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General Forums => The Mess Hall => Topic started by: chrisfranklin on April 01, 2010, 10:01:21 PM
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For you guys that have built your own or are using the Turbo City or some other version of adjustable MAP, what voltage do you have your set to for best performance for the modifications you have?
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Alright, I'll fess up -- the Turbo City Adjustable MAP I ordered showed up on my door step today. I know, it's $140 and you can do just as well building your own for $20. But I figured that I'd have enough to think about getting it set up correctly, let alone making sure I put the thing together correctly from Radio Shack parts.
So, I went Turbo City and it looks like a pretty sturdy unit that includes install directions and how to restore it to stock without removing it.
Of course, now we get in to Voltage and A/F ratios. I've got a grand total of 3/4 of a turn with the adjustable MAP screw voltage adjuster on the unit. I do have a voltmeter at least.
But without an A/F wideband sensor, I'm guessing at what voltage adjustments will yield in terms of A/F ratio. Since I can reset the thing to stock whenever I want, I'm mainly asking around for what voltage numbers have thus far yielded the best sop performance and not worrying so much about the A/F ratio that these numbers would tend to represent.
So, if you have one of these adjustable MAPs, please tip me off as to what Voltage you are running yours at. Thanks!
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I would monitor the voltage from the stock setup then work from there. No 2 MAP's are exactly the same as some have higher thresholds then others.
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Reading the instructions again, it looks like you are advised to increase the voltage by .2 from whatever your stock voltage reads -- stock is said to typically read 4.6-4.85 volts. So, I'll have to see what voltage I start off with.
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Reading the instructions again, it looks like you are advised to increase the voltage by .2 from whatever your stock voltage reads -- stock is said to typically read 4.6-4.85 volts. So, I'll have to see what voltage I start off with.
you modify your supply voltage which is 5v for stock, so start by measuring your new voltage regulator supply first.
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I got going on installing this adjustable MAP today and took a few photos I'll dig up later. Good news for YJs is that this Turbo City setup just plugs right in between the existing plug and sensor -- TJs need to do a little cutting and splicing but the extra plugs needed for that are included.
Bad news for me has been getting before and after voltages -- actually really just "before" voltage, though I am probably going to have the same problem getting an after. Directions advise you to keep the MAP sensor connected, then stick a paperclip up in the the rubber cap of the middle wire on the green plug and make contact with the metal plug or exposed wiring. Then get out your voltmeter and connect the positive end on the paperclip to the map sensor plug, and ground the negative cable. With the keys in the ignition and turned to get the accessories going, you then should be able to get a stock voltage reading for your MAP sensor.
So far I'm not getting anything -- maybe I'm not getting contact with the paperclip. I can just strip some of the rubber off the middle wiring harness and probably get a reading that way instead; taking a lunch break
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I got going on installing this adjustable MAP today and took a few photos I'll dig up later. Good news for YJs is that this Turbo City setup just plugs right in between the existing plug and sensor -- TJs need to do a little cutting and splicing but the extra plugs needed for that are included.
Bad news for me has been getting before and after voltages -- actually really just "before" voltage, though I am probably going to have the same problem getting an after. Directions advise you to keep the MAP sensor connected, then stick a paperclip up in the the rubber cap of the middle wire on the green plug and make contact with the metal plug or exposed wiring. Then get out your voltmeter and connect the positive end on the paperclip to the map sensor plug, and ground the negative cable. With the keys in the ignition and turned to get the accessories going, you then should be able to get a stock voltage reading for your MAP sensor.
So far I'm not getting anything -- maybe I'm not getting contact with the paperclip. I can just strip some of the rubber off the middle wiring harness and probably get a reading that way instead; taking a lunch break
you can take out the rubber seal so that way you'd have the end of the pins exposed. I suggest measuring the supply before connecting the map adjuster to make sure is not too high.
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how did the install go?
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I didn't get a chance to go round two with it today. Hopefully will get in there to work on it tonight or tomorrow night.
