gettin faster but something's up?

[dentmasters01]

Ok, first the car. 109 block (thanks jack). 70 gtq, 85 lbers and a XFI sys.
Car weighs 3830 with me in it.

Two weeks prior to taking the car to Reynolds, it ran great. No problems.

I made three changes to the car before going to Reynolds. I mounted my wide band O2 on the DP from the stock location and drilled and tapped my upper plenum for the temp. sensor. Precision large front mount.

Every run the car was missing and the last run it pulled 2 deg. before half track recovered and pulled another 10 deg. at the 8 sec. mark. It netted a 6.72 at 106 and 10.55 at 122 on et streets spinning with a 1.63 60'.

I had a a/f TARGET of 11.2 and the ACTUAL a/f from the gate was 9.1 and never got above 11.1 until half track. It stayed in the low to mid 10 mostly. It was taking out 7-8 percent fuel until half track.

At half track it fluctuated from 11.1 to 11.6 but stayed around 11.3-4 most of the second half of the track. Keep in mind it's missing from the gate all the way through the traps. Egt's were in the 1200's.

This is what I don't get. I let out of it several times during the previous runs thinking its detinating but fast reads its fat and taking out fuel. Then on the last run it pulls all that timing and retards 10 deg. but goes from taking out 7 percent to adding only 2 with the targeted a/f???

I have tested the coil and wires as several people told me to do with the simulator sold by caspers. The module, coil and wires seem to be fine if I'm reading this ign. simulator right.

The front four plugs were dark and a couple were actually wet and 5 and 6 were a good clean burn. Kind of light grey. This is the main problem. Why the difference, along with the fast readings, in the plugs. Were the two that are light grey really lean under a wot situation? Ign. checks ok? Maybe injectors?

Also, my inlet temp. started out at 98 and by the end of the run the plenum air temps were at 152.6. Just put on the big precision front mount. I don't have any data from the previous front mount to compare it to, but just wondered if this is normal?


I'm at a loss because it ran so good, I made the 3 changes, the ignition sys. seems ok, but now it'seems to be missing under a hard pull.
any ideas??

 

[dentmasters01]

Any of you FAST guys had any problems when you moved the sensors like this?? Any other electrical checks I need to make?? Can I test the W/B 02 to see if its good??

 

[GS70350]

Two weeks prior to taking the car to Reynolds, it ran great. No problems.

I made three changes to the car before going to Reynolds. I mounted my wide band O2 on the DP from the stock location and drilled and tapped my upper plenum for the temp. sensor. Precision large front mount.

This is what I don't get. I let out of it several times during the previous runs thinking its detinating but fast reads its fat and taking out fuel. Then on the last run it pulls all that timing and retards 10 deg. but goes from taking out 7 percent to adding only 2 with the targeted a/f???

I have tested the coil and wires as several people told me to do with the simulator sold by caspers. The module, coil and wires seem to be fine if I'm reading this ign. simulator right.

The front four plugs were dark and a couple were actually wet and 5 and 6 were a good clean burn. Kind of light grey. This is the main problem. Why the difference, along with the fast readings, in the plugs. Were the two that are light grey really lean under a wot situation? Ign. checks ok? Maybe injectors?

Also, my inlet temp. started out at 98 and by the end of the run the plenum air temps were at 152.6. Just put on the big precision front mount. I don't have any data from the previous front mount to compare it to, but just wondered if this is normal?

If you had mounted the WB in the up pipe before the turbo (stock location), it may have been hurt by the high EGTs. They are sensititive to high temps, and the location you have placed it now is much more suitable for a WB and will return more accurate 02 readings.

On the spark plug readings. Do you use a power plate from RJC? What you describe is typical of those engines not running one, as the back two cylinders get more airflow than the front thanks to a flaw in the intake/plenum design. You will be limited by these two cylinders when they detonate, yet your other 4 will still be rich. Get a powerplate and try it again if you dont have one.

On the computer pulling timing, You can also see detonation as a result of being too rich. If the computer was pulling close to 10% fuel, it just may have been rich enough to cause detonation in some of those front 4 cylinders that would explain the timing adjustment by the computer.

I say get a power plate, verify your WB 02 is in good working condition, and go try it again. Its going to need a little tuning is all.

 

[LV GN]

i think your too rich. had the same thing happen in noble a few weeks ago. take some number out of the VE table. our car kept getting faster as i did this. and the top end miss went away.

 

[Louie L.]

Did you check the grounds I suggested?? Just wondering..

 

[Razor]

First thing to do is bring the boost down and get the car dialed in 100%. your AF may vary a little.. but not be that fat.. if it is, then you need to pull fuel out until your corrections are minimal.

So.. put the car at 15 PSI and get it to run 11.0-11.3 all the way down the track...

Once you get this figured.. then start upping the boost. If you cannot get it to run properly at 15 PSI..no reason to go any higher.

No majic..

