Will Increasing Fuel Pressure Increase O2 Readings

[mmarlett]

Will increasing the fuel pressure per an adjustable fuel pressure regulator increase the O2 readings on my Scanmaster at WOT?

I have adjusted the TT chip to its upper parameter for fuel at 154 per my Scanmaster (43psi line off). However, the O2 reading under WOT is lower than what I like at 730-780. I have no knock, but I have also had to decrease the boost.

Therefore, with the TT chip maxed out on fuel parameter setting of 154, would the correct approach be to increase the fuel pressure (44-45psi) which will increase fuel supply, allowing for more boost and increased O2 readings at WOT?

Many Thanks,
Matt

 

[trbojo]

yes...increasing fp or injector pulse will increase your o2's, or lower your afr's (wideband) given the same boost level...

 

[mmarlett]

Thanks. It seemed logical, but though I would ask those smarter than me.

Matt

 

[Ttype6]

Will increasing the fuel pressure per an adjustable fuel pressure regulator increase the O2 readings on my Scanmaster at WOT?

I have adjusted the TT chip to its upper parameter for fuel at 154 per my Scanmaster (43psi line off). However, the O2 reading under WOT is lower than what I like at 730-780. I have no knock, but I have also had to decrease the boost.

Therefore, with the TT chip maxed out on fuel parameter setting of 154, would the correct approach be to increase the fuel pressure (44-45psi) which will increase fuel supply, allowing for more boost and increased O2 readings at WOT?

Many Thanks,
Matt

What is your boost and fuel pressure at WOT?

 

[mmarlett]

I have adjusted the boost down from 16psi to around 13psi. I was getting some knock, 1-2, at 16psi and O2s around 730-770; therefore lowered the boost.

At the lower boost, I have no knock, but also much less power.

I have not been able to check fuel pressure at WOT but know it is set around 43psi (line off) at idle.

Just wanted to make sure that the next step would be to increase fuel pressure per the fuel pressure regulator since the TT paramter for increasing fuel supply has been maxed out.

Thanks!

 

[trbojo]

might want to get a fp gauge on there and see if it's rising with boost....sounds like you're having to add a bit much fuel for that low boost #...

 

[trbojo]

I have adjusted the boost down from 16psi to around 13psi. I was getting some knock, 1-2, at 16psi and O2s around 730-770; therefore lowered the boost.

At the lower boost, I have no knock, but also much less power.

I have not been able to check fuel pressure at WOT but know it is set around 43psi (line off) at idle.

Just wanted to make sure that the next step would be to increase fuel pressure per the fuel pressure regulator since the TT paramter for increasing fuel supply has been maxed out.

Thanks!

make sure you reattached the vac/boost line!!!

 

[Ttype6]

I have adjusted the boost down from 16psi to around 13psi. I was getting some knock, 1-2, at 16psi and O2s around 730-770; therefore lowered the boost.

At the lower boost, I have no knock, but also much less power.

I have not been able to check fuel pressure at WOT but know it is set around 43psi (line off) at idle.

Just wanted to make sure that the next step would be to increase fuel pressure per the fuel pressure regulator since the TT paramter for increasing fuel supply has been maxed out.

Thanks!

The next step is to observe WOT fuel pressure. Unless you do this,you don't know what it is. If it's lower than 56 at 13 lbs of boost you'll need to find out why. If it's lower than 59 at 16 lbs of boost you'll also need to find out why. The next step is to observe WOT fuel pressure. If you're fuel supply system is currently not keeping up with the demands of the engine,it won't do any better raising your base fuel pressure.

 

[mmarlett]

Thanks!

I will hook-up my longer gauge and confirm that fuel pressure is rising lb for lb with boost at WOT.

Just finishing raising the fuel pressure at idle. Will check results during next drive.

Matt

 

[Jerryl]

What others said . . . . is the chip written for the current combo?

 

[jasjamz]

Stock injectors? If so, the may not flow like they should after all this time.

 

[mmarlett]

Thank for all the great advise.

I did replace the injectors and chip with a package from TT.

After reading so many stories on blown head gaskets, I wanted to be conservative. The main question I had was how to increase the O2's when the chip programing was at its maximum (154). From what I have read, raising the fuel pressure per the fuel pressure gauge will accomplish this. I will tune from there.

I will proceed with all your advise.

Thanks!
Matt

 

[Ttype6]

From what I have read, raising the fuel pressure per the fuel pressure gauge will accomplish this.

If you're hell bent on doing this,why are you asking advise? You say you have a fuel pressure gauge. Put it on. Drive the car and take note of WOT pressure. Your max chip fuel adjustment should make you very rich. Something is wrong. Again,the next step is to verify WOT fuel pressure.

 

[jasjamz]

Thank for all the great advise.

I did replace the injectors and chip with a package from TT.

After reading so many stories on blown head gaskets, I wanted to be conservative. The main question I had was how to increase the O2's when the chip programing was at its maximum (154). From what I have read, raising the fuel pressure per the fuel pressure gauge will accomplish this. I will tune from there.

I will proceed with all your advise.

Thanks!
Matt

Matt, Turbo Tweak instructions say set the fp line off to 43. Some like 45 psi. But you should not need to add 20% more fuel at WOT. Busted line in the tank is common. Let us know if the fuel pressure isn't risisng 1:1

 

[Ttype6]

If you're trying to avoid work,you could first try re-setting the chip back to default by disconnecting the orange wire at the battery then re-install previous adjustments and allow at least 10 seconds after each adjustment before proceeding to the next. Drive the car and take note of the O2s. If they don't richen up significantly,you'll have to hook up that gauge.

 

[trbojo]

what exactly is it you're trying to do? adding too much fuel to be conservative isn't going to help anything, and may actually cause a problem....if you ordered a injector/chip combo from tt, set everything, including your boost to what Eric burnt it for...if you're not getting any knock retard, then everything's good..if you're just getting it 1st/2nd, could/probably false....roll in it in 3rd then look at your readings.

 

[trbojo]

and you're better off getting a wideband for tuning....i've seen a whole lot of fuel one way or the other not make much difference in single wire o2's....

 

[NorEaster]

I bought a chip injector combo from eric....brand new pump, wiring and afpr. Im doing the same thing. Chip is maxed so I added base fp....its up to 45 and seems to run great. I have also double checked fp rising 1:1 with boost. O2s are right around 800

 

[Ttype6]

I bought a chip injector combo from eric....brand new pump, wiring and afpr. Im doing the same thing. Chip is maxed so I added base fp....its up to 45 and seems to run great. I have also double checked fp rising 1:1 with boost. O2s are right around 800

What turbo? what Boost? What WOT fuel pressure?

 

[NorEaster]

What turbo? what Boost? What WOT fuel pressure?

Stock turbo (billet bell that is ported) 15-16 psi boost so 60-61 psi WOT fp.

I just assumed the chip was lean.

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