Any solution for difficult cold starts?
Any solution for difficult cold starts?
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.
Last edited by Syrihl; Dec 9, 2006 at 09:02 AM.
Newbie
Joined: Dec 2006
Posts: 8
Likes: 0
From: PA
Cold Start Tuning
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.
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.
Newbie
Joined: Dec 2005
Posts: 14
Likes: 0
From: Australia
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.
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.
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.
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Newbie
Joined: Dec 2006
Posts: 8
Likes: 0
From: PA
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
>>>
- 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
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.
