DC199512V87

ok long story short, i cant get over 3k rpm. with my 3k gsk installed it would only pull to 2500rpm nicely under load, could go till 3 but it would run really rough/stutter and smoke a little black with no power. could get it to free rev to about 3400rpm but it sounded like a sick dog. so today i put in 60# springs and a 4k gsk thinking it would help. pulls very nice to 2700 rpm but now it wont even pull past 3k loaded or free revving after 2700 it starts sputtering like before but the instant it hits 3k it just sits and billows blue smoke. my thoughts are: either im seriouly messing up these gsks (and iv done TONS of research on them, trust me), or the timing is messed, or perhaps injector(s)??? pls help me get this puppy revving guys. im at my short wits end!

Clunk

Until someone knowledgable comes on, are you getting plenty of fuel to the injector pump? My 1st gen would do that until I changed out the fuel filter.

DC199512V87

i just changed the fuel filter today before proceeding to do the gsk. don't have a fp gauge yet tho.....

j-fox

Get the timing checked.
Also, the start plunger on the injection pump, tye wrap it in the up position and go try it. (It won't shut off until you cut the tye wrap.)

Also check the fuel filter. If your getting black smoke, I doubt it but take a look.

DC199512V87

timing is next on the list. fuel filter just got changed to a Baldwin before the gsk install.interesting thought on the fuel shutoff solenoid .will give that a shot for sure. also have an inkling that my lift pump is on its way out. as far as i know its original and i never got lotsa fuel on the top end even with the 3k gsk. no black smoke and egts never hit above 1250 at wot. seems odd for no fuel plate to me, no?

rebal

check the pre filter? could be plugged also are you sure... the spring is in right? not to tight.

DC199512V87

in-tank pre filter done about six months ago. u referring to the governer springs ? i set them both to .053 in. should b equal.....truck idle smooth and runs like a champ to 2500 rpm. too bad it costs $800 to bench a pump up here....

Tate

Fuel pressure and timing are the main culprits. Check both, fix as needed. Shut off solenoid not pulling up all the way will cause lower power, but not sputtering and smoke.

DC199512V87

been waiting for u to u to chime in Tate so basically the consensus is fueling issues. working on the fp gauge as soon as i can. also gonna get it timed to 17* should b lots ya?

DC199512V87

ok after some more searching .....could that b the overflow valve?

Tate

Infidel has some posts on checking the OFV or the pump. Get your fuel pressure gauge installed first, then the troubleshooting can begin.

9812vram

How's she start? Does it light right off? Idle rough when cold?

So, it pulls hard up to 2500rpm with no issues, then BANG!! kinda hits the wall......
But will free rev up to 3400rpm (running rough).....
I'd be awfully surprised if you had a fueling issue. You're using about 700 times more fuel pulling hard to 2500 than free reving to 3400. (maybe an exaggeration, but you get the point) The change in fuel delivery volume from idle to WOT is almost nothing with no load. In other words, if it was a fueling issue free reving to 3400rpm, it would still be starving on fuel while pulling hard to 2500 - so it simply wouldn't pull hard. Something else is going on here.

I'm thinkin' timing bud.

DC199512V87

truck starts awesome, 2-3 cranks on a cold morn and runs great all around except at high rpms. could rev it to 3400 with the 3k but now with the 4k it positively won't go past 3000, load or no load and neither in free revving starting at 2700 it gets rougher but by 3000 its done, finished, nothing left. im leaning hard on the timing thing, as i was gonna get that done with my 3k anyways, so hope that fixes it. if not then i should have my fp gauge in by then so troubleshooting will commence.