HELP! 7.3 powerstroke..

[Wicked72]

I have a 99.5 f 350 with a 7.3. Im having a small issue.(yes the real issue is its a ford) The idle gets rough then smooths out randomly and if I am slightly giving it throttle for say a speed correction it acts like it has a major miss for a second or two. I really dont want to replace injectors.. I was hoping you guys may have an idea of what else the issue could be and I do not have any codes. I am out of my element with diesels.
But one day I will get rid of the 7.3 and put in a cummins but until then I need the international to keep me going.

[elacruze]

You really need to see what codes it's thrown.
Sounds like fuel starvation to me, could be the lift pump, could be waxy fuel, could be an air leak between the tank and lift pump.

Could be as simple as dirty oil. If you haven't changed it recently, change it now.

[skip68]

Cam sensor is a common problem.  Look into it. 

[skip68]

I've had 3 7.3's turbo's and love them.  Very good motor.

[GPULLER]

Yes, get it to a shop that can check for some codes.
The wire harness for the injectors are molded into the valve cover gasket.  We had one in the shop with somewhat same symtoms, we ended up replacing the valve cover gaskets.   

[Wicked72]

Like I said.. no codes. and I replaced the cam sensor to rule it out. I really need to read live engine data but those readers are expensive. I just cant leave my vehicles at a shop... I dont trust anyone really. I guess Ill have to bite the bullet and get one  . I have a damn good reader but it doesnt show the live data. I also fixed the issue with the wiring harness slipping under the valve covers to rule that out too. I havent checked all my grounds yet so thats what Ill do next and maybe replace the pedals rheostat since thats a quick and cheap part to rule out. 

[jb666]

I have a 99.5 f 350 with a 7.3. Im having a small issue.(yes the real issue is its a ford) The idle gets rough then smooths out randomly and if I am slightly giving it throttle for say a speed correction it acts like it has a major miss for a second or two. I really dont want to replace injectors.. I was hoping you guys may have an idea of what else the issue could be and I do not have any codes. I am out of my element with diesels.
But one day I will get rid of the 7.3 and put in a cummins but until then I need the international to keep me going.

Really? The 7.3 is an awesome powerplant. The 6.UH-OH is the one I'd never buy again.

How many miles are on your rig?

[chargerboy69]

I have a 99.5 f 350 with a 7.3. Im having a small issue.(yes the real issue is its a ford) The idle gets rough then smooths out randomly and if I am slightly giving it throttle for say a speed correction it acts like it has a major miss for a second or two. I really dont want to replace injectors.. I was hoping you guys may have an idea of what else the issue could be and I do not have any codes. I am out of my element with diesels.
But one day I will get rid of the 7.3 and put in a cummins but until then I need the international to keep me going.

Really? The 7.3 is an awesome powerplant. The 6.UH-OH is the one I'd never buy again.

Yea what he said, 7.3's are a great engine.  If you have a crew cab, 4X4 send me a pm as I am looking for a 99-02 Ford 7.3.  I rarely see them through the auction so I am having to look on Craigslist.

[Todd Wilson]

Check the fuel system.   Fuel filter and does it have a water seperator. Also may be a rubber line in the fuel system somewhere giving you some air in the system. It could be something as simple as one of the steel high pressure lines being loose and just needs snugged up.


Todd
.

[elacruze]

No codes means you have a strictly mechanical issue. It's possible that the TPS has failed at some point above idle.
In the International engine controllers, you would throw codes for any electrical issues with the injectors so look into fuel quality, oil quality, and fuel system integrity. I don't know the 7.3 in particular, but the larger International engines like the DT530 have a rubber check ball in the fuel filter housing that can deteriorate and leave debris blocking passages upstream, and it will not show in the rail pressure if they are beyond the pressure sensor. Bleed your fuel rail and check for air entering somewhere upstream, also. Do you have rusty lines underneath?

[Silver R/T]

I'd check fuel pressure. If you don't have fuel pressure gauge I'd install that. Its a necessity on diesel trucks

[Todd Wilson]

No codes means you have a strictly mechanical issue. It's possible that the TPS has failed at some point above idle.
In the International engine controllers, you would throw codes for any electrical issues with the injectors so look into fuel quality, oil quality, and fuel system integrity. I don't know the 7.3 in particular, but the larger International engines like the DT530 have a rubber check ball in the fuel filter housing that can deteriorate and leave debris blocking passages upstream, and it will not show in the rail pressure if they are beyond the pressure sensor. Bleed your fuel rail and check for air entering somewhere upstream, also. Do you have rusty lines underneath?

