Code 34 with No Boost at all - New Turbo is all that changed

[CBatstone]

Problem
Cannot build any boost at all. Car can be driven only if very careful not getting into the turbo. Has a hard time even getting up to 30mph because it will throw codes described below. Specifically 34 which we all associate with Fuel Cut as a result of High-Boost levels.

Car runs very rich, idling and driving.

History
Days before I installed the new turbo I drove the car 3 hours to transport it to a garage with a failing turbo. Got to shop and replaced with a 60-1 upgraded CT26 (Bought w/2k miles used, mod done by a professional shop) Installed the turbo and Have been having what seem to us like electronics issues since. Turbo is spinning freely.


Code 34 Displays on ScanTool when trying to accelerate in any manner other than extremely gently. Barely makes it up hills, but down hills the turbo seems to be able to spool a little.

Options of Code as it Displays:
Wiring to the Pressure sensor is bad (open or short)
Pressure sensor is bad (not sure what the pressure sensor is?)
turbo is bad
ecu is bad

(Abnormal Overcharging) is how this code would read, but I am not building any boost

I have a hard time imagining that something as static as a turbo could cause this issue. AFM V sensor was dirty and covered with junk, we cleaned gently.

ECU was working well enough to drive the car back 3 hours, enough for me to get a speeding ticket over thanksgiving weekend doing 85mph.

My 90' Supra has been laid up for 3 years now after a full engine rebuild, paint job, and more and I am at wits end with how much I have spent and how much time I have into this thing. I feel like I can see the light, as all I needed was a new turbo, but after installing it and having even more problems without even reaching boost, SupraMania is the only place for me to turn to.

Thanks for any help you can offer, if I am missing something (and I probably am) please let me know.

Craig
Vermont/New Hampshire

My 1990 Supra Build

 

[Nick M]

Section of intercooler piping missing?

 

[rayall01]

+1 on that. Seems like a massive boost leak to me, too.

 

[92TealSupra]

I have maybe 5 times forgot to tighten a clamp on the inter cooler pipes because that is the last thing to do before I start the car, maybe you got excited and didn't put a clamp on all the way.

 

[dumbo]

What pressure sensor?? Leak sounds probable.

So what was wrong with old turbo?

 

[CBatstone]

Car struggles to get to 30MPH, its difficult to even get it to move.

Intercooler Piping is Complete, while not perfect, we are not missing clamps or pipes. If it had a leak here wouldn't it run LEAN?

Sometimes you can drive the car so long as you do not get into any boost, then a little while later we cannot even get 5mph out of it.

I am familiar with CODE34 as I recieved it previously at 12+ PSI, but is this REALLY a condition of a small intake leak? Why would it run so RICH? Car should be drivable. It builds no boost so why would it be getting an overboost code?



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The reason the old turbo was replaced was because we had it rebuilt and they f'ed it up. Excessive shaft play took out the oil seal and it was blowing crap loads of smoke. Car as not run right since we put the new turbo on.

 

[jetjock]

With a downstream of the turbo induction leak it'll run rich because the air previously metered is not reaching the engine. The same leak, if it was large enough, would result in a lack of boost. Either way the AFM is metering too much air...that's why you're getting the code. Either that or it's defective. Every symptom you have indicates one of these problems. Since your own words imply the car ran OK before putting the new turbo on I'd be looking in those directions. Could be the compressor outlet hose. A pressure test of the system would also be a good idea. Formulating hypothesis and then testing to prove or disprove them are what diagnostics are all about. You can't just say "everything looks good"...

And what "scan tool" are you using to read this code? Or are you simply referring to a scan tool's data base for possible causes?

 

[rayall01]

Car struggles to get to 30MPH, its difficult to even get it to move.

Intercooler Piping is Complete, while not perfect, we are not missing clamps or pipes. If it had a leak here wouldn't it run LEAN?

Sometimes you can drive the car so long as you do not get into any boost, then a little while later we cannot even get 5mph out of it.

I am familiar with CODE34 as I recieved it previously at 12+ PSI, but is this REALLY a condition of a small intake leak? Why would it run so RICH? Car should be drivable. It builds no boost so why would it be getting an overboost code?





