LOST 10mph AND ABOUT 6 TENTHS - Page 5

Adger Smith · 12-06-2020, 04:50 PM

I forgot about the water pump. My V-6 is a Cam trigger and the magnetic pickup is on top, behind the water pump. I had a pump start leaking as we were loading the car. When we got to Ennis we made one run with a towel taped to the pump. It was leaking too bad so I took the Cheaper brand pump I carried as a spare and put it on. The car popped and missed at high RPM. We looked at plugs and ignition and all the electrical. We had one more shot of qualifying left and as I was doing my burn out the car popped on the chip... It hit me that the pump was what we changed and the problems cropped up. As I staged I turned the pump off. Good run, no 9000 RPM miss. Got back to the trailer and took the other pump apart and robbed the seal out of the electrical gremlin pump. Finished the race with no pump or miss problems. I figure that pump motor was a small radio station tuned to my ignition frequency. It wasn't playing any tunes my ignition liked...It seems like the simplest fixes can be the hardest!

Lee Valentine · 12-06-2020, 05:16 PM

Quote:

Originally Posted by Adger Smith

I forgot about the water pump. My V-6 is a Cam trigger and the magnetic pickup is on top, behind the water pump. I had a pump start leaking as we were loading the car. When we got to Ennis we made one run with a towel taped to the pump. It was leaking too bad so I took the Cheaper brand pump I carried as a spare and put it on. The car popped and missed at high RPM. We looked at plugs and ignition and all the electrical. We had one more shot of qualifying left and as I was doing my burn out the car popped on the chip... It hit me that the pump was what we changed and the problems cropped up. As I staged I turned the pump off. Good run, no 9000 RPM miss. Got back to the trailer and took the other pump apart and robbed the seal out of the electrical gremlin pump. Finished the race with no pump or miss problems. I figure that pump motor was a small radio station tuned to my ignition frequency. It wasn't playing any tunes my ignition liked...It seems like the simplest fixes can be the hardest!

we had a bad ground on electric water pump slow us down one time.

Robin Lawrence · 12-06-2020, 05:25 PM

You stated earlier that you changed the ignition box and it picked up on one run. Then it returned to the loss of mph and ET.

What box are you running?

Robin

Bill Marshall · 12-06-2020, 07:15 PM

Quote:

Originally Posted by Robin Lawrence

You stated earlier that you changed the ignition box and it picked up on one run. Then it returned to the loss of mph and ET.

What box are you running?

Robin

The car has a MSD 7AL-2

HP HUNTER · 12-06-2020, 07:19 PM

Quote:

Originally Posted by monte8616

What else do you know about the magnetized thing? Very interesting...

Make sure the dist pickup wire is away from the other wires, I use a shielded pick up wire.

Bill Bogues · 12-06-2020, 08:33 PM

our car slowed down over a couple of races. Turns out it was the rubber brake line to the rearend swapped out line at track and picked up instant 5 tenths.

4543 · 12-06-2020, 10:03 PM

Can you post a net slip from both a fast and slow run? Can you post the race pack info from a good run with a bad one overlaid on it? What sensors do you have on the trace pack? Other thing would be send the race pack files from a good run and a slow one to someone you know who has been using a race pack for a while. Might pick up something.

MEXJOE · 12-06-2020, 10:44 PM

I would look at the rear brake hose. I have seen more than one collapse internally and hold the rear brakes on.

Steve Hurley · 12-07-2020, 07:28 AM

We had a power surge from the alternator, lost et chased our tail, replaced ignition box. First pass was good, and down hill from there. Replaced box again. One more good pass and then fell off again .5 to .6 . In our case it was the alternator.

Henrys Toy · 12-07-2020, 10:00 AM

Quote:

Originally Posted by Bill Marshall

If the engine ran good on the dyno , then what parts are different between the car and the dyno ? Usually the dyno has it's own ignition box and it's own fuel system . Maybe check these two systems out to start with .