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I've got a couple of things holding me up on putting this Turbo City Adjustable MAP in
- Getting the initial Voltage reading turned out to be a little more trouble than I expected the other day. Given the hour I spent on Saturday fishing around with the paperclip in the MAP, then pulling apart the Turbo City connectors I didn't need to examine their construction and where the clip would be making contact, I'm still kind of surprised my voltmeter didn't get a reading. I figured I'd at least get a jump in readings numbers as the clip connected briefly when I tried different positions. I thought it might have been the meter or its settings, so I tried it on the 12V battery and an AA cell, but it worked fine. Had the ignition key on, but engine not started. I'll pull out the rubber seal on the MAP wire and give that a go or maybe just expose a little of the wiring and get the voltage that way. But I'm still thinking maybe the MAP isn't getting power for some reason -- maybe key position is wrong.
- I'm also supposed to "Connect white wire of Map Modifier to +12VDC Key On Wire using multi-lock connector." The adustable MAP (aka "Map Modifier") does have a long white wire. I was digging around my Chilton's manual to identify where this 12VDC Key On Wire exactly was in the engine bay and then go from there. Of course Chilton's is leaving me hanging.
I'll get all this eventually digging around. But if you have any tips, please help me save some time Trying to get a photos of everything :biggrin:
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i'll dig in my notes tonight and tell you what wire to use for 12v switched (i had some wires listed in an excel spreadsheet when i connected the Split Second for my s/c setup, had the same problem and took 2 tries to get it right).
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i'll dig in my notes tonight and tell you what wire to use for 12v switched (i had some wires listed in an excel spreadsheet when i connected the Split Second for my s/c setup, had the same problem and took 2 tries to get it right).
white/yellow wire going to the PCM pin 9 is key switched +12v
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The PCM for the 92-95s is located in the engine bay, right? I personally haven't messed with it before. Is it behind the window washing fluid or is it on the other side near the battery and fuse box. Don't have my Jeep nearby unfortunately. Appreciate the tip on the pin #9 wire Sharp.
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The PCM for the 92-95s is located in the engine bay, right? I personally haven't messed with it before. Is it behind the window washing fluid or is it on the other side near the battery and fuse box. Don't have my Jeep nearby unfortunately. Appreciate the tip on the pin #9 wire Sharp.
you don't need to get to the PCM, just to the bundle of wires going to it. but yes, it is in front of the washer fluid bottle on the firewall, forget about pin 9, i just listed as it was in my spreadsheet, the white/yellow wire is the one you want, make sure you solder it if you cut it and use shrink tube on it.
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Alright I'll find the white/yellow wire in the bundle to the PCM.
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Alright I'll find the white/yellow wire in the bundle to the PCM.
forgot to mention, mine is a '95 and I'm pretty sure the 94 is the same, i'm not sure about the 92-93 if the wire color is the same.
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95 probably is the same as '94. I think I read that 93-95s all used PCMs. Turbo City kind of gives these one size fits all directions and seems to assume you know you're way around your Jeep's wiring or have a shop manual. I am going to have to peel back the taping or plastic wire tubing and see if I can locate a yellow/white wire in the bunch.
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95 probably is the same as '94. I think I read that 93-95s all used PCMs. Turbo City kind of gives these one size fits all directions and seems to assume you know you're way around your Jeep's wiring or have a shop manual. I am going to have to peel back the taping or plastic wire tubing and see if I can locate a yellow/white wire in the bunch.
it is white/yellow and not the other way around - it means a white wire with a yellow line (stripe) on it. 91-95 were all MPFI but someone here had a 91 or 92 and he mentioned the wire colors were different on the O2 sensor (and that got me thinking) - if you have a 94 or 95 then the white/yellow is the correct one.
