Weird Readings; Question for Bob Baliey, John Spina, Eric Marchall or anyone with insite!

[CGASTON]

This is a weird question that needs to addressing. PL file attached.


Was out driving the car last weekend and had a few things happen that are totally weird and a little confusing. Lets start with #4 listed below. The PL is showing that my injectors are almost or are maxed out. Here is what I am wondering about the duty cycle. At 94% duty cycle my injector pulse width is 19.91%. My car is an E85 car with 80lb injectors. I have my boost controller set to around 16-17lbs boost. My turbo\car is capable of making another 10-12 lbs boost and another 700-1000 rpms on my tune. If the injector pulse width is at 94% on 80lb injectors and E85, am I maxed out? Or is there a 20% increase on the duty cycle as the increase in the injectors as gas vs. E85? My thinking is that the injector harness is wiring is to small and not capable to provide enough voltage to injectors. I have ordered Carper’s high-output injector harness to see if this fixes the issue. What is everyone’s take on this?

Here is my second question. As you can see from the frames that I have listed below, there was no more than 1.5 degrees of knock. That is only 1% of the PL log showing knock; the other 99% there was no knock registered. But what I have an issue with is that in the frames listed below, my Casper’s LED knock detector and audible knock detector would spike. Now if you look at the log file, you will not see any of that. So can are the knock gauges correct or the PL in registering knock? I would like to say the PL is the correct reading. Something else that I am wondering is if that I am getting a voltage spike of a signal feedback through the ground of from my volt booster. I have the knock gauges powered of a mini fuse panel, sold by GNS performance. Now I have my main ground running to a junction box on my firewall that is feed by a 4 gauge wire from the block to the negative battery post. I am thinking that I am getting a voltage spike at WOT setting off the Casper knock gauges. I have Casper’s volt booster, which I am starting to think is the culprit.

1. 1. Frame# 12854 of 14904: From foot brake: 3737 RPM, 6.8# BOOST, 20.1 degree timing, A\F of 10.04, and 0 knock

2. 2. Frame# 12865 of 14904: At WOT: 5585 RPM, 17# BOOST, 20.2 degree timing, A\F 10.58, and 0 knock

F 3. Frame# 12889 of 14904: At WOT: 5649 rpm, 16.7# BOOST, 20.2degree timing, A\F 10.68, 0.5 knock, and injector duty cycle of 94%

4. 4,. Off throttle boost at frames# 12870, 12898, 12943: where I let of the gas do to break the tire loose.
5.
5. Knock Retard frame# 2257: The only noticeable knock. This is where I kick done from 4th to 3rd at WOT.

 

[Slow91z]

You're out of injector, I have a combo kinda similar to yours and at 25 psi I'm maxing 120's on e85, I'm going to upgrade my stock fuel line, but from what I have seen I still might need to upgrade injectors sooner rather than later.

 

[CGASTON]

You're out of injector, I have a combo kinda similar to yours and at 25 psi I'm maxing 120's on e85, I'm going to upgrade my stock fuel line, but from what I have seen I still might need to upgrade injectors sooner rather than later.

I really hope not and that it is power issue. But I am probably going to have to dish out the $800 bucks.

 

[Slow91z]

I know a guy with a stock motor and bolt on's (turbo, front mount, etc) that has 80's and runs e85...he is very close to maxing them a 25 Psi, and I can guarantee you his fuel system is good enough for 9's easy so there is no fuel delivery problem.

You are out of injector, sorry. Or switch fuels for a little while, or leave it as is don't turn it up.

Actually after reading your post again you could lean it out some like 10.8-11.0 and that will bring down your duty cycle slightly, might get you one pound of boost. You knock looks to me like it is probably false, with that tune on that fuel I find it difficult to think it really knocked unless there is a part of the puzzle I don't know about.

