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VW bus S40 Cold starting

Posted: Thu Jun 25, 2015 7:43 am
by yakboy
High a newbie here. I have a VW split bus with a 1776 engine. Have recently had a VW speedshop injection kit fitted with 38IDF throttle bodies and an S40 pro ECU. Me and my local tuners (Dynobike in Malton) are having a little trouble getting the cold starting programme right we have got everything else on the map dialled in fantastically but at the moment the starting map is very unsubtle and basically throws fuel at the engine for the first thirty seconds so the engine is as rough as a badgers a*r*e and still stalls unless you keep you foot on the gas. Does anybody in with a VW and a similar setup have any tips or a map they could share. Thanks in advance.
Simon

Re: VW bus S40 Cold starting

Posted: Thu Jun 25, 2015 10:52 am
by stevieturbo
Such settings are always trial and error.

But most importantly...it's all very well throwing fuel at a cold engine, but it also needs air.

And 30 seconds for warmup is nowhere near enough, and 30s for cranking enrichment is far too much.

Get good hot starting sorted, zero all temp related enrichments etc, then wait til it;s cold and work from there.

Some engines will need a lot, some very little

Re: VW bus S40 Cold starting

Posted: Thu Jun 25, 2015 3:08 pm
by Rob Stevens
As Stevie says, get the hot start and idle bang on first. then look at the cold start. I no longer use water temp compensations , I rely only on start up map only. Engine will need a little throttle (AIR) to start,.

Re: VW bus S40 Cold starting

Posted: Thu Jun 25, 2015 3:52 pm
by stevieturbo
If you dont use an air valve.

Set hot idle at say 2-300rpm higher than you'd like with say 20-25deg of timing ( assuming engine is happy at that )

then use ignition timing idle control to pull the rpm back down again for the hot idle.

Then when the engine is cold it should have sufficient air to achieve a decent fast or at least normal idle with the higher timing restored.

Re: VW bus S40 Cold starting

Posted: Fri Jun 26, 2015 2:37 am
by ignitionautosport
What stevie said.

I love the closed loop ignition timing idle - I just let it run open loop with reaosnably loose parameters and adjusted the throttle till it ran around 5 degrees at idle when warm. Then rechecked cold and it was fine. Guys wife actually drives the thing daily now lol. A Land Rover with a Holden(Buick) 3.8L V6.

The Start fueling map is a bit odd and can vary between engines a lot I've found. It works really well once set up though, and (as the others have said) I would think you might be lacking the associated air if you need to hold the throttle on a bit.

Re: VW bus S40 Cold starting

Posted: Tue Jun 30, 2015 5:06 am
by yakboy
Thanks for all the replies. I will take this info to the tuners on Thursday and see if we can get it sorted. It does sound like I have insufficient air initially

Re: VW bus S40 Cold starting

Posted: Tue Jul 14, 2015 8:05 am
by PhillipM
I used to have a VW 2.1 in the back of the buggy - you need plenty of air to get the thing started and warmed up, they like a good slug of fuel to prime the ports too - that way you don't need quite as much in the initial startup map.

Re: VW bus S40 Cold starting

Posted: Tue Nov 17, 2015 8:06 am
by rjwooll
Another tip from my own experience - make sure you're getting the full voltage to the ECU. In my case there was a voltage drop to the S40 and although hot starting was fine, cold starting was a b***er. I spent an entire winter tuning and retuning the cold start settings, but all was fixed when the voltage drop was discovered and a revised feed connected. This may particularly affect older vehicles where the power comes through the old wiring.

ATB Richard

Re: VW bus S40 Cold starting

Posted: Mon Jan 25, 2016 2:27 pm
by CRC
Hi, would you mind sharing your maps . I am just starting to programe 2.1 Vw boxer and it would help a lot
thanks

Re: VW bus S40 Cold starting

Posted: Wed Jun 20, 2018 8:56 am
by erniebay
Hello there I am picking this topic , as I have got a Vw 1914 air-cooled with dta S40 and the same Vw speed shop set up.
I have got really bad starting, but once get hot is running all OK...
I got al the idle parameters reasonable adjust, but still I can get rid of the long crank?? Any suggestions
Thanks