Toyota Tacoma Forum banner
1 - 17 of 17 Posts

·
Registered
Joined
·
10 Posts
Discussion Starter · #1 ·
I am starting to lose it so hopefully someone has experienced something similar. The truck will start in open loop normally then switch to closed loop but once it is in closed loop it will only briefly switch to open loop when you let off the throttle and not when you accelerate at over 80% like its supposed to. I have watched the truck on a scanner to confirm it is not entering open loop aswell as watching the afrs which never drop from around 14.7. If the truck is warm and initially starts in open loop it will boost just fine with proper afr's for one pull before switching into closed loop. I really don't think this issue has anything to do with the turbo setup aside from being able to diagnose it based off the afr gage which wasn't previously on the truck. When I purchased the truck it had burnt valves which I'm starting to think could have been from the truck running lean under load by not switching into open loop. So far I have looked at the TPS and confirmed that it is seeing full throttle, the MAF values appear to be within the ranges for idle and no load at 2500rpm that I found online, IAT seems to make sense, truck runs right around 14.7 afr in closed loop so I'm assuming that the o2 sensor is functioning properly. Would love any ideas or things I can test. The setup of the truck is below. Thank you

2002 2rz
stock ecu
Rebuilt motor
forged pistons compression drop for boost
pink injectors
stock fpr hooked to first port on throttle body
maf is factory housing pre turbo (recently cleaned)
No cats with a resistor and capacitor wired into rear o2
Lce low boost kit
Lce stage 1 cams
Lce valvetrain kit
Forged pistons
Arp studs
Cometic gasket
Homemade stainless exhaust with 14inch magnaflow muffler and a resonator
 

·
Registered
Joined
·
96 Posts
Interesting. So it’s staying closed loop under WOT throttle conditions. Have you tried unplugging an o2 sensor to see if it would trigger a closed loop scenario?
 

·
Registered
Joined
·
10 Posts
Discussion Starter · #3 ·
I haven't tried driving it with the o2 unplugged but I can do that, I believe it will force it into open loop. Some other parts that may be noteworthy,
Injectors - new oem toyota
throttle body, IAC, TPS - all new oem toyota
fuel filter - new
coil packs - new
Spark plugs - new
Air filter cone style - new
EGR - deleted with resistor
rear o2 spoofed with sensor in the exhaust
Maf is as far from the turbo as I could have it
 

·
Registered
Joined
·
23 Posts
I am starting to lose it so hopefully someone has experienced something similar. The truck will start in open loop normally then switch to closed loop but once it is in closed loop it will only briefly switch to open loop when you let off the throttle and not when you accelerate at over 80% like its supposed to. I have watched the truck on a scanner to confirm it is not entering open loop aswell as watching the afrs which never drop from around 14.7. If the truck is warm and initially starts in open loop it will boost just fine with proper afr's for one pull before switching into closed loop. I really don't think this issue has anything to do with the turbo setup aside from being able to diagnose it based off the afr gage which wasn't previously on the truck. When I purchased the truck it had burnt valves which I'm starting to think could have been from the truck running lean under load by not switching into open loop. So far I have looked at the TPS and confirmed that it is seeing full throttle, the MAF values appear to be within the ranges for idle and no load at 2500rpm that I found online, IAT seems to make sense, truck runs right around 14.7 afr in closed loop so I'm assuming that the o2 sensor is functioning properly. Would love any ideas or things I can test. The setup of the truck is below. Thank you

2002 2rz
stock ecu
Rebuilt motor
forged pistons compression drop for boost
pink injectors
stock fpr hooked to first port on throttle body
maf is factory housing pre turbo (recently cleaned)
No cats with a resistor and capacitor wired into rear o2
Lce low boost kit
Lce stage 1 cams
Lce valvetrain kit
Forged pistons
Arp studs
Cometic gasket
Homemade stainless exhaust with 14inch magnaflow muffler and a resonator
What is actually happening that you are concerned about it being in open loop and not?? Like are you losing power? Or you are pinging? Kind of lost about what the truck is doing.
 

·
Registered
Joined
·
2,720 Posts
I'm running Maf calibrator and o2 sensor calibrator. The o2 calibrator intercepts the signal from the front o2 sensor and its supposed to lower the voltage to trick the ecu that its leaning out so it compensates by giving more fuel (positive fuel trims). I tuned it to gradually lower voltage from -5 inHg to full boost. It helps with part throttle boost, and so far it running great. I used to run the pink injectors but it could only handle 9-10 psi, now i have 440cc injectors and up the boost to 14psi. Been using this setup since 2007.