I had a similair problem with my old GMC 6.2  with a small rubber type part coming part and spitting pieces into the pump. Had to punch out the little check valve on the pump and let the stuff pass until I could get it into the shop for a new pump. They encapsulated the piece in later rebuild kits and models to avoid this.  I too would go over the entire fuel system.


Todd

[GPULLER]

I did a little digging on this morning, and found this on Identifix.  It sounds like your symptoms but you have no trouble codes.


Customer Concern:
The engine will intermittently hesitate or stumble when driving along at steady speeds. Has trouble codes P1280 and P1211.

Tests/Procedures:
1. While driving, monitor the Injection Control Pressure (ICP) voltage on the scanner and also monitor the ICP pressure with a mechanical gauge if possible.

2. When the problem occurs, look for the voltage on the ICP sensor to be dropping to less than 0.2v. If monitoring the pressure on a mechanical gauge, verify the pressure is maintaining at least 500 PSI.

3. If the pressure is maintaining, but the voltage is dropping, check for connection problems right at the ICP sensor. If needed, replace the ICP sensor and also install an updated connector part #3C3Z-12224-AA. 

Potential Causes:
Injection Control Pressure (ICP) Sensor
Injection Control Pressure (ICP) Sensor Harness

Diagnostic Codes: P1211, P1280

Sounds like the sensor runs around $200 and is located behind the altenator to the right of the fuel filter housing.

You might want to google Injection control pressure sensor , get on a Ford diesel discussion forum and ask some questions.

[ACUDANUT]

 I have a 7.3 Turbo Diesel in my 00 4x4 Excursion... I love it.....Call Kent @ 913-980-7101...He specializes in these 7.3's. He will give you theeee best advise. Let us know what he says.

[71_Charger_R/T]

We had what sounds to be the same symptoms on our '01 wrecker with the "power joke" diesel. We checked everything and I mean everything related to the fuel delivery system. We finally brought it to the Ford dealership only to find out $360.00 later that it was a quart low on oil..... This thing has a 15 quart oil system and if it goes one quart over or below, it will exhibit this problem and somehow the injectors are fired by a hydraulic lifter that will not function properly if 1 quart outside the 15 quart specification. So I guess it wouldn't hurt to do as "Elacruze" says and do an oil change so you know you have the correct level. It's relatively cheap , can't hurt , and may solve your problem. 

[Wicked72]

Thanks for the advice guys. Ill get into it asap! and hopefully have an update. after I get a live data reader but ill get some random parts for the hell of it just to see if it clears up..

[Wicked72]

I am worried I may have damaged the high press oil pump... I forgot I ran it about 6 quarts low, I am sucking oil from the valve cover port a little and I had a bad leak due to a loose valve cover. However I did not have any issues I just decided to check and then oops.. My leaks are fixed so hopefully its nothing to major. btw Gpuller thanks for looking so far into it! I am going to check the fuel lines in the morning then look into just replacing the sensor if I got the funds.

[elacruze]

I am worried I may have damaged the high press oil pump... I forgot I ran it about 6 quarts low, I am sucking oil from the valve cover port a little and I had a bad leak due to a loose valve cover. However I did not have any issues I just decided to check and then oops.. My leaks are fixed so hopefully its nothing to major. btw Gpuller thanks for looking so far into it! I am going to check the fuel lines in the morning then look into just replacing the sensor if I got the funds.

Ah, the bubbles always surface.

International HEUI injector engines have an oil reservoir from which the high pressure pump draws oil. This reservoir is fed from the main engine lube pump. If your oil level gets low enough to aerate or fail to maintain an adequate level in the reservoir, the injectors will not fire, and there is no electronic evidence, since the rail pressure sensor reads air pressure just as well as oil pressure. One of the beauties of HEUI systems is that you can not destroy the engine due to loss of oil pressure, the injector system shuts the engine down first. We caught one MRAP team in Afghanistan on that one; PMCS is to be done before every mission and includes engine oil check; they were 20 quarts low...out of 24. No engine damage.

oh btw you can't hurt the HP pump that way.

[Wicked72]

So do you think this may clear up or is there something I can check in that area? Im still going to check everything else today while im at it

[elacruze]

If you have no DTCs stored in the computer, then it must be something you can track down externally.