First/Cold start issue, AND Warm running issue.

KoN_mkII · Post by **KoN_mkII** » Thu Jun 08, 2006 8:16 am

Okay, I'm running a VW 16v engine with Msns-E. MT 2.25. Extra024s13c.
Using stock distributor/Hall sender setup.

My problem that I've been battling since I've gotten the thing running, is getting the car to start and idle on its own from a dead cold start. It cranks, and starts everytime, but runs for hardly a second before dying. If I hold down the throttle (pretty far) it will start and rev up, and I must hold it at around 3000 RPM's for a couple seconds before it will idle on its own. If I let it drop down to around 2000 RPM's, it stumbles and dies no matter what I do do the throttle. If I barely touch the throttle after it starts, it dies immediatly. If I don't touch the throttle after it starts it dies immediatly. I'm pretty sure my warmups are up to snuff. Once I get the car idling on its own (after a couple tries, or holding the RPMs way up), the AFR is fine throughout the rest of warmup.

However, I have no idea what to do as far as afterstarts. I have them really low right now, but they don't seem to do anything regardless as to where I put them. I'm pretty sure the car is leaning out right after it starts. The 02 isn't warmed up by the time I start, so I can't be positive, but it does behave that way (dies as soon as I touch the throttle, white smoke comes out the exhaust when I have to hold it up at 3k). I'm not really sure where even start with this. Once the car is warmed, or after I have held the RPMs at around 3 for few seconds, the car will idle fine and run well. It will startup fine when warm, and behave normally.

The only warm running issue I have, is that after a while of driving (higher temps), the idle seems to go to crap, and it starts idling really poor, and sometimes stalling when I come to lights, etc. Any ideas there?

I'll post up my current MSq, but I doubt it will be much help.

renns · Post by **renns** » Thu Jun 08, 2006 8:53 am

Given it's only for the first few seconds after start, it sounds like your after-start enrichment (ASE) entries seem low. Try adding 10 to all ASE table entries, and re-test. Then try adding another 10 if needed. This should make a significant difference in fueling, as this is added on top of the warmup enrichments.

Roger.

KoN_mkII · Post by **KoN_mkII** » Thu Jun 08, 2006 9:09 am

Just looking at the ASE table, I noticed something that could be an issue.

I have the ASE Timer put to *cycles, and the ASE TOTAL time: set to 0. Does this mean that they are turned off?

renns · Post by **renns** » Thu Jun 08, 2006 10:02 am

OK, I just configured MegaTune to read that old .msq. Yes, you have ASE disabled by setting the time value to 0. Set it to 200 or so, and re-test. You should see an immediate difference, and can then bump up the ASE values if needed.

KoN_mkII · Post by **KoN_mkII** » Fri Jun 09, 2006 8:25 am

Do I have to set the ASE's to Sec rather than Cycle to see a change with the higher time value?

Also, any ideas with the warm running issue? It seems that if I drive around for a long time (usually over an hour), the car starts to idle poorly, and wants to stall when I rev it up and let the RPM's go back to idle on their own.

bertelli_1 · Post by **bertelli_1** » Fri Jun 09, 2006 9:10 am

I have an 8v Digifant Golf with the same version of MS as you on a V3 board and use the following settings -

ASE timer - cycles,
ASE TOTAL time - 250,
ASE mode - decay,
MAP mode - normal MAP.
My enrichment table is set to 30% at -40c to 6% at 54c.
Warmup enrichment is 160% at 4c to 120% at 54c
My accel wizard is TPS based, at 15.1 v/s it is 6.0ms. At 1v/s it is .7ms

The standard Megasquirt figures were a long way off ideal for my engine (in particular the accel enrichment was way too high) these figures should be a good starting point for your engine.

Re: your warm idle issue - I had a similar problem but just retuned my VE table when warm and it has been ok since.

Hope this helps.

bertelli_1 · Post by **bertelli_1** » Fri Jun 09, 2006 9:16 am

Just one other thing, I don't use the idle control valve and the car will idle poorly for a minute when cold. I believe KeithMac runs a G60 Golf with an idle valve.

KoN_mkII · Post by **KoN_mkII** » Sat Jun 10, 2006 7:38 am

Yeah, I'm not running an ISV either, but it idles fine. Or good enough rather. It's still a little floaty, like it doesn't like to keep a solid RPM for very long, but usually its in the ballpark.

My warm issue isn't a VE table issue. The car runs great when warm, and is tuned pretty well. My problem only occurs after a long time of driving. I'm guessing maybe because the intake temps are so high? It starts leaning out maybe. Perhaps I should have located my IAT sensor further away from the motor? Or does it use coolant temp?

superelbert · Post by **superelbert** » Sat Jul 08, 2006 12:29 pm

Initially, I had a lot of issues with my IAT sensor, in particular on hot re-start as it would heat-soak anf fool the MS in to thinking the intake air was lots warmer than it was...

Initially, I had the IAT sensor mounted in the throttle body, but It soon became obvious thayt I'd underestimated how hot it could actually get there, heatsoak in no time!

The sensor was ultimately placed at the intake to the air filter box.

Still, i was using a coolant sensor for IAT, and due to its mass, it did heatsoak some, and was thence replaced with an open element sensor. Thje open element sensor will allso heat.soak, but due to the very low mass of the sensor element, it cools down to ambient allmost instantaneously as the first gulps of air rush by during cranking!

This is what did the trick for me, hope it can be of any help!

Megasquirt Support Forum (MSEXTRA)

First/Cold start issue, AND Warm running issue.

First/Cold start issue, AND Warm running issue.

IAT sensor position