How do you know!!
 

Ok Guys

How do you know if your DME computer under your seat is blown?

Anybody experience this before,

How do you diagnose that it is the computer for sure?
Thank you
George

What are the symptoms in your car ...?

I have a 1980 SC updated to a slantnose, put a 3.6 in it , it started great , took it to get the interior put in, now the car wont start, took it to my mechanic, he says its getting no spark, and the fuel pump isnt turning on, he jumped the relay and the fuel pump turns on, he says its the computer

i just dont want to find a DME and waste my money if it isnt that

Does he replaced the DME relay ? because making a bridge on the relay will activate only the pump but how he knows if the DME is triggering the relay for the fuel pump activation .
Also when he jump the relay did the car started ?
A non start condition can be referred also to a defective Speed sensor , most commonly called crankshaft sensor .this one if defective will not send the right impulse signals to the DME to trigger the Fuel pump relay and also the ignition control units for spark.

how could my car go from starting like a million bucks to cranking over and nothing, also the fuse for the power for the DME was blown,

what do you suggest i do?

Sadly a blown fuse can mean many things, if you have a multimeter and want to spend some time troubleshooting the problem i can give you information on how to , also i can test you DME for free and that way you can save time on the diagnose .

No the car did not start when he jumped the relay, all it did was make the pump turn on , so he said the relay is fine cause it just turned on the fuel pump, also when you turn the key the relay makes that tick sound,

that would be great if i could trouble shoot it myself, also the wiring harness i got with the kit to install in my car, it has 1 wire that goes to constant power, 1 that runs to fuel pump, 1 that runs to speedomoter, 1 that runs to fuse panel so that when you turn the ignition off it turns the motor off, and thats its,

the fuse that blew is for the constant power 1 , this wire should be ran to the battery directly , but my mechanic when he did the install ran it to the fuse panel to a fuse that has constant power all the time, he said its better just incase something happens it will blow the fuse 1st and not do any damage,

Try swapping in a known good DME before you buy a replacement.

thats what i would love to do , or put mine in a car and see if anything happens, problem is to swap a good one in , where would i get one?

1. Ran and started perfect
2. Interior guys worked on it and now it's broke?
I would look for cut/pulled wires, unplugged stuff, etc. if that is the actual chain of events. Assume there is a DME relay in your updated setup? That's fuel only I believe so it wouldn't explain no spark, just no start.

i ripped all the carpet out of the car that runs down tghe driver side and inspected all the wires, from where it goes out thre the back in the chassis right to where it goes up in the dash to the trunk, and nothing, maybe they shorted something installing my seats? i dont know, they unhooked the battery when they worked on it, maybe they shorted the battery and it caused something, i dont know,

Mine has an SC fuel pump. It still buzzes with the key on as it's wired seperately. A new DME relay didn't cure the problem....I also have no spark.

Can't find an inline fuse, it's a Timmins harness and he's not answring emails. The crank sensor tested fine

I plan on sending the DME to a buddy that has a 964, a diagnostic Hammer AND a bench tester.....BUT I'd sure like to cure it myself.

I'll ask him to install a diagnostic port when it's down there.

EDIT, the 12volt line to the DME tests OK at the harness that goes into the box. So it's NOT an inline fuse.

I got mine from Timmins also, i called him the other nite at 830 PM when i was at my mechanic and he ran threw the colors and where they go, everything is fine, im wondering if it could be the chip??????? im going to go try that right now, put my oem chip back in it

My natural inclination would've been to investigate what GaryR says. If the new fuse doesn't blow now, it seems the condition that caused the blowing is no longer valid. A nicked wire could cause the fuse issue and might be difficult to see. The question is whether an internal short in the DME could cause the fuse to blow.....that's assuming that the the two conditions are related (IMHO a good assumption). If you've tried every logical alternative checking the DME is your next step. Good luck

Took the DME to a freind thats a tv tech , hes opening it up and going to see if there is anything blown or suspicious , I will keep you all updated ,

"So he has a lot of tools and can fix anything?"

Spicoli, Fast Times at Ridgemont High.....

I too, sent my DME to a friend. Hopefully he can slip it into his 964 conversion and diagnose/fix the issue.