How much boost are you? if you're at 9-10 then the pinks are too small and cause lean conditions.
 

·
Registered
Joined
·
10 Posts
Discussion Starter · #6 ·
What is actually happening that you are concerned about it being in open loop and not?? Like are you losing power? Or you are pinging? Kind of lost about what the truck is doing.
The afr is not dropping at all from 14.7 no matter what the throttle position is at which is dangerously lean. The truck should enter open loop/fuel enrichment when the throttle is over a certain percentage which it is not doing.

I'm running Maf calibrator and o2 sensor calibrator. The o2 calibrator intercepts the signal from the front o2 sensor and its supposed to lower the voltage to trick the ecu that its leaning out so it compensates by giving more fuel (positive fuel trims). I tuned it to gradually lower voltage from -5 inHg to full boost. It helps with part throttle boost, and so far it running great. I used to run the pink injectors but it could only handle 9-10 psi, now i have 440cc injectors and up the boost to 14psi. Been using this setup since 2007.

How much boost are you? if you're at 9-10 then the pinks are too small and cause lean conditions.
Interesting, I had only previously read negative things about the different calibrators but sounds like its worth looking into. Right now the boost controller is as low as it will go (about 4 psi) but it stays at 14.7 no matter how much boost the truck sees so I am keeping it out of boost aside from the occasional test. How do the 440cc injectors work during idle/normal driving? When you maxed out the pink tops at 9-10psi were you running all stock fueling or did you have an upgraded fuel pump/FPR?
 

·
Registered
Joined
·
23 Posts
The afr is not dropping at all from 14.7 no matter what the throttle position is at which is dangerously lean. The truck should enter open loop/fuel enrichment when the throttle is over a certain percentage which it is not doing.


Interesting, I had only previously read negative things about the different calibrators but sounds like its worth looking into. Right now the boost controller is as low as it will go (about 4 psi) but it stays at 14.7 no matter how much boost the truck sees so I am keeping it out of boost aside from the occasional test. How do the 440cc injectors work during idle/normal driving? When you maxed out the pink tops at 9-10psi were you running all stock fueling or did you have an upgraded fuel pump/FPR?
Sounds like your wife band is incorrect. You might want to recalibrate the wide band or replace it.
 

·
Registered
Joined
·
2,720 Posts
The afr is not dropping at all from 14.7 no matter what the throttle position is at which is dangerously lean. The truck should enter open loop/fuel enrichment when the throttle is over a certain percentage which it is not doing.


Interesting, I had only previously read negative things about the different calibrators but sounds like its worth looking into. Right now the boost controller is as low as it will go (about 4 psi) but it stays at 14.7 no matter how much boost the truck sees so I am keeping it out of boost aside from the occasional test. How do the 440cc injectors work during idle/normal driving? When you maxed out the pink tops at 9-10psi were you running all stock fueling or did you have an upgraded fuel pump/FPR?
Try tap into the maf sensor signal wire and ground to monitor the voltage while driving. The voltage should increase at wot about 4.5v but if it sees full 5 volts it will stall and can just shut off. If the afr aren't changing, it could be that its not seeing enough airflow.

How big is your intake pipe on turbo, and are you using the factory housing with the maf? How are your valve cover vacuum lines routed? Where is your iac hose attached to? What wideband o2 sensor do you have?
 

·
Registered
Joined
·
10 Posts
Discussion Starter · #9 ·
Try tap into the maf sensor signal wire and ground to monitor the voltage while driving. The voltage should increase at wot about 4.5v but if it sees full 5 volts it will stall and can just shut off. If the afr aren't changing, it could be that its not seeing enough airflow.

