Everything is back together and the problem remains. If anything, the missing started sooner.

The vinyl loop on fuel line does not show any bubbles (after clearing out the inital air from starting up after reassembly).

Torque shows high HPOP and IPR at low idle while the problem is occurring:Here is a link to a 13 second YouTube video showing Torque and the sound of the engine. I also tried to attach the .mov file to this post (1.5 meg).

 

Dam dude sounds like mine, and mine has a blown head gasket, probably something you didn't want to hear but a thought. Time to do a compression test.

 

Already did. Compression is fine.

But yeah, that's what it sounds like when only the back four cylinders are working.

 

Have you tried swapping the IDM just to rule out it's not the problem?

 

IDM arrives on Saturday.

I'll remove the chip this morning just in case.

 

Waiting for IDM to arrive, replaced turbo compressor wheel.

Before...


EBPV delete pedestal
(much easier to work with than the stock one)







What do I do with the now unneeded EBPV wire? Just tuck it away somewhere? Cut it?

 

Good grief what tore up that first wheel? Nice work!

 

I don't know for sure about the wheel, but what I'm thinking is..

Turbo wheel was pretty well dusted when i got the truck at 97k miles (i'm guessing). The engine compartment is still filled with offroad dirt and the intake filter housing was filthy when I took it out. I remember the air filter being really bad with sand burrs stuck in it. The little restriction gauge did not indicate a flow problem, so I didn't even look in there till I did the 6637 intake. About the same time, I chipped the truck and started standing on it all the time and then let my 18 year old use it as a daily driver. Probably enough to send a weakened wheel over the edge.

I recall on two occasions when the engine was under load hearing a sound like a little piece of rubber being sucked up by a vacuum cleaner. I was thinking something rubbed the radiator fan (the housings up there are loose), so I let it go after a visual inspection. In hindsight, I think that was the turbo wheel disintegrating and getting sucked in. If that was really it, it was not as catastrophic sounding as you might think. And the impact on performance was nil, which is why I speculate there was preexisting damage and this was the nail in the coffin.

Anyhow, it drove several thousand miles after that, including a long trip to my sister's, 1,000 miles each way making it whistle passing traffic at 95 mph.

Go figure.


I don't still have the actual filter, but here is the old housing showing some indication of what it was like when it came out.




Anyhow, the IDM came in the mail today, but I'm gonna take a break till Saturday on trukwork (need to reinstall downpipe and fuel bowl). Since this is a used IDM off eBay, I'm not certain I will have proven anything if it doesn't improve the situation.

 

Put in the other IDM and it did not improve the situation. It's misbehaving a little bit differently, but that's hard to say with an intermittent problem, y'know.

It had a hard time starting this morning and went straight into the misfiring. After turning the engine off and fussing with it some, it re-started without the problem, then went back into misfiring after a few minutes.

Just now, it wasn't just the front four cylinders that were missing -- it seemed more like it was the passenger side head. Certainly, 5 and 7 weren't contributing.

I'm monitoring ICP IPR and Pulse Width. When the problem occurs, the only change is that IPR % is higher than normal.

Also, I can't get the MAP reading to change at all in Torque. If I unplug the MAP sensor, I get a check engine light and the corresponding fault code in Torque, which goes away after I plug it back in. I can get EBP to rise by revving the engine, with no change at all in MAP.

I'm not sure what to do next, other than go back and re-check fuel pressure.

Any leads would be greatly appreciated.

 

I didn't go back and read the previous pages, but have you checked the under vale over harnesses, and the outer plugs/pigtails for burned pins, or melted connections? ^^^^This sounds like my what my 97 was doing. On it, the outer pigtail was melted, and I was in a hurry when I replaced it, and used butt splice connectors when I repaired it. It ran perfect for a couple of years, then it would start to miss and have a lack of power randomly, which progressed to all the time. I cut out the butt connectors, and soldered the wires together with heat shrink for covering, and the problem went away. It sounds as if the IDM is seeing a short, and is shutting one bank down to protect itself.

 

This thread's kind of long, so here's a summary so far.

Problem:

• Truck starts fine, but will eventually start stuttering/missing.
• While it is stuttering, fuel pressure looks fine at the schraeder valve (50-54 psi).
• While it is missing, Torque Android app shows pretty much normal readings for ICP and InjPW, but IPR % is high at idle (20% at idle is high). ICP and IPR % rise when engine is revved.
• Some of the injector outside-valve-cover plugs can be pulled while the truck is stuttering without making a noticeable change. It seems to move around. For a while, it seemed like it was always the front two plugs that could be pulled without making a change, but now, it's the two passenger side plugs.
• The problem can start immediately, or only after 60 minutes. It does not correlate with EOT.

