Engine/Transmission (1994 - 1998) I have no boost!

[JSmith]

In another thread I stated how my grid wires fried. I replaced the gasket under the intake horn and still have no boost. Would the PCM play a part in not having boost? When I floor it the truck acts as if it is not getting much fuel and boost goes only to 12psi. Before the fried wires I could get 34psi of boost. Any suggestions?

 

[bmoeller]

The engine controls on the 12v are 100% mechanical. No electronics invovled. One exception, would be the cruise servo.



Did the little hose going to the AFC housing get damaged? It's not far from the heaters. Aren't there 2 gaskets (1 on top, 1 below) the grid heaters? Was the intake manifold gasket affected by heat from the meltdown leaking boost, or are all the bolts tight?

 

[JSmith]

bmoeller

I checked the bolts on the top of the intake manifold, all are tight. I replaced the gasket under the intake horn. I checked the line to the afc. I guess tomorrow I will replace the intake gasket.

 

[DOWG]

Last time I had the same problem it was the fuel filter. Changed the filter, back to 35 psi boost.

 

[TPCDrafting]

check to make sure all the boost hoses are tight and on straight. Also make sure none have any holes in them.

This is probably preaching to the choir, but that's where I'd check first.

There is an article on low boost under the 12 valve section (I think) in the latest TDR issue.

 

[jtwcummins]

If central valley is Calif and you have an EGR equiped CTD you probably have lots of soot in the intake. When I did the upgrades on mine the Vac port to the turbo was buried under soot. Had to vacuum it out and blow the lines. It was thick. As a side note, if the EGR is removed you will get a Check Engine for a bad EGR solenoid. The problem is the PCM checks IAT to verify EGR operation, solenoid is not the problem. I used a relay in EGR solenoid line to add a pot in the IAT line and played with it until lite stayed off.



Some bad person took my egr so I couldn't put it back, same guy ran a 2" speed bit thun the cat when I wasn't looking.

 

[BPonci]

You might want to have your turbo,intercooler and intake manifold pressure tested as a set to see if there is any leaks. Remember fuel makes boost. What does your pyro read at cruise and wot?Low boost and low heat is a quick indication of a fuel problem. Good luck!

 

[BPonci]

Hey Jay. that same bad person took my egr to! Maybe we should go hunt that person down and ask for them back. What do you think?

 

[JSmith]

At cruise pyro is 650 to 700, wot I used to be able to burry the pyro, now I get 850 max. This thing is a dog.



It just gets me that one day I have electrical problems, compounded I have no boost, low egt, slug like speed. Yesterday I was on the freeway and the truck maxed out at 78mph. If I floor it nothing happens. Before if running at 85mph and I floor it the pyro jumped and boost would climb fast.

 

[JSmith]

Instead of pulling the intake off, I swapped fuel filters, no improvement. Started pulling lines, hoses. Found the plastic hose from the intake to the AFC inside the fitting was melted creating a blockage. I could not find a replacement so I inserted an o-ring (small) and put some Gorilla glue on the last o-ring to have a temp fix untill I can get to the dealer to get a replacement. I will test drive the truck after the glue has had some time to dry.



I will report back if this took care of the problem.

 

[DavidGardner]

There is an article in the latest TDR mag. about how to make an adapter to check for pressure leaks in the inter-cooler and associated hoses. Might be worth a try if all of the simpler things dont work.

 

[JSmith]

Gentlemen, I have BOOST!!!!

The plastic line was the problem. Now I will replace a few components and I hope all will be well.



Thanks to all who replied.

 

[bmoeller]

Glad it was simple fix.

 

[jtwcummins]

Yes, would like to find the person who took my EGR and ruined? my cat. Want to buy him a beer!



As a side note. Iused silicon vacuum line to replace all the pastic lines. Takes heat alot better. Cost is $2+ a foot but worth it. It is hard to find