engine shutting down after going REALLY lean!?

[decipha]

Nope

[red5.0fogger]

heat related seemingly electrical problem at highway speed makes me think of bad grounds or other corroded connections.
Could also be the ignition module on the way out, I think they act up when hot as they crap out. (but the restarting is odd.)

[canuck1]

Yea, I had the TFI module in mind but I have new Motorcraft spares on hand and swapping them out made no diff. When they've let me down in the past, they are usually reluctant to restart, but now it will restart readily, whether I bump-start it on the fly or even if I pull over and crank it with the key, seems to come right back to life. Never a problem at idle, but often only goes as far as clicking into second, then shuts down. It happens in other gears as well. I am leaning towards a failed ground or ignition switch connection. Most of my chassis gronds are through-bolts in chassis tube. While I doubt my little summer-only toy suffers much from corrosion, I can see a ground bolt vibrating loose or pehaps a ring connector cracked/broken.

I'm going to try to go through it tonight. Thanks for the ideas, keep 'em coming!!

Sean

[decipha]

sounds like overheat protection

have you verified?

instead of guessing post a log of it. You'll be able to see exactly what it is.

[canuck1]

jul 05 to fuel cutting out.xdl

(530.78 KiB) Downloaded 253 times

Here is a log of it happening several times. 3:21, starts to go lean, 3:31 dashboard shows ATMR go from 255 to 0 (because I shut the key off) and then start counting up from 0 again after I turn key back on and bump start it on the roll.

5:39, you can see the Fuel Error start to indicate leaner and leaner until ATMR cuts off at 137 (me turning key off again after I notice loss of power) then begin counting back up around 5:48 when I turn it on again.

Third example around 7:22 all looks normal, 7:26, starts going lean again and cycle repeats as before.

Sean

[decipha]

its obvious the ecu is loosing power

if your not turning the key off then either the ignition switch is bad or the ecu relay is bad.

[canuck1]

Only time I flicked the key OFF in that log was after I figured it had already quit on me, then I flicked it back ON to get it going again. Could be a key switch issue, I'll give it the wiggle test to see if I can replicate it dropping power.

Relay tests fine on my bench with multi-meter. I'm going to pull the dash off later this weekend as there are a couple areas I can see may have been impacted by my reaching around up there to find/connect to other wires to hookup things like WB02 etc. I might have loosened a connector or damaged a wire. I'll have a closer look.

Sean

[decipha]

You cant test a relay for an intermittent short with a multi meter. You have to load test it just like a fuel pump.

[Schemasservice]

Jump the relay, drive it and see if it's good. If so, you know it is either the relay, or something on the control side.

[canuck1]

I'm going through and checking all the main power supply and ground connections to be as sure as I can I've eliminated a feeble connection before I do anything that involves driving again. I don't want to end up having to call a ramp truck to get me home if it quits and then WON'T restart. Once the dash is back in place (everything tests fine back there), I'll proceed with road testing to see if the problem resurfaces. I'm still convinced its got something to do with a failing ground connection. I've been through all the ignition switch, EFI ground connection and my dash ground bus (where devices, switches or relays can tie into a common ground). The ground strap between my chassis & engine was clean, but a little looser than I expected. I'm wondering if engine movement may have caused the bolt there to loosen up? Kind of a long shot but it may be one of a number of items contributing to ECM or fuel pump losing power.

Sean