Mass air conversion

[stang0f87]

I bought a mass air kit off ebay which I believe is stock 88-93. I threw the computer in after making the wire changes. Then I installed the new tube with the sensor. Lastly, I disconnected the vaccum to the map sensor and plugged it off. At fist it seemed to run pretty good. Eventually it idled terribly. In fact it wouldn't stay running at all. I suspect the mass air don't like the 24lb injectors I got. (I changed it back to speed density for the meanwhile, but with the changes I've made , I don't like cause it just seems to idle fast.) I read that if I adjust the fuel pressure down a little, that'll fix the problem. To do that, I'll have to buy an adjustable regulator. Would I be better off buying a different sensor? Could it be a another problem I missed?

1987 Mustang GT
5 speed
HO 302
stock cam
stock intake
24 lb injectors
gt40 heads
gt40p headers
x-pipe
2 1/2" flowmasters

 

[bikerjoel68]

Might be because the stock mass air is set up for 19 lb. injectors.Looking at your setup I got to question why your running 24 lb. injectors in the first place.You should try throwing in a set of 19lbers. and retry it!!

 

[HISSIN50]

did you have 24's before with the SD (before you converted)?
i agree that those may be too much (too little duty cycle). if you dial the pressure down the spray might get all messed up. i would rather have smaller injectors at near capacity than large ones with small duty cycles.

can you pull codes (for fun)?

good luck.

 

[stang0f87]

Yes I've been running 24lb injectors with speed density and I know that sounds awd, but I have a reason for it. I decided to pull the intake, fuel rail, 19lb injectors, IAC, and clean it all up. My injectors were in sorry condition. It just wasn't feasible to try putting them back in. The plastic ends were coming apart on 3 of them. I know a guy who had these 24s with low mileage on them. It made sense to at least try it, since my cashflow wasn't that good at the time. Ran pretty fair and it was a cheap way out since he owed me a favor. Unless you guys are offering to buy me some 19s, I'd like to try and make this work. Any suggestions?

 

[jrichker]

The plastic cap (pintle caps) have nothing to do with injector flow. They have only one purpose: to keep the O ring from sliding off and down into the intake.

Fuel injector seal kits with 2 O rings and a pintle cap (Borg-Warner P/N 274081) are available at Pep Boys auto parts. Cost is about $2.74 per kit. The pintle caps fit either injectors with a pin sticking out the injector end or 4 with more tiny holes in the injector end. The following are listed at the Borg-Warner site ( http://www.borg-warner.com ) as being resellers of Borg-Warner parts:

http://www.partsplus.com/ or http://www.autovalue.com/ or http://www.pepboys.com/ or http://www.federatedautoparts.com/

Most of the links above have store locators for find a store in your area.

 

[Js5ohLX]

Get a maf calibrated for the 24's. You'll be good to go. That's what I have, and it runs like mad.

 

[stang0f87]

My computer is an A9S I believe. Will it work for 24lb injectors?

 

[~-Ws50's916-~]

YEAH IT SHOULD...I DONT SEE WHY NOT, BUT YOU NEED TO RE CALIBERATE YOUR SENSOR FOR 24LB INJECTORS INSTEAD OF THE STOCK 19. WHAT ITS DOIGN IS, IT READS THE AMOUNT OF AIR GOING THROUGH AND IT THINKS YOU HAVE 19LB INJECTORS WHEN YOU GOT 24, SO ITS NOT LETTIN IN ENOUGH FUEL THROUGH YOUR 24LB INJECTORS. SO WHEN RE CALIBERATE IT, IT WILL EVEN IT ALL OUT AND YOU WILL BE GOOD TO GO AGAIN. OR YOU CAN DO WHAT JRICHKER SAID AND BUY THAT KIT. SO BASICALLY, RE CALIBERATE, OR SPEND MONEY AND GET STOCK INJECTORS FROM CRAIGSLIST.COM OR SUMTHIN