Fuel Injection Question

D Styron · 02-08-2010, 01:46 PM

Hello all,
I just got a new to me fuel injected bracket car. This is my first attempt at anything fuel injection so I am totally lost. This is just a mid 13 second bracket/ street car. You guys are all very bright and I thought I would start here. It is a fuel injected 302 in a 1979 Zephyr. The problem I am having is when the electric fan kicks on the engine starts surging until the fan turns off. It surges in park or drive. It has a k&N cone air filter open under the hood, no sealed box. I put a metal shield between the cone air filter and the fan and it stopped the surging in park but not in drive. I thought the air coming off the fan was hitting the MAF sensor and throwing it off, but the shield didn't work. As long as the fan doesn't turn on the car runs great, just don't come to a stop and have the fan turn on. I am lost as to what it could be. It has a tweecer tuner but I have no Idea how to use it. Does this sound like a computer problem, too much air hitting the air filter when the fan turns on,etc....... I am lost, please help.
Thanks,
David Styron

Ron Middleton · 02-08-2010, 02:06 PM

There are quite a few guys running that same system on the turbo 2.3l Ford stuff and you can go to the forum and probably get some help on that system. http://www.turboford.net/cgi-bin/ult...?ubb=forum;f=2

mike natoli · 02-08-2010, 02:08 PM

is the check engine light on ? If you don't have any diagnostic info data of any kind ,check the o2 sensors with a lab scope/ graphing volt meter or just a dvom for response. Check map sensor frequency I did not beleive those had air flow meters are you sure this is not a variable venturi. You can check the air charge temp senso/iac valve if equipped they gumm up pretty bad, clean throttle bore and blade. Don't mess with minimum air screw unless some one else has srewed with it. Than check the TPS sensor. orry have to go now.
Good Luck,
Mike

novassdude · 02-08-2010, 03:58 PM

You may want to look into the wiring of the fans or the ecu. It sounds like when the fans are on they are drawing to much juice for the system to work correctly. Are you running relays for the fans?
I don't know squat about fuel injection but I do deal with wiring all the time and that is what it sounds to me maybe the problem.

D Styron · 02-08-2010, 04:00 PM

I will check out those things. Yes the fans are on relays. Do you think the air (wind) coming off the fan and hitting the air filter has anything to do with it or am I just totally off on that idea. It is weird it runs great until the fan turns on. It did it right as I was staging the car this weekend, not good.
Thanks,
David

partsbob67 · 02-08-2010, 08:00 PM

sounds like you are on the right track . what brand of maf does it have? some of them are real touchy especially with the fan blowing across the air filter. sometimes rotating the maf will take care of this.

D Styron · 02-09-2010, 12:27 PM

The MAF is a 75 MM Granatelli. I am going to try and look at some of these solutions this weekend. Thanks for the suggestions.
David

D Styron · 03-02-2010, 09:26 PM

Hate to keep bring it up but here goes nothing. First time out at the track. It ran a 13.72 @99.67 mph, with a mind blowing 2.057 60 ft. Next time out, I added a "shield" around the air cleaner and it slowed the car to a best of 14.32 @ 98.04 mph with a 2.288 60 ft. That seems like alot of ET loss for only a 1.5 MPH decrease. Still havent fixed the surging. It runs perfect as long as the stupid fan doesnt kick on. BTW it is in dire need of gears and a converter. It still has the stock converter and highway gears. Anymore ideas on the fan deal, someone else suggested it could be in the tuning?????
Thanks,
David

W J · 03-03-2010, 10:37 AM

Could the fans starting be putting too much of a draw on your electrical system for the computer to function properly? Good alternator and battery? A meter check of these might give you a hint....WJ

Harry 6674 · 03-03-2010, 11:55 AM

Can you route the intake away from the fans, maybe under toward the grill area? Maybe try the fans on a switch, you shouldn't need them going down the track.

02-08-2010, 01:46 PM	#1
D Styron Junior Member Join Date: Nov 2003 Location: Houston Posts: 25 Likes: 0 Liked 0 Times in 0 Posts	Fuel Injection Question Hello all, I just got a new to me fuel injected bracket car. This is my first attempt at anything fuel injection so I am totally lost. This is just a mid 13 second bracket/ street car. You guys are all very bright and I thought I would start here. It is a fuel injected 302 in a 1979 Zephyr. The problem I am having is when the electric fan kicks on the engine starts surging until the fan turns off. It surges in park or drive. It has a k&N cone air filter open under the hood, no sealed box. I put a metal shield between the cone air filter and the fan and it stopped the surging in park but not in drive. I thought the air coming off the fan was hitting the MAF sensor and throwing it off, but the shield didn't work. As long as the fan doesn't turn on the car runs great, just don't come to a stop and have the fan turn on. I am lost as to what it could be. It has a tweecer tuner but I have no Idea how to use it. Does this sound like a computer problem, too much air hitting the air filter when the fan turns on,etc....... I am lost, please help. Thanks, David Styron

