Turbo Installed - Check Engine Codes - Need Advice

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Cruiserhead05

Cruiserhead05

Joined
Jun 25, 2003
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Rixeyville, VA
Completed the Turbo install this weekend.

Wideband is on it's way but not yet installed.

After driving for a little, I got a P0125 engine code. Checked voltage on bank 1 02 sensor and it was reading zero.

Had suspected it got messed up during the removed process from stock exhaust. Cruising at 70mph, EGT read between 1000-1150. (EGT is about 4 inches after turbo, not ideal I know)

TODAY:
Replace 02 with suitable bosch replacement. Voltage on bank #1 was now reading and check engine stayed off. All seemed good.

Shut off truck for 5 min and restart. Got P0135 Code. Clear code and went for a 10 min drive.

Code P0125 reappeared after a few mins....:mad:

EGT's now sitting at 1200 and would clime if I added any boost.

Turn off truck for 20 mins while eating dinner. Back on the highway and EGT's seem fine again, not going over 1200 even with 6-7lbs of boost at intervals.

Any ideas on what's causing the P0125 and should I be concerned about the EGT's?

BUILD Specifics:
- MSGgrunt Turbo setup. T-62.
- Tweak many little things about the setup, but overall no major changes.
 
wait for your wideband,install your egt before the turbo and do not drive your L/C i think is lean! my .2 cents:meh:

what year?
 
Thanks for the input. It's a 1997.

Wideband should be here this weekend. I'm curious to know what others EGT's are running and where they have the probe.
 
Cruiserhead05 said:
Thanks for the input. It's a 1997.

Wideband should be here this weekend. I'm curious to know what others EGT's are running and where they have the probe.
Click to expand...

i drove my lc last saturday 75mph in vacuum 1400 6psi boost 1350 to 1400 if i drive under 60mph my egt is 1000 to 1250.

i installed my probe on the turbo manifold close to the 4 blots holding the turbo.

do you have pics of your build?:popcorn:


plus my AF is diferent than before now im running under boost 11.6
vacuum 13.5. i like to play with my laptop changing the fuel maps to see the diferents on my egt's :).
 
Thanks for the info.

My EGT probe is mounted on the down pipe a few inches after the turbo, so I know my readings are slightly lower than what the actual number is.

Seeing the wideband results and figuring out these codes will hopefully get my EGT's a little lower, but they certainly dont sound horrible high, compared to what others have reported.
 
I kept getting the 135 code with a Bosch replacement on the stock motor. Went back with OEM and it permanantly dissappeared. Very common, and I don't think it is related to your turbo setup.
 
Bosch sensors are infamous for their CELs on Land Cruisers because they use some kind of efficient heater which draws less power than an OEM sensor heater, which the computer then interprets as a busted heater and flips out. Go with OEM or Denso sensors, preferably OEM
 
Brandon,

If it turns out to be your 02 sensors, you can get Denso's over in Chantilly at Olympic Auto parts fairly cheap, that's where I got mine.
 
Just ordered new denso censors.

Keep in mind however, the P0125 was not related to the 02 censor replacement. It was there before. Only if the original was busted is that the cause.

I assumed that only the P0135 was related to the bosch sensor, which i did install today.
 
Last edited:
Update:

Replaced bank #1 Sensor with Denso today. Drove around for 10+ minutes at speed and everything seems happy. FSM says it will trip in 1.5 minutes at speed of 25-65 mph if the P0125 is going to reappear.

With this, I'm assuming the CEL was just a result of a faulty sensor.

WIDEBAND Kit arrived today as well and will hopefully go in this weekend.

Downside however, is that my EGT's seems to have gotten worse. Tonight they sat steadily at 1200 even just going 45mph. Mind you that my probe is on the downpipe so realistic temps were probably even higher. This obviously makes me uncomfortable as I want the truck to be able to pull mountain grades with a couple pounds of boost and be happy. maybe even with a small trailer behind it.

Quick question about the fuel pressure regulator as well:
On MAS280's build, he capped off his pressure reg and on MSGGrunt's build, he kept his connected with a T-section placed in for the BOV.

Are these both correct? I followed MSGgrunts setup...
 
Cruiserhead05 said:
Update:

Replaced bank #1 Sensor with Denso today. Drove around for 10+ minutes at speed and everything seems happy. FSM says it will trip in 1.5 minutes at speed of 25-65 mph if the P0125 is going to reappear.
that's cool!
With this, I'm assuming the CEL was just a result of a faulty sensor.

WIDEBAND Kit arrived today as well and will hopefully go in this weekend.

Downside however, is that my EGT's seems to have gotten worse. Tonight they sat steadily at 1200 even just going 45mph. Mind you that my probe is on the downpipe so realistic temps were probably even higher. This obviously makes me uncomfortable as I want the truck to be able to pull mountain grades with a couple pounds of boost and be happy. maybe even with a small trailer behind it.
Just ensure you have no exhaust leaks and worry about egt's once you get the afr's correct. How do you know the factory computer is not pulling timing on tip in boost?
Quick question about the fuel pressure regulator as well:
On MAS280's build, he capped off his pressure reg and on MSGGrunt's build, he kept his connected with a T-section placed in for the BOV.
IMO: I would never send FPR to anything other than a MAP sensor from the intake. Since the pressure difference between fuel pressure and intake pressure go hand in hand in proper tuning setups, I would always want to know, (*MAP*), what my FPR is seeing.
Are these both correct? I followed MSGgrunts setup...
Click to expand...

I can't comment on them, I have not seen their builds as of yet. I'll do a little search. IMO, fuel pressure is so important I would not share it with anything but MAP and make the line as aesthetically short as possible. For "proper" calibration, your fuel pressure needs to rise 1:1 = fuel pressure:manifold pressure.
 
and the nightmare starts...you'll now drive with one eye on the EGT, the other eye on the water temps!!!
 
1400' is not hot. i run 1700' all the time-at least until i pulled the egt guage. I dont even monitor anymore-i know its working and the truck is immortal. seriously 1400 is not a problem

my truck egt was hotter after i rebuilt my downpipe to a smaller diameter dump pipe. no big deal.

you should post up pics of your ducting.

id be more afraid of water temps-as long as they are ok no worries. if u are worried you could run an oil
cooler. i have one-probably a waste of time.
 
Dusty,

Thanks for the input. My water temps seem to stay around 190F; verified with obdII reader while driving.

Right now, after the 3" cat the exhaust tappers down to the stock setup. Eventually it'll be 3" all the way, but I just wanted to get it on the road.

The ducting is all 2.5" aluminum, tig welded with as few silicone joints as possible. Working this around the dual batts was fun but it came out real clean. Perhaps I'll get some pics of this weekend and of course post results with Wideband installed.
 
Update:

Installed wideband today. At WOT she is running 12.5 AFR so I'm comfortable with that.

Cruising at 70mph my EGT's hold around 1200 and water temp is 185*.

Everything seems real happy.....next order of business will be the tranny and seeing how long it holds up to 8-10lbs of boost.
 
Cruiserhead05 said:
Update:

Installed wideband today. At WOT she is running 12.5 AFR so I'm comfortable with that.

Cruising at 70mph my EGT's hold around 1200 and water temp is 185*.

Everything seems real happy.....next order of business will be the tranny and seeing how long it holds up to 8-10lbs of boost.
Click to expand...


12.5 close loop under boost?
what about open loop?
 
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