Where To Start?

[Foot Performance]

Recently had the truck apart to do some little things reroute inter cooler hoses, abs delete, and I put some new battery cables on.

Get it all back together and now the truck has to really work to build up 15 psi where before it would somewhat peg the guage out. It will only get up to around 13 from a dead stop and in third it may pick up to 15 maybe. On a down shift it really labors to get there but will in 2nd.

Checked for vacuum leaks over and over and over none found verified intercooler pipe was tight. made sure all the lines at turbo were ok and they seem to be. doesnt seem to knock(that I can here)

I never heard it before but if I let off under full throttle the turbo make that puttering sound like I have a blow off valve or some thing no very load but I can here it ( I dont think it did that before should it?)

Withing 6k i have replace all the vasuum lines, plugs, wires, cap, roto, and ignition module and It just started today.

I dont have a cable to hook up to the truck yet but If i cant find anythign I will trailer it to some people that do this weekend :tup:

truck was down for about 2 weeks without a battery I am sure fuel trims would have reset but I did drive it for around 30min and it didnt really change

 

[Ian Turgeon]

Re: Where To Start?

Things off the top of my head:

Turbo->IC connections
IC->Throttle body connections (easy to get a fold, or not tighten down properly)
And possibly a piece of the stock intake tube getting chewed up in the turbo
Maybe Backwards Turbo vac lines

 

[Foot Performance]

Re: Where To Start?

Things off the top of my head:

Turbo->IC connections
IC->Throttle body connections (easy to get a fold, or not tighten down properly)
And possibly a piece of the stock intake tube getting chewed up in the turbo
Maybe Backwards Turbo vac lines

Yeah I think I will recheck the i/c connection and I am going to order a new pipe tomarrow I may try and swap it out this week and see.

The pipe I got was off of ebay and didnt have any thing on the end to help hold the hose on so I put some welds down I may not of have gotten it to seal all the way.

I didnt have any vac lines off the turbo I just cheched to see if I might of busted on when i put the intake pipe on

 

[syclone0209]

Re: Where To Start?

if your hearing the turbo flutter more now than before then i doubt is a leaking connection after the turbo as it would relieve the pressure through the leaking connection as opposed to going back through the turbine. sounds like it could be an exhaust restriction like a cat going bad. check the turbine for slop or bent blades. does the truck actually feel like its down on power. if your going off the stock boost guage then changing the battery cables and connections could have made a difference in the guages readings. i think i have an old boost guage off of the corvette that i could send you to rig up temporarily to check actual boost.

 

[Tooky]

Re: Where To Start?

Listen closely to the sound of your truck. Does the turbo whistle's pitch continue to shriek higher than normal when it spools up, and then get slow? Only you will know for sure but you have to be careful in case it really is a boost leak, you can overspeed your turbo by simply going WOT with a leak.

You said you don't have a cable to hook it up yet. Any time the boost starts dropping and the truck gets slow it needs to be put on a scan tool. I would be very cautious driving it until you can get a better look.

 

[Foot Performance]

Re: Where To Start?

Listen closely to the sound of your truck. Does the turbo whistle's pitch continue to shriek higher than normal when it spools up, and then get slow? Only you will know for sure but you have to be careful in case it really is a boost leak, you can overspeed your turbo by simply going WOT with a leak.

You said you don't have a cable to hook it up yet. Any time the boost starts dropping and the truck gets slow it needs to be put on a scan tool. I would be very cautious driving it until you can get a better look.

I did notice aliitle more wistle that normal but it is only on the way up about 3-5 psi then it stops.

Put some new hose on the turo to cooler pipe seemed to build a little more boost but the turbo puter was still there

I am going to haul it to one of our mini meets in this weekend and hook it up to see what up hopefully

I did take the stock air box and cut a bigger hole in it and the braket but I wouldnt think that would have much affect (that is were I though I might have gotten a little more wistle out of :dunno: )

 

[Foot Performance]

Re: Where To Start?

Still fighting this thing it slowly builds boost up to about 8 psi and then in third it might get up to 12 tops. I pulled the hose off the waste gate valve ant it does the same thing. I can push the rod towards the rear of the truck and it seem to snap back and acts like it is making contact.

Would the exhaust restriction still affect it that heavily with the acuator un hooked from the solenoid???

I hooked it up to my tech one not the most informative but it is showing at the most 2 degrees of knock and the waste gate is a 100% duty cycle my TP goes wide open ( I thought it might have been sending a messed up signal)

 

[midnightbluS10]

Re: Where To Start?

Are you using a cobra elbow on the turbo? They've been known to collapse and cause a restriction.

 

[Syclone#2960]

Re: Where To Start?

If I remember correctly you will only get half boost (8lbs) with the boost solenoid disconnected.
Boost could be escaping around the the TB hose.
Shoot some air (15lbs.) w/ a compressor to the hose that controls the wastegate rod and see if it moves properly.

 

[Will_in_China]

Re: Where To Start?

Sounds like a partially pinched vac line that I had eons ago.

I love 'partial failure' mystery problems like this, NOT! :steamer: