map sensor operating voltage??

[DirtyDeeds]

Does any only know the operating voltage range for the map sensor on a 87 mj with the 4.0? I need to get a 2 bar to use the supercharger I'm mounting and need to match the voltage ranges.

[cruiser54]

Same as GM vehicles if that helps. 

[HOrnbrod]

Does any only know the operating voltage range for the map sensor on a 87 mj with the 4.0? I need to get a 2 bar to use the supercharger I'm mounting and need to match the voltage ranges.

 

The Renix ECU (nor the HO OBD1 ECU) is not programmable and can not read the 2-bar MAP voltage output signals. Plus the timing advance needs to be increased, fuel pressure increased, and larger injectors are needed with a turbo setup. Most use an aftermarket piggyback controller like a Unichip or Megasquirt. There are several forums around to read up on the basics, like:

http://msruns.com/

http://www.msefi.com/

http://www.msextra.com/

[DirtyDeeds]

 

Does any only know the operating voltage range for the map sensor on a 87 mj with the 4.0? I need to get a 2 bar to use the supercharger I'm mounting and need to match the voltage ranges.

 

The Renix ECU (nor the HO OBD1 ECU) is not programmable and can not read the 2-bar MAP voltage output signals. Plus the timing advance needs to be increased, fuel pressure increased, and larger injectors are needed with a turbo setup. Most use an aftermarket piggyback controller like a Unichip or Megasquirt. There are several forums around to read up on the basics, like:

http://msruns.com/

http://www.msefi.com/

http://www.msextra.com/

 

I'm only going to run 6psi to start and I'm installing a msd ignition to control timing, already have bigger injectors and a higher psi pump, the map was the only thing i was needing info on. however the m90 I'm installing only has a max boost of 10psi, and ive read that most stock maps will handle that but there are aftermarket 2 bar maps that are calibrated to put out the same voltage range as factory maps, i just needed to match the voltage range so the ecu can read it. just finish my bracket and did a test run of it, sounds SOOOOOOO GOOOD but now i have to get the inlet made and get the tube kit/blow off valve and a few other things still a month out from being ready 

 

[mnkyboy]

What MAP sensor are you looking at that has that adjustability without a tuner?

 

I tossed a 3bar on mine just to see what it would do,even with my MAP adjuster my OBD1 ECM couldn't figure out what to do with it,once the MAP starts seeing positive pressure the ECM freaks out.

 

Right now i have a stock 1bar,i measured voltage at the sensor and bumped it up .2v with the MAP adjuster, it ran a little too rich so i backed it off a little the other day.

I need to hook a meter to it and see what my voltage is at now.

 

Originally i had 19lb injectors and it would run a little lean even with the MAP turned up,i have 24s in it now and i think it would run fine without the adjuster.

 

I also tried 30lbs but the idle quality sucked.

[HOrnbrod]

MAP Voltage Table

 

MAP Adjuster

[DirtyDeeds]

MAP Voltage Table

 

MAP Adjuster

well if I'm reading the chart right, the factory map should be able to keep up with what little boost the m90 can put out, but ill look into the map adjuster 

[mnkyboy]

Remember when reading the chart that a 1bar is only reading atmospheric pressure,every pound of boost will be above atmospheric pressure,a 2 bar is good to around 14.5psi of boost,a 3bar will go around 30psi.

 

A 1bar won't be able to make any adjustments once you start building boost,so it technically won't be able to keep up,but at low boost it could be good enough.

[HOrnbrod]

Remember when reading the chart that a 1bar is only reading atmospheric pressure,every pound of boost will be above atmospheric pressure.

 

A 1bar won't be able to make any adjustments once you start building boost,so it technically won't be able to keep up,but at low boost it could be good enough.

 

Should be @ 6psi, but if not build or buy a MAP adjuster and crank up the 5V supply a bit until it is.

[mnkyboy]

So far my 1bar with the MAP adjuster is keeping the AFR happy,if i turn up the boost much more i think i will have to get a stand alone.

[DirtyDeeds]

https://www.facebook.com/100011357421019/videos/538117149910194/

[HOrnbrod]

An adjustable FPR really helps to help dial in the AFR too. Do you have one installed mnkyboy? I used it to dial in the new 703 injectors I put in recently; runs great. 'Course I don't have a blower either, and from everything I've read, 6psi ain't going to do much on a stroker.

[DirtyDeeds]

An adjustable FPR really helps to help dial in the AFR too. Do you have one installed mnkyboy? I used it to dial in the new 703 injectors I put in recently; runs great. 'Course I don't have a blower either, and from everything I've read, 6psi ain't going to do much on a stroker.

my engines sock, if i get a lil extra torque and the cool sound ill be happy!! 

[mnkyboy]

Do you have one installed Mnkyboy

I do not,i have looked at some but haven't got one.

I was going to try one if the adjustable MAP wasn't enough but it seems to be working with the 24lb injectors.

 

I just checked my MAP,without the MAP adjuster it is sitting at 4.54v volts with the key on. (It's the middle wire on the plug to check it)

I bumped it up to 4.74v with the MAP adjuster and ran a few laps around the neighborhood,it's running pretty good like that.

[DirtyComanche]

An adjustable FPR really helps to help dial in the AFR too. Do you have one installed mnkyboy? I used it to dial in the new 703 injectors I put in recently; runs great. 'Course I don't have a blower either, and from everything I've read, 6psi ain't going to do much on a stroker.

 

6 pounds is 6 pounds.  The M90 won't be capable of producing 6 pounds with the increased displacement of the stroker, that's the issue.  It just can't move enough air.  I think realistically it might make about 3 pounds on an engine like yours, and yeah, not much gain there after parasitic loss.

 

A M90 came up for sale locally, so I was doing some reading. :yes:

[DirtyDeeds]

 

Do you have one installed Mnkyboy

I do not,i have looked at some but haven't got one.

I was going to try one if the adjustable MAP wasn't enough but it seems to be working with the 24lb injectors.

 

I just checked my MAP,without the MAP adjuster it is sitting at 4.54v volts with the key on. (It's the middle wire on the plug to check it)

I bumped it up to 4.74v with the MAP adjuster and ran a few laps around the neighborhood,it's running pretty good like that.

 

post some pix of your rig

[cruiser54]

FYI, CobraMarty on Cherokee forum is very knowledgeable about M90s on Cherokees.

[mnkyboy]

My 89 MJ.

 

 

The 4 angry squirrels.

 

 

[cruiser54]

That's cool!!!

[DirtyDeeds]

That is bad @$$ is that a kit or custom? And what are the numbers before and after?

[Tex06]

The M90 is the stock supercharger on the 3800 Series GM motors, correct?  

[cruiser54]

The M90 is the stock supercharger on the 3800 Series GM motors, correct?  

I believe so. 

 

Here's a link regarding SCs on Jeeps. Marty is a good guy.

 

http://jeepm62superchargerkit.blogspot.com/

[mnkyboy]

 

That is bad @$$ is that a kit or custom? And what are the numbers before and after?

The Kenne Bell/Autorotor supercharger and Laminova water/air intercooler were part of an Avenger kit for a 2.5l TJ but i bought them separately and built everything myself.

 

I haven't had it on a dyno but Avenger use to advertise their kit at 182HP on a stock 2.5l,who knows what it's making on mine

[DirtyDeeds]

It came on the 3800 series engine but also came on the ford thunderbird super coup which is the one I have

[HOrnbrod]

Here's a link regarding SCs on Jeeps. Marty is a good guy.

I've been told Marty was canned from Boosted Technologies a long time ago.......

 

THIS is the their site. He's no longer part of the "team".