-----
The reason the old turbo was replaced was because we had it rebuilt and they f'ed it up. Excessive shaft play took out the oil seal and it was blowing crap loads of smoke. Car as not run right since we put the new turbo on.

I blew a small hole in my compressor outlet tubing, and had the exact same symptoms, minus the code, because I knew what the problem was so I didn't read it. Could not accelerate at all, and ran rich as fuck. Barely made it home. look at it this way, compressor pulls X amount of air past the AFM, ECU say's whoa, I need to put X amount of fuel to account for all that air. Then, the air the AFM read suddenly goes out through the leak, and the ECU doesn't know it. Voila, massive rich condition. Like it or not, you got a boost leak, or less likely, a totally fubar AFM.

 

[CBatstone]

You were all completely right on this one. Unfortunately The car is at my buddy's shop and I argued with him even before (and after) posting this question to the forum about the need to pressurize the intake system to completely rule that out. No assumptions can be made. He eventually checked over the intake piping which was the only other change we made and found exactly what you all expected, loose clamps, blown off pipe, etc.

Thanks for all your help with this, it's hard having to do some of this work remotely but I am lucky to have a friend with a shop that helps me out as much as he does when I can't be around. I'm going to buy some beaded piping with an intercooler that has the same size piping. Problem solved forever I hope.

 

[rayall01]

You were all completely right on this one. Unfortunately The car is at my buddy's shop and I argued with him even before (and after) posting this question to the forum about the need to pressurize the intake system to completely rule that out. No assumptions can be made. He eventually checked over the intake piping which was the only other change we made and found exactly what you all expected, loose clamps, blown off pipe, etc.

Thanks for all your help with this, it's hard having to do some of this work remotely but I am lucky to have a friend with a shop that helps me out as much as he does when I can't be around. I'm going to buy some beaded piping with an intercooler that has the same size piping. Problem solved forever I hope.

Due diligence is all you need to solve problems forever. Do it right, and double check everything, and all will be well.

 

[SUPRASTEVE]

My Supra does pretty much the same thing I was comeing home one day and I decided to floor it and i was hitting boost then and it was fine but when I got home let the car sit and then I took it out again the supra could barely make it to 30mph but I can drive it only with out hitting boost and its kinda difficult.

My question is where is the "compressor outlet hose" located? I might as well check it. I checked my lower IC pipeing and it seemed okay it had some rubber missing but it seemed okay. I couldn't check out the hose that came directly from the turbo I will do that this weekend.

 

[jetjock]

Last I check it was on the outlet of the compressor...

 

[rayall01]

Last I check it was on the outlet of the compressor...

Ha ha ha ha ha ha ha ha ha ha ha! Last I check it was there too!

 

[jdub]

:biglaugh:

 

[rayall01]

My Supra does pretty much the same thing I was comeing home one day and I decided to floor it and i was hitting boost then and it was fine but when I got home let the car sit and then I took it out again the supra could barely make it to 30mph but I can drive it only with out hitting boost and its kinda difficult.

My question is where is the "compressor outlet hose" located? I might as well check it. I checked my lower IC pipeing and it seemed okay it had some rubber missing but it seemed okay. I couldn't check out the hose that came directly from the turbo I will do that this weekend.

Seemed okay? You must VERIFY, through thorough inspection and testing.

 

[SUPRASTEVE]

Seemed okay? You must VERIFY, through thorough inspection and testing.

Yeah I didn't have alot of time I did it during the week but tomorrow is saturday and I will get a better look at it. A few guys said in my case it could be the Fuel filter which the car has over 317k and nothing has really been changed on the car because I have been fixing everything. it was the previous owners gas and go car. its an 89 turbo targa 5spd. Also I cleared all my codes. I remember something too when I first encountered the problem I let the supra sit for 2 days with no batt. then i took it out and it it pulled without the poping but then when I got to a stop light it began popping after 3K. Also I had code 41 not 34 but I will check all hoses. I also set the TPS too. So no more codes.