Megasquirting a 5 cylinder; some of what you need to know

[Alex Buchka]

I recently wrestled with this and I decided to get the most important information down in one place to make it easier for other people. This will NOT be a hold-your-hand-every-step-of-the-way guide. If you need an article like that you shouldn't be megasquirting an engine in the first place, let alone a 5 cylinder that requires some of the most complicated setup there is. When I say MS in this article I will be referring to Megasquirt-Extra running the latest 029y4 firmware. Also the engine I did this on is a '94 b5234t with S80 T6 ignition coils. I believe the information presented here should be applicable to any 5 cylinder built before '99 (possibly '01 but I'm not sure).

I'm going to assume all throughout this article that the reader is familiar with the setup and operation of megasquirt. If not, I strongly suggest you read the megamanual and the MSExtra manual several times first.

RPM signal/triggering and ignition settings:

MS MUST be run in second trigger mode using the generic wheel code. The engine has a 60-2 trigger wheel on the crank with a VR sensor and a one tooth cam wheel with a Hall sensor. You want to set up megatune exactly as is listed here:

http://www.msextra.com/manuals/MS_Ex....htm#5cylinder

EXCEPT, for a few things. Dwell should be set to 3.0ms cranking and 2.7ms running and the last screen with trigger positions and trigger return should look like this:

IMPORTANT: I made a mistake with this screenshot. Base teeth should be set to 120, NOT 60 as it says in the picture.


Cam wheel setup:

This gave me more grief than any other single thing, so read carefully. The wheel decoder takes the second trigger signal as an indicator that the next missing tooth is where to reset the tooth count. The second trigger needs to pass the sensor about 40-50 degrees BEFORE the missing tooth you want to be the start of the count. Take the little trigger wheel disc and grind the indexing tangs off, then turn the wheel so it's about to pass under the sensor when the crank sensor is 8 teeth before the missing tooth, then tighten it down hard.

S80 T6 ignition coil information:

IMPORTANT UPDATE: Use these coils at your own risk. I chased a resetting problem for weeks that was fixed by replacing the S80 coils with 960 coils. I soldered a +5v pull-up for each ignition output and connected them to 960 powerstages. The information in this section is being kept for posterity and for the part numbers listed.

These are internally identical to Bosch Motorsport Single Fire PT coils but with a 4 pin connector instead of a 3 pin. The pin out is as follows:

1 - Trigger
2 - Not Used
3 - Ground
4 - +12v

These coils pull to +5v to fire so the spark MUST BE SET TO INVERTED, this is VERY IMPORTANT. If you don't do this you WILL burn up the coils.

Unless you pull these of an S80 T6 and get the connectors and wiring included, you will need new connectors. These can be had from Volvo on special order. Getting part numbers was a royal pain in the ass and took me quite a while (thanks to doug for digging these up for me):

The plastic connector itself is part number: 9456341
The +12v feed pigtail is part number: 30656689 (you will need 5 of these)
The ground and signal pigtails are part number: 30656688 (you will need 10 of these)

VR and Hall Sensor information:

I used a V3 pcb which has a VR conditioner and an opto isolator on board. Lucky for us they are completely separated from anything else on the pcb so they can both be used at once for dual trigger applications. The VR sensor gets wired up just like normal according to MS instructions and the Hall sensor is wired up according to this diagram:




Coolant temp sensor resistance table:

Temperature F (C).....................Resistance (ohms)
32 (0) .............................................. 7300
68 (20) ............................................. 2800
176 (80) ............................................. 300
212 (100) ............................................ 150

Use this to configure easytherm.

[the poi]

And I'll cover MSII-e and 6cyl COP (and sorta PnP 960) in this post woo

[MikeSr.]

I guess this question is to POI- how do you get around emissions testing with MS?

[Karl Buchka]

Minor correction (until Alex can edit the image): The wheel decoder base teeth setting should be 120, not 60.

Fixed.

[JohnMc]

Originally Posted by MikeSr.

I guess this question is to POI- how do you get around emissions testing with MS?

Well, it sounds like this was a '94, so as long as it passes a casual visual inspection and has cats and a good tune, ti should be able to pass a tailpipe sniff test.

A 95+ OBD2 car would have to be able to fake a good OBD2 port readout. I wonder if anyone will ever write that into MS II?