After the first time this problem stopped the truck while driving, it "healed itself" and went a week without failing again.
After that, it got progressively more frequent, but occasionally it can go for an hour or so.
Before the truck stopped the first time, there was some occasional loss of power under load and occasional hard starts when hot. Occasional loss of power sometimes seemed to correlate with rear fuel tank below 1/2 full.


Tests Run, Parts Replaced:

Checked injector outside-valve-cover plugs. All looked OK, but one was missing a clip. It was seated fine, though, and continuity tests passed later.

Observed that the turbo wheel was chewed up bad. Replaced later.

CPS replaced. Tried with a non-Motorcraft from O'Reilly's and it made the truck spew white smoke and drop soot from the tailpipe onto the ground. Motorcraft CPS worked fine, but did not fix the problem.

Checked resistance from IDM plug. Ohms rose with heat to slighly out of spec, so replaced UVCH. Ohms read fine from IDM plug.

Compression test passed. All cylinders right at 360 PSI at EOT 115 degF.

Observed that all injectors were spitting oil evenly.

Replaced UVCH.

Replaced stripped plug on HPOP reservoir (note to self: it is Torx, not Allen)

Caused a leak on the thermostat housing removing upper radiator hose to get room to remove stripped plug, so replaced thermostat and re-seated housing.

Checked and re-loomed wiring down front of engine block to CPS.

Got fuel pressure tester. Fuel pressure looks fine at schraeder valve even when the engine is stuttering (50 - 54 PSI).

Rebuilt IPR with new seals. Old seals looked fine, but pigtail and plug were in bad shape. Have new IPR in hand if needed.

Replaced IPR pigtail with one from old UVCH. Decent soldering job -- not just butt connectors.

Re-loomed wiring around fuel bowl.

Scraped FPR screen from inside bowl and blew it out. (note: i have not disassembled the fuel bowl, but an o-ring kit is in the mail)

Installed clear vinyl hose from fuel pump to hard line and observed that bubbles did not appear while the engine was missing. There -were- little pinhead bubbles, but no significant bubbles. Have a video of that if needed.

Removed chip.

Replaced turbo wheel, reinstalled turbo with EBPV delete mod.

Replaced IDM with "tested" used IDM from eBay.

Noticed that MAP readings in Torque never change from zero (or "adjusted zero", meaning the barometric pressure). EBP will rise but MAP never moves. It is very likely that I bumped or laid on a sensor or a wire, but it is not nice to see this after replacing turbo wheel.


And now... out of ideas.

 

map sensor with Torque pro on and blowing air into sensor can test it


Truck don't need BARO connected to run, if you suspect it, then look above brake pedal for the sensor to unplug it. BARO can be tested also, I pulled mine apart and put pressure on it but no signal came out of mine so I deleted it since I don't go above 2k more than sea level.


IPR% changing could mean injector oring failed or just adjusting to keep idle up when it runs rough.




have injector orings ever been changed? less than 60 to know they are good.

 

Hey, I had some what of the same issue with my 97. It would limp and had very very poor throttle response. It ended up being the IDM. The injector drive module. I bought a performance swamps one and that fixed the issue, with good results. A stock one to a performance one is not too much of a price difference. Good luck

 

Hey there,

I had some similar problems, limping around town with horrible throttle response. It ended up being the IDM. Injector Drive Module. I bought a performance Swamps one and it fixed with better results. It is a simple fix with only a few screws. A performance to a stock one is not much of a price difference. I recommend the upgrade. Hope this helps

 

I've looked at those and might try it out now that I've got a core. Five hundred bucks is a lot of money. Maybe save two hundred and go with Irate 120V IDM?



Thanks. I'll try this test.

I've been wanting to build a boost leak tester, so I might make that project part of this task.


The injectors have not been changed and truck is at 110k.

I've been looking at injector removal/reinstallation and can handle it if needed, but I really want to rule out anything else before getting in there. And I'm opening up a whole can of worms, coz if I send injectors off to Jim at Rosewood, why would I not upgrade them? (and so on, and so on...) I'll have to think long and hard about upgrading a truck that don't run.

Did the compression test really tell me enough to be confident that there are no metal bits of the turbo knocking around in the cylinders and causing intermittent failure? Like getting hung up in valves or something like that?