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This sounds like a movie where their defusing a bomb -- "is it the white wire with the yellow stripe or the yellow wire with the white strip?! They look the same!" :lol:
Looking at this site, it looks like the guy attached the 12V wire to a wire on the diagnostic port of his XJ. http://www.jeep-xj.info/HowtoMAPsensor.htm
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This sounds like a movie where their defusing a bomb -- "is it the white wire with the yellow stripe or the yellow wire with the white strip?! They look the same!" :lol:
Looking at this site, it looks like the guy attached the 12V wire to a wire on the diagnostic port of his XJ. http://www.jeep-xj.info/HowtoMAPsensor.htm
you need a switched 12v that is on when you crank the engine (when the starter is turning), i know the PCM switched 12v is on then, not sure about the diagnostic port, if you verify and it's on then it is a good choice, most of the accessories are off when you crank it, not sure about the diag port (could be).
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I heard back from Turbo City with a little more information on wiring:
"Hi,
There are several solenoids under the hood that are powered with the key on.
Disconnect one of the connectors and with the key on, one wire will be "hot"
12v, the other will go to the computer. The computer grounds the solenoid to
activate it. Connect the white power wire of the MAP adjuster to the hot
wire.
You can use a straight pin to back probe the original connector on the map
sensor. It is smaller than a paper clip. The stock MAP sensor must be
connected and the key must be on to read voltage.
Thanks"
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I was Art's place in Ontario, Ca. today and he gave me some pointers and helped me get this MAP adjuster installed. Thanks again, Art! :biggrin:
We found the stock voltage reading on the map sensor was 4.63V . This falls in to the range the Turbo City directions suggested that most stock Jeep map sensors would read at, which was 4.60-4.85V
With the stock voltage obtained, you then plug the Adjustable Map between the stock Map connector and the Map Sensor itself (this is just for YJ 2.5s; TJs need you to do a bit more wiring and the Turbo City kit includes what's needed).
Then there's a long white wire on the Adjustable Map that you need to run to the side to connect to a +12V Key On Wire.
I started looking around the engine bay for the PCM and we identified it as behind the coolant and windshield washer fluid containers.
These containers looked like they were going to have to be removed to get to the PCM. So we looked around to see what else was available.
We ended up finding a 12V source on a exposed electrical connection very close to the PCM -- turned the ignition to on, did a voltage check on one of the end connections on the connector and found it reading 12V on and 0 switched off. The connector wire we ended up connecting the adjuster's 12V wire to happened to be white with a yellow stripe (wire color I would have been looking for if we had used 9 on the PCM)
So we went ahead and connected the white wire from the adjuster to that using the multi-lock connector included with the adjuster.
Once you get everything connected, the Turbo City directions advise you to turn the little plastic screw on the adjuster so that it is .2V higher than your original reading -- in this case, this would be 4.83V
So with the multimeter still connected, I turned the screw on the adjuster and took it up from 4.63V to roughly 4.83V according to the multimeter. (This adjuster is a little tough to dial in precisely in .01V increments -- the multimeter showed 4.82V after a lot of trial and error, so I just left it at 4.82V for the time being)
I then drove it around and on the highway for about 20 minutes and came back. It drove better all around just with this little .2V adjustment.
Obviously, I'll certainly experiment with settings higher than just 4.82V and see how it then drives on the city/highway. And I can always pull the adjuster or probably even just set it to the stock map reading -- 4.63V -- for emissions tests.
Do think it would be decent to have 02 Sensor-based readout for A/F so you could adjust raise the voltage to achieve a specific AF ratio with your current setup or even with additional modifications. So I might see what's out there along those lines.
I'll take a few photos of the adjuster in place and where we wired it to.
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The connector wire we ended up connecting the adjuster's 12V wire to happened to be white with a yellow stripe (wire color I would have been looking for if we had used 9 on the PCM)
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what a surprise :roflol:
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I've been meaning to ask: what voltage are you guys with adjustable maps running yours at?
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We plugged it into the ignition hot on the Chrysler diagnostic connector.
Chris the best way to get it adjusted is to look at the fuel trim with a scanner.
