Engine/Transmission (1994 - 1998) your diagnosis

[DPyles]

I was wondering, I have read on this forum that some of you fellows are getting round 40lbs. boost.

Well I ain't. WHen I hit the base of a pretty steep hill everyday on the wat to work at 45mph, I stomp the throttle and around 55-60 I turn on the OD with mystery switch engaged. It goes right to OD-lockup as it should. But with the pedal almost all the way down, I can't even get the boost to come up to 15 lbs! The truck lays there at 60 mph's at around 1800 rpm. until the hill begins to flatten out a bit. Even then I get no more than 18-20lbs. and no more than 65 mph's. On the level ground the truck pulls good but I never get any more than 20-22 lbs. boost. the truck quits pulling at a top speed of about 80mph's. Truck is pretty much stock except for exhaust (no muffler-3. 5in. )and the fellow I bought it from told me he had 370 injectors installed. (not going to swear to that though. )

Form what I have read that is pretty sorry performance.

A frien has a late 98 5spd with a puck and has no trouble buring the 120 speedo.

This being my first diesel I am not too farmiliar with the parts of the truck. I have a manual on order too get a little more intimate with the workings of it.

Oh, the truck has 150,000miles on it.



Any ideas?

 

[Joe G.]

Sounds about normal for stock. The waste gate on your turbo will open and that's all the boost you get. People who are getting 40 PSI boost have modifed engines with work on the turbo to give them that kind of boost. According to some, anything over about 22 PSI on a stock engine is not doing you any good anyway.

 

[bighammer]

A TST plate and boost elbow (part of the kit) will change all that. Mine was a dog until I put in the #5. Governor spring kit is a nice mod too.



You may have to look into transmission mods if you go big with the plate.

 

[WKener]

Do you have an egt gauge, if so how hot can you get it? If you can throttle it past 1200* with only 20# of boost then you probably have those 370's and a boost problem... What about smoke? Tell me more...

 

[DPyles]

wkenner

I have never seen anything past 900* running full throttle up hill with 3000 lbs. in the bed. There is a very faint trail of smoke at those conditions. I could only get 14lbs. boost and about 50mph.

got a lillte run before the hill and did not drop speed but also did not gain. normal driving there is almost no sign of smoke except for start-up.

 

[1dslram]

You do not have 370 injectors if you did at 20# of boost you would loose whole towns behind you. Do as others have said get a TST or Piers plate, I like the #4 with the 4,000 GSK and AFC then the 370's and a larger turbo.

Bruce

 

[illflem]

Sounds like an unmodified '95, they're dogs. Bighammer gives good advice, you'll think you have a different truck. Timing could be off also.

By the way you need to go to your user control panel and copy what is said on your truck profile to the signature box.

 

[DPyles]

illflem

Thanks for the help on the profile. I was wondering how to do that. My internet time is limited and I don't have a lot of time to figure out things on different sites.



I saw on the TST web site that the #5 plate is not recommended for stock trans. But I was wondering if anyone has used it with good results. I do mostly normal, unloaded driving with the occasional heavy tow or load.



Off the subject... . Has anyone ever used one of these or any diesel engines in a mud racer?

 

[Joe G.]

One thing you might do is get the #5 and install it moved back a ways. Then if you up grade your trans you can push it forward. Note that a little bit goes a long ways in positioning the plate.

 

[JGK]

15 lbs max?



I'd still check for leaks between the turbo and the intake manifold.



-Jay

 

[MLee]

power/plate

I was under the impression that a #5 plate was to radical for the auto, and something more mild recommended, or good by auto.

just my penny's worth



Marv.

 

[1dslram]

I have used the #5 plate but liked the way the truck ran with the #4 plate better. When I changed from the #5 to the #4 plate all I changed was the plate and the truck ran a lot better at the high RPM range. When I had the #5 in I ground about . 007-. 010 off the upper end and that helped but the #4 was much better for me.

Bruce