Mark D Chip Install

[BlueBMW]

In another forum Mark responded thus...

"Your car is running lean at WOT.... I'm not sure what is causing it, but it's much leaner than it should be.
With the AFR around 12.8, you will gain more torque and hp."

He asked me to get a table of the values so he could analyze it a little more and make sure its not the chip at fault.  For all I know it could be my car.

Also he suggested something about the WOT switch?  

"I just thought of something: make sure that the WOT switch is properly closing as if it's not, the DME does not go open loop and use the WOT fuel and ignition maps."

Any ideas on that?

[Ryann]

You can use a multimeter in Ohms mode to verify proper WOT switch operation.. with the butterflies fully open you should see zero resistance across the switch terminals. I'd bet on vacuum leaks, although I've read posts in which you said you have no starting/idling issues whatsoever. Hm.

[BlueBMW]

I think I've replaced every hose and line possible on this car.  First thing when I bought it I pulled the intake and replaced everything I could get my hands on.  But I will check the switch and see what I get.

[bmwconnect]

In another forum Mark responded thus...

"Your car is running lean at WOT.... I'm not sure what is causing it, but it's much leaner than it should be.
With the AFR around 12.8, you will gain more torque and hp."

He asked me to get a table of the values so he could analyze it a little more and make sure its not the chip at fault.  For all I know it could be my car.

Also he suggested something about the WOT switch?  

"I just thought of something: make sure that the WOT switch is properly closing as if it's not, the DME does not go open loop and use the WOT fuel and ignition maps."

Any ideas on that?

If your car is running at all then it's certainly not the chip at fault. I would bet on the fuel injectors, fuel pressure regulator, or  fuel pump. fuel pressure at wot (50psi) must be exactly to factory specs because after all the tune was based on a perfectly running m42

Once you sort out the lean out conditions your motor will come alive

[BlueBMW]

I'll figure it out

[carguy101]

sub for future ref great info!! I want one so bad...

[dude8383]

Great results and thank you for documenting it!

[fiftytakedowns]

I have a NarrowBand AFR and It says I Run  almost 14.7 maybe a little LEaner At WOT, according to many other people the cars do Run quite Lean at WOT.

I have 19 LB injectors in mine, I wonder if going up to 21 LBers would do the trick.  Hopefully my FPR or soemthing like that isnt going bad.

I think you measure the TPS through The VOLTAGE across the thing, Mine reads 2-4.XX Vs from open to closed.  I however have a bouncing AFR at IDLE from RICH to Lean, and the idle fluctuates. No vacuum leaks that I can find, however I am going to re-do all of the gaskets too.

I have mark D 91, 9lb JB flywheel, and COPs

OP- What Spark plugs were you running ... NGK BKR6eK?

I am going to Install a Vacuum Gauge pretty soon into the car, but not sure Which hose I could tap it into.

[ose30]

Most dyno figures i have seen from USA are made with Mustang Dynos. Here in Europe most dynos are based on Bosch machinery. I have seen several times same car measured first in USA with Mustang, produced much less HP when it was measured in Europe with european dynos. Quite many europeans are therefore quite sceptical what comes to HP figures americans write on internet. But overall, if you got app. 7hp; it's quite normal HP increase on N/A cars. You have to modifiy it a lot to gain more. Turbos are totally different story.

[BlueBMW]

I think you measure the TPS through The VOLTAGE across the thing, Mine reads 2-4.XX Vs from open to closed.  I however have a bouncing AFR at IDLE from RICH to Lean, and the idle fluctuates. No vacuum leaks that I can find, however I am going to re-do all of the gaskets too.

I have mark D 91, 9lb JB flywheel, and COPs

OP- What Spark plugs were you running ... NGK BKR6eK?

I am going to Install a Vacuum Gauge pretty soon into the car, but not sure Which hose I could tap it into.

I honestly can't remember the plugs we put in.  The guy running the dyno recommended one heat range higher than what was in there.  I know ngks came out of it and I think they were bkr6ek or bkr5ek that went in.  I guess whichever of those two are hotter are the ones I used.

I'll do some more investigation on the wot lean issue next week since I'm out of town this week.

[///m42 sport]

thnx for the post...now next thing I suppose would be to clean your injectors?