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Gutless 7.3L

13K views 26 replies 7 participants last post by  Gstoneburner 
#1 · (Edited)
Just bought a '99 CCLB 7.3 with 195k on it, 6 speed manual. Chasing a gutless engine situation. Absolutely no power, my 12 valve Cummins that's 10 years older will run circles around this truck right now... I'm very mechanically inclined, but not so electrically... So I need help!

History of the truck: Owned by an older couple, daily driven infrequently by the wife. It was taken in any time there was even a hint of something wrong. Have all the service records.. no real engine trouble. Just glow plugs and the occasional GPR. Oil always changed on time. Most engine work it ever had was a set of new HPOP lines a couple months back.

Things I've done/ checked:
Fixed a small leak on the pass head fuel line
Fixed a small leak from the back plug on the HPOP.
New CPS (International dark grey)
New fuel filter
New air filter
New ICP sensor (there was oil in the connector, probably need a new connector... Could this cause my issue?)
Disconnected EBPV, made sure it was wide open
Disconnected the Wastegate line, made sure the wastegate was closed
Pressurized all IC plumbing from the turbo on to 20psi. No boost leaks.
Checked MAP hose, clean and leak free.
Checked turbo shaft play. Has zero, spins freely.
Oil is clean and at the correct level.
Rebuilt and cleaned the IPR, ohmed out the electromagnet as well.
Cleaned EBP sensor, but found a gigantic hole in the tube. Pulled the tube and plugged the hole at the manifold, new tube arrives tomorrow. Left sensor plugged in, reading ambient pressure. (I know a plugged/bad EBP sensor will cause a defuels condition, but to what extent, I do not know. I can't image it defueling to this level though... )
Hooked up a fuel pressure gauge to the bowl, can't get it to drop below 60 psi, even at WOT.
Put it on a solus edge and buzzed the injectors, they sound okay.
IPR duty cycle is in spec cranking and at idle, as well as revving.
HPOP puts out 800psi at idle, spikes to above 2000 when I rev it.
MAP appears to read okay.
Didn't pay attention to the EBP value, or drive the truck while I was hooked up... Should have. Hindsight is 20/20...
Perdels are good except for cyls 3 and 8, which I've read is a CPS issue?
No codes.

Zero smoke, just sounds anemic. Just plain won't accelerate even up a slight grade in OD right in the power band. I can put my foot to the floor, and it'll just get real noisy and go nowhere.
Does anyone have any ideas? The only thing left is the injectors or the IDM if the EBP sensor/tube doesn't fix it.
I'll double check the IPR duty cycle on a scanner while driving as well.

On another note, I can't get the truck to enter programming mode for another key fob. Tried all the combinations of key cycles, door open, door closed, wipers on, etc, etc. Any ideas here?
 
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#2 ·
Yes #3 and #8 commonly fail with that cps.

Man that's a tough one.

How is the clutch? Does it only lagg in overdrive?
What happens in the other gears?

Are the Compressor wheel and turbine wheel both intact with no blade damage?

Have you checked the up pipes and verified they aren't leaking?

What does icp pressure and duty go to at WOT?
 
#3 ·
Clutch is in good working order... No slipping.
Pretty much any gear will do it, but overdrive is exaggerated because of the tall gear I'm assuming. Compressor wheel is good, turbine wheel I haven't seen yet, but im guessing it's in pretty good shape judging by the way they drove it. Up pipes show no soot, but I haven't determined if they're leaking yet.

Need to check the duty cycle while I'm driving, I'll hook up to a scanner again tomorrow eve.
 
#4 ·
My first thought is that if your only comparison basis is this one v8 powerstroke to a I-6 cummins which has lots more torque then it may not be as gutless as you think... these are completely different animals and 'feel' completely different as well.
My second thought is that if everything appears to be in working order get a bottle of hot shots secret oil additive and a bottle of their fuel additive to try to clean the injectors up a bit. Also inspect the fuel bowl really good to make sure it's not dirty and that you aren't getting oil into your fuel supply. (Black fuel filter points towards leaky injector orings.)
Inspect the main wiring harness where it goes over the valve cover for chafing on the bottom (injector) wires.
Report back.
Have fun! These are great trucks and motors but comparing them to a cummins is apples and oranges.
 
