Noob Fuel Question
 

I recently bought a completely stock 97 with a ZF5 and 3:55s. It starts great, gets great MPGs and is overall a very will maintained truck. It has a fresh paper air filter and fuel filter. I also recently cleaned the FPR screen.

I'm happy very with it so far but just want to make sure it is all it can be. I don't have any guages yet so I have little info to go off of. I do have the torque app on my phone and a reader that I hooked up but not a lot in there means much to me yet.

After putting about 5000 miles on so far I've noticed that it doesn't produce even a hint of smoke of any colour even pulling my 14k trailer. Which I am actually very happy with, however, my experience in the IDI world and Cat and Cummins in older semi trucks is that a hint of dark smoke (more grayish) under load means you are getting adequate fuel. Any more and it's time to check the filters and mind the EGTs.

So my question is this: Do I have a fuel issue or is this just the way it is tuned from the factory? I know I can look at a TS chip to up the fuel rate and might after guages. But for now I'm just wanting to know what is normal for a stock truck.

That was a lot of typing for a simple question.

Bob

Your diesel was perfectly tuned for fuel when it left the factory. Even with a chip in all likelihood you won't "roll coal" or produce black smoke with your 90CC injectors, or even 120CC Cali splits.

Sounds like your truck is operating as designed. Since you cleaned your FPR screen :-X22 (good for you-not many do this right away), did you check your fuel pressure at the FPR schrader valve? The "normal" range is 40 - 80 PSI. If you're below 40 PSI, or close to it, you can add a BB (search for BB mod) to raise your fuel pressure. You don't want to get above 80 PSI or you'll run into other fuel system issues.

If your fuel pressure is below 40 PSI, send me a PM with your contact info. I think I might have a spare BB I can send you.

Whats an FPR screen and where is it? also whats the schrader valve I would like to check my pressure as well.

Thanks gents. I'll get a pressure gauge sorted out and see what I have. Question: How large of guage am I looking for? Is 100 psi enough? does the regulator maintain a constant from idle to wot or is the 40 psi minimum just at idle?


Leatherneck007: Here is the article I referenced to clean the FPR screen. Pretty simple. One thing I noticed, when I pulled the regulator the sceen looked pretty clean however there was a big enough chunk of crap to block 3/4 of the screen sitting just inside the orifice that the screen pulls out of. It must have fallen off as the regulator was removed.

https://www.ford-trucks.com/forums/1...g-writeup.html

The shrader valve is on the regulator. You can see it in the second picture of the above article. Same as the valve stem on your tires.

Sorry, I should've mentioned the fuel pressure reading is taken at idle. A 100 PSI gauge is fine for this procedure. Remember, 40 PSI is the minimum reading. You want to be closer to 80 PSI, but not over that reading.

So is there a ball bearing in this orifice or not? I have read about losing the bearing in this thing? I would like to check the FPR screen in my truck too but don't want to the thing to grenade on me.

No. A BB, not a ball bearing, is inserted prior to the spring behind the schrader valve to bring the spring tension back up to OEM specifications. There is a "rebuild kit" available from Ford to correct a low fuel pressure condition, but the BB does the same thing for a lot less money.

There may be a ball bearing in another location, but I have not seen one installed as an OEM item behind the schrader valve.

Or you could just stretch the spring a bit by hand and re-check your pressure. That's what I did, I brought it up to 60-70 and called it a day.

thanks!!! the link was really helpful and I went and cleaned the screen. it had a little bit of sludge on itand I cleaned it off . I am also getting around 48-50 psi. Is that good??

It's on the lower end, but it is in spec. You can try stretching the spring as lemonshindig suggested. I have not tried this method, but I don't see how it could hurt anything. Just don't go overboard with the stretch. Small adjustments are better.

If you want to try it, stretch the spring, reinstall, and check the pressure again. Let us know how it goes.

Ok, I'll try that.

one more question, i saw a mod for the air filter.Its suppossed to increase HP and MPG's. they took out the stock one and bought a 6673 napa one (its huge) and put that in place of the stock one. have any of you heard of this and is it advisable???

A lot of folks have done this mod. It is the first thing I have done to all 3 of my strokes. You won't see huge HP gains with this filter, but it sets you up for future gains with other mods.

6637 is the NAPA number; Donaldson makes an equivalent (which some say is better). It's best done paired with an aftermarket full-round downpipe to replace the wheezing cobra-head stock downpipe. The two work in conjunction, helping the engine breate in and breathe out better at the same time.