EFI guru's I NEED YOUR HELP

[luvmybronco]

Hello,
I've done the 89 Towncar EFI swap, and I have a few questions, and need your input badly...
First, this is what I've done besides the EFI swap with AOD trans...Shorty headers with 2 1/2 dual pipes, and muflers, and NO H pipe, but will be added next week...No cats, or any smog equipment...
Right now it runs rich, and I can here a slight miss on the pass side bank...It runs good when cold, but better when the comp. comes online, but when i'm holding a certan speed, say about 35, the miss gets worse, and it starts jumping, and sputtering...As long as i'm on the gas, it runs light a raped ape...
Do you think the H pipe will help, or do you think I should go with a mass air setup? What i'm really asking, is did you guys have the same problems?

 

[lars]

An h-pipe and mass air won't fix your problem. Something is wrong. I've driven several Broncos with speed density setups like yours and they ran just fine. Begin with the basics: pull codes, the computer may well be able to tell you what's wrong. That's one of the nice things about the factory EFI setup, it can tell you where the problems lie. Also, make sure your spark plug wires and plugs are in good shape. Just because they were new when you installed the SEFI doesn't mean you can ignore them. If a wire got fried on a header while you were doing the install, or if a plug insulator got broken, they will cause problems. Also make sure the distributor cap is in good shape. The Ford ignition is a good one, and ellectrons will find their way out through the wrong places if there's a defect. From your description, it sounds like something is wrong, and in steady state cruise the computer is trying to compensate for the problem. In that case it would almost certainly throw a code (or codes) that could help you pin it down fast.

 

[luvmybronco]

Thats another thing i'm having trouble with...When I hook it up to the scanner, and hit "test" I hear alot of suction from the air cleaner, and the rpm's come up for a sec., then it goes back to idle, and NO codes are sent...I can pull codes with the key on, engine off, but not when its running...The codes I get with key on, engine off, is canister signle low (witch i'm not using), and air codition relay (also not using)...I'm running the vapor line right to the intake instead of going through the canister...Could that cause it not to let the engine run properly?
It ran great when I first got it on the road, but seems
to be getting worse...Also, i'm not using the cruz...I unpluged it, do I need that?
TIA

 

[rulebreaker]

You cant pull codes for the KOER test unless the computer thinks the tranny is in park. Take the neutral safety switch wire that goes to the tranny (PIN 30 on mine)and plug it into the single wire that plugs into the scanner and then you can do the KOER test.RB

 

[luvmybronco]

wow, I never new that...YOU LEARN SOMETHING NEW EVERYDAY...It does say something about the nutral safty switch, but I thought it was because I'm using the nutural safty switch that came with my B&M shifter...Thanks RB....

 

[lars]

Yep, that would be it. On mass air cars at least, it's pin 30. Only kicker with mass air computers was that the manual tranny computers wanted to see a signal ground at pin 30 in order to pull codes, whereas auto computers want +12 volts. Apply 12 volts to pin 30 on a manual computer and you fry it (though applying ground to pin 30 on an auto computer doesn't hurt anything). Fortunately I learned that from someone who did that, rather than finding out the hard way. Don't know if the same applies to speed density, though I suppose since it's a Town Car computer you won't have anything to worry about.

A neat feature of KOER testing is the cylinder balance test. The computer will sequentially shut off fuel to each cylinder and check for an rpm drop. Thus you can diagnose problems with individual cylinders.

 

[Broncobowsher]

If you have a miss, the unburned fuel also has a lot of oxygen in it. That will hit the O2 as being lean (too much oxygen in the exhaust). Adding more fuel, making everything else run rich.

I need to keep that code pulling requirements with pin 30 handy. I didn't know that before.