Jeep Strokers

I don't have anyway of seeing my AFR...sorry im cheap Can anyone suggest a voltage range to set the MAP too? It's a 91 wrangler OB1 4.6 stroker, 24# ford injectors, cammed, .43 HG, 63mm TB, 99+ intake. I do understand that this is not the best remedy but I seems to be rich or should I just leave it. I haven't really been able to drive my new motor too hard so I cant say if run's right at high rpm. What did you guys set your MAP voltage to?

Some recommended settings at the bottom of the page:

http://go.jeep-xj.info/HowtoMAPsensor.htm

So I guess with my setup its probably best to do is measure what my AFR is and adjust...What should I do to go about setting the voltage? Do I need any special tools...if so how much would they cost for a cheap one?

Failed smog 3 times now, so I must install my MAP adjuster NOW. Could anyone tell me which wires on the MAP sensor do what?

In a pinch you can read your spark plugs to see the condition of the combustion.

http://www.angelfire.com/fl4/pontiacdud ... plugs.html

Dunno where the map is on your YJ but on obd1 cherokees, it's on the middle firewall. The pcm has a 5v power supply that goes to the map and throttle position sensor via a violet w/ white stripe wire. You would first connect your adjustable map to a 12v switched power source and a good ground, then cut that violet w/ white wire a few inches from the map sensor, then connect the adjustable map output to the few inches of wire you left on the map input. Use female connectors on the adjustable map output and the now unused pcm supply and a male connector on the map input and you can swap back and forth if necessary.

Check Dino's site. He has plans for a diy adjustable map that you can build for a few bucks with radio shack stuff.

Indeed I do. Here it is:

http://www.angelfire.com/my/fan/MAP_adjuster.html

Right on guys, thanks for the help. I'm getting all stressed out because of this smog crap and I just want it to end. Basically my engine runs so lean that it's making me fail smog. All my emissions are great other than the NO(PPM). Not to sure what that is but the max is 714(I got 1060) at 15MPH and 616(I got 783) at 25MPH. I'm hoping this is the fix because idk what else im gonna do.

I'm still confused about the 3 wires on my MAP adjuster. So the 3 wires on the MAP adjuster just splice into the 3 wires on the MAP sensor?

Also, I reset my PCM by holding the positive and neg cables together for about 2 minutes to discharge the PCM and i've only driven about 20 or 30 miles since then. Is it to early to set up this map adjuster since the computer could still be "learning"?

You definitely need to enrich the A/F ratio. I have my MAP adjuster set at 5.2v.

I'm also pretty sure the reason my APN header cracked because of it running so lean. At the smog shop they put this tube in my exhaust to suck out the fumes but It ends up just melting and making the air smell worse.

I'll probably just guess when I dial in the adjustable MAP since i really just want to pass smog and get this nightmare over.

eventually I'll get a wideband and get it set really good...any idea what kind of power improvements I could see from doing this mod. Another thing...the adjustable MAP will adjust fuel across the entire rpm range right?

aaronkeiser wrote: Another thing...the adjustable MAP will adjust fuel across the entire rpm range right?

The MAP voltage input is most effective in open loop operation and on throttle openings 80% or greater. At all other closed loop throttle positions the A/F mixture is controlled by the ECU bades on it's inputs. How long has it been since you changed your O2 sensor?

About a year ago I had a running rich problem and check engine light. I changed the oxygen sensor thinking that would fix it but it still did the same thing. Then I realized the MAP vacuum line melted on the exhaust header. So the oxygen sensor is relatively new (about a yr.)I've since repaired it and doesn't smell like Fuel/cat like it used to.

It's running lean when just cruising at constant speeds. I have the stock air box with K&N drop in. exhaust is basically a 2-1/4 diameter so I don't understand why it runs lean. Would an adjustable fuel pressure regulator be a better solution for my problem?

Remove and cap the fuel press reg vac line and go for a spin. It bumps the press by like 5-10psi IIRC. I don't have a stroker yet but it made a difference on my cammed 4.0 @ the track

Thats a dam good idea! I just check my fuel pressure today and it's about 34 psi at idle(manual says 31) and about 41 or so with the vacuum line disconnected(book says 39psi). I've read also that theres a couple different regulators you can drop in to richen your setup which are the #4418850 or 5277829 or 5277864.

Anyone have and experience with this?