MAF conversion

Jerry77 · 08-02-2004, 07:51 PM

I have an '88 5.0 speed density, bone stock that runs "perfect" with the DA1 computer.
I aquired a second '88 SD computer harness that I added the 4 wire MAF conversion harness, an A9L and a 19# Ford MAF meter. I drove the '88 home and draped the new harness over the fender and had the engine running with the mass air within the hour. I has a "hunting" idle and I only idled it for about a minute; since I felt this wasn't right. I substituted another Ford 19# MAF meter and it made no difference. I checked the MAF harness at idle and there was the 5vref and a 1.76v return voltage.
I think the MAF meters are bad or the computer is bad. How should I verify this? With this simple conversion I thing the engine should have idled perfectly from the start.
PS: This harness and A9L will be used on my project car, a 390FE with EEC-IV. This harness idled on the 390FE; but wasn't idleing perfect and had a stumble when you open throttle from idle.
This is why I tested harness on the '88, to see if harness and computer were okay.
All the '88 sensors are ok, since I just drove it home. How does a bad computer act?
Thanks for any help.

88fivepointoh · 08-02-2004, 08:20 PM

did you go though and set your idle? there is a procedure on the corral that will help you with that. also did u disconnect your map sensor vacumm line and plug it? I did the conversion on my 88 and the three things to remeber is timing, fuel pressure, and vacumm. pull the vaccum line off the regulator plug it and see if that stops teh hunting. let me know from there.

Jerry77 · 08-03-2004, 12:08 PM

I did remove & plug the vacuum line. The timing and idle were set since it was ok with the speed density an hour earlier.
I still thing the computer of MAF meter are bad. I was going to buy a rebuilt computer from auto store to get a known "good" computer to try.
Did your conversion idle properly right from the start?

88fivepointoh · 08-03-2004, 07:05 PM

HAAA.. no way man, i had problems with it first off. My issues were fuel pressure. now granted my motor wasn't stock so that was a cause or fuel pressure etc.. raise the idle under the throttle body, until it stops hunting. then remove the battery let it sit for 20 mins, then re connect and fire it up.. it should be ok after that unless you have a defective sensor or wiring. let me know.

Jerry77 · 08-04-2004, 03:54 PM

It will be a day or two before I can try the idleing idea. Thanks for the input.

Mustang_289 · 08-06-2004, 06:37 AM

Just curious - why are you converting to MAF with a stock motor? Our 88GT ran better with SD with pretty much stock motor. It's good to convert when you've got many engine mods planned IMO.

Jerry77 · 08-10-2004, 07:20 PM

You might not have completely read through the orginal post. I am installing this A9L mass air unit on a 390FE Ford('66 Galaxie 500Xl) I figured the best test to see if all the harness converting was correct was to run it on my stock 302 SD engine.
I added a new idle air bypass Sunday, and I figure it is running 95% as best it will.

08-02-2004, 07:51 PM	#1
Jerry77 Registered Member Join Date: Apr 2004 Location: Texas Posts: 6	MAF conversion I have an '88 5.0 speed density, bone stock that runs "perfect" with the DA1 computer. I aquired a second '88 SD computer harness that I added the 4 wire MAF conversion harness, an A9L and a 19# Ford MAF meter. I drove the '88 home and draped the new harness over the fender and had the engine running with the mass air within the hour. I has a "hunting" idle and I only idled it for about a minute; since I felt this wasn't right. I substituted another Ford 19# MAF meter and it made no difference. I checked the MAF harness at idle and there was the 5vref and a 1.76v return voltage. I think the MAF meters are bad or the computer is bad. How should I verify this? With this simple conversion I thing the engine should have idled perfectly from the start. PS: This harness and A9L will be used on my project car, a 390FE with EEC-IV. This harness idled on the 390FE; but wasn't idleing perfect and had a stumble when you open throttle from idle. This is why I tested harness on the '88, to see if harness and computer were okay. All the '88 sensors are ok, since I just drove it home. How does a bad computer act? Thanks for any help.

Similar Threads
Thread	Thread Starter	Forum	Replies	Last Post
5 lug conversion	stanger9219	Windsor Power	2	02-25-2004 11:31 PM
What all do you need to do rear disc conversion w/ SN95 Parts	KG88GT	Windsor Power	1	07-29-2003 01:45 PM
questions about maf conversion	spankaveli	Windsor Power	10	10-19-2002 02:46 PM
5 to 4 lug conversion	mike_navigator	Blue Oval Lounge	7	08-14-2002 11:17 PM
mass air 87GT conversion	greydan	Windsor Power	3	01-02-2002 07:57 PM

08-02-2004, 08:20 PM	#2
88fivepointoh Registered Member Join Date: Aug 2002 Location: Rochester Posts: 553	did you go though and set your idle? there is a procedure on the corral that will help you with that. also did u disconnect your map sensor vacumm line and plug it? I did the conversion on my 88 and the three things to remeber is timing, fuel pressure, and vacumm. pull the vaccum line off the regulator plug it and see if that stops teh hunting. let me know from there.

08-03-2004, 12:08 PM	#3
Jerry77 Registered Member Join Date: Apr 2004 Location: Texas Posts: 6	I did remove & plug the vacuum line. The timing and idle were set since it was ok with the speed density an hour earlier. I still thing the computer of MAF meter are bad. I was going to buy a rebuilt computer from auto store to get a known "good" computer to try. Did your conversion idle properly right from the start?

08-03-2004, 07:05 PM	#4
88fivepointoh Registered Member Join Date: Aug 2002 Location: Rochester Posts: 553	HAAA.. no way man, i had problems with it first off. My issues were fuel pressure. now granted my motor wasn't stock so that was a cause or fuel pressure etc.. raise the idle under the throttle body, until it stops hunting. then remove the battery let it sit for 20 mins, then re connect and fire it up.. it should be ok after that unless you have a defective sensor or wiring. let me know.

08-04-2004, 03:54 PM	#5
Jerry77 Registered Member Join Date: Apr 2004 Location: Texas Posts: 6	It will be a day or two before I can try the idleing idea. Thanks for the input.

08-06-2004, 06:37 AM	#6
Mustang_289 Registered Member Join Date: Sep 2001 Posts: 512	Just curious - why are you converting to MAF with a stock motor? Our 88GT ran better with SD with pretty much stock motor. It's good to convert when you've got many engine mods planned IMO.

08-10-2004, 07:20 PM	#7
Jerry77 Registered Member Join Date: Apr 2004 Location: Texas Posts: 6	You might not have completely read through the orginal post. I am installing this A9L mass air unit on a 390FE Ford('66 Galaxie 500Xl) I figured the best test to see if all the harness converting was correct was to run it on my stock 302 SD engine. I added a new idle air bypass Sunday, and I figure it is running 95% as best it will.