How big is your intake pipe on turbo, and are you using the factory housing with the maf? How are your valve cover vacuum lines routed? Where is your iac hose attached to? What wideband o2 sensor do you have?
I put a new maf in last night and reset the ecu, I am waiting to put a few miles on it before trying WOT again but will this afternoon. I have a innovate lc2 wideband. Intake for the turbo is 3inch and im using the stock maf housing with an adapter I made to a cone filter. I am going from the front of the intake manifold to my boost gauge, the fpr to the 1st nipple on the throttle body. I have both pcv hose nipples capped off on the throttle body and the ports on the head now go to a catch can. The larger hose (IAC?) on the throttle body goes to the emissions crap (as it was routed before) with a check valve so it wont see boost. Ill see if I can upload a picture of the engine bay
 

·
Registered
Joined
·
2,720 Posts
Everything looks good, the fpr should be good there, pcv is good. I'm still thinking its the maf sensor, if not, i dont know what else. Try checking the maf sensor output voltage, not on a scantool, I think scan tools display grams/second -gm/sec not actual voltage.
 

·
Registered
Joined
·
10 Posts
Discussion Starter · #13 ·
Everything looks good, the fpr should be good there, pcv is good. I'm still thinking its the maf sensor, if not, i dont know what else. Try checking the maf sensor output voltage, not on a scantool, I think scan tools display grams/second -gm/sec not actual voltage.
I put a new MAF in the truck and after putting some miles on it when I gave it full throttle the afr climbed higher then 14.7 instead of staying constant like before. Ill have to figure out a way to check the voltages on the new maf and check the wiring from extending it. I am running out of ideas as to what could effect this and really dont want to throw an ecu at the truck.
 

·
Registered
Joined
·
23 Posts
I put a new MAF in the truck and after putting some miles on it when I gave it full throttle the afr climbed higher then 14.7 instead of staying constant like before. Ill have to figure out a way to check the voltages on the new maf and check the wiring from extending it. I am running out of ideas as to what could effect this and really dont want to throw an ecu at the truck.
You need to verify if you afr is even reading correctly,, does it read high as 18 when just key on?? Or when you let off the throttle if not then again your sensor or reading meter is not working.
 

·
Registered
Joined
·
10 Posts
Discussion Starter · #15 ·
You need to verify if you afr is even reading correctly,, does it read high as 18 when just key on?? Or when you let off the throttle if not then again your sensor or reading meter is not working.
When I first turn the truck ignition on the gauge reads 7.4 after starting it continues to read 7.4 for a few seconds until it warms up and reads normal. When I let off the throttle the gauge goes to 22.4. The sensor and gauge set up were brand new when I put this motor in and I calibrated the sensor. Could I have screwed something up in the gage install? It seems to read 14.7 normally but after the new maf now gets leaner at wot, it went to an afr of 16 before I got off the gas yesterday. I am pretty much keeping the truck completely out of boost aside from testing. I will have to doubel check that I did not switch the signal wires but I assume that would be more obvious.
 

·
Registered
Joined
·
23 Posts
When I first turn the truck ignition on the gauge reads 7.4 after starting it continues to read 7.4 for a few seconds until it warms up and reads normal. When I let off the throttle the gauge goes to 22.4. The sensor and gauge set up were brand new when I put this motor in and I calibrated the sensor. Could I have screwed something up in the gage install? It seems to read 14.7 normally but after the new maf now gets leaner at wot, it went to an afr of 16 before I got off the gas yesterday. I am pretty much keeping the truck completely out of boost aside from testing. I will have to doubel check that I did not switch the signal wires but I assume that would be more obvious.
I have a wide band by PLX and I would have to set it up to read when it wasn’t installed in the pipe.then i could install it, it should read max lean with just key on, then read actual mixture when runing. Sounds to me you o2 wide band is ****ed
 

·
Registered
Joined
·
10 Posts
Discussion Starter · #17 ·
Progress has been real slow after the truck developed some weird electrical issues and would randomly lose all power. I'm hesitant to say the electrical problems are gone after I replaced the positive and negative cable ends, ground cable and switched to new terminal blocks on the battery but, I haven't had a problem since. Pushing my luck I took the truck to a wedding an hour away and all the sudden it started dropping the afr down to mid to low 13s coming up long steep hills (while truck was out of boost but under decent load). After seeing that I tried a pull in a lower gear and it did switch down into lower afr numbers, still higher than I would like but if its atleast switching to fuel enrichment mode a fpr and bigger pump should be able to get it safe. Now the weird part, after leaving the wedding the truck would not go back into fuel enrichment mode again. I received the fittings to install my fpr800 fpr and and hoping to have the new fuel pump in as well before the roads get covered in salt. Once I get the truck on the lift I am going to look at the wiring and see if I can find something that seems off.
 
1 - 17 of 17 Posts
Top