HOW-TO: Build/Install/Tune Map Clamp

[lunchbox660]

OK, there USED to be alot of easy to find info on this stuff and it has come to my attention that many posts/threads/pics and what not have been either deleted or expired. this is basic info that anyone should be able to have access to, so here it is...

ok, first off heres the diagram for the MAP clamp with part numbers. many part numbers have changed at radio shack, so just look at the box and match the specs, they still carry the parts, just have different numbers, thats all.



now that youve got it built, i HIGHLY recommend you support the wires in some way because they are very brittle coming out of the potetiometer and are prone to breaking for no real reason...i used an SD memory card case and filled it with JB weld to permanently support the wiring after i sealed them with shrink tubing. here is what it looks like now:




obviously you dont have to use an SD case if you dont have one, you can use anything you have really, i like the SD case cus it is small and easy to tuck away.

now you need to wire it into your car. pretty simple really, all wires get spliced INLINE with the existing wires on the car. there is no need to CUT the car's harness, just peel some insulation back, thats IT. red goes to red or orange (its supposed to be an orange wire in your car, but ive seen a few of them that look more red than orange. you only have three wires to pick from, so its NOT the black or the green one, lol), white (i use a green wire in place of the white one so the colors all match up) goes to green, and black goes to black. easy. make SURE you seal up your connections. if you ground something out, your car will really hate you. i STRONGLY recommend soldering your connections, not twisting them like many people do.

also from time to time one thing i like to do is install the MAP clamp wires directly to the terminals on the harness. it gives it a much cleaner look, but is not necesary. if you want to do this, make a specific note to what wire is in what position in the plug, then unplug the harness from the MAP sensor, use a flat tip screwdriver to pry the red terminal cap out from inside of the connector, then undo each of the pins from inside by LIGHTLY prying the tabs away from them inside. slide out the pins and solder your MAP clamp directly to these pins. then just push them all back into theri corresponding postion in the harness and your done with that part.

now for tuning. you really ought to use a wideband O2 and/or a dyno to tune your MAP clamp, but it can also be done with a scangauge if youve got one. the potentiometer has 15 turns to it. there is a VERY LIGHT stop to it on either end, so when you first begin, you MUST be VERY careful not to turn too quickly or firmly or it is possible you could jump the stop and it may no longer work or may work improperly. counter clockwise means leaner and more timing, the reason why is because it will show the car less boost. on pump gas it is recommended you stay in the mid 11's AFR unless your pumps have some really nice gas like 94 or 95 then you may feel brave enough to go as lean as mid 12's AFR. the voltages on the table below show you what voltage corresponds to what pressure signal for both the 2 bar AND the 3 bar MAP sensors for our cars. please bear in mind that trimming TOO much MAP signal can cause unwanted effects too though. if you go as low as 13 psi signal i have noticed alot of hesitation in many cars. some people still recommend tunign that low, but i do not. the choice it yours though, it is your car. i recommend staying around 14-15 psi for better results. if youve got a scan gauge, you can tune your MAP clamp using the manifold pressure reading to show you where you are clamped at. whatever pressure it stops at is where you are clamped. go up or down as desired. while doing this, keep and eye on your knock retard count as well though, because going lower normally will increase your timing, but going too low will cause the car to knock and pull timing WORSE. i STRONGLY recommend using a wideband because it give you an intuitive and understandable number to look at for your AFR, but the scan gauge wil also show you your O2 millivolts. when at WOT if your O2 millivolts is in the 890-930 range you are relatively safe. this will put your car in the 10.5-11.5 range AFRs and will be safe enough for daily drivers on pump gas.

if you do not have a scan tool available, there is still another way you can get a halfway decent base tune. you can a boost leak tester to pressurize the system and probe the MAP sensor with the key in the ignition position. probe the green line with the positive lead on the tester and the black wire with the black lead on the tester. make sure your tester is set to the 20V reading and then SLOWLY turn the screw on the clamp counterclockwise until you see the voltage readings changing on the meter. reference to the voltage table shown below to aim for your desired boost setting. this is the setting that the car will not see ANYTHING HIGHER. from this point forward, unless you start messing with the boost and fuel settings mechanically on your car, you basically will never have to mess with the MAP clamp again.

DO NOT tune your MAP clamp on gas that you normally would not use, like race gas or 100 octane unleaded. doing this will make it appear as though you are not getting any knock and running safer at leaner AFRs but then when you go to use yout NORMAL gas your car will run VERY poorly.

the chart:


i hope you find this info useful. do not attempt to do this if you are unsure about something, you can cause very severe damage to your car if you make a wrong move. if you have questions, comments, or concerns, let me know so i can edit the post.

joe

[Goats]

awsome write up

[phubarr]

Yeah, I agree! Outstanding work, lunchbox660! I'm always glad to see guys sharing knowledge and information!

