Do these numbers look right?

Bobby Fazio · 04-05-2014, 09:03 AM

Quote:

Originally Posted by buzzinhalfdozen

Bobby, if you can please try the test I described using a hand held vacuum pump as I'm quite certain the MAP input you're seeing at idle is the cause of your rich fuel mixture. Please try and see if the gage and your MAP reading on the laptop agree while applying vacuum to it...you can do that with the engine off. If they are off by a wide margin then there you go, if not then please post up the results of bringing the MAP to around 40ish with the engine running and see if your pulse width number decreases. Joe

I'm confused because a conversion table says says 86kpa is 12psi so why am I idling at -2 psi? Anyways my vacuum pump is inHg.. so now I have to convert that also.

buzzinhalfdozen · 04-07-2014, 11:27 AM

I'm afraid I can't help with the conversion however I do know that on a properly functioning engine (stock) I'll see between 35-40 KPA at idle. With the larger overlaps in the race cams that signal very diminished...which is what you're seeing. Looking at your 2 screen shots you can see when you rev it up the vacuum gets much better and the KPA number goes down, also your pulse width goes lower (less fuel) indicating to me that with the MAP reading it's providing @ idle the ECU "thinks the engine is being loaded, hence the increase in fuel. Have you checked to see what the MAP shows with the engine off? Also it looks like you have a display of vacuum on the screen, though I'm unsure of the exact scale they are using. Have you tried using the vacuum pump to decrease your MAP down to a lower number and see if it improves your fuel rate? Last question...when it was tuned by your tuner did it behave in this manner?

Dave Noll · 04-07-2014, 07:19 PM

The control panel of the software show's almost all the conversion you need. The dial to the left of the tach & above battery voltage show's vacuum in PSI. The small box below the voltage dial, third from the left, is vacuum in KPA. To convert PSI to inches of vacuum, multiply by 2. (-15 psi is 30" of vacuum, -2 psi is 4" of vacuum)

buzzinhalfdozen · 04-08-2014, 09:46 AM

Dave, good info, I've honestly never thought of the conversion as I've become accustomed to using only the KPA reading. BTW Bobby have you any news regarding your tune and the possibilty of blending the MAP and TPS in the lower cells?

Bobby Fazio · 04-08-2014, 10:59 AM

MAP sensor is fine. I emailed the saved tune to my tuner and he and I went through it over phone and said all looked well with no weird numbers. So I decided to do a third compression check and number 8 was a little iffy for the first time, why it wasn't before bothers me but I did this one cold before ever starting the car. Pulled the head off and the intake valve is bent. Hit the piston when the rocker had loosened up on that last pass. No real damage to the piston thankfully. So now I feel like a complete idiot and this is what I get for trying to do all this without the help of my dad because I want to learn this stuff on my own. I'm hoping that this caused the over-fueling by tricking the MAP sensor into thinking the engine was under load since number 8 wasn't firing correctly? If not then I still have another issue. I will find out when I get the head back and put it back together. Thanks for your help.

04-07-2014, 11:27 AM	#2
buzzinhalfdozen Senior Member Join Date: Sep 2006 Location: Bellevue Ohio Posts: 984 Likes: 0 Liked 11 Times in 8 Posts	Re: Do these numbers look right? I'm afraid I can't help with the conversion however I do know that on a properly functioning engine (stock) I'll see between 35-40 KPA at idle. With the larger overlaps in the race cams that signal very diminished...which is what you're seeing. Looking at your 2 screen shots you can see when you rev it up the vacuum gets much better and the KPA number goes down, also your pulse width goes lower (less fuel) indicating to me that with the MAP reading it's providing @ idle the ECU "thinks the engine is being loaded, hence the increase in fuel. Have you checked to see what the MAP shows with the engine off? Also it looks like you have a display of vacuum on the screen, though I'm unsure of the exact scale they are using. Have you tried using the vacuum pump to decrease your MAP down to a lower number and see if it improves your fuel rate? Last question...when it was tuned by your tuner did it behave in this manner? __________________ Joe Buchanan SS/BX 3117

04-07-2014, 07:19 PM	#3
Dave Noll Senior Member Join Date: Nov 2007 Location: Div. 6, Eastern, WA Posts: 710 Likes: 2,708 Liked 240 Times in 112 Posts	Re: Do these numbers look right? The control panel of the software show's almost all the conversion you need. The dial to the left of the tach & above battery voltage show's vacuum in PSI. The small box below the voltage dial, third from the left, is vacuum in KPA. To convert PSI to inches of vacuum, multiply by 2. (-15 psi is 30" of vacuum, -2 psi is 4" of vacuum) __________________ Dave Noll, EF/S ,?/SA 6526

04-08-2014, 09:46 AM	#4
buzzinhalfdozen Senior Member Join Date: Sep 2006 Location: Bellevue Ohio Posts: 984 Likes: 0 Liked 11 Times in 8 Posts	Re: Do these numbers look right? Dave, good info, I've honestly never thought of the conversion as I've become accustomed to using only the KPA reading. BTW Bobby have you any news regarding your tune and the possibilty of blending the MAP and TPS in the lower cells? __________________ Joe Buchanan SS/BX 3117

04-08-2014, 10:59 AM	#5
Bobby Fazio VIP Member Join Date: Nov 2009 Location: Egg Harbor Township, NJ Posts: 1,470 Likes: 1,457 Liked 4,379 Times in 502 Posts	Re: Do these numbers look right? MAP sensor is fine. I emailed the saved tune to my tuner and he and I went through it over phone and said all looked well with no weird numbers. So I decided to do a third compression check and number 8 was a little iffy for the first time, why it wasn't before bothers me but I did this one cold before ever starting the car. Pulled the head off and the intake valve is bent. Hit the piston when the rocker had loosened up on that last pass. No real damage to the piston thankfully. So now I feel like a complete idiot and this is what I get for trying to do all this without the help of my dad because I want to learn this stuff on my own. I'm hoping that this caused the over-fueling by tricking the MAP sensor into thinking the engine was under load since number 8 wasn't firing correctly? If not then I still have another issue. I will find out when I get the head back and put it back together. Thanks for your help. __________________ '65 Mustang SS/L & L/SA DriverInterviews.com \| App.DragInsights.com Last edited by Bobby Fazio; 04-08-2014 at 11:41 AM.