Dyno and AF
Thread Starter
Burning Brakes
Joined: Jun 2012
Posts: 1,160
Likes: 13
From: póg mo thóin
St. Jude Donor '14-'15-'16-'17-'18-‘19
I believe in the Beer Fairy
Dyno and AF
So I brought my car to a local dyno tuner this afternoon for a couple of pulls. First time on the dyno. 2002 Coupe, Vararam, x-pipe and Corsa Indy exhaust. 328/353, not bad numbers but we noticed a couple of issues. AF ratio is really high at idle, and it shows what looks like as the knock sensor kicking in and retarding at about 4600 rpm. DIC is not showing any codes. Tuner suspected an air leak somewhere but could not find one. We pulled out and inspected the Vararam and cleaned the MAF. All looked good. He was unable to correct the AF with HPtuner. Tried everything, but could not change the AF. Please take a look at the chart and let me know your thoughts. I know little about tuning, so go easy.... ;^)
Thanks,
Mac
Thanks,
Mac
Last edited by MacNH; Apr 7, 2013 at 08:13 PM.
Racer
Joined: Oct 2001
Posts: 345
Likes: 8
From: Palatine Illinois
When he is tuning, he should be turning off the MAF anyway.
Its impossible to see what could be wrong without seeing hpt log files.
check plugs, wires, coils, grounds.
check fuel pressure
Are O2 sensors switching ok?
check vacuum at idle
stock injectors?
how much timing has been dialed in?
what kind of gas you using?
too many variables.
Its impossible to see what could be wrong without seeing hpt log files.
check plugs, wires, coils, grounds.
check fuel pressure
Are O2 sensors switching ok?
check vacuum at idle
stock injectors?
how much timing has been dialed in?
what kind of gas you using?
too many variables.
Thread Starter
Burning Brakes
Joined: Jun 2012
Posts: 1,160
Likes: 13
From: póg mo thóin
St. Jude Donor '14-'15-'16-'17-'18-‘19
I believe in the Beer Fairy
The tuner was concerned with the high A/F at idle and the drop in RWHP & RWTQ at about 4600 rpms. He could not affect either and stopped the tune and reloaded my stock tune. I don't think he was very experienced with LSx's, as his shop was full of SC'd Mustangs.
Thread Starter
Burning Brakes
Joined: Jun 2012
Posts: 1,160
Likes: 13
From: póg mo thóin
St. Jude Donor '14-'15-'16-'17-'18-‘19
I believe in the Beer Fairy
Melting Slicks
Joined: Jul 2006
Posts: 3,356
Likes: 1
From: Chesapeake Va
Ignore the wideband reading at idle. It's in closed loop and as long as the trims are fairly close that's all that matters. In all actuality, it's not lean or rich, it's stoich.
As for the knock retard, if you can't get it to go away, first thing to try is seafoaming the engine. If that doesn't work, just deaden the knock sensor sensitivity slightly.
As for the knock retard, if you can't get it to go away, first thing to try is seafoaming the engine. If that doesn't work, just deaden the knock sensor sensitivity slightly.
Supporting Vendor
Joined: Jan 2013
Posts: 407
Likes: 11
From: Mooresville North Carolina
Where are you located at? The fueling is not very good at all according to the dyno sheet. Look at the scaling. There are points where it looks 14:1 and 12:1. Also the dip in the middle almost certainly is knock retard. You may have some underlying issues but a good tuner should be able to fix it no problem. If your local to us in NC please come see us. We will be glad to help get the car back on track.
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Thread Starter
Burning Brakes
Joined: Jun 2012
Posts: 1,160
Likes: 13
From: póg mo thóin
St. Jude Donor '14-'15-'16-'17-'18-‘19
I believe in the Beer Fairy
Where are you located at? The fueling is not very good at all according to the dyno sheet. Look at the scaling. There are points where it looks 14:1 and 12:1. Also the dip in the middle almost certainly is knock retard. You may have some underlying issues but a good tuner should be able to fix it no problem. If your local to us in NC please come see us. We will be glad to help get the car back on track.
MacNH
Thread Starter
Burning Brakes
Joined: Jun 2012
Posts: 1,160
Likes: 13
From: póg mo thóin
St. Jude Donor '14-'15-'16-'17-'18-‘19
I believe in the Beer Fairy
Former Vendor
Joined: Jun 2002
Posts: 2,045
Likes: 3
From: Bridgewater Ma
As I said before. The tune should be pretty simple to correct. There are a few key spots to change with that intake on the car.When we are done there will be no knock and the A/F will be in check. Of course the numbers might be lower due to my Mustang dyno. LOL
Thread Starter
Burning Brakes
Joined: Jun 2012
Posts: 1,160
Likes: 13
From: póg mo thóin
St. Jude Donor '14-'15-'16-'17-'18-‘19
I believe in the Beer Fairy
MacNH
Safety Car
Joined: Jan 2012
Posts: 3,956
Likes: 520
From: Da U.P.
Pro
Joined: May 2011
Posts: 580
Likes: 1
From: Chicago Suburb
St. Jude Donor '13
Tuning protocols
When he is tuning, he should be turning off the MAF anyway.
Its impossible to see what could be wrong without seeing hpt log files.
check plugs, wires, coils, grounds.
check fuel pressure
Are O2 sensors switching ok?
check vacuum at idle
stock injectors?
how much timing has been dialed in?
what kind of gas you using?
too many variables.
Its impossible to see what could be wrong without seeing hpt log files.
check plugs, wires, coils, grounds.
check fuel pressure
Are O2 sensors switching ok?
check vacuum at idle
stock injectors?
how much timing has been dialed in?
what kind of gas you using?
too many variables.
Last edited by tacman; Apr 28, 2013 at 02:07 PM. Reason: Clarification
Former Vendor
Joined: Aug 2009
Posts: 1,184
Likes: 1
From: delware county pa
on a manual car you can adj fuel by playing with the maf. speed density turns the maf off, the maf measures airflow , everything needs to be tuned together in order to work together. you cant do one without the other.