3rd Gear Over Boost Issue

Brwndrvr05

Brwndrvr05

Member
Im having an overboost issue when at WOT and making the 2nd to 3rd gear upshift shift. If i do not let off, i will see as much as 18psi and have no doubt i will see 20psi if i stay into it. Something is not right! The TY is mostly stock except for all the reliability mods and upgraded trans cooler, deep trans pan, 255 fuel pump, IC hoses upgrade, and IC hot wire. Everything else is all stock, stock 2 bar map and stock chip.

Im seeing a bunch of knock when the overboost happens on the 3rd gear upshift and i know its because of the 2 bar map not being able to read boost past 15 psi and computer wont compensate for higher boost levels. Also did some data logging with tuner pro but cant figure out to take log and post it here.

Im not seeing a check engine light or any codes for the overboost.

Any ideas on my issue is greatly appreciated. Thanks in advance
 
Slyclone

Slyclone

Well-known member
Re: 3rd Gear Over Boost Issue

Wastegate arm getting sticky?

Out of adjustment? Do you have a manual to do the adjustments? If you need the page I can dig around I did scan it at one time for a member and posted. It might be on my comp. I could check in a bit for you if need be.

If you have a few more boost spikes you could be doing some more work in the future..
 
Brwndrvr05

Brwndrvr05

Member
Re: 3rd Gear Over Boost Issue

Boost is 13-14.5 psi between shifts, but when doing 2nd to 3rd gear upshift boost holds up to 18psi if i don't let off. I have checked and adjusted wastegate rod/arm and still will overboost the 2nd to 3rd gear upshift.

When cold wastegate arm moves freely, but have not checked when hot yet for being sticky.

Could it be a T.V issue? I have adjusted that to but looks like some of the teeth on the adjuster are worn down a lil. Maybe its out of adjustment a lil?
 
Syclone4life

Syclone4life

New member
Re: 3rd Gear Over Boost Issue

Sounds like you need to upgrade to the 3 bar map sensor. Personally I think it's the best way to go, you also might want to consider purchasing a manual boost controller if you haven't already done so, that way you can turn your boost way down if you want. May I ask what octane the gasoline you run is?
 
Brwndrvr05

Brwndrvr05

Member
Re: 3rd Gear Over Boost Issue

91 octane.. with a 3 bar i will have to run a chip correct? I think 91 octane will be the limiting factor also.

Do you think the 3rd gear overboost on the upshift is a boost control issue? I dont think this is a common issue with these trucks or i would of found info on this.
 
0966Sy

0966Sy

Code what?
Toss the stock wastegate and upgrade to a forge wastegate. Sportmachines can hook you up. You can set it up to run 15-16psi no problem
 
Brwndrvr05

Brwndrvr05

Member
Re: 3rd Gear Over Boost Issue

Stock Cat, not gutted, i checked.. I swapped from the actuator i have now to another stock one and same thing is happening.
 
Jimmy

Jimmy

Banned
Re: 3rd Gear Over Boost Issue

What's the RPM when it overboosts? I'm thinking TV cable adjustment but I may be wrong :dunno:
 
0966Sy

0966Sy

Code what?
It's common for a stock bin chip, the chip controls duty cycle of the boost solinoid. Eliminate both and use a forge gate. I've installed several forge gates on stock trucks with good results. You could upgrade to a chip with better boost control but the new gate would be better bang/buck
 
bundie

bundie

New member
Re: 3rd Gear Over Boost Issue

what muffler are you running?

I had the same thing when i swapped to a 3" cat back
 
It's just a six

It's just a six

Super Member
Re: 3rd Gear Over Boost Issue

0966Sy said:
It's common for a stock bin chip, the chip controls duty cycle of the boost solinoid. Eliminate both and use a forge gate. I've installed several forge gates on stock trucks with good results. You could upgrade to a chip with better boost control but the new gate would be better bang/buck
Click to expand...

Would a stiffer Forge wastegate cause to over boost more as compared to a stock softer wastegate?
 
Brwndrvr05

Brwndrvr05

Member
Re: 3rd Gear Over Boost Issue

Jimmy said:
What's the RPM when it overboosts? I'm thinking TV cable adjustment but I may be wrong :dunno:
Click to expand...

Shift RPM is around 4300-4400 in first to second up shift, and 2nd to third, but i will hit 18psi early like 3500 RPM and by that point i get off the gas.
 
dgoodhue

dgoodhue

BuSTeD 4.3
Re: 3rd Gear Over Boost Issue

Are the vacuum lines going to the boost control solenoid//wastegate possibly leaking?
 
dgoodhue

dgoodhue

BuSTeD 4.3
Re: 3rd Gear Over Boost Issue

What do you have for a chip? If it goes over ~15psi for more than 1 sec, the stock chip should gone into overboost. I would unplug the wastegate solenoid and see what the base boost is.
 
D

Davemc1963

93 Ty Owner
Re: 3rd Gear Over Boost Issue

dgoodhue said:
What do you have for a chip? If it goes over ~15psi for more than 1 sec, the stock chip should gone into overboost. I would unplug the wastegate solenoid and see what the base boost is.
Click to expand...

I agree, I was about to 'say' the same thing. I have same set up with same RPM cat back and same issue. A forge w/gate should help control better and allow more boost before it starts to relieve pressure (depending on which spring is fitted), but ultimately, as dgoodhue has written, at 15psi, the stock chip will cut your fuel off! The only way I managed to prevent the overboost was to adjust the wastegate rod which bleeds off more boost, or should I say, it opens earlier. The net result is you will probably go slower. A Forge gate will therefore help there, whereby if you have a stiffer than stock spring, the w/gate wont start to open as early. Best solution is to port your wastegate port, or fit an external one. I'm going with a ported gate and looking at an adjustable solenoid from another source atm.
 
Brwndrvr05

Brwndrvr05

Member
Re: 3rd Gear Over Boost Issue

dgoodhue said:
What do you have for a chip? If it goes over ~15psi for more than 1 sec, the stock chip should gone into overboost. I would unplug the wastegate solenoid and see what the base boost is.
Click to expand...

It has a stock chip. I unplugged the solenoid and did a quick run from 0-90mph with quick data log. 2nd gear up shift boost was at 7psi, 3rd gear up shift boost was at 9psi, and 4th up shift was 10psi. Is the catback causing all this? If the exhaust was all stock would it hold 8psi boost all the way through with solenoid unplugged.
 
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