It will show you what the ecm is doing with the fuel when you are done tinkering with the fuel pressure and map sensor settings/ engine load. You go to crazy with it you end up nuking the cat.
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We plugged it into the ignition hot on the Chrysler diagnostic connector.
Chris the best way to get it adjusted is to look at the fuel trim with a scanner.
It will show you what the ecm is doing with the fuel when you are done tinkering with the fuel pressure and map sensor settings/ engine load. You go to crazy with it you end up nuking the cat.
i don't think you can monitor the fuel trims on the YJ (OBD1) - i thought it's an OBD2 feature only but i could be wrong.
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Pretty much from the days of feed back carburetors on, if you could get a data stream from the ecm, it would show fuel trim/ block learn. The older Chrysler stuff had a fairly quick baud rate and yes even before OBD 1 they showed fuel trim on their data stream.
It pretty much shows where the computer moves the fuel inside it fuel map. If it jeeps taking fuel away when you crank up the fuel pressure and or map voltage then there is re3ally no point in fiddling with that is there? If it considers it running rich and takes fuel away then there doesn't seem to be a point in adding more fuel
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We plugged it into the ignition hot on the Chrysler diagnostic connector.
Chris the best way to get it adjusted is to look at the fuel trim with a scanner.
It will show you what the ecm is doing with the fuel when you are done tinkering with the fuel pressure and map sensor settings/ engine load. You go to crazy with it you end up nuking the cat.
I'm not really planning to mess around with the voltage again until I can get a readout on A/F, Art.
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Pretty much from the days of feed back carburetors on, if you could get a data stream from the ecm, it would show fuel trim/ block learn. The older Chrysler stuff had a fairly quick baud rate and yes even before OBD 1 they showed fuel trim on their data stream.
It pretty much shows where the computer moves the fuel inside it fuel map. If it jeeps taking fuel away when you crank up the fuel pressure and or map voltage then there is re3ally no point in fiddling with that is there? If it considers it running rich and takes fuel away then there doesn't seem to be a point in adding more fuel
it will always readjust in closed loop based on O2 feedback, unless you use a programmable signal calibrator inline with the sensor or a programmable/adjustable O2 sensor you can't fight the PCM - the only "place" you can make a difference is in open loop or by getting the PCM to go in open loop quicker (which is where the map adjuster would be a benefit imo)
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Once you push the the fuel trim past where it cannot adjust it self, it's essentially in open loop. It can only adjust it self so much. We had a problem with CNG engines where the fuel map was not quite generous enough, forced us pretty much to change more injectors than sparkplugs on them things. They would just run to lean after a couple of weeks to a month. Finally found some injectors that let a bit more natural gas through and pretty much solved our problem. We had the regulators cranked up as high as was safe to do so to try and get a bit more fuel in them. Seems to me fiddling with the resistance of the Coolant and or Air intake temp sensors is easier to give the engine a little more fuel, Used to work wonders for Cadillac Sevilles.
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The dealer drug a little black box with a Chrysler Logo on it and plugged it into teh 2" square connector that dangles near the driver hood hinge(94) and that little box displayed pretty much the same stuff I've seen on OBDII. Mechanic was cool and let me fiddle.
Dave
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Once you push the the fuel trim past where it cannot adjust it self, it's essentially in open loop. It can only adjust it self so much. We had a problem with CNG engines where the fuel map was not quite generous enough, forced us pretty much to change more injectors than sparkplugs on them things. They would just run to lean after a couple of weeks to a month. Finally found some injectors that let a bit more natural gas through and pretty much solved our problem. We had the regulators cranked up as high as was safe to do so to try and get a bit more fuel in them. Seems to me fiddling with the resistance of the Coolant and or Air intake temp sensors is easier to give the engine a little more fuel, Used to work wonders for Cadillac Sevilles.
not sure about coolant but wouldn't AIT be ruled by the same closed loop O2 feedback - it won't change the output of the oxygen sensor though, so wouldn't that only work for open loop?