[lunchbox660]

well then you should look at several of my other how-to's...lol cus most of the ones i have written are the ones with all the "secrets" that nobody wants to share...lol

i mean DAMN, the internet IS supposed to be used for information gathering and sharing purposes...if people dont want thier "secrets" told, they should patent the stuff. its basic common sense for most of this stuff tho, its just that many owners just dont feel like taking the time to learn or try so they just pay poeple to do it for them instead, and hey, theres nothing wrong with that at all, if people wann pay me to do stuff for them i am all for it you betcha! money in my pocket! but im not going to act like its a big secret what i am doing...usually when i do this stuff for people they are standing right next to me watching an learning how to do things so that when i am not around they can share that knowledge with other people too

[Goats]

Quote: Originally Posted by lunchbox660

well then you should look at several of my other how-to's...lol cus most of the ones i have written are the ones with all the "secrets" that nobody wants to share...lol

i mean DAMN, the internet IS supposed to be used for information gathering and sharing purposes...if people dont want thier "secrets" told, they should patent the stuff. its basic common sense for most of this stuff tho, its just that many owners just dont feel like taking the time to learn or try so they just pay poeple to do it for them instead, and hey, theres nothing wrong with that at all, if people wann pay me to do stuff for them i am all for it you betcha! money in my pocket! but im not going to act like its a big secret what i am doing...usually when i do this stuff for people they are standing right next to me watching an learning how to do things so that when i am not around they can share that knowledge with other people too

thats what im talking about

[tinctorus]

this needs to be a sticky

[lunchbox660]

Quote: Originally Posted by tinctorus

this needs to be a sticky

to be honest with you i dont know why all the old thread and info keep getting tossed out or broken links and what not. i used to have it all saved in my subscription folders but all those threads are no longer any good so it took me a while to compile all the pictures and chart into one thread again cus they all came from completely random places...

[reed32]

vwctor posted this awhile ago in one thread. its like 10 bucks in parts. thanks for the write up

[WantToRaceANeon]

this is probaly a stupid question i know you need to be under boost to see the voltage from the MAP clamp but if the clamp is under the hood(i want to keep it out of sight) how do you tune it? i do not have a scan tool but i do have a volt meter. also can you use the same setup for a TIP clamp and do you know the voltage for the TIP?

[lunchbox660]

you can run extra long wires and have the MAP clamp in your cabin if you prefer, thats how i have mine. and then what you do is you tap a wire off the ground and the signal wire BEFORE the MAP clamp to tell the voltage it is at. this must be done under full boost. 4.1-4.3 is normally the ideal range for most cars. anything less and you may start to get some unwanted effects. anything more and it will still be WAY too rich usually.

as for the TIP clamp, yes, same principle applies, but you really dont need to clamp the TIP to be honest with you. just disconnect the hose and leave it open and your problem is solved. if you have an 05 just do the fade tip mod. search for it on here. it basically just involves poking holes in the line to bleed excess off. it is free to do and works perfectly fine, so no reason to NOT do it really. to spend extra money on the TIP clamp just to compliment the MAP clamp doesnt make sense when there are FREE things you can do that will provide the same effect. just my 2 cents. the TIP sensor is also a 5v sensor, but i do not know the ranges it shoudl be in because i have never bothered with one.

[Terry Burger]

Once I've dialed the car in, how can I make a non-adjustable map clamp?

[lunchbox660]

if you want to make a non adjustable one just play around with resistors on your signal wire. thats what the VW guys do usually. look on the vw forums and find the diode mod, its the same thing. but why would you want to make a NON adjustable one if the adjustable one only costs 3 dollars more to make? what are you going to do when your fuel source changes or when your car gets more mods or when the weather changes? you need to be able to change WITH the changing conditions, if you cant change with them, then your tune will only be effective under the identical conditions to which you tuned it....not a good idea if you ask me.

[05SRTFOUR]

how much does this cost once all is done?

[lunchbox660]

it depends if you encase it and if you run it into the cabin. uncased and installed just under the hood you can complete one for under ten bucks. add a case, anywhere from $3 to $5 depending what you buy, run it into the cabin and youll need about 8 feet of wire to do it CLEANLY, so add anothe couple bucks.

granted, most people already have some extra wire and some random ass enclosure they can use as a case, so these may not be a factor at all if you are resourceful

[TurboLover!]

I am planing on installing this in a 1G Turbo to limit the PCM from seeing any boost at all. I plan on measuring the map output voltage with car turned off, no vacuum then dialing the potentiometer down to make that the max allowed voltage of the sensor. Then the stock PCM should not see any boost, and stop throwing a over-volt code when you go into boost. I will post how it works out.

This should eliminate code 14 for 1G owners running MS or other standalone.