Im Confused about boost solenoid

[rencrn8]

I have been searching trying to figure out why Sy2300's truck is pegging the stock and a cheap aftermarket boost gauge. Today we where out in it and at WOT the thing sounded like it had rocks in the exhaust. Found broken vacuum lines on the top of boost solenoid which I know cannot be a good thing . But here is where I get confused, will this cause under boost or over boost. I have been searching the forums like crazy and now I can't see straight. Someone set the record straight here please. Can the sound be because of overboost, is he really overboosting or are both gauges reading wrong, and finally will the solenoid make this thing over or under boost. While you guys set me straight I will be here testing the tensile strength of this wall :banghead:

 

[gkrcr882]

Re: Im Confused about boost solenoid

well, I do know that if you are overboosting (assuming you have a stock chip) the computer will cut the fuel to bring the boost levels back in check. You can get erradic boost if the wastegate actuater is bad or misadjusted, or as you stated, a vac line is loose or has a hole. I'm going to let the gurus take this one:rotf:

 

[Dr.Evil]

Re: Im Confused about boost solenoid

if the boost solenoid line has a leak or is missing, it will overboost. I found that out the hard way last week after changing the O2 sensor...I snaped off one of the lines and when I gave it some gas getting on the freeway afterwards, it went straight to 20PSI under only 1/2 throttle.

The rock sound could be severe detionaton under the really high boost with not enough/good enough fuel to deal with it. Either that or it is cutting out and backfiring through the exhaust causing a popping or clanging sound.

Replace the lines or solenoid if needed...I'm picking up my new one from GM tomorrow...only 23 bux too.

 

[rencrn8]

Re: Im Confused about boost solenoid

Since this only happens at WOT (not 1/2, not 3/4, just full throttle) my first instinct was detonation. This is not my truck it is Sy2300 and I am just a wrench to help out. But since I am a mechanic by trade I get to do most of the troubleshooting and fixing on it. Which woirks out for me cause I am working on getting my own Ty soon) If this is detonation it is the worst I have ever heard, but then again I have never experienced 20psi boost either. I called him last night and told him to stay out of the skinny pedal until he can get at least new lines if not a new solenoid. BTW you guys are awesome in the two weeks I have been involved in the SyTy world I have learned oodles. :tup:

 

[JSM]

Re: Im Confused about boost solenoid

My crystal ball says if you continue on this path you will be installing a new motor.

This has been said time and time again, if you own/work on a syty you NEED a scantool aka laptop.

Obviously you gotta fix broken vacuum lines but even then you are not assured success.

Not sure how else to get this information across and not to pick on you but this happens daily if not weekly with fresh owners.

 

[SeattleSy#1255]

Re: Im Confused about boost solenoid

You may want to just unplug the solenoid, thus reaching a max of 8-12 psi, or base boost, staying in a rather safer zone. Base boost vaires as you are working with a 14 year old actuator.

Jeff is right, Kaboom if you don't get a scan tool.

 

[rencrn8]

Re: Im Confused about boost solenoid

My crystal ball says if you continue on this path you will be installing a new motor.

This has been said time and time again, if you own/work on a syty you NEED a scantool aka laptop.

Obviously you gotta fix broken vacuum lines but even then you are not assured success.

Not sure how else to get this information across and not to pick on you but this happens daily if not weekly with fresh owners.

Like I said this is not my Sy, I am just wrenching on it. It doesn't seem cost worthy to get a scantool for someone else's vehicle. Now when I get a Ty you can rest assured I will have a laptop just for it. for the time being I will be just wrenching and offering what limited advice I can to Sy2300(aka owner of truck). I know this place is the holy land for info on these trucks and that is why I ask here first. Maybe someone close to Cincy can help Sy2300 out also and run datamaster on it for him once so he can see where he sits. Thanks again for all the help though.

 

[JSM]

Re: Im Confused about boost solenoid

I am 2 hrs from cincy, and would gladly help him out (Louisville area). In fact my other syty buddy from cincy is probably coming down saturday maybe he could hook up with him and roll down.

I will be working on Daron's truck Saturday with the new motor, 4l80e stuff. If he wants an education be a good time. I also usually have lots of entertainment around in the form of personal insults among friends.

Got about 6-8 bottles of Jimmy's favorite beer in fridge left over from nats. Yinglingdingaling or something.

 

[rencrn8]

Re: Im Confused about boost solenoid

I am 2 hrs from cincy, and would gladly help him out (Louisville area). In fact my other syty buddy from cincy is probably coming down saturday maybe he could hook up with him and roll down.

I will be working on Daron's truck Saturday with the new motor, 4l80e stuff. If he wants an education be a good time. I also usually have lots of entertainment around in the form of personal insults among friends.

Got about 6-8 bottles of Jimmy's favorite beer in fridge left over from nats. Yinglingdingaling or something.

Sweet I will let him know. I am on call this weekend so I unfrtunately will not be able to make it, but would definitely get together sometime.
nick
Email me at RENCRN8@yahoo.com some directions and I will pass them on

 

[93ty475]

Re: Im Confused about boost solenoid

Today we where out in it and at WOT the thing sounded like it had rocks in the exhaust.

you can and will bend/break rods by doing that....it doesn't take long at all as our factory rods were the crappiest ones ever installed in a 4.3....to make matters worse, you can bend one or more rods and not even know they're bent until you tear down the motor later.....I have "personally" seen two motors blow up due to the vac lines you mentioned...but don't stop there...there are many other things that you must replace such as fuel pump, filter, plugs, wires ect....the best thing you can do at this point is stop running the truck under boost and take up JS on his offer....good luck

 

[rencrn8]

Re: Im Confused about boost solenoid

you can and will bend/break rods by doing that....it doesn't take long at all as our factory rods were the crappiest ones ever installed in a 4.3....to make matters worse, you can bend one or more rods and not even know they're bent until you tear down the motor later.....I have "personally" seen two motors blow up due to the vac lines you mentioned...but don't stop there...there are many other things that you must replace such as fuel pump, filter, plugs, wires ect....the best thing you can do at this point is stop running the truck under boost and take up JS on his offer....good luck

Already done. I made sure he understood to not get on it at all until we get it fixed. Don't think we were out running around at wot all day long, he had his foot in it once and we heard it and started investigating. I am not dumb enough to let him keep doing it until we figure it out.

"Man what was that horrible sound? Do it again. OK now again. Wait...no...one more time...I don't know but it sounds cool :roll: "