#5 · (Edited)
The Cummins is putting out right around 550lb-ft and 200 something horse, the power stroke should be putting out about the same torque with a higher HP rating due to the fact that its a v8... Also feels really gutless compared to any other powerstroke I've driven. Something is definitely wrong. As for oil in fuel, the fuel system dead heads at the end of the rail, meaning there's no chance for oil to end up in the fuel bowl. I've been looking at archoil, hotshot etc, but have been on the fence. I did put a bottle of diesel clean in the last tank, and a bottle of grey power service in this tank. Been running it hard trying to get the EGTs and injection pressure up to clean out any clogged nozzles.
 
#6 · (Edited)
There IS a chance of oil getting into the fuel bowl. If the injector o-rings are leaking, HP oil will leak into the fuel rail and back up into the fuel bowl. It will also be injected into the engine and burnt, many times without excessive smoking.

Pulling the fuel filter to check is easy to do and as said, a black filter would be an indication that you need to dig deeper, possibly replacing the injector o-rings.

Your fuel pressure may not be up to snuff either. You should check that with a gauge. It should be a minimum of 45 psi, and 65 psi would be optimal, although you probably won't see that on a stock fuel pressure regulator setup.

Your 800 psi ICP at idle is a bit high as well. It should be more like 450-500 psi at idle with the IPR duty cycle in the 10-12% range. It should also hit 2200-2400 under full load, but just revving and getting to 2000 seems OK. If your IPR duty cycle is really low, that may indicate either a biased ICP sensor (reading higher than it should) or an obstruction in the relief path from the IPR. Can your scan tool do a recording that you could post? If so, recording engine rpm, ICP and IPR duty cycle might reveal an issue.
 
#7 · (Edited)
Well regardless,I had my bowl open yesterday and the filter is clean. I may have forgotten to mention in my original post that I hooked up a mechanical gauge to the bowl, can't get it to pull below 60 psi, even at wot.
I'll see if I can grab a recording. I don't have access to the solus any more, but I've got another scanner that is supposed to show up today that I can use.
 
#9 ·
I know you said you didn't find any boost leaks and the turbo spins freely but have you got any boost numbers? And what size are the tires? I noticed you are at almost 8,000 feet elevation but anything you are comparing to you also drove at 8K right?
 
#12 ·
I don't see any issues with your values at warm idle. ICP and IPR look normal. No smoking gun there.

IPR values above 40% or so at WOT would indicate that the HPOP isn't keeping up. But getting to 3000 psi is a good thing. At 65% IPR, it will throw a code.

EBP looks OK too. IIRC maximum is ~35 psi.
 
#13 ·
I didn't see any issue either. The new EBP tube helped power a bunch. At this point all I feel is left are bad injectors or an IDM. Could the uvch cause low power? I always thought bad uvch connectors would cause a miss or rough running among codes. All the Injectors buzzed at the same noise level as well.
 
#14 ·
I would rule out the IDM or UVCH. Like you suspected, they would cause a miss and would light the SES light. You would have also seen a code for any issues with the injector electrical side.

Question: Does your truck have a catalytic converter? I believe some did in '99 and if it were plugged would cause performance problems.
 
#15 ·
No cat. I may have discovered the issue.... I know in late 99.5 ford moved the baro sensor to the PCM. Before that, it was mounted under the steering wheel. Was watching my scan, noticed that I didn't have a barometric pressure reading. Went digging around under the dash, and came up with an empty connector for the barometric pressure sensor. Missing baro sensor= truck runs like poo? Or did they leave the plug in the wire harness even after the pcm mounted baro sensor swap? Can someone go check their truck?
 
#20 · (Edited)
My bad. I'm gonna blame my mistake on old age. :winking:
I just checked the service manual, and found this:
Barometric Pressure Sensor
The Barometric Pressure (BARO) sensor is a variable capacitor sensor that processes a signal indicating atmospheric pressure. This allows the PCM to compensate for altitude. The PCM uses this information to calculate injection timing and glow plug control. With the 1999-1/2 model, the BARO sensor is no longer a stand alone component. It is now contained in the PCM.
A BARO sensor fault will result in an out-of-range signal to the PCM. The PCM will assume a default value of 100 kPa (14.5 psi).

