2nd Gen Non-Engine/Transmission Fuel Pressure Gauge....fueling

[CCCRAM]

Hey gang, I need some help...

Has anyone reported a fueling problem (no fuel) causing problems with startup, after installing a fuel pressure gauge? I recently installed a Westach fuel pressure gauge for my rig. I used Geno's techs to help me lay out the sender using the "preferred" method for my model/year:

*remove banjo bolt and use correct replacement (Geno's)

*12" grease gun hose installed in banjo (NAPA)

*sender installed on bracket



Initial installation worked fine, one small problem with grounding was fixed easily and guage works fine. Now, occasionally (every week or so, with the truck sitting idle 3 or 4 days), I engage the starter and the engine is starved for fuel. I turn the starter on several times and the fuel pump charges the line and the engine runs again, til the next time. The gauge pressure is normally around 8 on my 1-15 scale.



It obviously appears to me that fuel bleeds back down the hose from the sender or air is somehow getting in the line. It's annoying more than anything.



Has anyone else reported this problem? Is it related to the type of installation I did? Any suggestions?



Thanks for any ideas to try out.

 

[Big White Beast]

Sounds like a leak........

Sucking air not necessarily leaking fuel. I would definitely look into it. May be your install or not.



As far as 8 PSI that's too low. Have them fix your lift pump. It should only take it one turn of the key to pressure up. You know you can bump the starter to get the pump to run for 20 seconds or so? Then try to start it.



I would get that pump changed after finding the leak,



Garrett

 

[Ron Bissett]

PSI ?

If you are only getting eight psi then you need a new pump ,Dodge lowest psi should be ten or more at idle , With new pump I see fifteen at idle and never less than ten so far , Have you checked the filter and felt the fittings for leaks,? sure looks like you could need a new pump as the injector pump could be sucking the fuel and account for half or more of the reading , You could try a second gauge to check . LOL Ron Bissett in LOUISVILLE KY:--)

 

[Thomas]

This may help you with the source of an air leak. Read the post by Dr. Kayak and the second post by Dresslered. Some Napa grease gun hoses don't have tapered threads.

 

[RustyJC]

Sounds like you're sucking air into the system at shutdown. I have a dual combo Westach gauge measuring pre-filter and post-filter fuel pressure, and my pre-filter pressure pops up to 15 PSIG as soon as I turn the key on (i. e. , before starting the engine. )



Rusty

 

[dresslered]

CCCRAM-

I believe that the others are onto your problem. I am assuming that you replaced the banjo at the bottom of the fuel filter. Put your hand down under the fuel filter and feel around the fitting and hose connection. If you pull your hand out with diesel all over it, this would explain your problem. If you properly installed this fitting and hose, the area should remain clean. If there is a slight leak, air will slowly enter the fuel filter causing this "hard start" problem. As others have suggested, the grease hose fitting should not fully seat. It should tighten before reaching the bottom of the threads. Some grease hoses don't seem to have a proper taper. Also, I like to use a little thread sealant on all my threads. Good luck,

 

[CCCRAM]

Originally posted by dresslered

CCCRAM-

I believe that the others are onto your problem. I am assuming that you replaced the banjo at the bottom of the fuel filter... . Also, I like to use a little thread sealant on all my threads. Good luck,

I installed the bango fitting on the engine side, pre-filter, as was recommended by Geno's and the literature from them. I also initially had problem with leakage on first installation, called Geno's and they suggested teflon tape and also retapping the banjo to accept the hose fitting (seems the banjo comes with a coating that needs to be cleaned off the threads). This fix worked, no more leaks. However, now I have this once in a while phantom hard start.



As far as the fuel pressure gauge, when I selected the correct gauge for my model, etc, the recommendation was the 1-15 gauge. If its supposed to be running 15, as some of the other posts said, does that really make sense? When I first start and generally at idle its around 10, on the hwy at 65, its around 8.



Any comments?

 

[Steve Campbell]

My experience has been....

That teflon tape used in diesel applications tends to start leaking over time. The diesel kind of eats it up. Use anti-sieze or "permatex" gasket sealer (A tarry looking,tacky, non-hardening substance) for assemblies that will not leak over time. (Assuming all of the fittings are compatible. )



As I said above... this has just been my experience over time.

 

[Big White Beast]

Phantom hard start.....

I still think your pressures are low. What's WOT drop it to? 8 PSI is not enough.



One pump I checked for someone was at 0 PSI and after you went out and drove it would come up to prerssure. Seems it needed help from the VP44 to get started. At idle it would quit again.



For piece of mind and the longevity of the VP44 get it fixed.



Garrett

 

[illflem]

I'm very surprised Geno's would recommend Teflon tape. It may take awhile but it will eventually leak, it just doesn't work with diesel fuel. What's worse is when you go to fix the leak it's close to impossible to remove all the tape debris. It wouldn't take much to foul a pump or injector. Permtex #2 or anti-seize is a much better choice.