02-08-2010, 02:06 PM	#2
Ron Middleton Member Join Date: Jan 1970 Location: Jackson, Ms. Posts: 350 Likes: 183 Liked 10 Times in 4 Posts	Re: Fuel Injection Question There are quite a few guys running that same system on the turbo 2.3l Ford stuff and you can go to the forum and probably get some help on that system. http://www.turboford.net/cgi-bin/ult...?ubb=forum;f=2 __________________ #4892 J/SA. We are what we repeatedly do. Excellence then, is not an act, but a habit.” - Aristotle

02-08-2010, 02:08 PM	#3
mike natoli Member Join Date: Mar 2007 Location: Valley Stream mini Gasoline Alley & Div I Posts: 100 Likes: 25 Liked 52 Times in 16 Posts	Re: Fuel Injection Question is the check engine light on ? If you don't have any diagnostic info data of any kind ,check the o2 sensors with a lab scope/ graphing volt meter or just a dvom for response. Check map sensor frequency I did not beleive those had air flow meters are you sure this is not a variable venturi. You can check the air charge temp senso/iac valve if equipped they gumm up pretty bad, clean throttle bore and blade. Don't mess with minimum air screw unless some one else has srewed with it. Than check the TPS sensor. orry have to go now. Good Luck, Mike

02-08-2010, 03:58 PM	#4
novassdude Senior Member Join Date: Mar 2002 Location: usa Posts: 751 Likes: 203 Liked 133 Times in 49 Posts	Re: Fuel Injection Question You may want to look into the wiring of the fans or the ecu. It sounds like when the fans are on they are drawing to much juice for the system to work correctly. Are you running relays for the fans? I don't know squat about fuel injection but I do deal with wiring all the time and that is what it sounds to me maybe the problem.

02-08-2010, 04:00 PM	#5
D Styron Junior Member Join Date: Nov 2003 Location: Houston Posts: 25 Likes: 0 Liked 0 Times in 0 Posts	Re: Fuel Injection Question I will check out those things. Yes the fans are on relays. Do you think the air (wind) coming off the fan and hitting the air filter has anything to do with it or am I just totally off on that idea. It is weird it runs great until the fan turns on. It did it right as I was staging the car this weekend, not good. Thanks, David Last edited by D Styron; 02-08-2010 at 04:04 PM.

02-08-2010, 08:00 PM	#6
partsbob67 Member Join Date: Apr 2005 Location: rohnert park,ca Posts: 411 Likes: 9 Liked 37 Times in 10 Posts	Re: Fuel Injection Question sounds like you are on the right track . what brand of maf does it have? some of them are real touchy especially with the fan blowing across the air filter. sometimes rotating the maf will take care of this. __________________ bob beals 7244

02-09-2010, 12:27 PM	#7
D Styron Junior Member Join Date: Nov 2003 Location: Houston Posts: 25 Likes: 0 Liked 0 Times in 0 Posts	Re: Fuel Injection Question The MAF is a 75 MM Granatelli. I am going to try and look at some of these solutions this weekend. Thanks for the suggestions. David

03-02-2010, 09:26 PM	#8
D Styron Junior Member Join Date: Nov 2003 Location: Houston Posts: 25 Likes: 0 Liked 0 Times in 0 Posts	Re: Fuel Injection Question Hate to keep bring it up but here goes nothing. First time out at the track. It ran a 13.72 @99.67 mph, with a mind blowing 2.057 60 ft. Next time out, I added a "shield" around the air cleaner and it slowed the car to a best of 14.32 @ 98.04 mph with a 2.288 60 ft. That seems like alot of ET loss for only a 1.5 MPH decrease. Still havent fixed the surging. It runs perfect as long as the stupid fan doesnt kick on. BTW it is in dire need of gears and a converter. It still has the stock converter and highway gears. Anymore ideas on the fan deal, someone else suggested it could be in the tuning????? Thanks, David

03-03-2010, 10:37 AM	#9
W J Senior Member Join Date: Jul 2009 Location: Paxton, Massachusetts Posts: 638 Likes: 0 Liked 0 Times in 0 Posts	Re: Fuel Injection Question Could the fans starting be putting too much of a draw on your electrical system for the computer to function properly? Good alternator and battery? A meter check of these might give you a hint....WJ

03-03-2010, 11:55 AM	#10
Harry 6674 Senior Member Join Date: Dec 2006 Posts: 589 Likes: 0 Liked 0 Times in 0 Posts	Re: Fuel Injection Question Can you route the intake away from the fans, maybe under toward the grill area? Maybe try the fans on a switch, you shouldn't need them going down the track.