DodgeDrivinAggie

Was climbing a decent grade today when i heard a small pop and then a loud whistle. the whistle seems consistent with my turbo spooling. I also got a check engine light with a p0234 (turbo overboost). My truck didn't de-fuel, and the boost guage seems to be reading the same as before. I had the vp44 replaced about 2000 miles back, and i noticed a considerable amout of turbo lag since then, but i don't know if its related. cleaned the map and iat sensors just before the new pump was installed as well. any ideas on the problem? thanks in advance.

Amish hauler

Dose your truck blow smoke on the bottom? What kind of boost are you making?

DodgeDrivinAggie

my truck does blow smoke, alot of smoke. the cummins house had replaced the rubber boot that connects the turbo to the intercooler, and it cured the smoking problem for a while. since the dealership replaced the vp44, however, the smoke has come back with a vengence. it smokes at take off, at every gear change, and in high gear motoring down the highway. also before the vp44 swap out, i would read high twenties to thirty on the boost guage. the highest i've seen since then is 24, and it took alot of effort to get there. but sunday, when i heard the pop and whistle, the boost guage never faltered. even in its present condidtion, i get the same boost readings as i've gotten since the dealer worked on it. the guage will climb to about 19 in each gear as i'm running through them, and sit right at 3 with the cruise control set on the highway. could this be a sign of a cooked turbo charger? seems i would get 0 psi on the guage if that was the case.

Amish hauler

Just a couple of things I would check..

1. All connections of turbo hoses at inter cooler on both sides. At turbo and at engine. Make sure there tight and did not slide back.

2. On the driver side of mine the lower intercooler hose rubbed on the inner fender well and sliced it. I would check both sides for this. If they are rubbing I would bend back the fender to give it clearance.

3. Over 20+ pounds boost my truck would throw the same code. And it would defuel then. I could tell cause as soon as it hit 20lbs. on the guage the smoke would dissappear from the mirror. Boost-fooler from B-D helped this.

4. Try having the code cleared and see if it comes back. Auto-Zone dose it for free for me or find some one with a scanner.

5. Pressure check your intake system to find leaks.I have heard of hairline cracks in the inter-coolers...although not that often.
Hope this helps..I see your sig says huge injectors. Mine smokes at low boost.

RustyJC

Check your wastegate actuator hose.

Rusty

DodgeDrivinAggie

thanks for the advice guys. one thing i thought of last night. i'm not very savy about the turbo charger and its internal workings, but the extremely loud whining sound i hear as i accelerate sounds like a valve or something is stuck open. is there anything on these tubos that can stick like that?

dsldan

also check aroint the heater grids for leaks...

RustyJC

Almost forgot - the rubber hose on my boost gauge once slipped under the tie-wrap clamp. It was still over the barb on the back of the gauge, and the gauge still worked, but it made a heck of a racket at 20 PSIG boost and above. I pulled the intake horn and replaced the heater grid gaskets, tightened boot clamps until my hands were bloody, etc., because it sounded like the noise was coming from under the hood. As a desperation measure, I pulled the a-pillar gauge mount and found the problem.

Rusty

DodgeDrivinAggie

i'm not finding any obvious leaks or lose hoses. i will get the intake pressure checked when i have time. does anyone know how the wastegate vavle operates? what i mean is does the valve open gradually as pressure on it increases, or does it slam open at one certain point. i would guess it would gradually open, but i think mine is slamming open, like it sticks until enough pressure builds up to jog it loose. i think this is the popping sound i hear. that would be consistent with the overboost code, but i still think i'm blowing too much smoke. i'll keep posted on what i find.

thanks for all the help.