 

[dresslered]

I also agree to using the Permtex #2. The 0-15psi guage should be just fine for the 24V using the OEM lift pump (I have not heard of the OEM putting out more pressure than that). I also am wondering why Genos is recommending pre-filter other than the additional dampening added by the filter (a clogged filter will still read good pressures while starving the injection pump in the pre-filter location). Your rubber grease hose should dampen the injection pulses adequately when used post-filter.



Also, what kind of pressure readings do you see under load (i. e. WOT up a steep hill)? You might want to unhook the pressure gauge for a couple of days and cap off the tapped banjo bolt to see if your problem goes away. Sometimes there is a completely unrelated problem that gets blamed on your latest install. :{

 

[zimman20]

Also from everything I've seen and heard/read 8 psi at WOT is fine and is the lowest the pressure reading should drop under any conditions per the STAR line. Supposedly anything UNDER 8 psi is considered suspect/warranteed by DC.



jm2cw, zman

 

[CCCRAM]

Originally posted by zimman20

... WOT is fine and is the lowest the pressure reading should drop under any conditions per the STAR line... anything UNDER 8 psi is considered suspect/warranteed by DC.



jm2cw, zman

At WOT, but not under load (haven't had the chance yet) it does go down to 6 or 7. I guess what I'm hearing here is I should take my rig in to Dodge and have them check it out? What pressure should be optimum or normal for OEM? The only modification I've added is the EDGE.



On the teflon and permatex, it's funny how you learn as you go along. When I purchased and installed the Magtec front and rear diffs, it said in the instructions to use permatex. Also used it on the EGT threaded fitting, all recommended in the literature that came with the equip. The gauge info didn't say that, and the Geno's tech said he used teflon, just to be careful not to leave any on the end of the fitting when I connected it. So I guess we keep learning, although I hope its not someday at the expense of this 36k+ machine.



Please keep the comments coming for any additional info.

 

[zimman20]

I don't think you 'd want to take it into Dodge at 6 or 7 psi, given the margin of error on your gauge it could easily be off by 1-2 psi. Also, it would be a waste of your time, you are not going to do any harm to the VP44 at 6 or 7. It bears watching, is all. 8 psi is a benchmark for DC to use when troubleshooting, but your pressures are fine.



When these pumps go bad, you'll know it. You'll see lower pressures, i. e. 1-5 psi under throttle and < 0 psi at WOT means the pump is dead. Again, just keep an eye on it as all of us are

doing!





zman

 

[zimman20]

Sucking air not necessarily leaking fuel. I would definitely look into it. May be your install or not

Is this possible? I just installed my FP gauge yesterday. Tapped banjo bolt at the outlet of the filter, the angled adapter that Geno's provides, and an 18" grease gun hose from NAPA with the silver ends. (Didn't catch the silver/brass colored note of the tapered ends on the brass until it was too late); the grease gun hose does in fact bottom out before tightening up, indicating non-tapered threads. Used Permatex #2 to seal. I do not have any fuel leaks that I can determine, ran my fingers around all fittings and came up dry.



Now, back to the original question: With the aforementioned grease gun hose with non-tapered ends and no leakage apparent, is it possible to be sucking air without leaking fuel?



FWIW with my hose connected post-filter it takes a few seconds after start-up for the gauge to climb its way up to 15 psi; after that with normal driving and at WOT I never see pressure drop below 10 psi.



TIA.....



zman

 

[Big White Beast]

Zimman20

As the tank is lower than the filter it would create a suction if there was a leak. So it sounds to me like it would be possible to suck air and not leak fuel.



As far as coming up to pressure, that's normal. The pumps are run at low power to avoid a hard start condition (Too much pressure). Once running they get full power and come up to pressure.



Garrett

 

[zimman20]

But once the engine is shut down and neither the VP44 nor the LP are drawing fuel any longer wouldn't you think that either the connection at the sender or the connection at the banjo bolt would start to leak if in fact there wasn't a leak-proof connection?

I assume the Permatex helps seal any possible leak due to the grease gun hose not being tapered.



I see your point though, with the filter and the VP44 being higher than the tank there would be a vacuum/sucking created while the engine is running that would preclude any leaks, but I 'd think a leak would develop after shutdown (once the vacuum is no longer present) and I'd think I would see fuel when it wasn't running if there was an imperfection of any kind in the connection.



Thoughts?

 

[dresslered]

... the grease gun hose does in fact bottom out before tightening up...

I would replace this hose whether it is leaking or not as it is the threads that are suppose to make the seal. My first hose from Napa did the same thing and I developed a slight leak. The second hose I got from Pep Boys (I don't have the part numbers with me at work) and it tightened within a few turns and has not leaked ever.

 

[zimman20]

Thanks for chiming in, Dave. Think I'll do just that, soon as time allows.



Man I hate doing things twice! Especially when I was so careful doing it the first time!



I guess (as I frequently tell myself whilst cussing and cutting myself all bent over the engine compartment, you all know what I'm talking about) if it was easy, everyone would be doing it!





zman :{

 

[dresslered]

I didn't appreciate doing it twice either, but it was much nicer doing at home in the garage than when off on a trip.