1990 CV Wagon Cranks but No Start

[85crownHPP]

The exhaust on your last waggin is what made me want to put pipes on mine

[Freshmeat]

Dang, thanks, Pete- didn't know I inspired anyone! This one will likely be similar in volume, but this time not with expensive ass Flowmasters. I'll be running the welded Summit mufflers... and this time I'll have tail pipes! I HATED driving the other wagon- anything above 2,500 RPM gave me a headache due to the lack of tails.
I'll be working on getting some sort of exhaust install completed ASAP so it can be done before the new motor goes in. The new motor will be somewhat choked down because of the heads, just for the sake of getting it in and going, but hopefully it won't take long before I can swap them out.

Thanks for all the suggestions and everything so far, guys. I'll post up ASAP on what I discover.

If the ground and cleaning the connectors doesn't work I'm going to replace both the ECM and MAP with spares from the local Mustang shop. If that doesn't work I may very well tear straight down to the timing chain today. Fuck rain. I'm tired of not having this thing running.

[86VickyLX]

That should be oxygen sensor grounds if I'm not mistaken. Two orange wires? Or is it the fatter black wire that goes over to the fender?

They were orange. Does the fuel pump run?

[Freshmeat]

The fuel pump spins up just fine.

[86VickyLX]

Do you have any fuel pressure at the rail?

[Freshmeat]

It's not fuel- sprayed starter fluid (tried two different cans) straight into the throttle body but it didn't help one bit.

[Freshmeat]

Real progress! The Mustang shop owner (buddy of mine) said that wire snapping off like it did can fry the ECM. Sure enough, TPS is only getting .09v which indicates ECM issues.

[86VickyLX]

Real progress! The Mustang shop owner (buddy of mine) said that wire snapping off like it did can fry the ECM. Sure enough, TPS is only getting .09v which indicates ECM issues.

Time to harvest an ECM from the junkyard!!

[Freshmeat]

That's a negative. Grabbed an ECM (and the rest of the parts I need for the "factory CAI" at the junk yard but it's still not running. The voltage on the TPS orange wire bounces all over with KOEO now. No clue what that indicates.

[gadget73]

unplug the tps and see if you get steady ~5v on the green wire. If you do, the TPS is shot. If not, you've got other problems.

[Freshmeat]

I'll try that Tuesday if I can.

[Freshmeat]

Apparently I wasn't getting good contacts while testing earlier. I had my dad hold the negative to the battery terminal while I probed the TPS wires. In the idle position it gave .88v and as I slowly opened the throttle it climbed to high 4.XXv, which means the TPS is working just fine.

That said, there's no clue that the ECM I pulled is actually functioning properly... but the chances of two ECMs being bad is a long shot. The car it came from wasn't wrecked and the ENTIRE drivetrain had been stripped out, so there's really no telling what caused it to be junked.

I'm going to try to pull another ECM from the Mustang shop tomorrow and see if it makes a difference, but at this point, I don't think it will. I'm at a loss.

I'm at the point that I'm ready to haul it to a shop, but at the same time, this has become a personal challenge and I'm so damn determined to figure it out.

[gadget73]

smidge lower than normal, but well within the self-test range.

When this thing died, did it quit while driving, or was it shut off and it just refused to go again?

[Freshmeat]

It quit while driving. What difference does that make?

[gadget73]

Not a huge amount, but I was just thinking if the iac wasn't opening, it would be a bitch to start. That wouldn't make it die while driving though. I wonder if a seriously crapped out MAP sensor would do this. They dont usually fail, and when they do, it tends to run like the vacuum line is unplugged to it. If you've got a spare, it probably wouldn't hurt to swap it, or maybe just unplug it to have the ecm try and run in limp mode.

Its getting well into the realm of not making a lot of sense anymore. I'm kind of getting to randomly swapping things to see if it changes anything. I hate troubleshooting that way but sometimes when normal methods fail, the only thing you can do is try something to see if anything changes.