as far as pushing a bunch of fuel i can't see how that would work at all ranges though, if your PCM can't adjust the duty cycle low enough i would guess that the engine would not run properly (might as well disconnect the o2 sensor, would run on a set fuel map which would be better i think) - once you're in open loop would be too rich in this case (too much fuel in closed loop)
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Basically all of it is mood when the engine runs right, now if it needs more fuel, then anything that tricks the ecm to supply a bit more fuel will work, Making the pcm think the engine is fairly cold will supply a bit more fuel. a lot of the aftermarket chips do something similar, they add a bit of advacce and add a bit of fuel. To me on a fairly stock engine buying an adjustable map sensor for 200 bucks is a waste of money, you can achieve the same with a couple of resistors in the CTS circuit. Now when it's supercharged or Turbo charged that is an entirely different thing
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Basically all of it is mood when the engine runs right, now if it needs more fuel, then anything that tricks the ecm to supply a bit more fuel will work, Making the pcm think the engine is fairly cold will supply a bit more fuel. a lot of the aftermarket chips do something similar, they add a bit of advacce and add a bit of fuel. To me on a fairly stock engine buying an adjustable map sensor for 200 bucks is a waste of money, you can achieve the same with a couple of resistors in the CTS circuit. Now when it's supercharged or Turbo charged that is an entirely different thing
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there's no reason to use a programmable map sensor for a stock engine.
not sure if that trick with the CTS would work in closed loop, if it does then it's a cheap way to get a bit more power although would hurt your mpg whereas if you only focus on making it a bit richer in open loop you can still get the same mpg when in closed loop.
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Well a 4 banger on the highway is pretty much in open loop all the time isn't it, lol pedal to the metal and going nowhere. Full throttle is open loop.
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Individual engines have personalities as well, for instance my 94 ran super rich from day 1, once I built teh motor it started actually running in the right AFR range, and I've changed out all the sensors a couple times chasing the issue, finally decided its a goofy ECU.
Dave
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Art, Sharp, in my case, I would have spent a bunch of time building the DIY MAP adjuster unit that I could have spent working or doing something else worth more than the dough I paid for the built adjuster unit.
Is there a real need for a Map adjuster on a 4banger without forced-induction or other big air flow mods over and above a 62mm TB, after-market intake, and cat-back? I'd guess you probably don't absolutely have to do a Map Adjuster, whether DIY or Turbo City or something else. I might see if I can grind out the intake opening before too long and headers are always a possibility
But I wouldn't mind getting an AF read-out and then determining what voltage -- if any -- above oem is worth setting on the adjuster in my case as is
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With the 02 sensor apparently dialing back any change in a rich incoming mixture below WOT, it sounds like WOT (or a range pretty close to it -- 80% throttle to WOT) is the only place where a map adjuster is going to be worth anything on the 4banger (and 4.0).
Or is it just WOT that gets you in the open loop where the O2 sensor can't interfere?
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Art, Sharp, in my case, I would have spent a bunch of time building the DIY MAP adjuster unit that I could have spent working or doing something else worth more than the dough I paid for the built adjuster unit.
i think both Art and I were talking about programmable MAP sensors (the kind Split Second makes) not the voltage adjuster (that's the one that cost you $200 but it is cheaper now).
what you installed would go both ways, getting you in open loop a bit sooner and giving a bit more fuel - i can't remember the exact behavior where the PCM is switching from closed loop to open loop but on the hwy would probably be when you go wot or close to that and during acceleration until the engine settles to a cruising rpm if you're below wot. Same goes for when you do city driving, it will go open loop when you start from a stop light and during first moments after a shift in gears, once it balances itself (the throttle opening matches the rpm and speed) would go in closed loop - you can easily monitor that with an LED based AFR gauge, it will cycle quickly back and forth in closed loop and will shift towards the rich side when in open loop - you can probably do that with a scanner as well but i never used one, Art might have so he can tell you more about that probably