Hello again, I just finished installing a new turbo (shaft play and lots of oil in the compressor side), RR up-pipes, and T500 (250k and once had a very long crank to get the ICP up to start).

Anyway, except for another exhaust leak at the pass side up-pipe to manifold, it seemed to run okay but with lots of white smoke. I only have about 50 miles after the install, when it suddenly starting surging and made a lot of loud knocking noises. This then went away and came back again rather quickly. I was close to home, so I made back under power. I also received the two codes listed. My IPR is original, but two summers ago I installed the IPR re-seal kit. Everything on the IPR looked good when it came off for the T500.

After reading around, I saw that low fuel pressure / air in fuel can cause problems. I connected a pressure gauge to the pre-filter port on the filter housing, and got 40psi at idle. I then took a diesel shower and blew out the fuel line into the tank. After re-connecting it, the fuel pressure stayed the same but the engines idles much better, but still has blue smoke. It's the original fuel pump (to me anyway) and original fuel line connections.

I have about 3/4 tank, and no place to put it, so I'd need to run it out for the Hutch mod, or least to get in there and inspect. Would eliminating the Ford connections at the pump be worthwhile for now, and is 40psi at idle adequate? Wondering if it's time for a fuel pump?

 

Not an expert by any means, but 40psi at idle sounds low. It should be around 55psi, while at idle.

 

echo=on
Fuel Pressure Tests
Measure Fuel Pressure at Fuel Bowl Test Port Spec. 45 psig min
a. Fuel Pressure at the right head
Verify that fuel is in the tank and the pump is being powered.
Measure fuel pressure at the front of right cylinder head Road Test- engine at full load condition Spec. Measurement / Head 0-160 PSI / WOT 45 PSIG min.
If fuel pressure fails low, Go to step 8c.
If pressure is above min. spec, Go to step 8b.
b. Fuel Pressure at the left head
Measure fuel pressure at the front of right cylinder head Road Test- engine at full load condition Spec. Measurement / Head 0-160 PSI / WOT 45 PSIG min.
CAUTION: Secure hose away from turbo and exhaust
If fuel pressure is below min. spec, replace left check valve
f fuel pressure is above min. spec, Go to step 9.
8c. Electric Fuel Pump Pressure
Measure Fuel at Fuel Bowl Test Port Spec. 45 psig WOT >42 psig
Measure at fuel outlet from electric fuel pump: 45-80 psig
Road Test- engine at full load condition 45-80 PSIG
If fuel pressure fails low, Go to step 8d.
If pressure is above min. spec, replace right check valve.
8d. Electric Fuel Pump Inlet Restriction
If fuel line is restricted above 6 Hg, check for: blockage between pump and fuel tank.
If fuel line is not restricted, inspect regulator valve condition and for debris, If OK replace pump
*This Broadcast Message Replaces Testing Procedures on all 7.3 DIT 1999.5-2003 F-250-F-550 Models*

echo=on
Injection Control Pressure Tests
Using a Bi-Directional Scan Tool
10a. Injection Control Pressure Tests (Oil Aeration - Poor idle quality)
a. All acc. Off
b. Monitor ICP and RPM with Bi-Directional Scan Tool Hold engine speed at 3400 RPM for 3 minutes
c. Spec: ICP: 1800 PSI MAX @ 3,400 RPM

10b. Low Idle Stability (ICP Pressure)
a. Check at low idle, EOT above 180 F
b. Monitor ICP and RPM with the Bi-Directional Scan Tool 400 – 600 PSIG @ 670 RPM’s If engine RPM is unstable, disconnect the ICP sensor, If RPM is still unstable, change IPR and re-test.
c. If RPM smooth’s out, the ICP sensor is at fault.
Note: ICP will default to 725 PSI when disconnected

*DC% 14 Default when RPM Drops out DC% 65 is fully closed. IPR Suspect
echo=off

 

my fuel pressure at idle is around 60. im new to diesels but you could check the fuel pump. if you look deeper into the codes, you might be able to solve. another to check is if your injectors are leaking, i was reading around on the codes and with the low pressure it could be caused by a leaking injector.

 

Thanks Tom. I had seen this same post by you earlier for someone else, and I'm glad you re-posted it. I have a few questions about it. But first, I did install a new Airtex fuel pump yesterday, pressure is now just a touch over 40psi (keeping the old pump as a spare now). There was a no difference in pressure when I blew out the line, but a definite difference in idle, so I'm fairly certain there's work to be done in tank.

Fuel Bowl Test Port. Does this refer to one of the plugs on the fuel filter housing? I'm currently measuring my pressure at the higher one, pre-filter (as it's much easier to get to). Since the fuel pressure regulator is located at the return line (I have the FRx installed, but I believe the same is true for stock?), I wouldn't imagine the the post-filter port would have higher pressure. Is there a preferred location for measuring fuel pressure?

This part is a bit confusing. I'm not sure what it's checking at this point, and why if it's "above min. spec" I would replace teh right check valve. Which leads to another question, where are these check valves located?

For the ICP test, 3400 rpm? I'm guessing this is no load, parked in neutral. And for the last line, I don't understand by what is meant when RPM Drops out.

Jason, I had just reinstalled my injectors, so I'm hoping a bad o-ring isn't the problem. The injectors have less 7k miles on them, so I'm hoping my recent turbo failure hasn't done any internal damage.

For all, thanks for the advice.

