Siemens 630cc injectors

[Biggy]

Did anybody have any problems with Siemens 630cc injectors? Having troubles with cold start on these injectors.

[EspenW]

What fuel pressure are you running?

Specific map for the 630's or have you adjusted fuel pressure?

[Jamo]

Has the car been remapped for the injectors? Sounds more like a mapping problem than the injectors themselves as the ECU tells them how much fuel to use at startup

[Biggy]

I'm using 3bar FPR, MS-based standalone ecu, so the mapping is custom. If you spend a couple of hours and get it started, it warms up, idles and runs perfect. The problem seems to be only on cranking.

If I make priming pulses short it doesnt even tries to start, if long enough to to start - it flood the sparks instantly. Injectors are new, but I tested them. Flow matched, seal perfect and spray fine.

Yesterday I got it started, and had a short ride. Runs perfect as always. Today I didnt even try to start it, took off all 5 injectors and they were wet, so were my sparks. Looks like they dont seal properly for some reason.

I'm confused.

I borrowed RC 750cc from my friend. Will try to make fit them tomorrow. If they work fine then Siemens are piece of s##t.

[Jamo]

Yeh it's mapping mate, cold starts are the one of the hardest things to map on a standalone ecu sounds like your putting in too much fuel on startup

[Biggy]

Yeh it's mapping mate, cold starts are the one of the hardest things to map on a standalone ecu sounds like your putting in too much fuel on startup

If i dont - it never starts.

otherwise - no problems with adu injectors. you can roughly map cold start and it WILL start anyway.

[Jamo]

And? the smaller the injector the more tolerance in mapping you will have.

[EspenW]

I've got the same injectors. Mine is running a map for ADU injectors @5 bar. However, AFR at boost and high rpm yielded 15:1 plus, so that was way off.
Got the 630cc's in, adjusted pressure down to 2bar, and it runs perfect on straight gasoline. Cold start and idle no problem. Tuning for E85 now, will probably end up right around stock fuel pressure once the 044 is in. The stock RS2 pump (supposedly 040) didn't deliver enough juice under boost, even if it sees 14.5v at the pump.

[gnutz2]

I run these injectors on mine and they are fine. It starts from cold perfect with no flooding so the problem you have is a mapping issue (I run DTA).

IIRC mega squirt has water temperature vs enrichment and water temp vs No of engine turns and injection time (in m/s) on cranking, so i think you have to play around with these.

When speaking to my mate he said that the lesser versions of ms use lower resolutions for injection time so controlling big saturated injectors could be a problem but i am not that exactly sure.

Mine idles at around 2.5 m/s when hot but not sure on cold.

[Biggy]

And? the smaller the injector the more tolerance in mapping you will have.

I agree. But anyway we have no problems on the same engine with RC 750cc...

I run these injectors on mine and they are fine. It starts from cold perfect with no flooding so the problem you have is a mapping issue (I run DTA).

IIRC mega squirt has water temperature vs enrichment and water temp vs No of engine turns and injection time (in m/s) on cranking, so i think you have to play around with these.

When speaking to my mate he said that the lesser versions of ms use lower resolutions for injection time so controlling big saturated injectors could be a problem but i am not that exactly sure.

Mine idles at around 2.5 m/s when hot but not sure on cold.

1,6-1,7ms at idle when hot. 1,8 cranking when hot.

what cranking pulses do you have?

[gnutz2]

My engine is in bits at the moment so i cannot really run it to find out.

Are the 750cc rc injectors low or high resistance?

[Biggy]

My engine is in bits at the moment so i cannot really run it to find out.

Are the 750cc rc injectors low or high resistance?

high.

why r u asking?

[gnutz2]

high.

why r u asking?

I read somewhere that saturated (high) can take longer to open than peak and hold (low).

But i would take it with a pinch of salt, whan speaking to allan at DTA (where i bought my siemens injectors) he said peak and hold injectors are a load of rubbish.

[Mark Halligan]

Funny I am having the same problem with my 630cc Seimens since I changed my IM. Perhaps I had a slight leak in the old IM and thats thrown the mapping out?

It still needs finishing so I'll get it sorted then.

[Jamo]

I read somewhere that saturated (high) can take longer to open than peak and hold (low).

But i would take it with a pinch of salt, whan speaking to allan at DTA (where i bought my siemens injectors) he said peak and hold injectors are a load of rubbish.

I hope not as I have RC 750 high injectors