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Installed Boost Gauge

1838 Views 18 Replies 11 Participants Last post by  1st_gen_Cory
I installed my Isspro mechanical boost gauge last night and took it for some test runs. I followed what everyone said on this forum and others where I take the bolt out of the manifold under the intake tube and put in the adapter that came with the gauge. Everything is all hooked up but what I don't understand is why the needle never gets off 0psi while normally driving, and when I floor it in 3rd or 4th, the highest it goes is 11psi then drops back down to 0psi. Is this normal for the H1C with the 21cm exhaust housing? I wouldn't think so with how I can hear the turbo while driving yet I'm not building boost (according to the gauge).
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· GA CUMMINS CREW PREZ & Captain of the USS FAILBOAT
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I installed my Isspro mechanical boost gauge last night and took it for some test runs. I followed what everyone said on this forum and others where I take the bolt out of the manifold under the intake tube and put in the adapter that came with the gauge. Everything is all hooked up but what I don't understand is why the needle never gets off 0psi while normally driving, and when I floor it in 3rd or 4th, the highest it goes is 11psi then drops back down to 0psi. Is this normal for the H1C with the 21cm exhaust housing? I wouldn't think so with how I can hear the turbo while driving yet I'm not building boost (according to the gauge).
sounds like you have a small boost leak, you should at least make 18psi when you hammer it. check all the connections good, make sure there isnt a pin hole in the line to the gauge, and retighten all fittens after making a run, vibration can loosen them.
 

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why did you put it in the manifold? ive never heard of that one before. i always put it in the air horn just before the air heaters.
 

· Diesel-less
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Discussion Starter · #6 ·
let me redo that, how did you put it in the manifold???? take the air sender out?
There is a bolt/plug directly beneath the intake tube, and all the topics on this site and others say to pull that out and screw in the adapter sent in the kit.

I did tighten up the connections and it seems to be working better now.
 

· Diesel-less
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Discussion Starter · #8 ·
Well then I must have a leak that only appears when the boost is higher than 10, because the gauge seems to show normal boost numbers (2-6 normally driving) but still when I floor it the highest it will go is 12-13. I will put teflon tape on all the connections and see if that helps it.
 

· hydraulic lifter crew
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i just put a boost gauge in my truck as well. installed it where the
boost tube goes into the manifold on the engine side.

i can hit over 30 psi all day long on the h1c. you may have a boost
leak somewhere or maybe the boost line is crimped ? i had to buy
some more boost hose cuz we crimped it pretty bad when installing
the line.
 

· Mule Barn Proprietor
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Well then I must have a leak that only appears when the boost is higher than 10, because the gauge seems to show normal boost numbers (2-6 normally driving) but still when I floor it the highest it will go is 12-13. I will put teflon tape on all the connections and see if that helps it.
You "may" have a very tiny boost leak. But, to my knowledge, I don't think it would be out of the ordinary to find a IC truck w/ 21 cm housing exhibiting those boost numbers. Especially since the fuel screw hasn't been touched. Done anything with the throttle linkage? Could be giving up alot of fueling there too!

i just put a boost gauge in my truck as well. installed it where the
boost tube goes into the manifold on the engine side.

i can hit over 30 psi all day long on the h1c. you may have a boost
leak somewhere or maybe the boost line is crimped ? i had to buy
some more boost hose cuz we crimped it pretty bad when installing
the line.

Way bigger sticks, and no intercooler to lower boost numbers, and more pump mods in your case Jason!!:thumbsup: How you lovin that thing??
 

· hydraulic lifter crew
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Way bigger sticks, and no intercooler to lower boost numbers, and more pump mods in your case Jason!!:thumbsup: How you lovin that thing??
i love it, really fun to work on and drive.
need to get some better rear tires so
i can get it inspected and i figure ill be
driving it to work twice a week till it gets
hot or i get the a/c fixed :hehe:
 

· Mule Barn Proprietor
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Well then I must have a leak that only appears when the boost is higher than 10, because the gauge seems to show normal boost numbers (2-6 normally driving) but still when I floor it the highest it will go is 12-13. I will put teflon tape on all the connections and see if that helps it.
3 things I would start looking at.
1) toss together a pressure tester and check for boost leaks
2) check fuel pressure...you may not have enough fuel supply
3) Make sure the throttle linkage is adjusted properly for full throttle travel. Alot of 1st gen owners leave alot on the table because they don't have the throttle linkage adjusted right. Once you have that adjusted properly you can back out the high idle screw and get some more. The next step would be reindexing the throttle levers if necessary or looking for a little more. :thumbsup:

he did mod his fuel screw....and took out one of the springs in the throttle linkage
His sig says "smoke screw" which doesn't really do anything but make a little preboost puff of smoke, and removing a throttle return spring will only lighten the feel of the pedal.:thumbsup:
 

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What he said^^^. I reindexed my throttle rod last week because when I had the lever off to take my pump top off (even though I didn't get it done) The throttle rod got bumped a couple notches. I bumped it back to where it was plus one notch and gained about 10 psi. I hit 32psi from a stop and it will hold 20psi on the highway.

Franco when I picked mine up I was only hitting 18psi max, maybe 12 on the highway with the pedal pegged and that's on a non-ic truck with the old bully dog cone i had and injectors. Mess with your fuel screw or your fuel cone and I'll bet you see some more boost. 12psi does seem a little low...
 

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i was getting 20 out of mine with a leaking intercooler and the stock turbo. now i run 5psi going down the road at 40mph, when i nail it goin down the road the waste gate stops it at 30psi. ive never got on it from a light yet. not sure what it would do.
 

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It should be higher than 11, definitely check for boost leaks..
 

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i dont know what kind of gauge pod you have but i had a similar problem with my boost gauge when i first put it in, and the hose was getting kinked in the back of the gauge pod since i dont have a pillar pod its very easy to get kinked. just a thought before you go tearing into other thing, could be something really simple.

i also used the bolt under the intake hose

right now i have my pump turned fuel screw 1/2 from stock and the star screw 1/4 turn and i hit 25psi, this is with the stock fuel pin, i havent put my bully dog in yet.
 
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