ecu diagnostic code

[dirtydevin]

I have gotten rid of the hacked up mas a while ago, I am running another stock mas that came with the parts car. I would think my t3/t4 would flow as much as a 16g or 18g. Do you think that a proper working stock tbi setup with a stock mas can support over 12 lbs of boost with this mild t3/t4 turbo and no way to adjust the air/fuel?

I am hesitant to throw the maft into the mix now, but have no other way to tune the car. I do appreciate the advise of the seasoned starquesters on here, but it seems like the maft is the route they have gone.

[Indiana]

The stock boost gauge doesn't use pressure as its reference and with a stock setup its not really accurate but above that its way off.

 

You could be pushing 30psi and not know it and that causes the knock sensor saving you as the ignitor pulls the timing back and yes you can tell when that happens. Right now you have no idea what is going on. At least go get a $5 vacuum/pressure gauge and run it to any of those ports on the throttlebody and run a hose so you can see what is going on.

 

A stock MAF w/big16g run 30psi cause I've did it lots of times and some others on here have too. Its whether or not the air flow through the MAF turns to crap or not so its very important that the air supply comes in evenly and not restricted or deflected and that means it shouldn't be hanging out in the breeze in a cone filter which is the most popular way to do it but look at all the issues when that happens that people can't explain. The issue comes from when the MAF signal turns to crap briefly and the ECU has to switch to the tach signal and then back. You'll see that MAF "code" and think the MAF is bad and its not, it what was done to it that caused the problem by screwing up how the air was directed into the MAF. The one sensor that is the metering device for the fuel and people mess with that the first thing thinking, oh ya it needs this infinite supply of HOT engine bay air and that makes it better. Wrong. Why suck up hot air only to heat it more in the turbo then try and cool it back down with an intercooler. That doesn't make much sense when it was sucking in cold air all the time behind the fender through that big can and a stock air fitler isn't small. If you measured the surface area of a stock air filter and the popular K&N cone you'd find you put on a SMALLER filter and then put oil all over it and the worst part is it tapers down on the end where the air all has to pass by to enter the end of the MAF.

 

http://www.b2600turbo.com/images/boostgauge1.jpg

http://www.b2600turbo.com/images/tc05td05.jpg

 

http://www.b2600turbo.com/images/154.jpg

http://www.b2600turbo.com/images/151.jpg

 

Same issue on newer MAF based cars. The air filter matters. This place below was stroking the motor to a 2.9 and doing things over there that still haven't been done over here.

 

Quote from RPWs site http://www.rpw.com.au/shop/

Certain models of the Mitsubishi range run the Mitsubishi MAS / MAF sensor which is an the electrical metering unit that goes after the air box. This unit reads how much air passes through the unit via ultrasonic waves and is a oval shaped unit. One of the major problems we see is the fitment of universal "Pod Filters" which then start creating problems with idle or power by running rich, stalling etc.

The reasoning behind this is the honeycombed section requires the air flow to be very straight and clean in order to be read correctly. A pod filter is cone shaped and instead, causes a swirling action which confuses the pod filter. Additionally many of the adapters fitted to the MAF / MAS sensor is square and cuts off some of honeycombed section in order to bolt on the round pod filter.

To combat this RPW has imported in from the USA specific K&N filter charger kits that are 100% compatible with the MAS sensor without causing problems. These are flat oval shaped filters with a proper cast adapter. To quote a common term : If K&N believed that a universal filter would do the job why did they make a specific filter for the Mitsubishi Air Mass Sensor.

These are guaranteed to not only improve the power of your car over any other filter design, they will not cause any running problems and are our recommended first modification to the vehicle, even before the exhaust.

This has been tested time after time again, we see at least 1 - 2 vehicles a week coming through our workshop where we replace there "Universal Rampod" with the specific K&N unit and the car immediately idles better, pulls harder and provides better fuel economy.

This is not supplied with any mounting brackets, these will be required to be made on the vehicle when installed. RPW Recommends for most vehicles, to retain the front half of the original air box to act as a heat shield from the exhaust system.

Edited December 23, 2011 by Indiana

[dirtydevin]

I went further in deapth on testing the isc, mps, and nose switch. When I did the tps reset and calibration it gave the value for the isc and all tested well, but I just found that my mps is not reading any resistance, so I took it all apart and found that there is a bad connection inside the mps sensor itself. This should account for my idle problem that caused my low and inconsistent idle and likely caused my car to show the mas diagnostic code.