But that last sentence would say that if the BARO sensor were missing, the PCM would use a signal corresponding to about 400 ft elevation.

The APCM connector will have 4 wires, black, red/yellow, pink/light blue, and tan/orange.

Are you sure you don't have a 99.5? Check the build date. The cutoff was 12/8/98.

I'll have to fire up an old computer to check my 99 service manual to see what it says about the BARO sensor, including wire colors.
 
#16 ·
It wasn't in late 99 that the baro sensor moved into the PCM, but with the first 99 model year truck.
Are you sure you aren't seeing the trailer brake controller plug or another connector? There are a few unused connectors under the dash. If your baro sensor isn't working, you'll need a replacement PCM.
Can you post a picture of the connector you're looking at along with the wiring colors and position? I can look it up for you and let you know what it's for.
 
#17 · (Edited)
I did some digging on the plug, searched for the baro sensor plug and came up with the same one. Went and looked at a picture of the baro sensor, and the profile also looked like it fit the plug... Unless the brake controller plug also has the same profile, but my brake controller is already wired in to the factory plug, unless there's a second one.

Also called multiple parts houses, they all list an external Baro sensor for my year as well.
 

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#19 ·
Your pic looks like the APCM (Idle Controller) connector. That's where it's located on my truck (also empty). I was thinking a 94-97 baro sensor connector looked like the one for our MAP sensor under the hood, but I can confirm tonight.

Do you really trust what parts houses tell you? They'll also tell you there's such a thing as a '98 F250. Ford skipped that model year and introduced the SuperDuty line in '98 calling it a '99 Model.
 
#21 ·
I verified, I was wrong! Came to the same conclusion about that connector after some digging. Ran the esn, my engine has a build date of January 99, and the esn is past the cutoff for late engines. Late 99 it is!
Still confused as to why I'm getting a nonexistent baro reading in both torque pro and forscan.
Replaced the EBP sensor, as it was reading 18-20 at idle with a new tube and clean fittings. Still reads 14-15 psi at koeo, while my map reads 11.5 ish, which is correct for my elevation. Harness issue?

Dropped the tank to clean the mixing chamber screens, they were spotless at 196k!

I did throw a code yesterday evening, a p1670. Seems to have been a fluke, didn't affect engine performance and hasn't come back yet either. This has me concerned about a bad IDM though, combined with my other issues. The only other thing I havent done is see if the 'check valves' in the heads are clean, but I know I'm at least getting good pressure to the bowl.
 
#22 ·
Just had a thought. Are torque pro and forscan displaying your BARO in gauge pressure instead of absolute?

The three sensors (BARO, MAP, and EBP) will never read exactly the same, even accounting for the difference in gauge versus absolute pressure. I've seen 1-2 psi difference. I use AutoEnginuity, but don't recall whether it displays the sensor readings in gauge or absolute, or a mix.
 
#24 · (Edited by Moderator)
I rescued a 1994 F250, retired fire truck, with 7.3 Intl Turbo, last year. Fixed minor issues. Love the truck and everybody that sees it wants to buy it. Am new to deisel and reading posts like crazy. So when I write, please keep that in mind. My truck intermittently fusses about starting after sitting a few minutes. Starts, dies, then starts fine after sitting about five minutes. Feedback welcome. Was reading about the uphill power loss problem. I have had a Buick and a Chevy truck that did the same thing and both were catalytic converter problems. My deisel does not have a converter but am told newer models do. Just a thought.
 
#25 ·
Bev,

Gstoneburner already said he didn't have a CAT. A 99.5 7.3L with manual tranny came out of the factory cat-less.

But thanks for the comment, and welcome to TheDieselStop
 
#27 ·
So, we have a solution! Was looking around on some other forum posts about an unrelated issue and happened to read about the MAT sensor affecting fueling.
When I was sorting through the PIDs, I didn't realize there was a reading for an AIT sensor and a MAT sensor. I just clicked the ait sensor and thought that surely it was the only intake air temp sensor on the truck, so I never got a reading. That sensor was definitely bad, unplugged it and most of my power came back. New sensor going in later today and I'll report back,bu I think I've got it whipped.
 
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