 

[CGASTON]

I know a guy with a stock motor and bolt on's (turbo, front mount, etc) that has 80's and runs e85...he is very close to maxing them a 25 Psi, and I can guarantee you his fuel system is good enough for 9's easy so there is no fuel delivery problem.

You are out of injector, sorry. Or switch fuels for a little while, or leave it as is don't turn it up.

Actually after reading your post again you could lean it out some like 10.8-11.0 and that will bring down your duty cycle slightly, might get you one pound of boost. You knock looks to me like it is probably false, with that tune on that fuel I find it difficult to think it really knocked unless there is a part of the puzzle I don't know about.

There is no knock via PL log, but according to the Casper's knock gauges I am getting knock. Which one to believe? I think that the PL would be the truth.

 

[Slow91z]

Knock gauge is unfiltered, can pick up other noises easier

 

[Chuck Leeper]

Insufficient volts to the injs. [I've tested inj voltage requirements. Got down to <10VDC, before the system would fail. And, that was due to low volts not starting the pump.] You likely don't have a low volt issue. Log batt volts and see.
Don't see a mention of fuel psi...You log it?

 

[BEATAV8]

Here's a bit of data for comparison. I run 120's on E85.
3900lbs+
132mph
5850RPM
Inj Duty 87.2% @ 5850
Boost 28psi
Fuel Pressure 72-74psi
Air/Fuel 11.0:1

 

[Slow91z]

Here's a bit of data for comparison. I run 120's on E85.
3900lbs+
132mph
5850RPM
Inj Duty 87.2% @ 5850
Boost 28psi
Fuel Pressure 72-74psi
Air/Fuel 11.0:1

That gives me hope, what do you have for a fuel system.

 

[jasjamz]

I really hope not and that it is power issue. But I am probably going to have to dish out the $800 bucks.

Hi! You are out of injector, all of you are LOL! Time to step up to the 160's and have some fun gentlemen. CGaston has more compression that us others so this is another reason he has ran out of injector at a lower boost level.

 

[jasjamz]

That gives me hope, what do you have for a fuel system.

Remember, TurboCliff went 10.11 on 120's. But, for some strange reason, I don't think you guys are going to stop at low 10's.

 

[BEATAV8]

But what I have an issue with is that in the frames listed below, my Casper’s LED knock detector and audible knock detector would spike. Now if you look at the log file, you will not see any of that. So can are the knock gauges correct or the PL in registering knock? I would like to say the PL is the correct reading. Something else that I am wondering is if that I am getting a voltage spike of a signal feedback through the ground of from my volt booster.

Around frame 12887 you have a lot of knock counts, that's what sets off the knock detector gauge. So it's likely both the casper gauge and the PL are working correctly.

The knock "system" is pretty neat the way it works, and in my experience it's pretty reliable too.
This is my crude understanding of how it functions, not completely accurate I am sure, so take it with a grain of salt.
The sensor has a piezo electric crystal in it which is tuned to get "excited" at frequencies consistent with engine knock. When the crystal is excited, the sensor completes the ground between the engine block and the sensor wire. This completed ground is what the casper's gauge is seeing too if I am not mistaken.
The sensor wire goes to the knock filter which is mounted on the passenger side fender. When the filter sees the completed knock sensor ground, it drops it's own voltage below 9 volts and this is what the ECM sees. Any time the knock filter voltage drops below 9 volts, the ECM recognizes it as a knock event. A single transition from above 9 to below 9 is a count. If it stays below 9V for a long enough period of time, the ECM will retard timing. (or something like that!) I think that's why you can get some knock counts without any knock retard. If the counts are far enough apart and the filter doesn't spend enough time below 9V then not much happens, you could call it tickling the knock sensor. Eric has some tech about the KR system posted on his TT site it's pretty interesting. Also some chips are programmed to ignore the counts completely for a period of time after WOT, or if below a threshold vehicle speed.

In a perfect world you will get no counts and no retard.

My most recent issue was due to valve springs. If you see KR showing up consistently at high RPM, when you know you should not be seeing anything because timing is low and fuel is rich... then it's probably valve springs.

