Any solution for difficult cold starts?

Syrihl · Dec 9, 2006, 09:55 AM

Ever since the weather started getting down to the 30's and 20's overnight, I've been having problems starting my car in the morning. I am running the plug-in EVO 8 Autronic board SMC 1.99 in my '03 Evo. I've searched through the Autronic forums and messed with the Crank Ignition Timing, advancing up to 40 degrees and I've also richened my cranking fuel to about 10 above idle values. Battery voltage is above 12V for cranking. These helped out a little but it still takes me about 2-3 cranks at 5 sec each for the car to start first thing in the morning. Any time later in the day after the car's warmed up it's fine. Any help or tips would be appreciated.

2k4EvoVIII · Dec 14, 2006, 05:36 PM

If you want you can send me your map and i can see what i can do. I have a SM4 myself.

Chris

Ackerson · Dec 18, 2006, 02:40 AM

Sounds like not enough fuel during startup. Is there a fuel correction table based on coolant temp? That would be the first place I would look.

Lugnuts · Dec 19, 2006, 12:12 AM

Go to:
Menu M-5 , P-S (Post Start) Enrichment Mult

and

M-5 , P-S Enrichment Timeout.

The P-S Enrichment adds fuel during cranking and poststart conditions.
You have to watch the Timeout setting though.
When a start is attempted, and fails, the timeout setting counts down backwards to zero before it resets. This in some cases (high timeout setting/too low ps fuel setting) will cause poor cold starting.

Example:
p-s mult setting 2.0
p-s timeout 10 seconds

First start fails, cranking time was 10 seconds, after which the fuel decayed to 1.0(no enrichment).
The timeout will then count from 10 to zero before adding the enrichment back in.
So if you were to immediately hit the key again after the first start there would be insufficient fuel to start the engine.

Solution, raise p-s mult setting, lower p-s timeout setting.

Syrihl · Dec 19, 2006, 12:06 PM

Nice, thanks for the advice. I'll try it out.

Lugnuts · Dec 20, 2006, 09:35 AM

No problem.
Keep in touch with the results either here or PM. Maybe we can post the results once you have it nailed.

quadcam · Dec 23, 2006, 04:06 PM

Quote:

Originally Posted by Lugnuts

The P-S Enrichment adds fuel during cranking and poststart conditions.
You have to watch the Timeout setting though.
When a start is attempted, and fails, the timeout setting counts down backwards to zero before it resets. This in some cases (high timeout setting/too low ps fuel setting) will cause poor cold starting.

Example:
p-s mult setting 2.0
p-s timeout 10 seconds

First start fails, cranking time was 10 seconds, after which the fuel decayed to 1.0(no enrichment).
The timeout will then count from 10 to zero before adding the enrichment back in.
So if you were to immediately hit the key again after the first start there would be insufficient fuel to start the engine.

Solution, raise p-s mult setting, lower p-s timeout setting.

From my understanding the timer works slightly differently. I think the PS timer does not start counting down until the ecu determines that the engine has exceeded cranking speed (maybe > 400rpm ??). Then it starts to scale the multiplier out over the time set at that temperature. So be careful that you don't wet the plugs with extended cranking with a high PS multiplier.

Also be aware that the ecu takes the highest value of the WU and PS tables, it does not apply them together. So as the PS tapers down after a start when its value goes below the value in the WU table at that temp / load the ecu swaps tables.

For slow starting I would check your stepper setup and IAC parameters, particularly the IAC Min RPM value. If the stepper is set to do a Closed direction recal then the stepper won't start to open to assist starting until the IAC Min RPM value.

Lugnuts · Dec 23, 2006, 06:54 PM

From my understanding the timer works slightly differently. I think the PS timer does not start counting down until the ecu determines that the engine has exceeded cranking speed
>>>

- Yes that is correct, the P-S mult does not begin to decay until cranking rpm is detected.

<<<For slow starting I would check your stepper setup and IAC parameters, particularly the IAC Min RPM value. If the stepper is set to do a Closed direction recal then the stepper won't start to open to assist starting until the IAC Min RPM value.>>>

- good info

evo_08 · Dec 23, 2006, 07:04 PM

i had an autronic it was fine during the summer but very agrevating in winter.

Hic · Jan 2, 2007, 02:29 AM

I use mine sm4 at -30C every winter without problems. Your map has to be a bit wrong.

Lugnuts · Jan 3, 2007, 10:08 AM

hi Hic ,how about posting your settings, or a log showing a cold startup.
Or you can send to me and I'll post a screenshot.

Hic · Jan 11, 2007, 04:28 AM

Hm...did you removed your resistor pack for injectors? These are know for making cold start hard!!! It just came to my mind, sorry

Hic · Jan 17, 2007, 05:18 AM

Any news on this?!?!?!

Syrihl · Jan 17, 2007, 07:42 PM

Ray Hall suggested removing the injector resistor pack too but I think I'd have to remap the ECU afterwards, which I wouldn't know how to do. I checked the IAC minimum engine RPM value which is set at 0 RPM, so it shouldn't be a problem. Fatbastard helped me alter the W-U and P-S values, increasing the enrichment values a little bit. The changes helped a little but I still have problems in the morning when it's been 30's or below. How high is too high of a multiplier value? The W-U Enrichment Multiplier is at 1.5 for 0 Celsius.

Mark S · Jan 18, 2007, 10:52 AM

You will have starting problems if it is to rich also you need it tweaked by someone with a proper wideband meter.

Mark