Megasquirt using 318i intake. (parts list mostly)

[slash02]

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When i did my MS project I had many questions as to what is actually needed for a megasquirt conversion. Here's my attempt to quantify the parts and stuff needed to convert your standard 02 to Megasquirt using a 318i intake. Best bet is the pick and pull. Some parts should be new and I will allude to which. I'll try to provide part numbers where nessecary.

Intake, Injectors, Fuel Rail :

Source yourself a Nice E30 Intake manifold with Fuel Rail, Throttle body and fast idle valve intact. Try to get the rubber boot and piping as well.

My suggestion: fabricate or have fabricated an adaptor that will allow an M30 throttle body to be used, they are a straight flowing, large bore no nonsene TB that I think makes for a nicer install. *note* after much driving

and such I have decided that an m20 throttle body will work just fine. you end up with quite a twitchy car with the m30 TB

**Update** I put an m20 throttle body on the 02, using a nice

m10-m20 throttle body adaptor from www.02again.com

Works much better, throttle response is more sane.

Throttle position sensor: Yes, MS needs a throttle position sensor, not a throttle switch. Bosch Part number :0 280 122 001 will fit the shaft, but will not bolt up to the holes. It is too small. I suggest building an adaptor. Measure the old throttle switch , note where the holes sit and measure the new one. They are I believe 90 degrees out from one another. build your plate, drill some holes and mount the new sensor to the plate and then mount the plate to the throttle body.

Fuel Rail: I suggest a very very hardcore cleaning on this. If there is rust, I would hesitate to use it, as rust may flake off and clog an injector. I did the following:

Clean the fuel rail in gasoline or varsol and get off all dirt and grease, next let dry and clean in muriatic acid solution (dilute about 10:1 water:acid) this shoul kill off the rust. *disclaimer* wear eye, and body protection and do this outside while standing upwind from the acid, its some very very mean stuff, but will get the job done...

Injectors: The stock E30 318i injectors are fine, they are about 13 pound per hour. Ford Crown victoria (the 4.6 litre engine to be most exact) has some nice yellow 19 pound injectors. they are ideal, high impedance injectors and are extremely plentiful at a PYP. You may also choose to buy them new, or do as a friend did and send 8 PYP injectors off to be cleaned and flow tested etc. be careful with non-bosch injectors, they may fit but you need to have the clips engage the slots on the injecors

Fuel line:

I reccomend the following. Buy 25-30 feet of stainless tubing and run your own fuel line. I ran mine inside the car, but I think that in the future, I'd run the fuel line under the car. 5/16th or 3/8th tubing works great

The return line is sometimes a matter of argument. later 02s have a steel line on them, but in my car's case its 30 years old and wasn't connected anymore. I just ran 2 new ones. Generally the return doesn't take all the pressure of the main line, but better safe then sorry, run a steel line for return as well.

Fuel pump:

Option 1 (under the car): If you've ever looked under an E28, you'll see a nice little bracket for the fuel pump and filter units. You could mount your fuel pump under the car's body and let gravity do its work. (or pilfer an in-tank transfer pump from an an early e30 (note to self:insert pn here) ).

Option 2 (in the fuel tank): Specifically a later model E30 325i has our saviour! A high pressure in-tank pump that fits the carby 02s fuel tank just fine. (i'll get to length in a bit). It clicks in just the same, and works like a charm NEW PART ALERT buy it new, yes they are expensive, but unless (like my lucky self) you can buy one that's month old then you are gambling.

The E30 pump and sender are too short for the 02. The sender works well, and honestly I dont mind it reading "low" when it's not as low as you'd think. I measured out the length of the original 02 pickup screen and just extended the pickup on the E30 part using a peice of house, a clamp, some JB weld and a few zip ties while the JB weld was setting. Pretty simple stuff.

You will have to run some wiring from the Megasquirt relay board to the fuel pump of course (I ran it same time I ran the fuel line), and depending on your option depends on where you run the line.

Sensors:

Coolant:You need to get the coolant neck from your 318i. The intake won't clear the 02 neck or a 320i neck (ask how I know ) Once again, the used parts guys or PYP are your friend. There is a sensor on that neck that you will need (note to self, pic and part number) for providing the MS coolant input with a temperature.

Intake Air Temperature sensor

Go to napa, ask for a GM AX1 sensor. That will be the easiest thing. I installed mine in the cone filter up near the front nose of my 02... Some people drill a hole in the throttle body and put them there, others put them

in the rubber boot. So Its a preference thing.

Wiring

Really, this is a bone of contention for most people, clean wiring is hard to

pull off. One thing you could do is retain the top part of the engine wiring from that 318i. its stock and looks nice, only thing is you will have to do some splicing and wiring tracing to get the correct wires to the correct places.

I opted to build my own wiring, it took some time, and I actually did it in 2 peices. I decided that at the firewall side i would use a pair of 4-pin connectors to allow me to remove the intake manifold more easily in the future *NOTE* use GM weatherpak connectors, buy the tools and plugs, the work like a charm and aren't ugly.

I heartily reccomend using the Relay board that you can purchase as part of the megasquirt kit. Reason being, the 2002 isn't an EFI car and does not contain all of the relays, fuses etc for running your system.

Ignition

You have a few options for ignition, i will just address the 2.

1) Stock: Stick with your stock igntion, however triggering the megasquirt can be finicky with this option. I still sometimes see spikes on my logs. What i plan on doing is running an MSD unit, and use the MSD tach output (nice square wave) to trigger the Megasquirt. See step 2 as to why i haven't bothered yet.

2)Ford EDIS: This is a fantastic opportunity to get rid of your !@#$%$! Distributor. The ford EDIS system is a wasted spark distributorless ignition system triggered via a 36-1 toothed wheel (a 35 toothed wheel). the megasquirt can control the EDIS brain and you can customise your advance/retard curves, also GONE are the valvetrain induced dwell flutters etc. YAY!

[Zenon]

Great start, Karel. Most of any detail I can add is here:

http://www.zeebuck.com/bimmers/tech/Megasquirt/preparation.html

However, since that was written (nearly two years ago!), I switched to some ~19lb/hr high-impedence 3rd-gen Bosch injectors originally from a Ford - I think a 90's 5.0. Got a set of 8 cheap on eBay. Bosch number 0 280 155 710, Ford F6VE-A5A. They look quite different but fit the same. They have four fine spray holes instead of one and no protruding pintle. The design is supposed to improve atomization, especially at idle - not so sure about that but at least they are a nice Colorado-ish orange.

One of my originals was dribbling anyway but I mainly did this to get a longer pulsewidth at idle since the 24lb injectors I was using were overkill for my stock low-comp engine. Also nice to simplify the setup by deleting the resistor pack.

I have also gone back to using the 318i throttle body and run the MS using MAP-based accel enrichment triggering. Ideally I would adapt a linear TPS but it has been fine using the original throttle position switch wired with two resistors to give OV at idle, 2.5V anywhere in between, and 5V at WOT so the flood clear and overrun fuel cut functions are still available. The 318i TB might be a bit small but my engine pulls hard up to ~6K and hits the rev limiter easily enough in 1st and 2nd so I am plenty happy. Great low-end torque and smoothness with the 318i manifold, at least with the stock cam.

Look forward to seeing more.

regards,

Zenon

[robspeed]

thanks guys!!!!!!!!!!!! =)