E28 Megasquirt FAQ

russc · Post by **russc** » Jul 04, 2009 3:15 PM

Ahh,
nothing here. Now using it. Blocked it off. It will still vent through the canister, I believe.

SamSpade wrote:With MS, what do you do with the evap fuel tank vent valve (aka breather/purge valve), especially for the M30B35 and 533i where the vent valve is electronically controlled by the ECU?

Lee in Ottawa · Post by **Lee in Ottawa** » Jul 07, 2009 1:22 AM

Need a little more help. Being held back from starting right now by 2 problems.

#1. megatune shows 3.90volts when the ignition is on yet my battery is fine. When the car is turned over voltage shows fine however and that is the only way we were able to load a tune onto megatune.

#2. TPS seems to be hooked up fine (M50 tps) however it is not responding with megatune and won't let us calibrate it?

Those are the only 2 problems but their big ones. Any help would be greatly appreciated.

Car is a 90 535i, goatthumper MS 2 v3.0, TCD stg 2

bornagain · Post by **bornagain** » Jul 07, 2009 5:32 AM

I would check your grounds, i know when i was dry running my megasquirt with no motor in i had a ground not hooked up and i was getting 3 to 24 volts some how, once the grounds were hooked up i no longer had the voltage issues, once you get the power issue sorted then i would take another look at the tps, til then dont even bother with that issue.

my 0.02$

Xenocide · Post by **Xenocide** » Jul 11, 2009 12:56 AM

Big bronze rim wrote:If you do not use the adapter board you will need a 3 wire Bosch PWM idle control valve board available through Glen’s Garage

Sorry if I'm just going blind, but I can't find these adapter boards anywhere, I'm planning on using my stock 2 wire idle air control valve from my m20b27. Is this possible? I assume from your post that I'll need some sort of adapter board, could someone point me in the right direction?

This thread has been pure gold, it's taught me TONS about megasquirt. I can't thank you enough for this vital resource

Post by **Brad D.** » Jul 11, 2009 1:49 AM

DIYAutotune sells Ryan Nimick's (goathumper on most forums) adapter board.

Post by **Brad D.** » Jul 11, 2009 1:51 AM

Xenocide wrote:
Big bronze rim wrote:If you do not use the adapter board you will need a 3 wire Bosch PWM idle control valve board available through Glen’s Garage
Sorry if I'm just going blind, but I can't find these adapter boards anywhere, I'm planning on using my stock 2 wire idle air control valve from my m20b27. Is this possible? I assume from your post that I'll need some sort of adapter board, could someone point me in the right direction?

For the two wire valve you could do the mods outlined in the Megamanual which include upgrading one of the transistors to drive the valve directly. The other option would be to use a 535i 3 wire valve and use the GG board.

Xenocide · Post by **Xenocide** » Jul 11, 2009 7:31 PM

Thanks, I must have read that whole assembly manual at least 5 times and still didn't manage to pick up on that little blue box

Thanks for bearing with me, and thanks again for this very well organized resource.

if anyone else stumbles across this, here's a link to how to wire the IAC

http://www.megamanual.com/ms2/IAC.htm#fidle

My ECU is the 35 pin, I've got a donor ECU all prepped with pigtail wires already soldered on. That board must be a godsend for 55 pin users.
I'm thinking I'll do a compromise between what goathumper did and what megasquirt wants you to do: I'm planning on using the DB-37 connector, testing w/ megastim, then getting an opposite gender DB-37 and soldering my 35 pin ECU pigtail wires on to it

I've been carefully reading and digesting information posted here and goathumper's tutorial here

Hopefully I'll be ordering from DIYautotune.com next week sometime. And of course I'll document the process and post pics

with any luck at all, in about a week or two I'll be searching for and asking for default tuning configs for the b27

edit: fixed url formating

alijonny · Post by **alijonny** » Jul 13, 2009 11:20 AM

Just got my MS back! plugged it into my car for a quick startup and I have RPM range!! Now I need to bring my laptop and do some data logging.

Post by **Brad D.** » Jul 13, 2009 11:27 AM

What ended up being the problem?

russc · Post by **russc** » Jul 13, 2009 1:00 PM

Ya, please go tell?

RussC

alijonny · Post by **alijonny** » Jul 13, 2009 1:08 PM

Peter said he changed the VR input to be more like the 3.0 box (change SMD resistors). He also said there were 2 pots bad on the jimstim.

alijonny · Post by **alijonny** » Jul 14, 2009 8:20 PM

I took the car out for a spin finally! The car has some real light bucking issues at lower RPM on takeoff, otherwise seems good for getting the bugs worked out. My laptop decided to have a dead battery (of course) so I have that on the charger for tonight. WB numbers were between 12-14 I didn't pay too close attention (or datalog) as I was just putt-putting around the block. RPM is high at about 1500 rpm, but everything seems to be doing what it is supposed to be doing.