We took the coil and ignition box out of the car and ran it on the Dyno made good power[/QUOTE]

Over the course of time the two things that would kill my car was a bad MSD box or a broken converter!
I had a Sprague break in my old Trans Torque converter , that I sent to Mike Munsinger at the time and he said the converter was good - put it in the car - still slow.
I finally sent the converter to Coan , they found a broken sprague , fixed it
Result - car fast again! These bloody things will really make you chase your tail.
Try a converter from a friend ,hopefully a known good piece, I think you might just find the "cure". Bill you might remember my MSD problem from Lebanon Valley a few years back, my car was slow and you said it didn't leave like it used to. We changed a bunch of stuff ( including the converter ) then last time shot on Saturday morning Glenn and I put spare MSD and coil , Result - car fast again. Engine never missed or did anything outwardly stupid just not fast.
I hope this helps, we have all been down this path!

12-06-2020, 04:50 PM	#41
Adger Smith VIP Member Join Date: Dec 2001 Location: Texarkana Ark/TX Posts: 2,446 Likes: 575 Liked 880 Times in 311 Posts	Re: LOST 10mph AND ABOUT 6 TENTHS I forgot about the water pump. My V-6 is a Cam trigger and the magnetic pickup is on top, behind the water pump. I had a pump start leaking as we were loading the car. When we got to Ennis we made one run with a towel taped to the pump. It was leaking too bad so I took the Cheaper brand pump I carried as a spare and put it on. The car popped and missed at high RPM. We looked at plugs and ignition and all the electrical. We had one more shot of qualifying left and as I was doing my burn out the car popped on the chip... It hit me that the pump was what we changed and the problems cropped up. As I staged I turned the pump off. Good run, no 9000 RPM miss. Got back to the trailer and took the other pump apart and robbed the seal out of the electrical gremlin pump. Finished the race with no pump or miss problems. I figure that pump motor was a small radio station tuned to my ignition frequency. It wasn't playing any tunes my ignition liked...It seems like the simplest fixes can be the hardest! __________________ Adger Smith (Former SS) Last edited by Adger Smith; 12-06-2020 at 04:52 PM. Reason: add

12-06-2020, 05:25 PM	#43
Robin Lawrence Sponsor Join Date: Jan 2002 Location: Galesburg IL. Posts: 177 Likes: 254 Liked 715 Times in 120 Posts	Re: LOST 10mph AND ABOUT 6 TENTHS You stated earlier that you changed the ignition box and it picked up on one run. Then it returned to the loss of mph and ET. What box are you running? Robin __________________ STK 308 SS 3088

12-06-2020, 08:33 PM	#46
Bill Bogues Member Join Date: Apr 2005 Location: Bethany La. Posts: 323 Likes: 96 Liked 169 Times in 53 Posts	Re: LOST 10mph AND ABOUT 6 TENTHS our car slowed down over a couple of races. Turns out it was the rubber brake line to the rearend swapped out line at track and picked up instant 5 tenths. __________________ Bill Bogues 4696 STK

12-06-2020, 10:03 PM	#47
4543 Senior Member Join Date: Apr 2005 Location: Texas Posts: 644 Likes: 63 Liked 647 Times in 140 Posts	Re: LOST 10mph AND ABOUT 6 TENTHS Can you post a net slip from both a fast and slow run? Can you post the race pack info from a good run with a bad one overlaid on it? What sensors do you have on the trace pack? Other thing would be send the race pack files from a good run and a slow one to someone you know who has been using a race pack for a while. Might pick up something.

12-06-2020, 10:44 PM	#48
MEXJOE Senior Member Join Date: Jun 2008 Location: nhranumbers.com Posts: 875 Likes: 137 Liked 165 Times in 51 Posts	Re: LOST 10mph AND ABOUT 6 TENTHS I would look at the rear brake hose. I have seen more than one collapse internally and hold the rear brakes on. __________________ Glen DeMenge 1969 Camaro Stock Eliminator

12-07-2020, 07:28 AM	#49
Steve Hurley Junior Member Join Date: Nov 2010 Posts: 22 Likes: 9 Liked 4 Times in 2 Posts	Re: LOST 10mph AND ABOUT 6 TENTHS We had a power surge from the alternator, lost et chased our tail, replaced ignition box. First pass was good, and down hill from there. Replaced box again. One more good pass and then fell off again .5 to .6 . In our case it was the alternator.