 

What is the extra hose for that goes from the airbox part with the mas on it to the intake accordian hose to the turbo, and what is the large adjustment screw on that fitting used for. It seems to allow air in without being read by the mas, mine is just open to air now as my hose to the turbo from the mas does not have a place to connect this other hose to. Do I need to hook this up?

[Indiana]

You can't leave the accordian hose with a hole in it but that was added in 88 in an attempt to better adjust the idle air/fuel ratio at the factory. If its open on the air can lid its not a big deal it just can't have the hole open on the other side because it would let in unmetered air.

[traps]

Mr Devil, you said .44 factory gap.... with factory style plugs. If issues are with boost would "flame out" apply? I am not seasoned like Mr. Indiana but I see everyone disputing the "style" plugs and I have witnessed first hand in my own car the difference of AZ/O'Reilys and parts shop cross reference plugs and the .44 gap as said by parts place's and under the hood from the factory it says .32-.42 gap. True factory plugs are ordered from the NGK wharehouses's to local parts stores then in your hands. Indiana your thoughts on a possible simple overlook? With all the small gremlins contributing could the plugs and gap be the last "weakest link" Mr Indiana sir? Edited December 25, 2011 by traps

[Indiana]

I looked this over again and I didn't see where he said what plug he was using and it could have been in another thread but the range on the hood tag doesn't specify which plug in the service manual that applies to and the easy way to put something on a tag for a range of different plugs is a range for the gap.

 

Don't remember if his vac. adv. was tested. If his distributor is gummed up. If its just a plug wire not pushed all the way into the cap, or the coil wire. The boot on the wires traps air and its a good idea to lift the boot with a wire or stick so you can push the wire in fully then pull that out so no trapped air under the boot tries to push it back off after the engine heats up and that's easier to happen. He had a hacked up MAF but switched it. His idle motor is dead or dying but that is just idle related. Still not sure exactly what turbo that he is using. Haven't asked what vacuum hoses exactly are connected and to where. If he has used a vac. gauge and verified the reference ports for the FPR and vac adv are clear. What the compression numbers are. If he has a bad exhaust leak at the manifold or turbine housing. If jet valves are present.

 

Seems there's half dozen new members with the typical issues and have multiple threads and all the answers aren't in one place. Changing plug gap isn't going to hurt anything but I don't know if that's his problem or not. It looked like the last guy just moved the distributor to make it run better and didn't use a timing light so until he gets a timing light and sets it and makes sure the reference hoses are good I'd just wait and see what he finds out.

 

and he gets a real boost gauge

 

There is more than one MAF that he could have and its possible he has a n/a DSM part. I don't know if that was asked either. If he put a 1G MAF in the stock air can that won't work. The DSM MAF connectors have locations for 8 pins. Stock is only 6. If his K&N is the correct filter for the stock can which is just a large oval that's open on the bottom end it could still need washed. There's a short loose fitting rubber hose that goes from the air can to the fender apron and a baffle behind the fender I think, maybe it has a Mud daubers nest blocking it. -they love to make nests under the hood.

Edited December 25, 2011 by Indiana

[dirtydevin]

I never did get a answer on what plug gap to run with these NGK BUR7EA-11 plugs, so it is still at 044. I am running a stock unmodified conquest maf with stock unmodified air box with stock replacement clean oval K&N filter. I have checked the vac advance and retard with a complete overhaul of the distributor, along with new cap, rotor, plug wires all plugged in correctly and routed per the factory manual. Once I get the mps replaced and my idle straitened out, I will install a good boost guage, and the wideband, then probably run it on the dyno for some baseline's and watch the fuel pressure under boost to get some insight on what is happening when this thing acts up.

[Spooled_Starion]

How's your compression? If the head gaskets leaky you'll never get it to idle right no matter how much you try.

[Indiana]

With only a stock boost gauge and a non stock turbo there's no way to tell how much boost you are really running. I'd suggest you not use any type boost controller and only use a single hose from your intercooler plumbing to the wastegate actuator. I'd also avoid sustained wide open throttle runs in a higher gear. After you figure out what boost you're at and how much fuel you have then you can worry about what plug gap works best.

[traps]

start at .32 and go up from there making a few pass''s mine seems to like .36 - .38 depending on plug. If ya have too much boost and no true way to measure ie fac boost controll then your blowing out the larger gap. More gap seems like more fire but on a forced ind veh it can backfire literally when the gap is too much...shorter spark is stronger, simple thing to check sir. Thats my newbie input.