I have a 2000 Excursion 7.3, 6 position tune, and exhaust as far as mods (on truck when bought). Last couple of weeks I get no power while on the throttle, foot on the gas and the whole truck shakes at higher speeds - 40mph and above. At first it wouldn't go above 60 or so, would hit the gas and Rpms would just stop not be able to generate any further power. Changed the IPR, ICP, and CPS. I still get the high/low range ICP codes, P1280, P1281. First night the IPR was changed I got it up to 90mph and thought it was all solved but got a little shake right at the top and I let off the gas. Next day back to square one and has seemed to get progressively worse, almost wasn't able to make it up a hill by my house not even going 20mph, but it's like intermittent. I have a scan tool, here is at idle and at around 60mph - what do you guys think could be the issue. Thank you.

At ~60mph

 

Here it is at idle

 

MAF at 0 looks like a dead sensor. Trucks probably in limp mode.

 

Hmm, interesting get no codes - I'll check the pid more closely on the scan tool and see what's up with it. I thought there was no MAF but a MAP sensor - not sure if the pid is the same on the scan tool, have to check tomorrow. Ty for the suggestion

 

I was thinking it was odd that there's a MAF right after I posted that. Everything else sounds like limp mode though.


Have you checked your fuel filter lately? In-tank sender? Not being able to build revs is either air or fuel.

 

Also, when's the last time you drained the water out of the filter? A load of H2O sloshing around the bottom of the tank could cause this too.

 

Could a bad MAP sensor cause the 'limp mode' or would I have gotten a code? Better yet could it be the chip? Bad HPOP? Bad injectors? It does feel like something to do with fuel, I mean the truck shakes/studders pretty good and I have to let off the gas and putt around - normally under 40mph or so it feels 'fine'. Fuel filter was changed with oil change, probably less than 1k miles. I haven't dropped the fuel tank to check the sender in there.

Haven't drained the filter of any potential water (had the truck 2 months) - I'll check to see if any water comes out. Thanks Jim

 

Any dead sensors should trigger a code. Any sensors out of range should show up for that matter. Limp mode doesn't appear as a code though, it's a protective measure to keep the engine from eating itself when it doesn't have good data.


I've had my truck 2 weeks and put a new fuel filter in it as matter of practice (original was black). Assume the previous owner didn't, because they were selling the truck.

Draining the water out of the filter can be done in dress clothes if you can reach the valve. If it's full of water, you'll get rough running and maybe some white smoke when it's acting up. Stick a clean catch pan under the oil pan and crack the valve for 20 seconds - see what it looks like.

 

The fuel filter I replaced from the prior owner looked pretty good when I threw it out - wasn't black at all. Will try draining any water - are there any conclusive tests I can run/monitor on the scan tool? I haven't seen any smoke that I've been able to notice.

Any mechanics/experienced people in/around NH willing to help diagnose?

 

You want MAP on the list, not MAF. I'd also get rid of the first EBP on the list, it's just confusing.

Check your IPR tinnerman nut - make sure it's there. When the ICP sensor fails, the PCM ignores it and fills in the value with what it thinks it should be. Check your ICP sensor for oil in the connector. If oily, I'd clean it up with electronic contact cleaner and try again.

 

Took the truck for a drive, below is the MAX ICP and IPR values at wide open throttle - wont go anywhere past these ICP and IPR values. I tried to run a KOER Contribution Test and it stops the test because of the ICP code (P1284). Can a bad ICP *limit* the pressure getting to the motor and stopping it at 2465.7 psi? The IPR does not go above 33.59%. Both the ICP and IPR were just replaced. The ICP was an aftermarket part, and the IPR was motorcraft oem.. can the ts chip limit these values by any chance - i tired on all positions and same max values - thoughts?

 

A black fuel filter is an indication that you are getting oil in your fuel system. The black is from the soot in the oil. How? Bad injector o-rings allow high pressure oil to push past the bad o-rings and mix with the much lower pressure fuel (3,000psi vs approx 50psi fuel). Check your coolant de-gas bottle. I'll bet you will see black gunk in there, indicating a similar contamination of the coolant, with soot, by the same means/mechanism mentioned above.

 

It's not black like oil slick black. It's charcoal black like dirty and hasn't been changed in forever.

The coolant res is clean and so is the coolant. Light green, no slime.

 

My bet would be that the socks in your fuel pickup are getting plugged. Every symptom echoes what I had going on. Time to do the h and h mod.

You can disconnect the fuel pump aft side and blow few pounds of compressed air thru the line and see if the problem dissolves momentarily. (it will come back if that's the cause) It's a simple free 20 minute diagnosis.

My truck did exactly what your laying out.

Denny

 

BTW pop your fuel fill cap if you do this procedure. (sorry)