Explanation needed
Thread Starter
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Lead Driver
Joined: Mar 2008
Posts: 7,193
Likes: 387
From: Near Los Angeles
Explanation needed
I recently installed a single speed electric fan, with a 30 amp thermostatic relay. I also have an msd box running off the batt. +
When the fan kicks in, the engine hesitates. Can someone pls. tell me how to resolve this issue.
Thanks.
Truck: 75 F350 with a hp 4.9
Alt.: G3 130 amp.
Fan: It is the larger of the two fans from a dual set up on a Ford Windstar.
When the fan kicks in, the engine hesitates. Can someone pls. tell me how to resolve this issue.
Thanks.
Truck: 75 F350 with a hp 4.9
Alt.: G3 130 amp.
Fan: It is the larger of the two fans from a dual set up on a Ford Windstar.
Senior User
Joined: Apr 2005
Posts: 108
Likes: 0
I might be able to help.
Below is how I wired up my MSD 6al box up in the engine bay.
Step 17 - Wiring Harness (Painless)
Below is a link to how I wired up my fan. Once you ckick on the link go to page 23 and 24. I believe page 24 is better since you fan will come one when it gets hot.
http://www.painlesswiring.com/Manuals/10101.pdf
Your fan requires a lot of juice to run it. If your alternator or battery are weak then your fan will starve your engine of the eletricity that it needs to run it.
Some systems do use a diode but think of a diode as a one way street for electrons. A diode is often used when your engine does not want to shut off. This is not your case.
Below is how I wired up my MSD 6al box up in the engine bay.
Step 17 - Wiring Harness (Painless)
Below is a link to how I wired up my fan. Once you ckick on the link go to page 23 and 24. I believe page 24 is better since you fan will come one when it gets hot.
http://www.painlesswiring.com/Manuals/10101.pdf
Your fan requires a lot of juice to run it. If your alternator or battery are weak then your fan will starve your engine of the eletricity that it needs to run it.
Some systems do use a diode but think of a diode as a one way street for electrons. A diode is often used when your engine does not want to shut off. This is not your case.
Thread Starter
|
Lead Driver
Joined: Mar 2008
Posts: 7,193
Likes: 387
From: Near Los Angeles
I might be able to help.
Below is how I wired up my MSD 6al box up in the engine bay.
Step 17 - Wiring Harness (Painless)
Below is a link to how I wired up my fan. Once you ckick on the link go to page 23 and 24. I believe page 24 is better since you fan will come one when it gets hot.
http://www.painlesswiring.com/Manuals/10101.pdf
Your fan requires a lot of juice to run it. If your alternator or battery are weak then your fan will starve your engine of the eletricity that it needs to run it.
Some systems do use a diode but think of a diode as a one way street for electrons. A diode is often used when your engine does not want to shut off. This is not your case.
Below is how I wired up my MSD 6al box up in the engine bay.
Step 17 - Wiring Harness (Painless)
Below is a link to how I wired up my fan. Once you ckick on the link go to page 23 and 24. I believe page 24 is better since you fan will come one when it gets hot.
http://www.painlesswiring.com/Manuals/10101.pdf
Your fan requires a lot of juice to run it. If your alternator or battery are weak then your fan will starve your engine of the eletricity that it needs to run it.
Some systems do use a diode but think of a diode as a one way street for electrons. A diode is often used when your engine does not want to shut off. This is not your case.
Senior User
Joined: Apr 2005
Posts: 108
Likes: 0
I'm sure you know this but I am amazed at how much current a good fan draws. I have my battery charger hooked up and I use it when I'm testing circuits in my car (so I don't drain my battery) and it is not strong enough to make my fan run. It will make everything else work but my fan is to big of a draw for it.
I notice you are running a powerful alternator. Mine is only 65 amps.
I use to have a boat and the belt would squeel like a pig when I trimed the motor. I guess the current draw was so much (my belt might have been loose too) when I raised the motor that it caused stress on the engine whereby making the belt squeel.
I notice you are running a powerful alternator. Mine is only 65 amps.
