Cold Start Injector

[RadioTek]

Sincere apologies if this has been covered before, but what I could find with a search didn't answer my question.

I'm installing a MegaSquirt into a Mercedes 450SL, with a Bosch D-Jetronic ignition system. It sort of seems like an ancestor to the MegaSquirt. TheBosch system has an extra injector that fires a shot of fuel when the ignition is first turned on and the coolant temperature is less than a given value.

Does the MS have an output to connect to this, or does it take care of that by an initial shot from other injectors?

Thanks,
Scott

[DonTZ125]

Not exactly. The 'priming pulse' happens on power up, before cranking, but it's more to purge the rail and injectors of air. Once you actually start cranking then running, the 'Cold Start Enrichment' and 'Warm-up Enrichment' come into play; these are multipliers to the pulse-width calculations based on air and coolant temps.

Not to be rude, but it sounds like you need to start burrowing your way through the manual. Welcome to the addiction, and start learning!

[RadioTek]

Thanks, I'm just beginning here, so I don't have the "feel" for what info is where. Again, sincere apologies.

It looks like the CSI isn't really needed, the function is taken care of elsewhere.

This looks like it could be a fun project. I hope I can get enough experience to pay back for all the help I'll get from this group before I'm done.

Scott

[DonTZ125]

No worries - I too had 3 posts once, and asked LOTS sillier questions. I figure a 35-year Electronics Tech who could tear apart a mess like an old D-Jet system will have few real issues getting a handle on the MS system. As you say, it's just figuring out where to look.

[kjones6039]

FWIW......

GM also used a cold start injector in it's TPI setup. I deleted it with no problems.

Ken

[trakkies]

I had a similar system with my Lucas injection on a Rover V-8. The cold start injector was entirely independent of the injection ECU being operated by a thermotime switch. If it's the same you can retain it with MS - or remove it. MS can be set via cranking pulsewidth to cope with either. I've tried both.