Engine/Transmission (1994 - 1998) low power after mods

[Earlschultz]

all right guys need your assistance truck is a 96 4x4 manual

4inch ex, 3kgsk tst#10, 370injectors. bhaf Plate is 3/4 foward afc a littlepast center (foward) star wheel untouched. The recent mods prior to the problem were the injectors and the gsk. Spring kit went in ok idle went down about 100-150 rpm adjusted the idle back to previous rpm.

Ok truck runs like a dog at low boost but when boost hits 2000-2100rpm takes off like a rocket. engine seems to stutter??is that the right word ? does the engine need more fuel ?? or less ?I also have white smoke when it stutters when cold seems to go away when warmed up. idle also seems to have developed a bounce when coming down from upper rpms (no LOad) I know this is alot to diagnose but you guys are the ones who can



thanks for your time



Earl

 

[JSmith]

My advice to you is to contact Piers. He helped RHarvey with his #10 and 3gsk. RHarvey may be able to help you.

 

[Deezul1]

Check the lever that rides on the plate for adjustment. After my 4k GSK mine was really gutless, after the lever adjustment (thanks Cord and Jim) it was awsome. Piers website has good pics of how it is supposed to be.

 

[JoshPeters]

I've heard that the 370's can devolp a stutter like your talking about. They say the 191 delivery valves will help cure that. I've been lucky with mine. I can only feel a little "hesitation" once in a while in rush hour traffic if I'm on the throttle really light.





Josh

 

[Andy Redmond]

What is your fuel pressure and timing like?



The "bounce" you describe on "idle back/idle down" is about 1200 rpm's right? then it falls back to where the idle was set?

I see this often with 12v, 215 pumps. I think it is the different spring seat that allows the springs to transition less smoothly than oe to the idle springs? I bet you see no drivablity concerns.



The stumble you describes seems like timing or fuel volume/fuel psi issue. The 370's (you used the . 020 sealing washers?) are not known for their idle/off idle qualities sometimes. Your delivery valves should be fine. Sometimes the ones in the auto trans 160 hp trucks (94-95) cause probs. , with the 370's.



The gov. strap doesn't usually catch on the #10. .



Where is the pre-boost fuel screw set on the AFC housing? If you followed the instructions, you set it to where it "just touches," try screwing it in 3/4 of a turn, if this helps and it doesn't become a misquito fogger at idle, you might turn it in until it feels better. You should be having better bottom end than you describe.



Good luck

Andy

 

[SMorneau]

I thought the 96 215hp pump didn't suffer from the small delivery valve /370 stumble.



Both the arm adjustment and the AFC housing position and star wheel setting are worth checking.



I would be especially interested in your performance, once you gt the bugs worked out. Do you have a stock turbo and housing?

 

[Earlschultz]

ok guys played with afc screw a little turned towards engine about 20 clicks better acell off the line but the stutter is something else. once truck is started (cold)ambient 68 degrees. give it some fuel in neutral starts to stutter punch it to the floor rpms will not raise due to engine stutter white smoke pouring out!!I checked the arm when adjusting my plate back arm catches right at the bottom tip of plate tried throttle arm slid up ok

I havent done anything to the pre boost fuel screw yet. snap on guy was here today picked up timing kit will look at how hard this weekend fuel pressure will be looked at as well

 

[Cooker]

If when cold, the truck runs exceptionally rough, like you are explaining, my guess would definitely be timing.

 

[rdrose]

timing

my truck did the same thing. i timed it last week to 16 deg and no more cold rough running. the shop that did my timing about a year ago say it was dead on 16 deg, when i got it from the shop it never did run right so i got all the timing stuff for the spill port way and was easy to do and my timing was right at 11 degs and the guy never put the washer under the del valve. i call and reem the guy can't wait to see in person.

 

[Bob V]

rdrose, if you are talking about sealing washer shown in the timing TSB from Fritz's site, your '97 should not have it.