Lee in Ottawa · Post by **Lee in Ottawa** » Jul 15, 2009 7:18 AM

So I fixed my TPS problem, and found out my voltage proplem.

When my wideband (which I spliced into the factory harness as per goat thumpers instructions) is plugged in megatune shows 3.9 volts. When I unplug it it goes to 12v.

Do I have a wire crossed? Should I just be connecting it straight to the main relay?

Post by **Brad D.** » Jul 15, 2009 9:49 AM

Ali your bucking could be timing related (too much advance) or it could be too lean. Your wideband will tell you that. From here on out, make sure you datalog everything so you have data to look at if the car does something weird.

alijonny · Post by **alijonny** » Jul 15, 2009 11:57 AM

definately!

alijonny · Post by **alijonny** » Jul 17, 2009 7:44 PM

well, I got the car all going, problem is, I got myself into a hurry and ran over my laptop's power inverter

. so now the laptop's battery is dead and I am now waiting on a replacement. BOOOO. The good thing is I got the exhaust all done (need to post pics now) all 3" mandrel bent. yeah! The car runs and drives, but I try to not to drive it as it has a low rpm bucking issue that needs to be ironed out. It will drive well under load like second gear, but first gear and idling down the road at a steady state will set the car bucking. I dare not build boost yet, I have not attempted to at this point. boy I can't wait until I get this car worked out. I have saved datastream, but cannot access it since the laptop battery is dead!

edit: back in business! got the laptop up and running, now I need to figure out how to post the files.

alijonny · Post by **alijonny** » Jul 18, 2009 1:13 PM

this is just slightly holding the throttle above idle and doing nothing more. It will rev up fine, but if you try to hold a position with the throttle, it will start breaking up. no backfires or anything though. I will start looking into other things myself, but want to see if anything is sticking out like a sore thumb to the veterans.

THANKS!

russc · Post by **russc** » Jul 18, 2009 5:16 PM

Not enough info, need accel. enrichment, AFR, timing. I bet the timing is jumping all over.

RussC

alijonny wrote:this is just slightly holding the throttle above idle and doing nothing more. It will rev up fine, but if you try to hold a position with the throttle, it will start breaking up. no backfires or anything though. I will start looking into other things myself, but want to see if anything is sticking out like a sore thumb to the veterans.
THANKS!

alijonny · Post by **alijonny** » Jul 18, 2009 5:28 PM

I need help figuring out how to do that. The car runs little bit better after setting and changing a few things, but still isn't right.

Post by **Brad D.** » Jul 19, 2009 1:37 AM

Can you post your timing, VE, and acceleration enrichement pages? Screenshots will work.

FirstFives Dictator · Post by **FirstFives Dictator** » Jul 19, 2009 10:09 AM

You're getting false Acceleration Enrichment triggers. Increase your TPSDot threshold until they stop.

MS2 AE docs are out of date, but I've posted my drafts here

http://www.pftuning.com/megasquirt/docs ... html#accel

You may need a value higher than 50 as the calculation of TPSdot (rate of change of TPS) has changed as of May 2009 releases.

alijonny · Post by **alijonny** » Jul 20, 2009 3:44 PM

sweet that seems to have worked.

alijonny · Post by **alijonny** » Aug 19, 2009 6:14 PM

can someone please show me how I can load an entire file from my megalogviewer to the internet? I have some files, but can't seem to figure out how to do it. BTW, do I have to purchase the entire MLV to do more? I saw a spot to buy the licenseor something. Thanks!

Post by **Brad D.** » Aug 19, 2009 6:24 PM

You don't have to buy a MLV liscense, it will just ask you to register each time. I went ahead and registered it as I had no problem paying for the product as it was instrumental in tuning my car.
As for uploading your files, use something like fileshack or rapidshare to host them. Someone else may be able to recommend a better solution though.

turbodan · Post by **turbodan** » Aug 19, 2009 6:33 PM

I use 100% TPSdot accel enrichment. With MAPdot I was getting erroneous accel triggers as MAP fluctuated under boost. TPSdot can be made to work very well.

I have my TPS threshold at 4%/sec. The lower the better until you get into the noise. I also use different accel PW settings: .3 seconds accel time, .3 taper time and 0 MS end PW. Works great for me and my code variant. A 2 MS end pulsewidth would be huge with the injector sizes I'm used to. Gotta be careful with settings like that.

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E28 Megasquirt FAQ