Car stalls when Xcal2 unplugged?

[Teebs]

2000 Cougar Full 05 Taurus 3L swap. Anyone got any ideas? I'm scratching my head on this one... As is the tuner.

Finished the 3L swap and got the car tuned. Car runs great with the xcal2 plugged in. Made 208HP/204ftlbs, but once the tuner took the car for a drive he noticed it was running rough and wouldn't idle. Plugged the tuner back in, and it ran fine. Unplug it and it would stall.

You can get the car to idle if you give it some throttle, eventually the car compensates and runs. But backfires everytime you let off the gas... Any ideas?

Thanks, Tim.

 

[CSVT#49]

that's weird... wonder if it is somehow providing power or a ground to something else on the circuit when it is plugged in. I'd start doing some continuity checks...

 

[BrApple]

I know with my car every time the pcm is reset or i have flashed a tune the car doesn't want to idle right at first. take a few minute for it to learn the idle then its good to go. other then that sounds like something might be shorting out as mike indicated.

 

[Teebs]

It learns to idle eventually, but then backfires every time you let off the gas. You have to disengage the clutch every time you want to slow down.

Anyone have some schematics that would help me out here?

 

[BrApple]

isn't a backfire caused by a rich condition?

 

[Teebs]

isn't a backfire caused by a rich condition?

And vacuum leaks too I think? And apparently also caused by little blue boxes as well!

After much frustration, found the source of my problem... I figured since plugging the Xcal2 in caused the car to work, that my focus should start at the OBD II connector, and work my way back from there. Didn't work out well... Many frustrating hours looking through the Ford Service CD which has terrible diagrams IMO.

Decided to check at the ECU, maybe I would find a grounding issue. Disconnected the plug, and climbed under to pull the ECU out from the dash. And there staring at me was the source of my problems! A little blue box that was the source of my headaches!

Say hello to my little blue nemesis...

Talked to my tuner and he recommended I return the car to stock from the Xcal2, remove the chip and reflash the ECU with the dyno tune. Did what he said and now it runs perfect!

So somehow by plugging in the Xcal2 I bypassed the Superchip. From what I understand these superchips just piggy back and modify the signals?? So by plugging in the xcal it must bypass the superchip. But not when I would plug in my OBD II scanner...

Problem solved! Anyone want a Superchip for a 2.5L? lol

 

[CSVT#49]

HA! That's awesome. Nice find. Now you can go and sell that in the classifieds :laugh:

 

[Detailed]

Or send me a p.m with a price

 

[double_u_4]

And vacuum leaks too I think? And apparently also caused by little blue boxes as well!

After much frustration, found the source of my problem... I figured since plugging the Xcal2 in caused the car to work, that my focus should start at the OBD II connector, and work my way back from there. Didn't work out well... Many frustrating hours looking through the Ford Service CD which has terrible diagrams IMO.

Decided to check at the ECU, maybe I would find a grounding issue. Disconnected the plug, and climbed under to pull the ECU out from the dash. And there staring at me was the source of my problems! A little blue box that was the source of my headaches!

Say hello to my little blue nemesis...

Talked to my tuner and he recommended I return the car to stock from the Xcal2, remove the chip and reflash the ECU with the dyno tune. Did what he said and now it runs perfect!

So somehow by plugging in the Xcal2 I bypassed the Superchip. From what I understand these superchips just piggy back and modify the signals?? So by plugging in the xcal it must bypass the superchip. But not when I would plug in my OBD II scanner...

Problem solved! Anyone want a Superchip for a 2.5L? lol

will this chip work in a svt. what can i expect from this chip