??!! Burned Out 2 SMEC's In 10 Miles !!??

[cudagirl77]

R&R'd the battery, SMEC, and chip, checked grounds, added another from firewall to other side of fuel rail with no effect. No spark/fuel and clicky clicky from ASD. Anyone have a match?

Codes???


Sent from my iPhone using Tapatalk

[chromguy]

I didn't because I *thought* it was solved, I will tho because I'm back to square one-ish, Thanks for the suggestions. So the harness needs to be connected and during cranking to get those values you listed, and I'm checking the back side of the connector(harness side?) then? I can pull a motor but electrical is my Achilles

Hate to say but I am not surprised we are back. Lets turn the page and solve your issue. Several have mentioned to check codes, this is a great idea to check first. After that we can back probe the connections pin to determine voltages. A statement from the DVM bible "Thou should be measuring voltages" . This is the best way to troubleshoot as measuring current and resistance can be misleading. For most simple systems using a water flow analogy will get you 95% of the way there. Voltage =pressure and current=flow.
I believe I have seen an ecopy of the 88 powertrain troubleshooting manual that will take you step by step. If you can't find it I will see if I can find it again.

reference https://en.wikipedia.org/wiki/Hydraulic_analogy

[blk86trbo]

Best of luck Alan. I'm in the same boat as you...can pull drivetrains in my sleep, but am confused as hell with electrical gremlins. Crossing my fingers for ya bro

[lightbulb010]

I know it has already been asked but, are you getting code 42. Take this with a grain of salt. I got code 42 after trying to start MANY times with a bad ground connection. I tightened the connection. There is a wire that runs from the logic board directly to the power board to give it an ASD signal(as in the wire runs from the logic board directly to the power board AND the ASD relay coil). The pin is shorted on the logic board in my original SMEC(3.0l). I could only get the van to start by clipping this wire and connecting the power board side(the ASD relay was also connected here) to the DK blue ignition switch wire. Even though this doesn't seem at all(at least from my understanding of the original post) like the situation at hand, It can't hurt to check this wire. I'm pretty sure the wire was blue with a white tracer. Testing the function of the ASD will not help you if this signal is not present. This wire " enables" both the ASD relay AND the power board.

[2.216VTurbo]

I should have addressed the code question when it was first asked, my bad Both Cordes and I tried to pull codes at SDAC and during the trip home and were unsuccessful in getting them to run. We were thinking it's possible the custom cal wasn't set up for them or? So we tried several times, no luck. However, I have NOT tried to run them in the last 24 hours(or since when the additional/revised grounds got it running briefly) so possibly they are working now, I won't be home for a few more hours tho, more tests, more xrays, more labs (about 4 different doctors today alone) for my impending spinal fusion surgery that's only a few days away now.

[jonnyb]

No DRB to troubleshoot Jonesy? Hook that up and forget about the key dance - it could be a miswire in the smec conversion or could be the cal, but without a scan tool it's a guessing game.

I'll ship you my old OTC if you want it. Makes running thru the 88 diagnostic tests a breeze! I can send you the 88 diagnostic manual as well.

Jon

[2.216VTurbo]

No DRB to troubleshoot Jonesy? Hook that up and forget about the key dance - it could be a miswire in the smec conversion or could be the cal, but without a scan tool it's a guessing game.

I'll ship you my old OTC if you want it. Makes running thru the 88 diagnostic tests a breeze! I can send you the 88 diagnostic manual as well.

Jon

I have an OTC 4000, which end do I plug in again?

[2.216VTurbo]

OK, so I've swapped SMEC's, checked fusible links, cleaned all the pins on the 60 pin and the 12 pin connectors, looked for shorted wires(possibly *inside* the harness somewhere?) cleaned all the chassis grounds, checked for voltage tests at J1/ J2 injector circuits, added a couple grounds because it seems like a good idea... Still no codes come up and when I try to run them with the key cycle or the DRB. As soon as the ASD starts it's wild clicking(key power on) it blanks and flashes the screen on the DRB Something is not happy. Fuel pump will run if I bypass ASD with 12V onto + coil and I have swapped out the ASD Relay. Still no spark or fuel(unless ASD is bypassed then I get fuel)

Such a nice car begging to be driven and debuted at Cars and Coffee yet this is the third Saturday that it wont cooperate Wish I was better at electical

[jonnyb]

Bad pin on the socketed smec? I've seen something similar on a socketed smec that didn't have anything covering the chip and the pins got corroded and didn't make good contact with the socket. I've also seen something like that from a bad soldering job on the socket (tach bounced and there was a clicking noise when you keyed it on, but nothing else in the ignition system worked).

