Weak engine.

[riggz]

Hey, I just started my project K5 about a week ago. I'm restoring my K5 that has sat in the driveway for about 2-3 years. The engine is a 350 TBI that ran strong when it was parked. I've drained and replaced the oil & oil filter, replaced the old gas with new fresh gas. The battery is new, and the cables are also new. The air filter is a clean K&N. Fuel filter was replaced about a year prior to it being parked for the extended period of time. O2 sensor was also replaced about the same time as the fuel filter.

Now when its idleing its pretty rough. It will idle up and then back down to where it almost stalls, then back up again. It also stalls when i put it into gear, i have to keep the throttle up in order to move it, but even then its barely got enough power to move it. I have true dual exhaust but one cat is bad with a loud clank clank clank.

I'm trying to get this running enough to a point where I can drive it a few miles to where I'll be rebuilding it. I'd rather not have to tow it, plus I'd like to get an idea how everything else is holding up.

Any ideas why the engine is so rough?

 

[RustyMule]

Sounds like a vacuum leak to me. Depending on year, check the carb base gasket. Go buy a can of starting fluid and spray around the tbi/carb and intake while its running (or trying to). The idle will change if there's a leak. Have fun

 

[riggz]

i assume you mean on the outside of the TBI and not INTO it with the air filter housing off?

 

[RustyMule]

Sorry, around the base of the carb and the base of the intake where it goes into the heads. Not INTO the carb but around it.

 

[fatbob]

I'd still replace the fuel filter. You could very well have got condensate [water] in the tank just sitting. Did you ever see dew sitting on it in the morning? The same thing could happen in the gas tank. If the filter was doing its job it could be full of gas/water, and while you changed out the old gas in the tank, the filter could be loaded with crap. It is cheap enough to buy a new one. Bob

 

[riggz]

k ill give that a shot then. its a bitch to change out now cuz when i had the exhaust shop run true dual exhaust they ran the pipe right in front of the filter so i have to squeeze a wrench in about an inch of space.

 

[riggz]

ok i replaced the fuel filter, seemed to idle a bit smoother. i also sprayed some starter fluid around the TBI and it seemed to idle a bit higher when i sprayed around the passenger side just under the air cleaner intake.

its still weak as hell. i cant even make it up the driveway (which is a decent hill) if in gear and i floor it, it just barely goes and the engine doesnt increase that much in RPM. if not in gear it revs up high when i mash the gas but with a sluggish repsonse.

any more ideas?

 

[riggz]

i guess the next step is to check the plugs and/or replace them and look at the ignition system.

 

[sweetk30]

with the truck running remove air filter assbly and watch the injector spray pattern. the fuel might have dryed up in 1 of the injectors. and if this happened you need to get a new tbi or reman it with new injectors.

 

[riggz]

ah ok. ill try that. thx if i do need to replace the TBI. which would you recommend? im planning on rebuilding the engine and boring it, changing the cam, and such to add some more horsies. im looking to get about 350hp out of it. can i go ahead and purchase the TBI i'd want to have after the rebuild now and just bolt on? or should i get one out of a junkyard to temp?

 

[sweetk30]

for now i would go yard hunting. to se if thats the problem if injectors are not squrting proporly. and there is a diff in tbi size per motor. 305 1 size 350 other size and do on. thay have bigger injectors as thay get bigger.

 

[jk5blazer]

yeah it sounds like the injectors to me.

 

[riggz]

so look for a full TBI or just the injectors?

 

[riggz]

ok so its been confirmed the injector on the passenger side isnt spraying at all. the one with the red/blue wires running to it. now can i just replace the injectors by getting a part from a junk yard or auto parts store? or do i need to replace the entire TBI?

If i need to replace, which model # Holley should i get if i plan to rebuild the engine and beef it up to about 350hp?

 

[sweetk30]

you can do just injectors but only in pairs for good mesures. and or the hole tbi if easyer. as for holley unit i have heard of some problems with running correctly on bone stock motors. i know you are going bigger . but this might cause you some problems now . try www.howell-efi.com thay do t.b.i. swap stuff all day. and or the vender area has 1 company listed as vender her?