Inconsistency

Dave Noll · 07-16-2014, 12:14 AM

Targus, In the submit reply window, top row, there is a paper clip next to a smiley. Right click that & a window opens with a button to browse your computer for the files you want to upload & in the lower right of that frame an upload button. That said, I have never been able to upload a .pdf, only a .jpg or .bmp. Can you save the file differently ?

1320, how bout we help with his upload issue 1ST.

targus · 07-16-2014, 02:46 PM

Attached are RPM graphs with the red line showing a "good" pass and the black line showing a "bad" pass where is slows .2

Dave Noll · 07-16-2014, 10:22 PM

I haven't had the privilege of reading many of these graph's but with the black line rough, does the engine have an intermittent miss ?

targus · 07-17-2014, 02:34 PM

There is not a noticeable miss. With the lower stall of the converter you can feel that it is on a lazy pass. The up and down movement in the black line equals about 100 RPM.

Dave Noll · 07-19-2014, 05:18 PM

With only RPM to read it's hard to telling. I would say more input is needed. I would expect a convertor problem to swing that graph wider.

targus · 07-29-2014, 01:45 PM

Is there anything in the fuel system that you believe could be causing this? The fuel pressure seems to remain consistent throughout the run but the gauge is hard to read accurately with so much vibration. Fuel pressure definitely doesn't move more than a half of pound or so. We are getting desperate for answers.

Dave Noll · 07-30-2014, 02:00 AM

Well, I'll go this route.
.
First I would want weather station input to see if it's changing & then how much. Then see how it follows how the car is running. Next, besides an RPM sensor I would want an output shaft sensor. With these you could see if there was a traction or transmission problem. Next I would want either a pyrometer or O2 sensor. With these you can see where your fuel metering is @ & if it fell over the edge on the bad run.

Without the sensors,

There are many things that can go wrong inside a carb. Do you have a known good piece that you can swap onto the car ?

Dick Butler · 10-13-2014, 07:59 PM

Convertor is good test.

Wilson1 · 03-20-2015, 12:38 PM

Do you have a trans temp gauge? Sounds to me like your trans might be getting a bit too hot in the later rounds. I use to have that issue but since I have been putting a small carpet drying fan on my trans between rounds, that has gone away. I try to leave the line at 160 to 180 trans temp. It is usually 200 to 220 when I get back to the pits. I believe this helps with reaction time consistency also. Just my humble opinion based on trying a few different things.

67champ · 03-23-2015, 09:36 PM

On your "bad runs", how much is the 60 ft off??

07-16-2014, 12:14 AM	#1
Dave Noll Senior Member Join Date: Nov 2007 Location: Div. 6, Eastern, WA Posts: 710 Likes: 2,671 Liked 240 Times in 112 Posts	Re: Inconsistency Targus, In the submit reply window, top row, there is a paper clip next to a smiley. Right click that & a window opens with a button to browse your computer for the files you want to upload & in the lower right of that frame an upload button. That said, I have never been able to upload a .pdf, only a .jpg or .bmp. Can you save the file differently ? 1320, how bout we help with his upload issue 1ST. __________________ Dave Noll, EF/S ,?/SA 6526

07-16-2014, 02:46 PM	#2
targus Junior Member Join Date: Jul 2014 Posts: 8 Likes: 0 Liked 0 Times in 0 Posts	Re: Inconsistency Attached are RPM graphs with the red line showing a "good" pass and the black line showing a "bad" pass where is slows .2 Attached Thumbnails

07-16-2014, 10:22 PM	#3
Dave Noll Senior Member Join Date: Nov 2007 Location: Div. 6, Eastern, WA Posts: 710 Likes: 2,671 Liked 240 Times in 112 Posts	Re: Inconsistency I haven't had the privilege of reading many of these graph's but with the black line rough, does the engine have an intermittent miss ? __________________ Dave Noll, EF/S ,?/SA 6526

07-17-2014, 02:34 PM	#4
targus Junior Member Join Date: Jul 2014 Posts: 8 Likes: 0 Liked 0 Times in 0 Posts	Re: Inconsistency There is not a noticeable miss. With the lower stall of the converter you can feel that it is on a lazy pass. The up and down movement in the black line equals about 100 RPM.

07-19-2014, 05:18 PM	#5
Dave Noll Senior Member Join Date: Nov 2007 Location: Div. 6, Eastern, WA Posts: 710 Likes: 2,671 Liked 240 Times in 112 Posts	Re: Inconsistency With only RPM to read it's hard to telling. I would say more input is needed. I would expect a convertor problem to swing that graph wider. __________________ Dave Noll, EF/S ,?/SA 6526

07-29-2014, 01:45 PM	#6
targus Junior Member Join Date: Jul 2014 Posts: 8 Likes: 0 Liked 0 Times in 0 Posts	Re: Inconsistency Is there anything in the fuel system that you believe could be causing this? The fuel pressure seems to remain consistent throughout the run but the gauge is hard to read accurately with so much vibration. Fuel pressure definitely doesn't move more than a half of pound or so. We are getting desperate for answers.

07-30-2014, 02:00 AM	#7
Dave Noll Senior Member Join Date: Nov 2007 Location: Div. 6, Eastern, WA Posts: 710 Likes: 2,671 Liked 240 Times in 112 Posts	Re: Inconsistency Well, I'll go this route. . First I would want weather station input to see if it's changing & then how much. Then see how it follows how the car is running. Next, besides an RPM sensor I would want an output shaft sensor. With these you could see if there was a traction or transmission problem. Next I would want either a pyrometer or O2 sensor. With these you can see where your fuel metering is @ & if it fell over the edge on the bad run. Without the sensors, There are many things that can go wrong inside a carb. Do you have a known good piece that you can swap onto the car ? __________________ Dave Noll, EF/S ,?/SA 6526

10-13-2014, 07:59 PM	#8
Dick Butler VIP Member Join Date: Oct 2002 Location: Richmond Indiana Posts: 1,196 Likes: 5 Liked 32 Times in 19 Posts	Re: Inconsistency Convertor is good test.

03-20-2015, 12:38 PM	#9
Wilson1 Junior Member Join Date: Sep 2014 Posts: 17 Likes: 0 Liked 0 Times in 0 Posts	Re: Inconsistency Do you have a trans temp gauge? Sounds to me like your trans might be getting a bit too hot in the later rounds. I use to have that issue but since I have been putting a small carpet drying fan on my trans between rounds, that has gone away. I try to leave the line at 160 to 180 trans temp. It is usually 200 to 220 when I get back to the pits. I believe this helps with reaction time consistency also. Just my humble opinion based on trying a few different things.

03-23-2015, 09:36 PM	#10
67champ Junior Member Join Date: Feb 2002 Location: Ohio Posts: 48 Likes: 7 Liked 4 Times in 2 Posts	Re: Inconsistency On your "bad runs", how much is the 60 ft off??