[RattFink]

Alright, I want to try and help out with this. I was following progress on this project and want to see it running! Electrical can be tricky. First off, what tools are you using? Your gonna want a good brand Digital Meter and a test light. I also like to use a headlight bulb or something that pulls a good amount of current to check my grounds. I'll hook one side of the bulb to power, then the other side to the ground I am checking. If the ground is good, the headlight will light up nice and bright. Another thing to keep in mind, resistance will not show up in a circuit until current is flowing. In other words, you could pull the ASD relay and read 12v on the fusible link terminal, but once the circuit gets turned on and current flows, the fusible link could be dropping voltage. Voltage drop tests are the only way to go in my opinion. You said it was an 89 T2 Lebaron harness? I've got that wire diagram pulled up right now. I'm going to study it a bit then post on how I would test it.

[Reaper1]

AJ, this sounds EXACTLY like what happened to my turbo van I had. I wish I could tell you I figured it out. I had swapped computers, whole wiring harnesses, jumped grounds...all kinds of stuff!

I know...SOOO helpful, but I figured I'd let you know that I have experienced the EXACT same problem. No codes. Wouldn't pull codes on a scanner.

I did find that the ground to the fuel rail was faulty (it would ohm out OK, but was really hanging on by a tiny piece of metal, which finally snapped when I went to remove the harness from the engine). I know you've already been there, done that.

It is an L-body...replace the horn!

[mopar-tech]

As soon as the ASD starts it's wild clicking(key power on) it blanks and flashes the screen on the DRB

A good clue! Check the power and ground that feed the scanner plug and see if voltage goes away/drops during the event.

My money is on the ground circuit, you are getting a floating ground issue which will cause all sorts of havoc.

[RattFink]

After reading the symptoms and studying the wire diagram, it sounds to me like the SMEC is having an issue staying powered up. I would check all power and grounds at the module via a voltage drop test. Get something to back-probe the wiring at the module. Cheap hat pins from the arts and crafts section of Wal-Mart work good. Back probe pin 41, J1 Red Fuse Link, at the module while leaving the module plugged in. Set meter to read DC Volts. Place red lead of meter onto the back-probe, place black lead of the meter on the battery POSITIVE terminal. Turn the key on and let the ASD do it's dance. You should get a reading very close to zero on your meter. Max .2 volts. This test shows how much voltage that fusible link is using. You don't want it using any. Any voltage your wiring is using means your module has that much less to use. If your wiring is using 2-3 volts, your module is only getting 9-10, it won't power up or may trip out. Repeat this test all power wires going to module. You can test grounds like this too, just back-probe the ground, positive lead of meter on back-probe and negative lead of meter on NEGATIVE battery terminal. Keep in mind, the key needs to be on and the circuit needs to be in use. Hope that helps you out.

[2.216VTurbo]

OK, sweet, I'll check the SMEC pin 41 and those other suggestions too when I get home :-) Thanks!

[chromguy]

OK, sweet, I'll check the SMEC pin 41 and those other suggestions too when I get home :-) Thanks!

Hello AJ, any update???

[2.216VTurbo]

Hello AJ, any update???

My Brother is coming over tomorrow to go thru the harness wire by wire with me, gonna get like an 8 O'clock start to try and beat the heat. Now if I just had a wiring diagram for an 89 TII Lebaron where the harness came from...

[RattFink]

I can get you a diagram off Mitchell Pro-Demand...

[2.216VTurbo]

I can get you a diagram off Mitchell Pro-Demand...

Sweet, somewhere I have a box of FSM's that's proving elusive. Could be in any one of three different locations

[RattFink]

[2.216VTurbo]

Thanks Fink, we've got the harness loose at the connector and the SMEC ends and chasing them down. This harness was 'converted' to TII years ago so there are obvious signs of modification to it, Found a couple wires a little crusty with corrosion so far. I hate electrical