What did I burn up?

[cdlongjr]

I attempted to do a Nutter bypass yesterday. I failed to read the entire article. I ran the orange & purple wires from the distributor to the ignition module, then cranked the engine. No start. I put the wires back how they were originally, cranked, no start. I'm not getting spark.

 

[BrockGrimes]

I attempted to do a Nutter bypass yesterday. I failed to read the entire article. I ran the orange & purple wires from the distributor to the ignition module, then cranked the engine. No start. I put the wires back how they were originally, cranked, no start. I'm not getting spark.

Nothing that I can see, check your fuses?
Battery re-connected?

After the mod it should be connected like this:

 

[cdlongjr]

Thanks Brook. I think the by pass has already been done. The orange & purple wires are twisted together thru the entire loom. This is on an 87. I double checked he wires, the ign fuse id ok. I have 2 yellow wires that come off the coil, 1 isn't hooked to anything. The distributor is HEI I think. Nothinkunder the cp but the rotor & a pickup. Still doesn't start.

 

[cdlongjr]

I have replaced the ign module & coil. I still have no fire from the coil. I do have voltage to the coil.

 

[CJ]

You didn't burn up the pickup in the dist did you?

 

[BajaEdition]

is the old system running a ballast resister?

 

[cdlongjr]

It has a DuraSpark II ign system. I don't know about the resistor. Where would I look to find it? What does it look like?
CJ,
I'm trying to replace the pick up now. Can't figure out how to remove it.
Thanks

 

[rushpowersystems]

The 87's are the first of the true computer controlled units, think of it as OBD.5. the ignition system wires are twisted as a was of canceling out noise in the ignition system. Yellow is hot for the system, in other words the yellow wire should have voltage during cranking and when the key is on. Your system uses a ballast resistor so you should have between 6 and 9 volts at the coil positive. It is pulsed negative from the distributer. Using an ohm meter measure the resistance, of the two wires of the pick up coil in the distributer. If you have on resistance in the coil it is bad, if it is showing resistance then use a hair dryer to blow heat on it for a few minutes to simulate driving conditions heat. Check it again when it is hot, if you have resistance the part is good.

The ECU controls spark on 87's we have had some success isolating the ignition system from the ECU but we only do it in case of emergency or last resort. The ECU controlled ignition is far more accurate than any hal effect or mag pick up system because it can adjust the spark to provide the best possible ignition under a given condition. The ignition module is more of a signal amplifier than a module, it more or less protects the ECU from damage.

So if you go back to stock wiring, and your pick up coil is good, then is sounds like you are faced with two solutions. First replace the damaged ECU second install an HEI and use it as a stand alone. Of the two choices I would go with replacing the ECU, the other option will work but not as well as the stock system.

Hope that helps.

 

[CJ]

~~~ I don't know about the resistor. Where would I look to find it? What does it look like? ~~~

On your year the resistor is built in to your positive feed wire. If your getting voltage to your coil the resistor wire is OK...

 

[cdlongjr]

Replaced pickup coil. Still won't start. sounds likr ECU is next.Thanks guys!

 

[rushpowersystems]

That may be pricy, we have a company that rebuilds ECU’s and they are very good. We have never had them rebuild an 80's jeep, however they did do a Chrysler Conquest ECU a few yeas back and they are the same technology platform, seems like it was around $300 but the brain gets fuzzy with age.

The ECUs are quite tough though, I think I would find my best price on a used one, just make sure it is the same, that is year, AT or MT, AC and so on. I will normally give the wrecking yard the vin number or the number off the ECU.

When you pull your ECU stick you nose in the opening of the plug, if it smells like an electrical fire you found your problem, you will know the smell if you smell it.

BTW you did have power at the coil with the key on right?

 

[cdlongjr]

Yes, I do have power to the coil with the key on. My YJ was a manual new, but the PO replaced the manual with a B&M TH350. Will that make a difference with the ECU? The ECU is the box behind the glove box correct? I get confused with the MCU & ECU. Probably why I screwed up the Nutter by pass. My ECU didn't have 2 orange wires.

 

[cdlongjr]

Double checked power to the coil. Had none. Yellow wire had pulled out of the cap. Repaired & she fired rite up!
Thanks guys.
Now to get her to go faster than 40 mph.

 

[CJ]

Double checked power to the coil. Had none. Yellow wire had pulled out of the cap. Repaired & she fired rite up!
Thanks guys.
Now to get her to go faster than 40 mph.

Glad you found it but... Ouch! Well - at least you have some spare parts now!

 

[cdlongjr]

Dist pickup was fried.