Engine/Transmission (1998.5 - 2002) Fuel Pressure-No Sending Unit

[Jerky]

I just got a fuel pressure gauge that just hooks up to the scharder valve and it seems to work just fine,using Geno's adapter hose,. I am wondering what all the fuss is about sending units and things of this nature when this small gauge does not use anything. I must be missing something about gauges or something.



Has anybody ever hooked up a fuel pressure gauge not using all this other stuff? It is a 1. 5" autometer gauge made for fuel pressure. It is not supposed to be used all the time though, just to check your idle fuel pressure. There must be something out there that is much less costly. This gauge has fuel going right to the gauge. By the way it read 13. 9 lbs at idle. (Post Filter)



Thanks - Dean

 

[dresslered]

You're using a mechanical gauge. The electrical gauges are the one's with the senders. Be sure to tape yours to the windshield (temporarily) for measuring the pressures under full load for accurate measurements.

 

[illflem]

A lot of folks use a mechanical gauge plumbed right into the cab without a problem.

Don't have to worry about it being accurate like you do an electrical gauge, most times when a electrical isn't reading right the problem is the sender, not the fuel pressure.

Sometimes the simplest solution is the best...

 

[y-knot]

Their are way to many people of this site that like to play follow the leader. And this fuel pressure issue is getting old. I could not have imagined there was so many people that lacked the "good sense" to install a mech fuel pressure gage in the interior of a vehicle. Nothing wrong with a mech gage in the engine compartment, but please in the passenger compartment, good lord! how can so many people that "marvel" at the engineering of a cummins, and then come up with some monkey rigged crap like that. If you are not going to do the job right, leave it alone. And if you are to cheap to buy the isolator, then leave the gage out. Just type in your little signature you have one if it bothers you so much.

 

[Rob Thomas]

And there it is... ... Mr. y-knot has all the facts straight.



Wake up on the wrong side of the bed did you?



Done properly, there is nothing wrong with in-cab mechanical fuel gauges, without an isolator. In my case it wasn't being "cheap" as you say, but a realibility thing, which is why I used the mechanical gauge in the first place. To many failiers of isolators for me to bother with, I never question my fuel pressure, and I trust my work.



Rob

 

[MD500E]

I have to agree with Rob. Out of my 4 gauges the two that are electrical have had the senders fail and both had to be replaced, now 6 months later guess which two don't work?

As for Mr Y-not's comment that mechanical gauges in the cab are "monkey rigged crap" Have you ever taken a look at aircraft. What about a new 1 million dollar jet-ranger helicopter. You will find mechanical gauges for trans pressure (150psi) engine oil pressure, and fuel pressure, all with wet lines to the back of the gauge.

If its done right with a quality gauge I see no reason for it to be problem.



Kevin

 

[Jerky]

Thanks guys for the input. Is there anyone who would dare to reccomend a good 2" mechanicle gauge or know a web site to get them from? Thanks again - Dean

 

[Jerky]

Oops! forgot to include my measley signature. Will continue adding to it. Truck sure runs good though. Dean

 

[Jerky]

For some reason it won't come thru with the show signature box checked. Oh well!

 

[dresslered]

Jerky, the signature will only come through once per topic, hense your signature is showing up just fine on the first post. The mechanical gauge is a perfectly acceptable way to go if it is done right (i. e. watch for sharp edges when coming through the firewall, etc. ). I went with the electrical, and again, if done correctly it will be problem free. I found it easier to route the electrical wires up to the A-pillar (even though I also have a mechanical vacuum gauge on the pillar). Try the search feature and you will get more than enough recommendations.

 

[y-knot]

You will and can do as you please, But I still contend that fuel does not belong in the cab of any vehicle. Not angry, just my opinion. And I do wake up " on the wrong side of the bed", quiet often.

 

[illflem]

If you use a needle valve just barely cracked open at the head of the line to your mechanical FP gauge not only can you shut it down if there is a problem but if it does leak it will be little more than a slow drip. The valve will also prevent any pulsations from the injection pump and only set you back $4.

 

[Jerky]

Thanks illflem for the info.

 

[kboettcher]

Use the mechanical gauge with the isolator. You get the true reading of mechanical and the security of the electrical gauge. If the line between the isolator and the gauge leaks or ruptures, you will only get a little bit of non-flamable, non-toxic oil type fluid, ussually glycerine or something like it. The gauge set I got was made by Hewitt Industries, they seem to be exccelent quality and the price was great, got them on e-bay.

 

[BWagner]

I don't live to far away from Auto meters factory here in ILL, well anyways TWO of there engineers were at a high performance engine builder right next to my work, I ended up talking to him about the whole sender problem, he said they where aware of the sending unit problem but as of now you can use a elec. sender with diesel or a mech. guage with the isolator because it ruins the diaphram in the isolator. they say you can only use the straight mech. gauge.



This is just what I heard.

 

[BWagner]

sorry I miss wrote it is you can not use elec. with deisel and cannot use the mech. with the isolator

 

[Cariboo]

I have an Isspro mechanical guage, no isolator, but a marine on-off valve on the fule filter so the guage can be shut off if it leaks, etc. Hasn't yet.



The problem is that the dang guage buzzes, apparently from fluctations in the pressure. I put in about 10 feet of fuel hose to hopefully provide anough air in the line to cushion the guage, but it still buzzes and drives me nuts. Now I drive around with the valve off and only check it periodically to make sure the pump's stiill working.



Is there anything I can do to quiet the bleedin guage down?

 

[illflem]

Originally posted by Cariboo



Is there anything I can do to quiet the bleedin guage down?

With the truck running and someone watching the gauge very slowly open the valve till the gauge just starts to read, that should stop the noise. It may take less than an eighth of a turn. Not familiar with the type of valve you have but if it has a packing nut under the valve handle tighten it to prevent your setting from changing.

The air cushion method with extra hose or an inline fuel filter usually only lasts for a little while before the line fills with fuel.

Another cause of gauge noise but not in your case is the line from the engine to the gauge stretched too tight, sort of like the two tin cans and a string telephone trick.

 

[Cariboo]

Whaddya know... it worked. Thanks very much.



Another example of overcomplicating the problem, which I'm famous for

 

[Royal]

I have a electric FP gauge on my 99 CTD since new in July 99. Never had any problems. I would not use a direct reading gague in the Passenger compartment,even with diesel which is relatively safe compared to gasoline. Remember in the early 70 GM pickups the gas tank was behind the driver seat. That all changed with new DOT regulations. If you use a direct gauge you could be liable in case of an accident. Lawyers would love it. Also for your info aircraft DO NOT use any instrument panel direct gauges in the cabin/cockpit that are in any hazardous fluids, pressures etc. The only direct pressure gauge is the airspeed indicator which is ram air pitot and static outside air pressures.

This was true on the B 29 thru the B 52 etc.