Wastehog

Okay, so as you all can probably tell.. I'm a new face on the forums. I've been lookin' for some help on my truck. I recently found these forums and I figured here would be a good place to get help. In my signature, you can see my truck is an 1985 K1500 Silverado.

To start off, a few things about me.. The truck became mine when my father passed away in 07' (I'm not here looking for grief, by the way.) I'm currently in high school, and just turned 16.


About my baby. A few months before my dad passed away, he had the worn out 305 replaced with a GM Performance crate engine from Jegs. (http://www.jegs.com/p/GM-Performance...52506/10002/-1) At the time it came with everything shown on the link except a dress up kit. The engine came with an Edlebrock Performer RPM air gap intake, topped with a 600cfm Edelbrock Performer 1406 carb.

Well, the truck has never ran right. For an engine that produces roughly 260 hp/ 350 ft. lbs. of torque.. this truck is sluggish. I've never liked Edelbrock carbs, so I replaced it with a well proven Holley 600 cfm 4 bbl off another vehicle which ran great. Still to no avail. I'm stumped on what the problem is.. I've adjusted timing using the marks, and a vacuum gauge, I've moved the dist. advance from manifold vacuum to timed vacuum and still poor results.. If anyone has any clue as to what it could be, please let me know. Any help is greatly.. and I mean greatly appreciated. Please don't be too harsh on me =p I know a lot, but this ole girl is giving me a test.

Thanks again
~John~

suzuki-guy

Check for vacuum leaks with some ether by spraying it around vacuum lines and intake base. If it idles high or chokes you have a vacuum leak. Also you have timed it with a timing gun? 0 degrees before top dead center? You have the idle air mixture screws adjusted right? I always screw these all the way in then two and a half turns out. I am very sorry to here about your dad! I cannot imagine! Also you got good Acdelco plugs in there? What about distributor cap, rotor and wires?

Wastehog

Thanks for the quick reply =p. It's all good about my dad.. he's in a better place. (Not that I didn't love him.. he just had a lot of health problems(Didn't wanna seem heartless.. I miss him a ton =( )) Anyways.. It had AC Delco plugs, but they started to rust so I threw in a pair of NGK V power plugs. It has a new set of Accel wires (I think I spelled Accel wrong lol). The dist and rotor came with the motor. I've tried timing it with a timing gun. When I put the dist to where its on 0 degrees on my timing mark, the motor starts to die. It idles fine at about 10 degrees past the timing indicator (if you will, the name for it escapes me at the moment lol).

Also how would I go about checking it with ether? Just spray the lines or what? I'm kinda confused, as it is almost 3 am =p.

One more thing.. the Edelbrock had a square bore carb spacer, which was maybe an 1/8th in. thick.. I didn't put it on, would that hurt the carb performance or not?

I have fumbled with the idle screws a ton.. and nothing seems to help. The truck actually loses power when the secondaries open.. I never seem to get the motor pas 3k rpm, even with it matted, unless its in park/neutral.

When I get up in the morning, I think I'm gonna try the paper clip method on the 4's and see if they open all the way or not. I'm starting to suspect that they are not because, the throttle is real hard to push down, there's no feathering it. I saw a throttle bracket and 700r4 kick down cable on Holley's website, I'm thinking of giving those a try too.

Just to list: the things I have changed,
Bosch or some cheap wire brand to Accel Wires
AC Delco to NGK V power
Edelbrock carb to Holley carb
and the oil lol.

P.s. Sorry for such long replies. Also, Suzuki, I like your truck =p.If I think of it, I'll post a few pics of my truck up tomorrow.

suzuki-guy

You spray ether around the intake manifold base if it chokes or idles high vacuum leak. Also spray around vacuum lines. Ten degress advanced should be fine I alsways timed my 85 by ear. I would throw some Acdelco plugs in it. The spacer off of there shold be fine I never thought they did anything to improve performance myself. Also how is your fuel filter? Air filter? It is 3 am here to just gor back from the truck pulls!

Wastehog

Haha, truck pulls are always fun =p. Um, air filter is clean. It's either on or off because of tuning the carb, Hell, I even lost my air cleaner hold down lol. Anyways, I've done a bit of reading about spacers and they didn't seem to do much except make the manufacturers money.. When I vacuum tested mine, it always pulls 15-17 in. of vacuum at about 1k rpm, which is my smoothest idle. Any lower and it starts to idle rough and backfire on take offs and such.

Um.. What else.. Wouldn't losing power with the fours open indicate too rich? If so, how would i tune that out with a 2 corner idle screw mixture on my holley? Just jet it lower?

Fuel filter I have no clue of to be honest. I have an inline one, past my mech. fuel pump to get any last minute debris, but other then that I honestly don't know if the pump near the tank has ever been changed. I'll fumble with the timing in the morning and do the paper clip method, and see what my results are.

Also, I think I know why it loses power at WOT, I may have blown my PV when it backfired, out of the numerous times, and I've heard of that running it too rich, Am I correct?

suzuki-guy

What kind of choke you got on there? Electric or manual? Try this advance your distributor till it pings(spark knock) Then back it off untill it stops try driving it now.

Wastehog

Mech. Choke, I never need it =p. I'm not too good at detecting ping, Ill have to see if I can figure that out.

Could a Blown PV run the engine too rich at WOT? I think I may have blown mine with the numerous backfires I've had.

suzuki-guy

Yeah bad pcv valve would make it run bad for sure! Shake it if you here a rattle and the hose is good with no cracks it is good. If not there a couple of bucks. How old is the gas? Well I g2g I have to work in 5 hours lol. I will continue with this tommorow but just try advancing it a little when the ping is there you will know beleive me! The more you advance it the leaner it will run the more you retard it the richer it will run! Godd luck!

Wastehog

Alrighty =p Have fun at work. Ill post a progress report in the afternoon tomorrow letting you know. Gas is new.. Just put my last $21 in the pig to fill her up. Typical 87 octane. I think the power valve in my holley is blown, so I'll get the primaries tuned first before I worry about the big picture lol. She goes thru gas quick, so i'm leary about washin the cylinder walls and screwing up a brand new motor with less then 500 miles on it.

Gots to get a job before I go too crazy on fixing her. You would think with a new motor, these problems wouldnt happen lol.

I think I'm off too, so I'll talk to you tomorrow. Maybe I'll get some pics of my baby up too. Anyways, Thanks for the help, and it gives me something to do tomorrow.
Thanks again, talk to you soon
~John~

suzuki-guy

Yupp ttyl man! First is first before you drive urself nuts get a good carb. on there! I will leave you with that goodnight!