 

[VadersV6]

On the spark plug readings. Do you use a power plate from RJC? What you describe is typical of those engines not running one, as the back two cylinders get more airflow than the front thanks to a flaw in the intake/plenum design. You will be limited by these two cylinders when they detonate, yet your other 4 will still be rich. Get a powerplate and try it again if you dont have one.

.

Misfires that go undetected can cause a false rich condition, and then can pull fuel and cause detonation and KR. I would look into ignition or an A/F thats causing intermittent misfires. Eddy Hill did run that first 4 second pass on 7 cylinders. Most people dont know about that.
Also, where are you reading the plugs? You're not supposed to use the color of the porcelain as a detector of A/F. Only look at the porcelain for detonation. The flat ring that the ground electrode is welded to is where you look to get a true idea of A/F.
As far as the power plate and stock plenums go, all 6 plugs look EXACTLY the same on my car. I dont have a power plate, but I do have a 1/2" phenolic spacer under the lid. People say those are worthless, but I could see it evening the air flow out a bit.

 

[dentmasters01]

Ok guys, thanks for all the input. I did check the grounds and I do have the spacer plate. I was reading the plugs on the flat ring at the end of the threads. The wierd thing was, even though it was taking out fuel at the track, I could make the adjustments on the ve table but it would still take out more fuel on the next run.

Yesterday I went down to the local parts store and took my casper simulator with me. I plopped it up on the counter and tested a brand new coil along side of the coil that was on my car. You could visually tell NO difference on the simulator. If I, however, checked with my ohm meter, the old coil tested at 10.3 accross the board and the new one at 12.3 and 12.7 on two. I put the new one on the car. I put in a colder plug (23's) and also put on the caspers volt booster. I, with the suggestion of cotton, bought a new temp sensor and just left the old one in the plenum and plugged the new one in and laid it in the engine bay like it was before. The car runs great now. I started off at 13 lbs and just did a couple of rolling wot blast. Checked the log, made some adjustments and eventually ended up at 21 lbs with no misses. Its still fat and taking out some fuel but no missing anymore. I also took my fuel pressure down from 45 to 41. I honestly don't know what caused it. Could have been the hotter plugs? or the coil? the fuel pressure? or even the temp sensor. I am going to plug in the other temp sensor in the plenum and see if it reoccurs. If not I am going to put the other coil back on and see if it's there. The coil readings seemed wierd. I will try and find out what it was but I may never know. I do know I'm ready to get back to the track and see what its capable of !! I appreciate everyones input.

Oh yea, the voltage booster by caspers is freakin awesome !! At wot my lights get so bright, all my instrument gages get super bright. This thing really turbo charges the electrical system. Everyone should get one in my book.

 

[V6RACER]

Ok guys, thanks for all the input. I did check the grounds and I do have the spacer plate. I was reading the plugs on the flat ring at the end of the threads. The wierd thing was, even though it was taking out fuel at the track, I could make the adjustments on the ve table but it would still take out more fuel on the next run.

Yesterday I went down to the local parts store and took my casper simulator with me. I plopped it up on the counter and tested a brand new coil along side of the coil that was on my car. You could visually tell NO difference on the simulator. If I, however, checked with my ohm meter, the old coil tested at 10.3 accross the board and the new one at 12.3 and 12.7 on two. I put the new one on the car. I put in a colder plug (23's) and also put on the caspers volt booster. I, with the suggestion of cotton, bought a new temp sensor and just left the old one in the plenum and plugged the new one in and laid it in the engine bay like it was before. The car runs great now. I started off at 13 lbs and just did a couple of rolling wot blast. Checked the log, made some adjustments and eventually ended up at 21 lbs with no misses. Its still fat and taking out some fuel but no missing anymore. I also took my fuel pressure down from 45 to 41. I honestly don't know what caused it. Could have been the hotter plugs? or the coil? the fuel pressure? or even the temp sensor. I am going to plug in the other temp sensor in the plenum and see if it reoccurs. If not I am going to put the other coil back on and see if it's there. The coil readings seemed wierd. I will try and find out what it was but I may never know. I do know I'm ready to get back to the track and see what its capable of !! I appreciate everyones input.

Oh yea, the voltage booster by caspers is freakin awesome !! At wot my lights get so bright, all my instrument gages get super bright. This thing really turbo charges the electrical system. Everyone should get one in my book.

Do you have GN1s? If so you got the wrong plugs.. If you have your limit on your positive and negative O2 correction set at 10% then it may take a few passes to get the VE numbers down to the right range. If you set the O2 correction higher you may see that you need more fuel out.. Remember the ECU is trying to match your AFR value and if you limit it to 10% then it can't hit the number.. Not a bad thing, but it will take you longer to tune it.

 

[dentmasters01]

I don't have the gn1's. All I have is a set of ported irons. Thanks for all your input.

 

[Razor]

Its still fat and taking out some fuel but no missing anymore.

Drop fuel in your VE tables until its on target with minimal correction... then work on cranking the boost up. And see what responds better timing and target AF wise.

Like I said.. get it running 110% at low boost levels then crank it up.

There are other AE parameters that can affect your AF ratio..

HTH