i just installed a boost gauge on my '93 and am getting between 2 and 9 psi (2 putting around at 55 empty, and 9 WOT with a trailer behind it). is that normal? i had a banks setup on a gm 6.2 that got more than that and it's pump didn't compensate for boost.

it is (as far as i know) stock turbo, intercooler,etc. she is real weak lately at the top end, so i just wanted to eliminate obvious things, like air leaks. i couldn't find any, but that really seems low. i've been suspecting my IP far a while...could that also cause low boost? i'm figuring that it would--less fuel=less exhaust=lower rpms in the turbo=less boost.

 

Before i started to do pump mods i could hit 18-19.

you might want to check the clamps real close, and your intercooler........I just don't think you can tell if a intercooler leaks by just looking, like you could with an a/c condencer.

You could have a torn boot but i would thing that you could here it hissing if you did.

EDIT my truck was straight piped thow!

 

You should be getting around 18psig stock if all's well.
REF~ http://dodgeram.org/support_pgs/diesel_ix.htm

You'd do well to look very hard at all the inter-cooler plumbing as well as the inter-cooler itself (they spring leaks too).

Have someone work the fuel pedal while you look at the linkage at the IP. Are you getting full throttle travel? Ours get sloppy that way.

Fuel filter clean?

Work the basics and let us know what you find.

Hope this helps.

 

When my 92 was stock (with the dog of a 21cm housing) it could only hit 13 psi and it was winter, so it may be one or 2 lower in the summer, i wouldn't know, i turned it up and haven't looked back . i would first of all do what BC847 to check for the slop in the throttle linkage, on top of that i would check fuel filter and also check the air filter. and if you haven't already get rid of the horrible kink over the rear axle.

 

how much does the crimp over the rear axle hurt it? i did notice that, but didn't figure that it would turn my truck into the dog that it is.

fuel filter, lift pump, air filter are new. linkage adjusted a month ago.

 

Recheck your gauge plumbing, I could get 25psi on my '92 with 4" ex. from the trans. to the end of the tailpipe and pump tweaks only.
Where are you taking pressure from? Intake gooseneck or manifold top with a pipe plug port (where I had mine)?
The tailpipe crimp really hurts exhaust flow...seems like I picked up 3 to 4 lbs. boost after replacing that restriction....got to turn the pump up some more

 

I just started running a boost gauge yesterday and saw no more than 12psi so far. 85 degree temps at 5,000ft. Seemed normal, dunno. I'll get on it once really good on the way home today, just to make sure what the max reading goes up to...

 

where can i get a piece to splice in there? i'll check the intercooler monday or tues.

gauge is in the pipe plug port right below the air ilet into the mainofold. i may try blowing soapy bubbles into the inter-cooler. does that work? i can't hear or feel any leaks.

 

as far as the part over the axle all i bought one 3" exhaust clamp. i cut it off behind the back of the muffler, just on the muffler side of the clamp, i have able to use a seal puller and get the remaining pipe. then i cut a 90* angle out of the peice i cut off, shoved it in to make a turndown and clamped it in place.

as far as the boost, you can look for a leak but i am guessing it is just the fact that the pump is stock and truck is like 13 years old, lol. how many miles on it? mine that hit 13psi stock only had 110k on it and those were really easy miles.

 

Your numbers sound a little low for a stock truck I think. You might have a small (hard to find) boost leak somewhere like the intercooler. I didn't put a boost gauge on until after I did some pump tweaking so the lowest boost I ever saw was 16-18psi.

Do you guys normally get max boost in 1st gear on flat ground? I'm able to hit my max of 32psi in 1st gear before the 1-2 shift.

 

i did find a little leak in the inter-cooler. unfortunately its the inter-cooler itself, not the plumbing.

at 20 psi it leaks 60 gallons in 10 minutes.

 

a little leak that a big leak!!!!!

I thing you found your leak

 

14psi WOT top gear at 60mph. Stock 91.5 (intercooled) at 5000ft. 65degrees.

 

So....your going to replace the intercooler? stock or improved after market?

 

Before you condemn the intercooler, check to see if it meets Cummins spec for pressure decay.

Pressurize the intercooler to 25 psi and remove the air supply, Cummins says that it shouldn't lose more than 7 psi in 20 seconds.