transistor."
Very true, however, in un-restored trucks/cars this can sometimes be a challenge. Often just adding a ground wire from the battery neg post to the mount screws of the ECU box will solve
what can be a intermentent problem (cut out, false signals, misses, ect)since not all ECU boxs are mount by everone on the fire wall were a good ground can be had from engine ground to fire wall strap (assuming that the strap and engine
to battery strap are both in good shape).
*~~> I didn't say ECU is always mounted on firewall did I? It isn't. I find it a much cleaner installation to simply run a short ground wire from inner fender panel to firewall, and be sure ECU is properly grounded to fender panel, with jumper or otherwise. What I said is correct.
"The 5 wire ECU & connector has a spare wire terminal not used in 4 wire ECU, green with red stripe, which is an auxiliary ground lead. You can use a 5 wire ECU in a 4 Wire ECU vehicle but not vice versa, as no 4-wire ECU works in a 5-wire vehicle."
The green wire with red strip is NOT a aux ground lead! it goes to one of the posts on the 4 post ballast resitor used with a 5 pin ECU box. You CAN NOT use a 5 pin ECU box in place of a 4 pin ECU box unless you install a 4 pin balast.
>>You CAN use a 4 pin ECU box in place of a 5 pin ECU box that is in all early Mopar EI systems without changing the 4 pin old ballast(assuming that the wires are all stock and unchanged), it is a bolt in swap without any mod's needed.
*~~> Green with red stripe is the ground on 5 pin looms, not needed with 4 pin ECU. All instructions I have found indicate that Green/Red is not used with 4 pin. Where on a 4 pin installation are you using this ground wire?
Note: I'm obviously talking about a 5 wire electronic ignition equipped Mopar's wiring loom. Wouldn't expect an earlier vehicle to use the same wire color code, maybe, maybe not.
*~~> 4 pin ECU can be used with 5 pin car, but 5 pin ICU cannot be used with 4 pin car unless wire harness is changed, my one mistake.
http://www.imperialclub.com/Repair/Electrical/Electronic/index.htm
72-79 5 pin, later is 4 pin.
"To quickie wire up an ECU connect one wire from the 'IGN' pole on the ignition switch to one side of the single ballast resistor and from the other side run a wire to the side of the coil. This drops voltage in the 'Run' position. Now run a wire from the 'START' pole of switch to the other side of resistor, the coil side. This gives you full 12v for starting."
Correct.
*~~> Yes, that's what I said...
"I believe most big blocks have counter-clockwise rotation of distributor rotor, small blocks clockwise."
NO, all Mopars v8's turn clock wise with a fire
order of 18436572.
*~~> Incorrect, big blocks 361-383-413-426-440 are all counter-clockwise!
http://www.mymopar.com/downloads/elecignconv.pdf
http://boxwrench.net/specs/bchrys_B.htm
http://boxwrench.net/specs/hemi_426.htm
http://store.summitracing.com/partdetail.a
sp?autofilter=1&part=DCC-3690428&N=400172 115&autoview=sku
http://store.summitracing.com/partdetail.asp?autofilter=1&part=DCC-3690426&N=700 400172 115&autoview=sku
SMALL BLOCKS are Clockwise rotation!
"Remember that engine-to-firewall ground strap is required, clean bare metal ground on both ends."
YES!
*~~> ??? That's what I said...
"If engine just doesn't want to start check ballast resistor, they are a common fault. Some will only start as you release key from 'Start' cranking position to 'Run' position, indicating a bad ballast resistor."
Above can also say-- bad ground.
*~~> That's why I emphasized throughout that clean bare metal grounds are reguired! The large majority of the time it is the ballast at fault in this condition, they're famous for it.
Much easier to replace ballast and test than trace out a whole electrical system looking for an elusive bad ground. If ballast doesn't fix then it's something else, but always good to have a good new ballast in there for a few bucks insurance.
Wrenching on Mopars since '62 I found it was the ballast in every single case. I have never found any other cause for the ailment of not starting at cranking but only when releasing key.
"Mopar Electronic Ignition Testing:
It is critical to proper operation of ignition to make sure there is a solid bare-metal ground between ECU case and ground and between Regulator case and ground. Sometimes a jumper wire is needed."
Yes! I often add the extra ground wire (jumper) just be sure the ECU box is grounded.
*~~> That's what I said I think?
Rest of the info sounds right so here is were I stop.
*~~> So, from the looks of it I was only mistaken regarding crossing 4 pin-5 pin ECU and the rest of the information is correct. Thanks... |
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