low boost

[saint d]

ok I'm not new to the forum been here for several years but finaly landed myself a ty,#1025 to be exact. I bought it and drove it home 12 hours. I stopped within 20 minutes and had fresh mobil 1 put in and the fuel system flushed as the truck sputtered a little and the check engine light came on often. I made it home uneventful drove it easy, speed limit but nothing crazy. I knew the truck was short on boost prior to buying. I got it home but now I can't seem to figure out whats going on I need some kind of scan tool badly but I'm holding out for my new laptop. I kind of know someone close but? I' went through the vacuum lines and matched what was there with what was on all the diagrams on here. I also disconected the battery in case the ecm was in limp mode. at this point the truck runs sporadically at best but I feel that is just the nature of these beasts. my concern is the 10lbs of boost. it led me to think limp mode or vac leak. I'm not sure what direction to go? I'm headed for tune up (plugs,wires, cap, rotor) but that won't solve no boost.I'm considering the boost solenoid? also my temp guage doesn't work and I took the brand new one off my s-10 and put it on and nothing so? I need help or else I'm aimlessly panicing because I can't track down my problems.cany help is appreciated.

 

[ghettosled]

Re: low boost

easiest thing to do first is pull the line going from the wastegate to the turbocharger.. it should make LOTS of boost. If it doesnt then you have a leak or restriction.. ie., loose intercooler piping, clogged cat or broken turbo.

If it does make boost when you pull the line, then its a function of the elecronic boost selenoid. make sure it is plugged in, and the vacuum lines are good and secure

 

[saint d]

Re: low boost

ok disconnected the boost solenoid.I drove around the block and just tapped the gas a little and boost went instantly 20lbs. I tapped the gas once more to make sure and got one detination and then idled it home. prior to this I checked the vac lines to the solenoid. so where do I get a new one?

 

[typhoon92]

Re: low boost

http://www.raceprovenmotors.com

 

[jwaller]

Re: low boost

I just had a truck in my shop with low boost and after a few weeks of head scratching and replacing parts come to find out the boost control relay had died.

 

[saint d]

Re: low boost

I think I'm going to go ahead and replace the boost solenoid anyhow. I am curious though what is intaled in fixing the relayand/or testing it. these parts are definately vehicle specific and a little difficult to get a hold of. I couldn't find the solenoid on raceproven even using the search so need somewhere else. I know the guys on the sti forum use gm boost solenoids for some reason why I don't know but they may be able to lead me to one.

 

[typhoon92]

Re: low boost

http://www.detroitturbo.com/cart/product_info.php?cPath=244&products_id=78

U might want to try your local dealer

 

[jwaller]

Re: low boost

I've got about 20 of them I've taken off of trucks over the yrs if you want/need one lemme know.

 

[ghettosled]

Re: low boost

yeh, unfortunately we dont stock the new selenoids.. not a very common part to go bad.

 

[EcSy#2671]

Re: low boost

LMC truck also as them

 

[saint d]

Re: low boost

I went to the chevy dealer today and ordered one. I drove the truck there and it was hesitant and stalling out so I drove back home and got my other truck. then later this evening my dad came over to see the truck and go for a ride as I've just gotten it and all. I had my wife start the truck before I got home and let it run for 15 minutes or so. when I took my dad for a ride it never hesitated or anything. I took it out to a open stretch and got on it and low and behold it went to 15lbs ? did it again and 15lbs! wasn't as quick from 10 to 15 as it was from 0 to 10 lbs and it was only there high rs and then start over , I don't know maybe if I go order and pre pay for all my suspension components all the slop will work its way out of the wheel!

 

[saint d]

Re: low boost

well, changed the boost solenoid let it run for the 15-20 min warm up session again. drove around town a little bit with no hesitation, ran smoothly. finaly jumped on it a little and pop,miss, knock? sputter cough. tried a couple more short spurts, no avail. pop it outta gear, revs right up smooth. I'm lost. I haven't had much time lately. next step plugs wires cap and rotor! recheck vac lines! any other suggestions?

 

[cameronsclone]

Re: low boost

well, changed the boost solenoid let it run for the 15-20 min warm up session again. drove around town a little bit with no hesitation, ran smoothly. finaly jumped on it a little and pop,miss, knock? sputter cough. tried a couple more short spurts, no avail. pop it outta gear, revs right up smooth. I'm lost. I haven't had much time lately. next step plugs wires cap and rotor! recheck vac lines! any other suggestions?

This is what mine does the first few minutes or so everytime I start it.

 

[ghettosled]

Re: low boost

sounds like its either overboosting or breaking up the ignition with load. verify boost with good aftermarket gauge (stock is 14psi) and plugs need to be correct spec (no splitfire, etc) and no larger then .035" gap.

 

[saint d]

Re: low boost

I definately need plugs, wires, etc. no doubt about it. I do have an autometer A pillar boost guage and it won't go past 10lbs, only has that one time mentioned above, and now it isn't again.

 

[nello]

Re: low boost

I just had a truck in my shop with low boost and after a few weeks of head scratching and replacing parts come to find out the boost control relay had died.

Boost relay??? Is this the same as the boost solonoid which on a stock turbo would be mounted right on top of it?

 

[ghettosled]

Re: low boost

Boost relay??? Is this the same as the boost solonoid which on a stock turbo would be mounted right on top of it?

yes same thing.

 

[MikeMcNair]

Re: low boost

i would get a logging tool and stop searching blindly. the truck will tell you what is wrong with it if you ask it

also, are you sure you are not running out of fuel? sounds to me like you are either low (1/4 tank or below) or the fuel pump is quitting on you.

i just went through this a few weeks ago (only had the truck a month, but basically got it running perfect in 3 weeks)

 

[turbodig]

Re: low boost

Boost relay??? Is this the same as the boost solonoid which on a stock turbo would be mounted right on top of it?

This is where you get into semantics...

The Boost Relay is on the firewall next to the others. It was designed to kill boost in the event of a low IC coolant condition.

The Boost Solenoid is the thing on top of the turbo that gets modulated to control boost.

If either one is dead, you could get a low boost condition.