Overcoming 2LTE fuel cut limit (2 Viewers)

[GTSSportCoupe]

Thanks Nick,

Out of interest do you know if the current location would alter the gauge much post filter (as it stands without the bleed off). Im away from the truck today so cant test it, but my max reading is currently 12psi with the T in that location, would this actually be higher at the manifold and ive been reading the boost wrong till now? im still going to add the bleed off and move this now, but would be interesting if this would have been putting my numbers off the last few months or not.

No, I don't think it would. Might just delay the boost reading a little bit is all.

 

[Lenny33]

I have been tuning back and forth between my boost controller (after turbo) and my fuel cut (as referenced in this thread) and boost now tops out at 16 psi. The curiosity to me is that I have slowly tightened down the fuel cut bleed valve so that it is all the way tightened (which should let the MAP sensor see all boost and not bleed any boost off), yet I get no fuel shut off from the engine. Since the MAP should cut off fuel if it sees sustained 16 psi of boost, should I assume that my MAP sensor needs replacing?

 

[Jarrat]

I have been tuning back and forth between my boost controller (after turbo) and my fuel cut (as referenced in this thread) and boost now tops out at 16 psi. The curiosity to me is that I have slowly tightened down the fuel cut bleed valve so that it is all the way tightened (which should let the MAP sensor see all boost and not bleed any boost off), yet I get no fuel shut off from the engine. Since the MAP should cut off fuel if it sees sustained 16 psi of boost, should I assume that my MAP sensor needs replacing?

Try disconnecting the air bleed off first, as I found with the screw is all the way down (tight) it still bleeds off air.

 

[Jarrat]

I had a weird thing happen the other day while drivin. I'm about to get on the freeway and my boost spiked up waaay past 20 psi and my truck had an insane amount of power for about 1 full second until I let off the gas. Then I pressed the pedal down again and it went way past 20psi again with lots of power, almost like the waste gate had seized shut. I feathered the throttle to get the truck to drive normally until I was on the freeway then the truck started to run normal again and hasn't done it since. Any ideas guys what happened?

 

[Lenny33]

Try disconnecting the air bleed off first, as I found with the screw is all the way down (tight) it still bleeds off air.

i haven’t thought to test that....
So you are saying that even with it all the way tightened down, I might still be bleeding off some boost? Interesting..... thanks.

 

[GTSSportCoupe]

I had a weird thing happen the other day while drivin. I'm about to get on the freeway and my boost spiked up waaay past 20 psi and my truck had an insane amount of power for about 1 full second until I let off the gas. Then I pressed the pedal down again and it went way past 20psi again with lots of power, almost like the waste gate had seized shut. I feathered the throttle to get the truck to drive normally until I was on the freeway then the truck started to run normal again and hasn't done it since. Any ideas guys what happened?

I think you're too close to run-away on the spill valve. Turn it back out an 1/8th turn or so. Although maybe you're onto something there... 2LTE TURBO MODE!!!!!!

 

[Jarrat]

I haven't adjusted it for almost 3000kms, and this happened once and hasn't happend again and I've driven 500kms since.... I've also had the spill valve adjusted 1/4 more then it is now and it drove fine then also....

 

[GTSSportCoupe]

I haven't adjusted it for almost 3000kms, and this happened once and hasn't happend again and I've driven 500kms since.... I've also had the spill valve adjusted 1/4 more then it is now and it drove fine then also....

Well, I must say I have no other ideas. But if you could make that happen on demand, I'd be interested to know how!

 

[LeonLJ78]

could it just be a case of the boost tap failing and creating a boost spike? is it a cheaper tap?

 

[GTSSportCoupe]

could it just be a case of the boost tap failing and creating a boost spike? is it a cheaper tap?

But it would make the computer think the boost is too high, in which case it would cut the fuel?

No matter what I've done on my motor I've never been able to get enough fuel for more than 20psi.... (it takes lots of fuel to spin the turbo that fast).

 

[LeonLJ78]

edit- stupid question resolved.

 

[LeonLJ78]

Also with fuel up just over half a turn and the bleed off in I’m getting 13-14 psi (was 12 before) will turning the bleed off in increase boost further by altering what the map sensor reads? Or better to just play with the boost tap?

 

[GTSSportCoupe]

Hey all. I discovered the easiest way on earth to tune these bleed valves properly. Not sure why I didn't do this earlier. Just measure the MAP sensor voltage while you're driving at maximum boost (may need a helper). You need to tune the air bleed valve so that you get 4.0V maximum out of the sensor. This equates to 10psi as seen by the sensor. 10psi is where the computer will deliver the maximum fuel map. Any more, and the computer starts to reduce fuel.

