Hello FTE,

I have a 1999 Ford F250 with 206000 and the 7.3L engine in it; this is my first diesel truck and I am working my way to make her run just like she was when she rolled off the assembly line 15 years ago. I just got the truck back from the shop with a fresh front end, I would have done all the work myself but I did not have the time to do so. The mechanic mentioned a bad misfire that was very consistent on the entire rpm range. I thought the truck was not running exactly right the day I bought it but I had no other experience with the f250 models. The truck seems weak until 2,000 rpms and then the pull of the turbo makes up for the missing (and I am sure the computer is compensating.) Through this handy site I have performed a few tests on the UVCH connections and the results were normal with exception of one glow plug:

Driver side test between "I" and "C":

3.4 ohms
3.3 ohms
3.3 ohms
3.4 ohms

Driver side test between "G" and battery ground:
0.8 ohms
1.4 ohms
1.0 ohms
0.8 ohms

Passenger side test between "I" and "C":

3.5 ohms
3.7 ohms
3.3 ohms
3.6 ohms

Passenger side test between "G" and battery ground: (also what the ??)


Infinity (open) (I know this is a bad glow plug)
0.9 ohms
0.9 ohms
0.9 ohms

I do not have access to a scan tool to perform the injector tests mentioned in plenty of these posts. Is anyone in the Tennessee area that might have access to one the scanners? http://images.ford-trucks.com/forums.../happy0161.gif

Secondly, I made my own boost tester gauge and found a boost leak in what I believe is called the Intake manifold cover. Is there some sort of gasket I need to replace? Picture should be attached or in this post ( I am a complete posting newbie).






This is NOT my truck engine, I have a boost leak in between the block and the part I have arrows pointing to. What is this part and is there a gasket for it?

 

No gasket. Go to ford and get a tube of the grey goo sealant.
Pull the plenums...
Clean all the old stuff off them, and the block.
Try and keep as much out of the intake as possible.

Clean with acetone.

Apply a 1/8 to 1/4 inch bead of the sealant on the plenums 1 at a time and reinstall.
Let it set for a good 12 hours (24 to be on the safe side)

 

Thank you for the reply, I will do that sometime soon. Does the turbo need to come off in order to remove them? Any clue on the missing?

 

Anyone else have any suggestions?

 

To properly diagnose the miss you are going to need a scanner capable of talking to these trucks.

AutoEnginuity, torque obd pro, ngstar, etc.

Im not sure torque is capable of initiating buzz, and cct testing...

Buzz test the injectors.
Run a cylinder contribution test
Compression test the engine.

In popping the valve covers you might discover your problem visually by noticing a broken rocker arm, or bent pushrod...

Sometimes its that simple.

 

I think I have a buddy lined up to scan the truck for $40 bucks. If I did have a bent rocker arm or valve wouldn't the engine be running a lot worse? I am hoping that it isn't a compression issue, I just bought this truck.

 

Is this a normal amount of blow by? You can hear the miss in the engine. Video link attached:

99 7.3l blowby:

 

The rule of thumb on blowby is put the cap upside down on the tube; if it blows off that's too much. Rattling off due to vibration is normal. That smoke out of the oil fill tube looks ok to me. Maybe it's just my bad hearing due to the congestion in my ears from this damnable headcold, but it also sounds fine to me. Not hearing the miss, just normal 7.3 noises.

Do you have a infra red thermometer, aka a temp gun? Check the exhaust manifold at each exhaust port and see if one is significantly colder. That would be the bad one.

What kind of scanner does your buddy have? Many will not read the codes on a 7.3. If you do get codes, write them down.

 

Is it a early 99 or late 99. The arrows are pointing to the intake plenums. I just got done doing these on my truck a couple of months ago. Yes you do have to pull the turbo to get to them and be able to do a good job of replacing them. If you have a late 99 and want to make sure you don't have these problems anymore check out riffraff and there billet plenums. Pricey but well worth the money. Quality is great and will put your mind at ease for them ever leaking again.

 

Only the left side plenum is leaking, the other side passed my simple pressure test. The truck has terrible response and power on the low side of the rpm range; however, pass the 2000 rpm mark you would never notice the miss. I did the oil cap test and she passed with flying colors,I even placed my hand over the cap with no pressure. The blow by coming from the doghouse was somewhat pressurized but it is venting gases from the block. Is this normal? From what I described would you gentlemen (and ladies) think I could be dealing with a fouled up injector? My buddy has a scanner that is able to performer injector buzz testing and contribution testing. Not sure of the brand though.

 

I don't have an infrared temperature gun :/

 

How do you tell if it is a late or early 99?

 

Late and early 99 is by the build date. If the build date is before December 1998 it is a early 99. You could also check your turbo. If your compressor housing only has 4 bolts instead of 5 it is an early 99. If one side of the plenums is leaking then the other will be soon to follow. Especially if you are planning any performance mods that bump boost psi the factory seal on the plenums are a weak spot. My truck with leaky plenums and some other things was doing the same thing. Very doggy and unresponsive. Very fixable stuff, you just have a sick truck that needs a little wrenching to feel better.

 

From what I can tell the truck is a late 99 due to the vin # having an "X" in it; also the turbo housing seems to have five bolts. I counted four bolts and I could not see the back of the turbo housing and I doubt they would leave the back side of that sucker without reinforcement. The truck is sick, I will make another video today of me accelerating the engine so you can hear what exactly I am talking about. Videos help

 

Here is the video of the truck engine being accelerated the miss is pretty clear in the video.

https://www.youtube.com/watch?v=o7Hi...ature=youtu.be