 

There are three different test points in the procedure so as to rule out a problem at either of the check valves where the fuel lines connect to the heads. If the pressure at the post-filter port on the filter housing is within spec, but the pressure at a test port on one of the heads fails low, it indicates a problem with the check valve on that head.

A fuel rail crossover renders the test pretty much meaningless as far as the check valves are concerned because now if one head has a stuck check valve, it will be back fed by the fuel exiting the other head, making the results largely irrelevant. You'd probably still see some sort of pressure differential between the two heads, but it would be more difficult definitively tell if it's being caused by a check valve.

14% IPR duty cycle 'when the RPM drops out' refers to loss of RPM signal from the cam position sensor, such as in the case of a bad sensor, or with key on engine off.

Yes, 3400 RPM, in neutral with no load for the oil aeration test.

 

There is a lot of information passing through here. I'm going to pare it down:

40 PSI is less than recommended, and I'd be worried if I was running as low as 45 PSI in any condition. I have an OEM pump (new) with my fuel pressure sensor after the filter:



I have an FRx with the weakest spring in the package, a Hutch mod with a proper pre-pump screen, and "Stinky" can hog way more fuel than a stock truck. I have 60 PSI at all times, except when I'm WOT - then I get 55 PSI.

If my OEM pump delivers that on Stinky, I think you can ask more from yours - something is up.

 

I'm now getting just a touch over 40psi (gauge is 0-200psi) with the new Airtex pump, measured at the pre-filter port. I too installed the "weak" spring with the FRx. Since I never measured fuel pressure before, I really don't know whether I potentially screwed up the FRx install, or what my fuel pressure has been all along.

I suppose my next check is to run the pump directly into the pressure gauge. If the pump puts out more than 40psi, then I'm losing it somewhere. Just tossing ideas here:

1) - Even though I blew out the line from the tank, my in-tank blockage is now limiting flow for pressure, but still allowing a smooth idle and no load up to around 2000rpm. I loathe taking her out for a real test, as I don't want to get stuck.
2) - I messed up my FRx, and it's only maintaining 40psi.
3) - Is there a path in the fuel filter housing that could be losing pressure? Although I doubt this as the regulator is now "external" with the FRx.
4) - Worst case, an injector / injector o-ring is leaking fuel. Could this show up with a perdel reading? Or am I stuck removing the FRx to test each cylinder bank separately?

 

And for anyone who might be interested (or maybe this is the cause of my problem) my fuel pressure gauge is comprised of the following:

0-200psi Filled Gauge from Harbor Freight
18" Grease whip, Harbor Freight
Parker 4-1/8 F50G adapter, grease whip 1/8" NPT to fuel filter housing port
1/4" NPT to 1/8" NPT fitting, grease whip to gauge.

If the quality of the gauge has anyone concerned, as it does me, then this 0-100psi gauge from Grainger is an option. And then there's getting an in cab gauge, which is certainly much more useful for road tests...

 

I wouldn't be too concerned with the overall accuracy of the gauge. For the most part, they're all the same with different face plates ie: K-D, Snap-On, U.S. General, etc.

You could test it against another though. Using air or water to see what the relative difference is, if any.

From what I'm gathering, you may well have a restriction at the Mixing Chamber in the Sensor Unit inside the tank. If you have an 8' Bed and an AFT Tank, that's even more suspect.

 

Air in fuel absolutely killed my fuel pressure, and a proper Hutch mod brought it back. A cavitating pump is an unhappy pump - does your pump make a lot of noise?

I have yet to see a fuel pump rated for diesel, with 34 GPH @ 60 PSI, a service life beyond 500 hours, and priced better than OEM.

Every time I read the fine print on a pump other than OEM, the brochure gets tossed aside.

 

I bought the Airtek because the OEM Bosch pump wasn't available anywhere, and it seemed to be the best alternative from reading about here. Since my pressure hasn't changed I'm assuming they're both good. What confuses me is that blowing out the fuel line from pump to tank, although allowing the engine to idle, also had no bearing on pressure.

I would think that the air bubble intake through the line fittings would be somewhat random, making the pressure fluctuate, but at idle it holds steady right at 40psi.

Dropping the tank this weekend is not an option, and next week I'm traveling for work. I like your pre-screen filter Rich, what was the complaint about spin on filters, such as the one in the Driven Diesel Hutch mod kit? I like your clear housing, easy check for dirt and air bubbles.

 

You must have the Airtex E2236 , my pump of choice (in my signature) and Made in USA .
#1 above sounds like you disconnected the infeed line from the pump and blew compressed air into the fuel tank, for several minutes. If you only did the air for seconds, not long enough.
I did mine for 10 minutes or more (way back when).
Can you tell I agree you still have a restriction in the tank?
Be sure to remove the fuel cap during this procedure.

EDIT: I see you posted again while I edited this post.

 

Yup, that's the pump.

I put air thru that line for a while, but not ten minutes. Once I finally got the air hose into that factory line fitting to seal enough to stop spraying me with fuel, I didn't want to stop because I was trying to work out in my little brain how I was gonna get that line back onto the pump before the fuel came running back out. I have over 3/4 tank in there. I also had limited time because once I started I realized I hadn't turned the air compressor back on from the day before.

Has anyone tried pinching the line just before the fitting? It looks to be like regular fuel hose, but I wasn't sure and didn't want to break it.

 

You didn't attach a 5/16 rubber hose to the factory hard line before putting air to it?
I added a two foot loop to mine before finally doing the hutch and running all 30R7 hose from tank to pump.