So, you need to tap into the boost sensor wires to do this. Either run a wire from the engine bay, or find it at the ECU. In the LJ78 its the Yellow-Blue stripe wire. It runs to the PIM input of the ECU which is pin 5 of connector A. Measure with reference to ground.

This is a much easier way to tune than the seat of the pants method.

 

[Jarrat]

Sweet... Im doing that tonight!!

 

[Lenny33]

Hey all. I discovered the easiest way on earth to tune these bleed valves properly. Not sure why I didn't do this earlier. Just measure the MAP sensor voltage while you're driving at maximum boost (may need a helper). You need to tune the air bleed valve so that you get 4.0V maximum out of the sensor. This equates to 10psi as seen by the sensor. 10psi is where the computer will deliver the maximum fuel map. Any more, and the computer starts to reduce fuel.

So, you need to tap into the boost sensor wires to do this. Either run a wire from the engine bay, or find it at the ECU. In the LJ78 its the Yellow-Blue stripe wire. It runs to the PIM input of the ECU which is pin 5 of connector A. Measure with reference to ground.

This is a much easier way to tune than the seat of the pants method.

Still doing good work for the “community” I see! Seeing old threads pop up make me miss my Prado...

 

[GTSSportCoupe]

Sweet... Im doing that tonight!!

How'd it go @Jarrat ?

When I figured this out, I'd done a couple hours of 'seat of the pants' tuning already. Funny enough I was actually bang on 4.0v max. But this will make it so much easier next time. Seems every time I do any significant work on the motor it throws out the tune. Now I have an easy way to get it back.

 

[Jarrat]

Still haven't done it yet... been spending my free time on my little honda crx so I can drive that next week.. soon as Ive got it Ill let you know!!

 

[Mountainwolf509]

Also with fuel up just over half a turn and the bleed off in I’m getting 13-14 psi (was 12 before) will turning the bleed off in increase boost further by altering what the map sensor reads? Or better to just play with the boost tap?

Gday from Australia.
What will my car do if I fit manual bleed valve on map sensor and wind waste gate to higher setting will it hit 20psi plus ? Currently on 12 psi with big front mount intercooler 3inch turbo exhaust and trust atf cooler for supporting mods. Will I see and gains above 12psi? Cheers Joseph

 

[GTSSportCoupe]

Gday from Australia.
What will my car do if I fit manual bleed valve on map sensor and wind waste gate to higher setting will it hit 20psi plus ? Currently on 12 psi with big front mount intercooler 3inch turbo exhaust and trust atf cooler for supporting mods. Will I see and gains above 12psi? Cheers Joseph

It depends what engine you have. 2LTE? 1KZTE?

The 2LTE only has a 10mm injection pump, so your limit is how much fuel the pump can supply. I've found around 18psi is the maximum I can really get with the factory turbo. My water/meth system will give me up to 20psi.

The 1KZTE has a 12mm injection pump. It can supply as much fuel as a 1KZ can take. I think you can get around 25psi, but you might be beyond the limits of the turbo at that point - or at least it won't last long.

Yes, you'll need some sort of fuel cut protection to do this. The bleed valve works well on the 2LTE anyhow; I have not tried it on a 1KZTE personally. Compared to a traditional fuel cut device, the advantage of the bleed valve is it preserves the shape of the boost compensation curve. Most fuel cut clamp devices just clamp the curve, so it goes flat and you don't get more fuel as the boost continues to rise.

 

[Mountainwolf509]

It depends what engine you have. 2LTE? 1KZTE?

The 2LTE only has a 10mm injection pump, so your limit is how much fuel the pump can supply. I've found around 18psi is the maximum I can really get with the factory turbo. My water/meth system will give me up to 20psi.

The 1KZTE has a 12mm injection pump. It can supply as much fuel as a 1KZ can take. I think you can get around 25psi, but you might be beyond the limits of the turbo at that point - or at least it won't last long.

Yes, you'll need some sort of fuel cut protection to do this. The bleed valve works well on the 2LTE anyhow; I have not tried it on a 1KZTE personally. Compared to a traditional fuel cut device, the advantage of the bleed valve is it preserves the shape of the boost compensation curve. Most fuel cut clamp devices just clamp the curve, so it goes flat and you don't get more fuel as the boost continues to rise.

Thankyou for reply yes we hit 18psi today no engine light. 2lte auto mate. I used boost controller inline of map sensor now I want to up fuel should I revert The fuel resistor back to stock or try a different one to make it richer.
cheers Joseph