I Have Hope.

"Brickman" (legomaniacman) 03/24/2016 at 16:33 • Filed to: None

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Still working on my 96 caravan no spark issue. I replaced the coil, spark plugs and wiring, cam and crank sensor with new wiring harnesses. All voltage to those are perfect, exactly to factory service manual specs.

Still no spark. Im about to rip my clothes off and run down the street naked (that thought occurs more than once in my life :P)

So I chill out, do a bit more research. I need to test the pulse signals going to coil. I need a 12v LED. Then I remember I made a LED lightbar for my RC rock crawler. Grab spare LED, LED driver (resistors are for suckers :P), solder the wires to the LED, tape, and connect positive to battery and neg to the coil pulse wire. Crank engine and the blue wire flashes like it should. I move onto the grey wire and the LED stays on. Even with the key off. I have to disconnect the battery or PCM connector for the LED to turn off.

Somewhere the wire is grounding out in the harness. I’ll remove all that tomorrow or so.

I previously thought there was a bad wire around the crank sensor and inspected those wires. Seems I skipped the other half the harness.

Mattbob > Brickman 03/24/2016 at 16:40

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What kind of LED driver are you using that fits in that there tape?

KatzManDu > Brickman 03/24/2016 at 16:42

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Good find & Good luck!

Brickman > Mattbob 03/24/2016 at 16:49

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These.

http://lighthouseleds.com/20ma-led-curre…

Future next gen S2000 owner > Brickman 03/24/2016 at 16:57

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Electricity is voodoo. Good luck, I hope your sacrifice is sufficient.

Tohru > Brickman 03/24/2016 at 17:43

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Hope is a dangerous thing.

Fed(oo=[][]=oo)uken > Brickman 03/24/2016 at 17:54

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Hopefully this isn’t a herp derp type reply, but have you swapped in a known good ECU (if that would make sense for a caravan)?

Brickman > Fed(oo=[][]=oo)uken 03/24/2016 at 18:30

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That would be the last thing I do. A PCM costs half what the van is worth. If it’s not, I should be able to get my money back if it’s not the computer?

Mattbob > Brickman 03/24/2016 at 21:00

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Thanks! I’m an EE, and I had not heard of these chips. Learn something new everyday.

Fed(oo=[][]=oo)uken > Brickman 03/24/2016 at 23:03

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I get that. A used part might be the way to go. Junkyard or eBay?

Brickman > Fed(oo=[][]=oo)uken 03/24/2016 at 23:11

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Just looked on eBay. Three with my same part number for $303. Not too bad.

Fed(oo=[][]=oo)uken > Brickman 03/25/2016 at 09:25

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This suggestion is coming from experience with my cars. Mid-eighties electronics are probably more fragile than yours, but at least for me a bad ECU is the next step after doing everything you’ve done.

Clean all your grounds just in case? Important relays?

Brickman > Fed(oo=[][]=oo)uken 03/25/2016 at 09:53

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One ground is a bit rusty on the fender well. Got good ground, but I’ll clean it anyway. Also tested the relays and all work perfect.

Brickman > Tohru 03/25/2016 at 20:50

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Yeah I think you are right :) I think my ignition is grounding out inside the PCM. Damn.