Hello all, I was referred here by a member of another automotive web board I frequent. I am looking for some guidance to fixing an issue that has me stumped:

I have a 2000 Ford expedition 5.4 (with an older twin screw KB supercharger) that has had the engine replaced. (I had a shop handle it for me because my garage is too tight and I didn't want to work in the snow.)

The set up: Fresh engine, new plastic intake manifold, New Fomoco COPs (coil on plug), new Fomoco spark plugs, freshly flowed and matched injectors, new fuel filter. Recently refreshed trans and TC from Extreme Automatics.

The issue: Truck starts and idles nicely. It was idling a little low (600 rpm) so, I swapped in a new IAC and the idle is better now at 750rpm. I can drive down the road and it runs and drives fine. Then, out of the blue it will simply die. This can occur coming to a stop or while driving down the road. It can be cold or warmed up to operating temperature. Sometimes it will shudder a little, if it plans to die at a stop. When it dies while driving, it sounds like it's been punched in the gut. Like someone just turned off the key. The weather has been 30*-50*F dry and wet. As a side note, the previous engine has 114k on it and NEVER had any issue like the one described below.

When the truck stalls, I pull over and sometimes it will start right up. Sometimes, I have to wait a few minutes. Sometimes, it will happen only once, and for the rest of the day it will be fine as I run errands. The last time I was having issues I dropped it back at the shop, They checked everything and claimed to have found a loose vacuum line. They claimed they had driven it up and down the street with no issues. I took the truck and got onto the main road. It died a within a few blocks. It took a few minutes to finally start. I turned around and it died before I could get to the stop light. I sat through a few light changes trying to start it again. When it finally started my "theft" indicator was flashing- I've never seen it do that before. I drove back to the shop and parked it. I turned the truck off and then on again and no "theft light" came on. I took the shop owner on a drive and did not have any issues at all. Figures...

The truck has absolutely no codes. I checked with my Autel scanner. The shop used their scanner and could find nothing (not even old stored codes). This shop works on these engines all the time and they have no idea as to why this is happening.

Things I've considered and discounted:

1. Fuel pump- it either works or it doesn't (usually not intermittent)
2. Ground wire- I think if one was loose I think it would have other issues
3. Vacuum line- would throw a code
4. Ignition Control Module- It would likely act up when it warmed up and then work when cooled down. With the way it usually starts right up and can have many miles with no issues it does not feel likely.
5. MAF- it was tested as working fine

Anyone have any ideas??? I'm at a loss. Any input is appreciated. This is getting frustrating.

 

hopefully I did not steer you wrong and guys will chime in with some suggestions.
You might also consider a search on here... plus there is a performance, engines & trouble-shooting section for these engines as well.
Good Luck!

 

Well, I’d start out with a fuel pressure gauge taped to the windshield and see what the fuel pressure is when it shuts down. And what the fuel pressure is as you attempt to restart it.

That would either implicate fuel supply issues or look else where.

The experts should be along shortly.

 

P.S. When it shuts down is the tach at zero or does it wind down as the engine winds down?

 

Do you have a second key and does it occur with both keys?

 

Tach drops to zero immediately. It does not wind down at all...

 

I only have one key for the truck. I've owned it since 2007 with no issues like this ever.

 

It was a thought that crossed my mind. Truck is at the shop currently. Just want to kick around some ideas. I'll recommend it.
The only issue I can think of with fueling is a bad FPR, but how could it be? It starts and runs and idles perfectly. It simply dies when it feels like it. Fuel filter is new as are the injectors. Fuel pump usually works or it doesn't. I've not seen intermittent FP issues before...

 

That "theft" light you got could be the tell tale.
If it we're me personally I would have a second key made and programmed. I have seen them fail. Also the Transponder could be a possible fail condition.

Do you have the torque app and device to view? You need real time info to diagnose this with out throwing parts at it for no reason.

 

The flashing "theft" light seemed like an issue, but since the engine has been swapped, I maybe have 100 miles on it. It never once gave me the light. Only this most recent stall failure...

Additionally, I forgot to mention that the while the truck is a regular gas hog, this time it's been really bad. It drank 1/4 tank of fuel and I got about 40 miles out of it. The shop claims that a new engine with tighter clearances had more resistance and will thus use more fuel for a little while. Not sure it should be drinking so much but I suppose it's plausible.

I have a scanguage II that I had hooked up while driving but I couldn't nail down a pattern on anything.
I've not tried the torque app and currently the truck is at the shop- I'm kinda at my wits end... Just trying to see if I could enlist the assistance of enthusiasts who usually seem to know more than repair shops and dealerships.

Would a key transponder have such an issue so as to cut the engine off?? It doesn't seem plausible. I suppose I need to read up on keys...

 

My SWAG is that you have a problem with the power feed to the PCM. If the PCM key on power is interrupted it will do exactly what you're describing.

 

Can you please elaborate?
1. What does SWAG mean? (sorry, I have no idea)
2. Would a PCM power feed just quit working out of the blue? I mean, it sounds like it could be an issue but maybe I'm getting wrapped up around the fact that it's never happened before and "coincidentally" after an engine swap it's now decided to start acting up? Just seems weird to me. Where do I find the feed? Can anyone post up a pic? I'll pull my service manuals as well, but pics are always helpful
3. Any thoughts on how to test to confirm? And if the feed is bad, how to repair?
4. As an aside, I do get the CEL when I turn the ignition- so it's working. I also tested the TPS and MAF a few months ago- so I presume that the input/output of the PCM was working.

 

I have seen intermittent fuel pump issues. The gauge on the windshield will either implicate or eliminate fuel supply issue when it dies.

 

Then I would investigate the CKP sensor or follow Mark’s SWAG (aka Silly Wild A$$ Guess). If the CKP goes intermittent the PCM has no clue that the engine is rotating and has no idea when its time to fire which ever plug or injector, or where to position the tach so it goes to zero.

When the engine was changed did they use the old CKP? Or did the CKP harness get pinched? Is the connector fully connected and clean?

 

SWAG, funny.
Crank Sensor was swapped from old engine. It was clean and good to go. I suppose it could be an issue. It makes sense.
I will ask to see if the wire got pinched or if it's not well connected.

My biggest issue is that the car will start and idle perfectly. Some days I can drive down the road with no problems at all. Stop and go traffic, running errands and absolutely no issues. Then, just out of the blue it will die. The worst part is that if I'm driving it normally, it will die. If I am actively trying to get it to die, it will run perfectly with no issues at all (like going to the doctors office! LOL)

I guess my thought is that an issue with a sensor will happen more often than not. Not sure why my issue is so odd.

Someone else mentioned a second key. My service manual mentions extra keys and the PATS system. I've owned this truck for 11 years and only ever had one key. Not sure why all of a sudden this would be an issue. Can anyone elaborate?