I have aa 94 3500HD service truck with crane and welder. Loaded the truck is about 13,500 to 14,000 lbs. I needed a little more go so I put on the following: 3" up to 4" exhaust, K&N cold air intake, homemade turbomaster w/ 11.5 lb spring, gauges (boost, trans temp, tach, and pyrometer). The truck will not go over 4 lbs boost no mater what and it takes a few seconds to even get that. What could the problem be here folks? I am planning on getting a Heath GLE prom for the truck but work has been slow and so have the funds, maybe January on that. I know the truck is heavy and I'm not looking to win any races here, I just want it to go when I need it to and get better mileage. Any suggestions on the low boost.

 

check for exhaust leaks and did change the cross over pipe also check make sure air filter is clean

your cold air intake is it open filter under hood if so bad idea sucking in the hot engine temps you going want to go with 97+ air box

help get cooler air and some more boost you add intercooler

you may have to turn tm up some get the boost you want

 

i would definitely try a heavier spring. when i made mine i used too light of a spring and it made similar boost numbers. that and make sure your gauge is accurate.

 

Gauge is brand new, I know I'm not getting boost I can barely hear it out at the exhaust. I talked to Todd at Heath and he gave me some good ideas on what to look for. Thanks guys.

 

OK here is where I am at, the lift pump which was non working and the oil sender/switch was also bad and both replaced. The truck accelerated faster and idled better but that was it the boost is still at 3 psi I thought it would get a bit better with the available fuel. I will take mudder's advice and put a heavier spring, there is a 11.5 lb spring on it now. I tightened it up a bit and still nothing better. Todd at heath said the LP and switch which are new and working. What else aside from a spring could it be? Thanks for the help guys.

 

do you have an exhaust leak at the manifolds or crossover. possible leaks in the intake manifold or the wastegate flapper isnt sealing.

 

where did you get the new gauge from ?

are sure boost gauge working right other then i have say X2 what Woody35 said

 

No exhaust leaks at all from anywhere in the entire exhaust system. The flapper lever moves freely on the outside of turbo but that doesn't mean that there isn't a problem inside. I will check the gauge tomorrow and see if it is working for sure. The thing that bothers me is that I have open 4" exhaust and I only here a very faint whistle sound at first throttle and when letting off the fuel. Please help, any other things that it could be like the turbo is shot. I will also find a heavy spring to install tomorrow and see where I stand. Thanks folks.

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I am ordereing new injectors in the near future for the truck due to the weight and suggestion from Heath. The truck only has 75,000 on her. Due to the weight alone the truck needs to produce boost asap to get up and going so the engine is training to get it up and going so I should at least hear more that I am.

 

what are exhaust temps running

 

Pulling up a hill between 800-1000, Normal driving I'm at 4-600. I'm also going to check the point where my boost gauge tube is to make sure it is air tight along with the back of the gauge. Any other suggestions please let me know this is annoying.