Boost Gauge

[Alaskdave]

Anyone out there have an idea on this? My Geno's combo boost gauge quits without notice or symptom. Just all of a sudden, no boost reading. Then it comes back and works just fine... ... ... ?? Would appreciate any hints you may offer. Thanks Dave

 

[dresslered]

I'm assuming that you know that boost will go away when you back off the throttle or are operating under a "no load" condition (others have not realized this). The only thing that I can think of is that you have a crimp or a slight leak in your nylon tubing. Leaks can be caused by overtightening the tubing at the source or at the gauge. When the engine moves under load it can cause this crimp or leak to reappear/dissapear. I suggest checking the tubing for any kind of pinches where it passes through the firewall, dashboard, etc. Good luck,


[This message has been edited by dresslered (edited 05-04-2001). ]

 

[Dave Fritz]

Sometime during the winter, my combo gauge began sticking at 0 psi to 5 psi. The pyrometer still works, but the boost reading is intermittent. Lately, it has not been working most of the time. Mine is several years old; when I get a chance I will remove it and see if there is something loose inside the gauge. If not, I'll need to order a replacement (I miss watching the boost).

Dave


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1994 2500HD 4X4 modified for off-road camping
2001 2500 ETH/DEE QC SB 4X4
Fritz's DodgeRam.org

 

[illflem]

Alaskdave, your tubing most likely has a kink in it. That type of small stiff tubing is very susceptible to it. The way I've found to prevent it is to push the small tube though another 1/4" id tube. This will also prevent it from getting cut on any sharp edges.

Dave F, I have found that mechanical pressure gauges will get damaged during a hard freeze, even if there is just air in them. They usually read high and don't return to zero, but will also sometimes not work at all, no leakage. Of the at least 50 pressure gauges on my orchard irrigation system I will lose maybe five every winter. Sometimes I've been able to remove the glass and pull the needle off and reposition it at zero, but most of the time I just replace the gauge. They are very delicate inside, you would almost have to be a watch maker to repair one. My mechanical fuel pressure gauge bit it last winter on a below zero night when I forgot to plug in, started reading 5 psi high. I have found that plugging in the block heater will keep the cab above freezing even when the temp drops below zero. Replacing a gauge is probably cheaper than paying for power for most folks, although a combo gauge can get pricey, maybe it isn't the best way to go for this reason.

 

[tmacc]

Oh great. Now they tell me. Now what was the warranty on that Geno's gauge?lol BTW Westach has a soft rubber type of hose, but if it's kinked or pinched it would make it harder for the air to reach the gauge.
Bill, I used your idea of running it thru a larger pc of hose to protect it. Works great.
Highly recommend it to other folks.

 

[Alaskdave]

OK, I'll start looking for "kinky" tubing but I still do not understand why I can leave the house and it does not work at all and while I'm motoring around here in Federal Way it suddenly is working again. That is what has kept me wondering. Yes, I realize that "no load" pretty much equals "no indicated boost" Thanks Guys, I will follow up and let you know what I find.
Bill, retired @ Boeing Monday of this week.
Rgdz to all Dave

 

[illflem]

Congrats Dave !!! Get out of there before they move to Kansas City or whatever. Moving to the Eastside now?

 

[Alaskdave]

We hope to be settled in Winthrop by mid June Bill. We're doing a little packing every day around here. Will keep you posted. Dave

 

['956Wheel]

Remember the boost gauge must have current in order to function. I would be checking that too, are the connections soldered well?

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9535hundred

 

[EMDDIESEL]

What mechanical boost gauge requires curent to operate? Westach?. Every boost gauge i have ever installed, Autometer, VDO, etc need no power to operate, only for the lighting.

 

['956Wheel]

From the Westach literature, "NOTE Power must be applied to pin #4 and ground to pin #5 for boost to operate".

 

[Alaskdave]

Well the mystery deepens, yesterday I pulled some tubing into the engine bay and found a crushed spot. AAHA! sez I, this is the problem. However when I ran to the store, NO Boost. So I rerouted the tubing and pushed about 4" into the hole in the firewall creating slack inside the truck. Yahoo, boost is OK. Until today, I have changed nothing and the boost has gone away again. As soon as I can take the time I am going to rip the dash facia off and trace both electrical and the sensing tubing and get to the bottom of this mess. Dave

 

[EMDDIESEL]

Oh, i cant figure out why you would need power to operate a mechanical gauge. Must be something Westach knows that we dont

 

[JohnE]

<blockquote>Originally posted by Alaskdave:
OK, I'll start looking for "kinky" tubing but I still do not understand why I can leave the house and it does not work at all and while I'm motoring around here in Federal Way it suddenly is working again... ... </blockquote>

I concur on the <em>kinky</em> hose theory. My thought on the intermittent operation is from underhood heat. Cold, the kink is rigid enough to prevent getting enough pressure to kick the guage. Once warmed, the kink will open and allow the guage to read manifold pressure.

Cheers;
John E

 

[illflem]

If you do have to replace the small tubing don't buy the kit that has the fist sized tightly coiled roll, although you can straighten it with hot water it's a hassle. Napa sells it by the foot from a less tightly wound spool, it is almost straight when you go to use it. They also carry the ferrules you will need to replace.

 

[gitchesum]

I found out hte hard way the Westach needs power for the boost gauge. I'm a real man, don't need no stinking directions. So I just hook up the hose and try it out. NOTHING. Get back, read the directions, hook up the 12V power and it works like a charm. Sounds like an electrical problem to me. I'd trace everything that goes to power. Just my . 02.

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Curtis Harris
1997 3500 Club Cab
"CASPER"
Check out the Lone Star TDR

 

[Alaskdave]

Eureka! This weeks Kewpie Doll goes to Statland and Gitchesum. I followed up on the power vs ground reasoning. I removed the Beverage holder and "manipulate" the wiring while accelerating slightly and was rewarded with a "bounce" in the boost needle. I found that if power is available, an intermittant circuit will provide a slight needle deflection while sitting in the driveway engine off. This allowed me to locate an intermit ground connection where I had installed a wire "tap" I really appreciate the input guys, you made it fun to find and fix. And I learned something more to boot.
Thanks again. Dave

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96 2500 4x4 5sp 3. 5 gears TST#6 16 cm2 K&N Geno's Combo Gage Pac Brake Aux tank 15K 5er hitch
HF/VHF/UHF mobile KG7HD Retiring May 1st to finish the Winthrop house