P0234 overboost with boost fooler

[Rex Watson]

I have a 2002 Dodge that’s all stock besides a cold air intake 4 inch exhaust and a boost fooler when I’m driving and get on it the truck won’t go over 2500 rpms and the boost gauge is reading around 25-28 psi I’ve changed map sensor put the boost fooler on it and I looked at the waste gate and it looks fairly new every time I reset the code it comes back not long after and I talked to a guy from thoroughbred diesel and he was saying it could be my ecm has anybody else had the same issue and found a fix for it

 

[KATOOM]

What "boost fooler" are you using? And what have you done to the truck? Are there power modifications?

 

[Rex Watson]

What "boost fooler" are you using? And what have you done to the truck? Are there power modifications?

It’s an ats boost fooler has the cold air intake and 4 inch exhaust everything else is stock

 

[KATOOM]

A boost fooler's function is to bypass the ECM so that it doesnt get a signal from the MAP higher than the factory boost parameters. Whats likely going on is the boost fooler isnt working or isnt connected right and someone disconnected the wastegate in order to increase boost. The real foolish part here is trying to get more boost without adding fueling is pointless and does absolutely nothing for power.

My suggestion is to eliminate the boost fooler and make sure the wastegate is functional. Depending on what transmission you have, you have an HX35 or an HY35 turbo. The HX has a rubber hose going to the wastegate. The HX is a hard metal tube. There's an elbow for increasing boost on the HX but on the HY people use a turnbuckle to hold the wastegate closed. Find out what the previous owner did...

 

[Rex Watson]

I’ll try that and I added the boost fooler was trying to get rid of the overboost code so it would stop goin into limp mode and I have the hy it doesn’t have a turnbuckle I’ll make sure the waste gate is working properly I’ll let u know tomorrow what I find out and could it be the wastegate actuator it seems like the waste gate only opens after I let off the pedal

 

[KATOOM]

it seems like the waste gate only opens after I let off the pedal

Why do you say that? The wastegate is activated by the boost the turbo makes. Its not mechanical in any other way.

 

[Rex Watson]

When I’m driving it and get on it it stays at that 2500 rpms the boost psi stays between 25-28 and you don’t hear the wastegate open till after u let off and I read this article it seems like some of the same issues I’m having and I’m new to the diesel world so I’m still learning https://flatironsrally.typepad.com/faq/2007/12/what-is-boost-c.html

 

[KATOOM]

You should never hear your wastegate on these trucks. What you're likely hearing is the turbo howling from boost rushing back through the compressor when you let off the throttle at higher RPM's. This howling noise is the lesser non-damaging version of turbo "barking". Turbo barking is when you're hard on the throttle and running really high boost levels, but then let off the throttle too quickly. All that boost has no where to go and will push back through the compressor and actually cause the turbo shaft to violently stop spinning and/or spin in the opposite direction. The noise it makes sounds like a dog woofing. This can be very damaging to the turbo too.

The wastegate function is smooth and quiet and only engages as the boost climbs to the point where the gate opens enough to keep the boost from reaching unsafe levels...set by the factory. Turbos with external wastegates can be more noisy. But dont mistake what you hear on turbo gas engines with blow-off valves which give that pssshhhtt sound when they let off the throttle.

Turbos work within a "map" range of efficiency and performance. The compressor and impeller must spin at speeds relative to the exhaust flow and boost created otherwise they can build heat, self destruct, or offer low performance. People who run more fuel than their turbo is intended can easily run into unwanted problems. The HX35 is good to about 35 psi, whereby its starting to create more heat than its offering air flow. The HY35 is good to about 30 psi before that happens.

 

[pfmoale]

KATOOM, et all : Was having the same problem, with that P0234 code too. The turbo, on my 2001 24V engine, is an HX with the hard metal tube. Another set of eyes noticed there was a small hole, maybe 1/16" diameter in the steel 90 degree tube. Mechanic sealed it off temporally, as that seemed to NOT bring up the P0234 code, when you throttle down. My question is : Can I remove the HX turbo, with steel tube, set up the turbo housing in my milling machine and tap for either 1/8" (or 1/4", or which one fits correctly) NPT, so as to replace the steel (aka NON friendly maintenance), to the rubber, but preferably heavy duty polyurethane tubing ? Good, or not a good thing to do ?
Thank you KATOOM for your great advise on keeping our machines up and running...............correctly ! Thanks to all the rest of the folks who help in "Keeping the up time up, and the down time down" !

 

[pfmoale]

KATOOM, et all : Was having a somewhat similar problem with my 2001, 24V turbo / wastegate. Getting that P0234 code. Another set of eyes noticed a small, maybe 1/16" diameter hole in the steel 1/4", 90 degree line from turbo housing to the wastegate. Mechanic temporally patched it, and seemed to not bring up the code when throttle down. My turbo housing is an HX, with steel tube. Very NON maintenance friendly. My question is : Can I remove the turbo housing from the engine, set it up in my milling machine, drill and tap for an 1/8" NPT (Or 1/4" NPT ?) fitting, and to replace it with a rubber , preferably polyurethane hose ? A good or not so good thing to do ?
KATOOM, thanks for your great advice in helping others. Other forum readers / posters, thank you too for your input. Your great advice helps us to "Keep the up time up, and the down time down" !
Peter Moale

 

[KATOOM]

Here's a page to help you identify the differences in the turbos. http://dodgeram.org/tech/dsl/FAQ/turbo_faq.htm
It sounds like you have the HY because the HX doesnt have the metal tube but rather a rubber line.
They're interchangeable too and the HX is better than the HY. They used the HY on later 2nd gen automatic transmission engines because the HY has a 9cm housing for faster building of boost. But that small housing reduces volume considerably which is why they build heat at such low boost levels.