No spark issue with 87 TII Z

[blk86trbo]

Swapped a few pieces underhood to see if I could resolve the lack of spark. I thought for sure a known good Power Module was going to make a difference but that didn't help.

I've tried 2 different HEP's, but they aren't actually known to be good.

When I turn the key on, the fuel pump primes, but when it cranks there doesn't seem to be power to the coil. No fault codes other than a #12

[Turbodave]

The fuel pump and coil should be getting the same 12V power feed, Coil is fired by the computer switching it to ground.

Is there 12V at the coil when you first turn the key on?

Do you know anybody with a car you could borrow a known good HEP from?

[blk86trbo]

Well I was gonna grab a known good HEP from one of my running cars if it got to that point...but I know the fuel pump is working, and I realize they both run through the ASD so I was scratching my head...

Is there 12V at the coil when you first turn the key on?

No

Am I correct in believing a power module from a 87 TI car will work with a TII car?

[Turbodave]

Am I correct in believing a power module from a 87 TI car will work with a TII car?

Any 85-87 Turbo power module should work

[turbovanman²]

Have a helper around so you can check for power like Dave suggested. If power, then it's a wiring issue from the LM or a bad computer on the neg side. If no power, check wiring, fusible links. Any codes after messing around?

[blk86trbo]

Nah no codes yet...I was surprised when I jumpered the coil and I still didn't have spark...how much does the LM have to do with spark?

Can u point me towards some info on how to check fusible links?

[Turbodave]

LM does quite a bit so if it is bad or connections to it are corroded that could be part of it.

[Dodge Aries K]

The LM tells the PM to fire the coil... so it does have a lot to do with it... but if the LM has an issue like that it should set a code.

[Turbodave]

Can u point me towards some info on how to check fusible links?

http://minimopar.knizefamily.net/electrical-links.html

Also here is good info on the power feed for the coil and fuel pump.

http://minimopar.knizefamily.net/ele...owerfeeds.html

Now you need to check the Z1 feed. The Z1 feed supplies power to the ignition coil, fuel pump and fuel injectors. If you have a 1987 or earlier vehicle, the Z1 feed comes right out of the power module (the ASD relay is inside). On later models, the Z1 feed comes from the ASD Relay.

* Turn the ignition key to the "on" position.
* With the negative probe of your meter grounded to the chassis or negative battery terminal, connect the positive probe to Z1 supply to the ignition coil (may be dark green and may be with a black stripe...consult your wiring diagrams).
* Have someone crank the engine while you watch the meter. As the engine is cranked, 12V should appear on the coil.
* Repeat the test for the fuel injectors and the fuel pump. Stick the positive probe into the fuel injector connector by the rail to measure there. For the fuel pump, measure the voltage at the fuse panel by pulling the fuse and testing on each of the two contacts.
* If you find the voltage at every place where you saw that wire, then your Z1 feed is probably good.
* If you only measured it in some spots but not others, then you probably have a bad splice. Consult your wiring diagrams for exact Z1 splice location on your vehicle.
* If you couldn't measure it anywhere, then your Z1 feed from the ASD relay is the problem.
* Connect the positive probe from your meter to the positive battery terminal and use the negative probe to test the ASD control line. If you have a 1987 or earlier vehicle, this wire leads to the power module (pin 5 of the 12-way connector, dark blue with a yellow stripe). Try to push the probe through the back of the connector into the contact. If you have a later model, you can disconnect the ASD relay and connect the probe there.
* Have someone crank the engine. While the engine is cranked, 12V should appear at the relay control line.
* If a voltage appeared, then your relay is probably bad, but you may want to check the connections. Verify that the power module or relay is getting the J2 feed and that the Z1 output makes a good connection. If you have a power module, the entire module has to be replaced. If you are good with electronics, the unit can be disassembled and the relay replaced (with some difficulty). Otherwise, just replace the relay.
* If no voltage appeared, then it is likely that the computer is not seeing a signal from the ignition reference sensor. You may want to consider replacing it. Be sure that you have good connections at the sensor. The contacts in those two round connectors are prone to getting loose. Be sure that the cables to the sensor are properly secured so that they don't swing around and damage the wires inside.

[BadAssPerformance]

Nah no codes yet...I was surprised when I jumpered the coil and I still didn't have spark...how much does the LM have to do with spark?

Can u point me towards some info on how to check fusible links?

Easy way to check a fusible link is give it a little tug. The link will come apart if it is bad and sometimes the wire next to the link is corroded and you'll see the insulation stretch...

[Turbodave]

Easy way to check a fusible link is give it a little tug. The link will come apart if it is bad and sometimes the wire next to the link is corroded and you'll see the insulation stretch...

Yep, but since the fuel pump is coming on and the coil and pump share the same power feed I'm thinking it's not a fusible link.

[BadAssPerformance]

Gotcha... so its in the Hall Effect circuit or LM then?

[blk86trbo]

Dang...I was just outside in the driveway trying to figure out how to jumper the fuel pump through the relay on a 91+ Daytona (underhood fuse block)...it's friggen cold out there! The 30+ mph wind cuts right through you!

Was hoping to go out to the unheated storage building and fiddle with the Z a little more, but sitting under the blanket and watching TV sounds a little more appealing

[Captain Chaos]

1992 (3) Dodge Daytona IROC, Blue TI 5 speed
1991 Dodge Shadow Convertible, Blue TI auto
1990 Plymouth Voyager LX, White TII 5 speed
1987 Daytona Shelby Z, Charcoal TII
1987 Chrysler Town & Country wagon, Tan/Woodgrain TII auto
1987 Shelby GLHS #454

Gotta be one good HEP in this stockpile. lol

[Dodge Aries K]

Aww... is Paul too cold to go outside?

[blk86trbo]

1992 (3) Dodge Daytona IROC, Blue TI 5 speed
1991 Dodge Shadow Convertible, Blue TI auto
1990 Plymouth Voyager LX, White TII 5 speed
1987 Daytona Shelby Z, Charcoal TII
1987 Chrysler Town & Country wagon, Tan/Woodgrain TII auto
1987 Shelby GLHS #454

Gotta be one good HEP in this stockpile. lol

Ha ha yes there is...I'm gonna guess that the 2 or 3 HEP's I tried are ok and the issue is somewhere else. In the next day or so I'm gonna pull some parts from a running car and see what I find out. Like I said earlier, I'm certain the power module is good, it ran the turbowagon minutes before I swapped it into the Z.

[blk86trbo]

Aww... is Paul too cold to go outside?

LOL the wind is chilling to the bone! Maybe I'll head out to the Z after I thaw a bit

[Captain Chaos]

Ha ha yes there is...I'm gonna guess that the 2 or 3 HEP's I tried are ok and the issue is somewhere else. In the next day or so I'm gonna pull some parts from a running car and see what I find out. Like I said earlier, I'm certain the power module is good, it ran the turbowagon minutes before I swapped it into the Z.

The LM would too. Just cannibalize the wagon and I'll be by in the spring to retrieve the carcass.

[blk86trbo]

Just cannibalize the wagon and I'll be by in the spring to retrieve the carcass.

Ha I seriously just laughed out loud! Heck, the wagon was only (how many?) miles from you when I snagged it from Matt's yard?

[Dodge Aries K]

Did you swap the coil? I didn't see if ya did.