[AndrewEG]

Buchka boys how are you going to wire up the twin knock sensors on the block? Thought it might be a bit of an issue if only one was wired up and couldn't detect knocking at the opposite end of the engine. The ecu i've got can only handle one :(

[Karl Buchka]

You can connect them in parallel.

[powernut]

Originally Posted by the poi

And I'll cover MSII-e and 6cyl COP (and sorta PnP 960) in this post woo

hi couple of reasons if anyone can assist with any furthur info on the 850 t5 on ms
first is this a ms1 or ms2 on a 850 t5
dose anyone have the stock ecu pinout numbers/colours to to ms colours
unsure why the trigger is set to 120?some nice person will explain , as i thought they had a 60- 2 teeth missing
as i want to order my ms (what ive read i pref the ms2 )
if anyone can possible with firmware and a base msq on the t5 it would be very great as im new to the volvo engine tbh , its mostly the settings that i may have a problem with

second point is ive run megasquirt 1 v3 on my r32 hybrid turbo 4wd engine of 25psi with no problems and ive also upgraded to the ms2 , reasons mostly because of the more ram/faster processor , and managed to contect the vvt timing with this as well ,

[bmvvm5@hotmail.com]

thanks for the help

[jacobrussell]

so i know this is a old post and im fresh to volvo tuning..

the ms needs to run simutanius fire and has to have both the vr wheel on the crank and the opto on the dizzy becuase we need a 180 or 360 rotation refference correct(becuase its 5 cylinder)?

[Karl Buchka]

Originally Posted by jacobrussell

so i know this is a old post and im fresh to volvo tuning..

the ms needs to run simutanius fire and has to have both the vr wheel on the crank and the opto on the dizzy becuase we need a 180 or 360 rotation refference correct(becuase its 5 cylinder)?

I'm struggling to make sense of your post.

Assuming you mean simultaneous fire? I don't know what that is. Rotation difference between what? Since one complete four stroke cycle comprises two crank shaft rotations we need the cam sync to let the MS know where in the cycle it is.

[thebornotaku]

Originally Posted by JohnMc

Well, it sounds like this was a '94, so as long as it passes a casual visual inspection and has cats and a good tune, ti should be able to pass a tailpipe sniff test.

A 95+ OBD2 car would have to be able to fake a good OBD2 port readout. I wonder if anyone will ever write that into MS II?

^this

Pre- OBD-II cars can pass if you tuck all the wires and such well and make it look factory.
OBD-II cars will take a little more trickery.

If not in MS, you could probably program an Arduino or somesuch to output to the OBD-II port and spoof the data (just program the thing for what it needs to say).

[Anders-R32]

Can you use the original coil and the IGN Chip on the coil board on a 4 cyl ?

[Tom_]

Hi,
I have a noob question,can i use this setup on Audis I5 , especially a 7A engine ?I want to turbocharged it,but i am looking for a ecu,which is not too expensive and MSII have a very good prize.

Thanks

edit : sorry,now i noticed,that is a Volvo forum.

[Karl Buchka]

These trigger settings are for MS1 with a 60-2 crank trigger and a single tooth cam wheel. So if you change trigger wheels and don't use MS2, sure.

[Tom_]

i want to use a 60-2 trigger wheel.How does it mean that "single tooth cam wheel" ? And if use a 60-2 tw and msII ?Do not works?

[Alex Buchka]

You can pretty much use whatever trigger wheels you like, but this particular guide is tailored for the combination Karl mentioned. For MSII this thread is of no use to you.

[Captain Bondo]

Try here, mostly VEMS guys but some run MS as well:

http://www.s2forum.com/forum/forumdisplay.php?f=61

[Leon_pp]

Is anyone have a general MS wiring for 5 cyl?

[Karl Buchka]

It's basically identical to any other MS install.

[Leon_pp]

I had a doubt about wiring 5 injectors.
So i will connect 3 injector to bank #1 and 2 to bank #2

[Karl Buchka]

You might as well just wire all five to one channel.

[JohnMc]

Or if you're feeling frisky, use MS2X and run sequential injection. MS3X also makes COP's ridiculously easy.

[Leon_pp]

I am lloking for Megasquirting a '98 S70 2.5T with the original wiring harness (except for the 960 COP),

[gross polluter]

Originally Posted by JohnMc

Or if you're feeling frisky, use MS2X and run sequential injection. MS3X also makes COP's ridiculously easy.

MS2 only has 4 injector channels.