86 GT Engine and Fuel Questions

Comatose · 12-10-2001, 02:00 AM

I read in another post about a fuel pump whine. My 86 has a very prominent whine or hum coming from the rear of the car while it's parked.....is this normal?

Also, the idle is inconsistent. It will sometimes idle at 1000 rpm, and sometimes idle at approx 575-600 rpm. When it idles at the 600 rpm, it doesn't vary at all, when it idles in the 900-1000rpm area, it surges mildly. The throttle response seems to be better when it idles at 1000rpm, in the 600rpm range there is some hesitation.

When I come from a dead stop and stomp it, the throttle response is good, but at the next stop light, it idles about 1300rpm. Gas mileage has gone down 2-3mpg as well.

Please Help.

Mods are: Hypertech chip.

Thanks for the help.

kystang86 · 12-10-2001, 03:38 PM

is your car speed density? if so mine did the same thing. mine was worse when it was hot outside. i converted to mass air and i have had no problems with idle or running anymore. also the whine from the pump, mine does the same thing it,s a little louder than normal, but it still works fine.

Comatose · 12-11-2001, 11:17 AM

The induction system is stock, so I assume it's speed density, correct?

How hard is the conversion to MAF? How much does is cost, and what's the affect on performance?

Thanks,
Jeremiah

gtsr515 · 12-12-2001, 09:50 PM

The hum you hear is normal

12-10-2001, 02:00 AM	#1
Comatose Registered Member Join Date: Oct 2001 Location: Goldendale, WA, USA Posts: 84	86 GT Engine and Fuel Questions I read in another post about a fuel pump whine. My 86 has a very prominent whine or hum coming from the rear of the car while it's parked.....is this normal? Also, the idle is inconsistent. It will sometimes idle at 1000 rpm, and sometimes idle at approx 575-600 rpm. When it idles at the 600 rpm, it doesn't vary at all, when it idles in the 900-1000rpm area, it surges mildly. The throttle response seems to be better when it idles at 1000rpm, in the 600rpm range there is some hesitation. When I come from a dead stop and stomp it, the throttle response is good, but at the next stop light, it idles about 1300rpm. Gas mileage has gone down 2-3mpg as well. Please Help. Mods are: Hypertech chip. Thanks for the help. __________________ Jeremiah 1986 Mustang GT K&N Filter, Removed Air Silencer, Black Magic Fan, 65mm Explorer TB, 110lph BBK Fuel Pump, F/M Force II Cat -Back, O/R h-pipe, U/D's Timing@14* 1986 Mustang LX SSP--new project car AOD, 3.27's, Dumps, 238k miles

12-10-2001, 03:38 PM	#2
kystang86 Registered Member Join Date: Jul 2000 Location: frankfort,ky Posts: 54	is your car speed density? if so mine did the same thing. mine was worse when it was hot outside. i converted to mass air and i have had no problems with idle or running anymore. also the whine from the pump, mine does the same thing it,s a little louder than normal, but it still works fine. __________________ 86 gt 3.73's,underdrives, welds, pro-5.0 shifted, chip,autometers,flowmasters, k&n,2.5" cowl hood, new motor in the works.. 00 250 powerstroke diesel

12-11-2001, 11:17 AM	#3
Comatose Registered Member Join Date: Oct 2001 Location: Goldendale, WA, USA Posts: 84	The induction system is stock, so I assume it's speed density, correct? How hard is the conversion to MAF? How much does is cost, and what's the affect on performance? Thanks, Jeremiah __________________ Jeremiah 1986 Mustang GT K&N Filter, Removed Air Silencer, Black Magic Fan, 65mm Explorer TB, 110lph BBK Fuel Pump, F/M Force II Cat -Back, O/R h-pipe, U/D's Timing@14* 1986 Mustang LX SSP--new project car AOD, 3.27's, Dumps, 238k miles

12-12-2001, 09:50 PM	#4
gtsr515 Registered Member Join Date: Nov 2001 Location: Sunny, Hot, Sebring, Florida Posts: 725	The hum you hear is normal __________________ Remember...2nd place is 1st place for losers!

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