Author Topic: why did my car take a crap? (Read 9137 times)

Blip Bavarian · « **Reply #30 on:** June 15, 2009, 12:10:38 PM »

Sounds simple enough. But when you say plug them in one at a time do you mean reconnect the sensor, or is there another way to deprive power from each component?

Also, i have read a couple of places; and it was mentioned in one of your posts, that you can test the power to the DME. Something about checking for power at pin 27....

in a post on a different forum someone mentions jumping power to the ECU pin, and then the car will start. Dont know exactly what this means.

Where is the pin located? Do i have to remove the ECU to do this?

Sorry for the barage of questions. THanks for all the help. -Matt

DesktopDave · « **Reply #31 on:** June 15, 2009, 12:34:29 PM »

Yeah...unplug whatever you find connected to that power line, then turn on the key. Reconnect each sensor/component one at a time while the ignition is on and wait for the fuse to pop.

The ECU pins are on its connector and harness above the glove compartment. I'll bet he's just using a probe to jump power to the DME or using an inline tap to jump it inside the engine compartment.

You have to be careful about that because the DME is pretty sensitive to +12v in the wrong places. That's an easy way to trash it IMHO. I'd focus on other sensors or a short in the wiring harness somewhere - I don't think the DME could possibly be pulling enough current to pop that fuse. Maybe I'm wrong...anyone else know better?

Blip Bavarian · « **Reply #32 on:** June 15, 2009, 07:29:42 PM »

so i started by unplugging the fuel pump sensor at the pump, both Crank and cam sensors, the TPS, the MAF sensor, the ICV sensor, and completely removed the DME. I hooked up the battery cable and pop. the fuse blew...

DesktopDave · « **Reply #33 on:** June 15, 2009, 08:02:03 PM »

Damn...that doesn't make it very easy, does it? Maybe start doing continuity tests on that positive wire? At least the wiring harness is easy to get to...

Blip Bavarian · « **Reply #34 on:** June 15, 2009, 08:14:38 PM »

i have continuity all the way to the main realy. Therefore the short or issue must take place after the main relay.

I dont know how to do continuity tests from the main relay to any of the components that the main relay powers.

The fact that the fuse blew when the DME was unplugged completely leads me to believe that the prob is not the DME itself

DesktopDave · « **Reply #35 on:** June 15, 2009, 08:22:14 PM »

I agree. I'd pull the small battery connector on the firewall, then start testing continuity to a good chassis ground. Unplug things until you don't have continuity; that should be your troublesome circuit. Since that harness is always 'hot' nothing should have continuity to ground.

I looked at that harness...you'll need a little luck and a lot of persistence...do you have the wiring diagram? That'd help a lot.

Blip Bavarian · « **Reply #36 on:** June 15, 2009, 08:29:43 PM »

I printed out the troubleshooting manual that you gave me the link to, so i have that. Do you have pics or a description of the small battery connector on the firewall that you are talking about. Im not quite sure what to look for. there are 2 circular plugs between the fuse box and the "firewall relays" is it one of those? Thanks Dave.

Quote from: DesktopDave;73699

I agree. I'd pull the small battery connector on the firewall, then start testing continuity to a good chassis ground. Unplug things until you don't have continuity; that should be your troublesome circuit. Since that harness is always 'hot' nothing should have continuity to ground.

I looked at that harness...you'll need a little luck and a lot of persistence...do you have the wiring diagram? That'd help a lot.

Blip Bavarian · « **Reply #37 on:** June 18, 2009, 03:19:42 PM »

WOOT WOOT. hooray. i got my car started.. Thanks so much DD for all of your help and advice. I really appreciate it.

I was about to roll over and pay to have it towed to a shop. I decided to give it one last shot, and check every wire in the engine bay again... Turns out when i put the upper manifold back on after the hose swap, I pinched part of the "fuel injector wire", and it was shorting out on the manifold, thus blowing the fusible link, and in turn not allowing the DME to power up.

I now have a fault code because of the mangled wire but that is for a new thread. For now i am enjoying the small victory of getting it started.

Thanks again Dave for helping so much.