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Who’s done 318 Jetronic EFI with MAF conversion?


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20 hours ago, 2002iii said:

That is the same thing used on e21 320i with k jetronic fuel injection. Look

Ha, shoot, well I guess that makes it all even one step easier!  I thought the 320s used the ICVs like the later E30s, my bad!  So yeah, if you have the old aux valve with that motor, just keep it for warmup regardless of whatever engine management system you use! :P

17 hours ago, irdave said:

(Although I'd have to think you can get an AFM for next to free as well- what terrible inventions. Mine came off a couple weeks ago and I have no intention of putting it back on.)

Truth spoken here! But for some strange reason, they routinely seem to go for real money, though I can't for the life of me understand why.  I think I listed the one out of my E30 locally for $150 and sold it for $120 or something, crazy!

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I'm still going to chime in here with a vote for Microsquirt as the best starting point.  Set it up for either speed-density (MAP based) or Alpha-N (TPS based), and basic single-coil ignition control

Seems like it's no more money and a hell of a lot less time to trash the Motronic system and install a low cost (that's all it needs for a M10) aftermarket ECU and ancillaries if you want to go MAF.  

It’s those funky period-correct folks ...

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1 hour ago, AustrianVespaGuy said:

Ha, shoot, well I guess that makes it all even one step easier!  I thought the 320s used the ICVs like the later E30s, my bad!  So yeah, if you have the old aux valve with that motor, just keep it for warmup regardless of whatever engine management system you use! :P

Truth spoken here! But for some strange reason, they routinely seem to go for real money, though I can't for the life of me understand why.  I think I listed the one out of my E30 locally for $150 and sold it for $120 or something, crazy!


It’s those funky period-correct folks ...

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Setting up the E30/M3 ICV is not that straight forward.  What the E30/M3 diagrams do not show is the need for 3 wire bi-directional control at 100 Hz with Main and Slave circuit control.  If the ECU can handle it, use it.  If not, then use a open closed solenoid valve with a throttling orifice or needle valve for trimming or baby sit the throttle.

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3 hours ago, Harv said:

Jim, do you use the Haltec can bus WB controller?

 

john

Not today, but will be ordering one next week.  Call it a delayed Christmas present to myself.

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On 12/29/2020 at 1:06 PM, Mucci said:

@AustrianVespaGuy - Ah! I wasn't aware of that MS unit. That's much more my price point. I had only seen the $1-2k setups. I'll look into it.

 

@irdave I don't see how a carburetor would be less of a headache than Jetronic.

I was the one that did the Volvo conversion. It worked great for what it was. It was also a system I knew well (I had a 740 turbo that I monkeyed with for a number of years.

 

What am I running now? Microsquirt...and I love it. I ultimately made the switch after rebuilding my engine and the LH started running rough. I thought it was the MAF, so I dove in with the full programmable, since it was about the same cost as replacing the MAF and other sensors. I came to realize that it was a failing pertronix unit that was giving a bad signal, but I don't regret moving on. 

 

Having said all of that, I've got mine tuned pretty well with standard speed/density, but I'd like to get back to using MAF like Jim. There's really nothing more accurate than actually measuring the air coming in, versus calculating what the engine *should* be bringing in ala speed/density. HTH.

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I just drove Martin’s 2000 with a Ben ten and his Volvo fi conversion. It’s very strong and the drivability was staggering. U-turn in 2nd gear and floor it at 900 rpm? Not a problem. 
 

Makes me look at my ITB setup. 
 

john

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  • 2 weeks later...

Firstly, sorry for the pseudo thread-jack. . .

On 12/29/2020 at 3:26 PM, jimk said:

Here is a trace of a cold start from my car taken about 1 week ago.  Notice the throttle was NEVER touched from cold crank to full warm.

Hey Jim, finally got around to doing this no-throttle warmup test also, good idea!  All in all I'm quite happy with it.  There's one little random surge in there that I can't explain, but for an open-loop stepper motor setup I think it's hard to have any complaints!  ~1800 RPM for 2 seconds when it first fires, then settles to a cold idle of about 1300, drops down to about 750 when the stepper closes down completely (170deg), then comes back up to 850 fully warmed up (180deg).  And ROCK solid AFRs at ~12.6 during cold enrichment and then 13.6 when warm!  What a fun log to grab, so thanks again for the idea!

 

image.png

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If your stepper control table allows a 2nd axis, I have mine set up to follow coolant on one axis like yours and a second axis that follows engine run time.  this allows quicker drop in rpm.  I listened to a modern car and there was the initial drop in rpm after the initial burn off of the priming fuel then after about 30 seconds the rpm drops again but not to the final rpm  (per Electromotive, it takes 30 seconds for flame to become stable).  From them on it follows coolant temperature only.

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