 

[BEATAV8]

That gives me hope, what do you have for a fuel system.

It has two walbros and beefed up supply and return lines. No volt booster on it yet.
I want to switch to a pair of aeromotives for some more capability.
here's some pics
http://turbobuick.com/forums/threads/dual-feed-double-pumper.374968/

 

[Slow91z]

It has two walbros and beefed up supply and return lines. No volt booster on it yet.
I want to switch to a pair of aeromotives for some more capability.
here's some pics
http://turbobuick.com/forums/threads/dual-feed-double-pumper.374968/

Cool, I might be ok then.

 

[Slow91z]

Remember, TurboCliff went 10.11 on 120's. But, for some strange reason, I don't think you guys are going to stop at low 10's.

Actually that is about all I want, can't afford all the crap needed to run deep 9's bottom 10's has been my goal all along.

 

[jasjamz]

Actually that is about all I want, can't afford all the crap needed to run deep 9's bottom 10's has been my goal all along.

120's should do it then.

 

[BEATAV8]

120's should do it then.

X2

 

[Slow91z]

Nice to know, I'm going to run a -8 and try again, I was completely out of fuel before.

 

[CGASTON]

Around frame 12887 you have a lot of knock counts, that's what sets off the knock detector gauge. So it's likely both the casper gauge and the PL are working correctly.

The knock "system" is pretty neat the way it works, and in my experience it's pretty reliable too.
This is my crude understanding of how it functions, not completely accurate I am sure, so take it with a grain of salt.
The sensor has a piezo electric crystal in it which is tuned to get "excited" at frequencies consistent with engine knock. When the crystal is excited, the sensor completes the ground between the engine block and the sensor wire. This completed ground is what the casper's gauge is seeing too if I am not mistaken.
The sensor wire goes to the knock filter which is mounted on the passenger side fender. When the filter sees the completed knock sensor ground, it drops it's own voltage below 9 volts and this is what the ECM sees. Any time the knock filter voltage drops below 9 volts, the ECM recognizes it as a knock event. A single transition from above 9 to below 9 is a count. If it stays below 9V for a long enough period of time, the ECM will retard timing. (or something like that!) I think that's why you can get some knock counts without any knock retard. If the counts are far enough apart and the filter doesn't spend enough time below 9V then not much happens, you could call it tickling the knock sensor. Eric has some tech about the KR system posted on his TT site it's pretty interesting. Also some chips are programmed to ignore the counts completely for a period of time after WOT, or if below a threshold vehicle speed.

In a perfect world you will get no counts and no retard.

My most recent issue was due to valve springs. If you see KR showing up consistently at high RPM, when you know you should not be seeing anything because timing is low and fuel is rich... then it's probably valve springs.

When I look at the frame # 12887, the PL file shows no knock at all. At this area in frames, my tires were breaking loose and I was lettin of the gas.

I forgot to put in my problem a couple bits of key information. I am running Bob Bailey's Extender Extreme G chip and GEN II. The GEN II has timing set at 25* until 3000 rpm. At 3000 rpm, my timing is backed of to 20* all the way to 7000*. So I find it a little hard to believe that I am getting knock (I may be wrong) at 20* of timing.

Also I have the Gen II set up for A/F correction when the TPS hits 3000 rpm.

I will have to look into possible valve spring issue after all else fails. I don't think it is the springs here, but will check. If the springs were bad, I should notice floating, blow-by or lack of responsiveness.

 

[Eric Stage I]

The chip is designed to ignore knock when it's likely to be false knock. That's why it doesn't always retard the timing when your knock gauge goes off.

On the duty cycle. You only had 94% for a split second when your MAF had a spurious reading. The rest of the time you were averaging in the 75-80% area. No problem there. You were also running on the rich side (deep down in the 10's for a/f), so when you lean it out, you'll be even better on fuel.