Potential Fuel Pressure Issue

[jschildm]

It has gotten cold here in Southeast Iowa, and the truck has began to start really hard. It turns over like it has, but when it normally would start, it bangs and clangs around and instead of firing, it doesn't start if i let off the key.

The batteries are pretty new and so is the alternator. I put an adrenaline HPOP on this fall but have had no prior starting issues with it, and it does have a chip (i haven't tried different settings or pulling it off to see it makes a difference). I tested the GPR and it has 12V when the glow plugs should be on. I checked the fuel bowl for fuel and HPOP for oil before I started it to see if either were potentially draining down, but both were full. This is all background info to lead you to why i think it might be fuel pressure related.

I borrowed a fuel pressure gauge and hooked it up to the valve just off the regulator. I had my wife start the truck while i watched the gauge. It took it a bit to react at all (likely fuel getting into the hose), but while idling it was only at 10 PSI, and i revved it up some and the highest it hit was 15 PSI.

Is there something wrong with my set-up for testing the pressure, is the little FPR screen clogged, or is my fuel pump going south? I haven't noticed any power difference, and the fuel filter was replaced in september.

Sorry for the book, and any thoughts are appreciated.

Thanks.

 

[Patrick Feeley]

Those numbers are definitely low (which usually indicates fuel pump), but check your filter to make sure its not all crudded up, maybe check your FPR spring for kinking and the plunger/bore for scoring. From what I've read, and I've never had my 97's disassembled, there's another brillo-pad mesh in the line that comes into the bottom of the regulator too. Cheers!

 

[Tom S]

I agree with Patrick that it is probably time for a new pump.

 

[jschildm]

Aka electric fuel. Haha.

 

[jschildm]

I am just surprised it runs as well as it does with that kind of fuel pressure. It started up pretty well yesterday, when the temp got up to the upper 30's.

 

[jschildm]

So from anyone who has experienced it ... is this how a fuel pump normally begins to fail, or is it usually more of a sudden thing?

 

[Patrick Feeley]

I've had one pump fail like this, but all the other fuel pumps just leaked (but worked fine otherwise). Cheers!

 

[kampy]

Just an idea...the GPR should have 12V all the time, the PCM makes the ground for the relay then power is sent to the glow plugs. Ohm out the glow plugs to make sure they are all working ok. Then wait an extra 10-12 seconds after the WTS light goes out before you try to start it.

When you check fuel pressure either remove the schrader valve or the whole fitting and put the gauge directly in its place, you can get inaccurate readings with the schrader valve in place.

Good luck.

 

[jschildm]

I have a stancor relay on it, and it is functioning properly. I didn't ohm out the glow plugs ... Is there a way to do it without pulling the valve covers? Just from the way it is starting differently than it used to, it doesn't seem like a GP issue. Very will could be though. I didn't like having the schrader valve on there, but I gave it plenty of time to get up to the pressure. Even with it restricted, I would think it would eventually climb to the pressure its at. I still have the borrowed gauge, so I will try and get that done tomorrow. Thanks for the advice Kampy.

 

[kampy]

You can ohm out the GP's by disconnecting the harness from the UVCH, sorry, I don't know which pins are which. I was thinking when the GP's are on you should have less than 12V at the relay because of normal voltage drop.

I just checked mine, when the GP's come on my battery V drops from 12.7 to 11.6. If yours holds 12V with the plugs on you either aint getting power to/thru the plugs or you have some really kick butt batteries.

let us know.

 

[jschildm]

Mine was right at 11.6V with the plugs on also, down from 12.7ish. I will have to do some research to find the correct pins and what the resistance through them should be. Thanks again for the info. The batteries are less than a year old, but the NAPA Golds probably aren't much to write home about, haha!

 

[Patrick Feeley]

On the valvecover gaskets, each connector (4 total on the engine) has 5 pins. The outer 2 on each connector are for the glowplugs (middle 3 are for the injectors). Use a DVOM from each outer pin to ground (should be from 0.1 to 2 ohms). Cheers!

 

[jschildm]

Thanks Patrick, I will try and get that checked out tomorrow. As well as taking another fuel pressure reading with the schrader valve out. Although it does make for a good excuse (for the wife as well as convincing me its OK) to get an electric fuel set-up.

 

[kampy]

Patrick always comes up with all kinds of awesome info.

Try waiting an extra 10-15 seconds after the WTS light goes out, mine starts much much better if I do. I think its the difference in the TDE1 programming they use as a base line for the chips and the NAW4 programming mine came with, if I remove my chip the WTS light stays on almost twice as long as with the chip in it. It sounds like your GP's are working ok though based strictly on voltage.

Not trying to send you down the wrong path or waste your time, I'd just hate to see you buy a fuel system if thats not the problem although its always nice to upgrade.

 

[jschildm]

I always wait 20 seconds or so after the light goes off anyways (habit after having a 7.3 idi that was an SOB to get started below 45 degrees, haha. In fact, when it gets cold out i will cycle them 2 or 3 times to make it easier for it if its been sitting a while.

I appreciate all the help. I also don't need to waste money, or even if I do go with the fuel system (payday with bonus on thursday), put that in and have it not fix the problem. I have 8 tested good glow plugs if they do end up being the issue.

 

[kampy]

Heres a little mod to monitor the gp cycle so you don't need to key it more than once - http://powerstrokearmy.com/forums/showthread.php?t=9597, I'm thinking about doing it, seems simple, cheap and effective.

That said, it sounds more and more fuel related based on everything you've said. let us know what you end up finding out, likely to help many people down the road.

Again, good luck.

 

[jschildm]

Well ... that back fired. I took out the shrader valve tonight and tested the fuel pressure again. Same thing ... was right around 11 psi. Just for the hell of it I decided to check the resistance in my glow plugs too. They all checked fine, but one of the plugs (back passenger side) broke when I pulled it out. The plastic on the plug and the outside pins broke off of it. I have attached some pictures that are hard to see.

With that said, is there a repair bundle for these plugs or would I be able to have the dealer re-do that plug for me? I dont think it hurt the UVCH. I dont have the weather pak (or whatever this particular style is called) of tools to fix it.

After that I couldn't get the truck to start. I dont know if that is from the glow plugs not working on that one anymore, or if the plug messed something else up even more.

Thoughts?

 

[jschildm]

Forgot the pics.

 

[Tom S]

That is repariable for sure. Here are some part numbers to get you started.

Valve Cover Harness Repair Kits (contains 4 hard shells w/seals, w/o terminals)
(Ford) F7TZ-14489-BA (94-96)
(Ford) F7TZ-14489-AA (97)
(International) 1830829C91 removal tool and Shells w/o pins
(International) 1661875C1 Pins
(International) 2501055C1 Pins with 6" wire
Valve Cover Pigtails with plug and wires, OBS
(Performance Specialties) 99288

 

[kampy]

Another option if you have a diesel repair shop anywhere close...most times they will have the pigtails for sale, all you have to do is cut the old one off and solder the new ones in place. I think NAPA has them as well.