I use to have a boat and the belt would squeel like a pig when I trimed the motor. I guess the current draw was so much (my belt might have been loose too) when I raised the motor that it caused stress on the engine whereby making the belt squeel.
Thread Starter
|
Lead Driver
Joined: Mar 2008
Posts: 7,193
Likes: 387
From: Near Los Angeles
I'm sure you know this but I am amazed at how much current a good fan draws. I have my battery charger hooked up and I use it when I'm testing circuits in my car (so I don't drain my battery) and it is not strong enough to make my fan run. It will make everything else work but my fan is to big of a draw for it.
I notice you are running a powerful alternator. Mine is only 65 amps.
I use to have a boat and the belt would squeel like a pig when I trimed the motor. I guess the current draw was so much (my belt might have been loose too) when I raised the motor that it caused stress on the engine whereby making the belt squeel.
I notice you are running a powerful alternator. Mine is only 65 amps.
I use to have a boat and the belt would squeel like a pig when I trimed the motor. I guess the current draw was so much (my belt might have been loose too) when I raised the motor that it caused stress on the engine whereby making the belt squeel.
Senior User
Joined: Apr 2005
Posts: 108
Likes: 0
I'm old fashion. I like older trucks and I like V belts. Give me a carb and a oil sender unit that I can get to. Give me a truck where I can replace the engine myself. I look at an older truck and I see lower insurance, easier to maintain, easier to get to stuff, lots of stuff in the junk yards for them and you don't worry so much about a scratch.
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Joined: Jan 2001
Posts: 57,005
Likes: 2,750
From: Virginia
I recently installed a single speed electric fan, with a 30 amp thermostatic relay. I also have an msd box running off the batt. +
When the fan kicks in, the engine hesitates. Can someone pls. tell me how to resolve this issue.
Thanks.
Truck: 75 F350 with a hp 4.9
Alt.: G3 130 amp.
Fan: It is the larger of the two fans from a dual set up on a Ford Windstar.
When the fan kicks in, the engine hesitates. Can someone pls. tell me how to resolve this issue.
Thanks.
Truck: 75 F350 with a hp 4.9
Alt.: G3 130 amp.
Fan: It is the larger of the two fans from a dual set up on a Ford Windstar.
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Lead Driver
Joined: Mar 2008
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From: Near Los Angeles
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Joined: Jan 2001
Posts: 57,005
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From: Virginia
Are you running the recommended size wire for the MSD box? I don't know what that is, but I assume it's at least a 12 gauge wire to feed the box?
Does it hesitate when the engine is idling or does it hesitate while you are driving down the road and the fan kicks on?
Does it hesitate when the engine is idling or does it hesitate while you are driving down the road and the fan kicks on?
Thread Starter
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Lead Driver
Joined: Mar 2008
Posts: 7,193
Likes: 387
From: Near Los Angeles
I only notice hesitate for a few seconds when idling and the fan turns on.
I was very careful to follow the directions provided with the msd unit.
Another forum member says he encounted the same issue on another thread, and the problem was rectified by grounding the msd directly to battery -, and the fan to the body. As it is, I have the msd grounded to frame, and fan to body. A starting point for me would be to make that change.
I was very careful to follow the directions provided with the msd unit.
Another forum member says he encounted the same issue on another thread, and the problem was rectified by grounding the msd directly to battery -, and the fan to the body. As it is, I have the msd grounded to frame, and fan to body. A starting point for me would be to make that change.
Moderator
Joined: Jan 2001
Posts: 57,005
Likes: 2,750
From: Virginia
You can try the other suggestion, but I believe you just have a alternator output problem at low rpm. I wonder if you set the idle up a little bit would the problem go away.
I was running a snowplow setup with an original 63amp alternator, and the electrical system would hardly pick the plow up with the defrost on, etc. I set the idle up just a little bit and it then would work fine.
I was running a snowplow setup with an original 63amp alternator, and the electrical system would hardly pick the plow up with the defrost on, etc. I set the idle up just a little bit and it then would work fine.