Can wont start in Cold

[vtirulz786]

I have a honda civic 1.8 VTI powered By Hondata s300. Here in the UK weather is very cold in the mornings. I noticed my car wont start in the morning without me pressing the pedal for about 5 seconds, after that it starts perfectly fine.

Spec List is
Skunk2 stage 2 cams with cam gears
Skunk2 pro intake manifold
skunk2 full valve train
370CC injectors
aem v2 intake
tenzo r type 2 full exhaust system
walbro 255LPH fuel pump

Car has been professionalytuned on the dyno in the UK.

Its made great power.:)

I neeed some help on this cold start problem, i have tried to adjust the fuel cranking trim to 15% but this doesnt seem to have helped.

Your info would be helpful guys.

Thanks

[Johnny_9]

You will have to tune this over a series of days when the engine is cold - (this is not easy for a beginner and 2nd you need to track changes to cranking pulse, decay rates and ECTc at diffrence warm up temps)

First tune your warms ECTc with a wideband. Only then (the next day with a cold engine) tune your cranking pulse and decay rate.

------------------------------------------------------------------------------------------
STEP 1

If car wont fire, go to step2 , then come back to step 1

Warm up Fuel - This is what I am doing currently Turn OFF closed loop and richen/lean out the mixture at each ECT until the engine stumbles, then use the mid-point. Jumper the service connector to remove the delay in ECU response to changes in ECTc Then enable Cloop. Note the HO2/STRIM only kicks in when the sensor is warmed up to 600 C (approx 30+ secs post start).

Use a Wideband and ensure it is heated up before firing the engine and data-logging the whole warm cycle - approx 10 minutes

-----------------------------------------------------------------------------------
STEP 2 - TUNE YOUR Cranking Pulse and Decay Rate

Cranking TRIM - try depressing the gas, while cranking - engine fires (rpm>500), your crank trim is too rich. Try adjusting the Cranking TRIM at 10% steps then narrow down to 5%/3%.

If your engines fires and stalls, the inc/decrease the decay rate - cold engines initially need more fuel ( to compensate for fuel which get stuck of the cold manifold/port walls) which is tapers off over 30 seconds. The decay rate is to tune this. It is important to have tuned your open loop ECTc first, to eliminate this as factor.

if the cranking and ECTc are tuned right, its the decay rate.

the ECTc can be tune on a wideband - the crank pulse and decay are by trial and error

Also be aware that after firing (>500 to 1100 rpm) what load cells your engine is hitting (normally 9-10, 6-7, then idle load) - useful to have a Wideband to log the warm up AFR (make sure the WB is to heated up, before the datalogging the start & warm-up. Assuming those cells are not way out

_________________________________________________

Look at the Flash Pro help - there is amore detail - why didnt your tuner tune your start?

[vtirulz786]

All Sorted out now, car starts Brilliants as normal without Hesitation.

Cure: After full diagnostics found out that it was a BAD IACV (Idle air control Valve) which was replaced.

Very happy to cure this problem after a long time.

Thanks :)

[hpmx18]

You will have to tune this over a series of days when the engine is cold - (this is not easy for a beginner and 2nd you need to track changes to cranking pulse, decay rates and ECTc at diffrence warm up temps)

First tune your warms ECTc with a wideband. Only then (the next day with a cold engine) tune your cranking pulse and decay rate.

------------------------------------------------------------------------------------------
STEP 1

If car wont fire, go to step2 , then come back to step 1

Warm up Fuel - This is what I am doing currently Turn OFF closed loop and richen/lean out the mixture at each ECT until the engine stumbles, then use the mid-point. Then enable Cloop. Note the HO2/STRIM only kicks in when the sensor is warmed up to 600 C (approx 30+ secs post start).

Use a Wideband and ensure it is heated up before firing the engine and data-logging the whole warm cycle - approx 10 minutes

-----------------------------------------------------------------------------------
STEP 2 - TUNE YOUR Cranking Pulse and Decay Rate

Cranking TRIM - try depressing the gas, while cranking - engine fires (rpm>500), your crank trim is too rich. Try adjusting the Cranking TRIM at 10% steps then narrow down to 5%/3%.

If your engines fires and stalls, the inc/decrease the decay rate - cold engines initially need more fuel ( to compensate for fuel which get stuck of the cold manifold/port walls) which is tapers off over 30 seconds. The decay rate is to tune this. It is important to have tuned your open loop ECTc first, to eliminate this as factor.

if the cranking and ECTc are tuned right, its the decay rate.

the ECTc can be tune on a wideband - the crank pulse and decay are by trial and error

Also be aware that after firing (>500 to 1100 rpm) what load cells your engine is hitting (normally 9-10, 6-7, then idle load) - useful to have a Wideband to log the warm up AFR (make sure the WB is to heated up, before the datalogging the start & warm-up. Assuming those cells are not way out

_________________________________________________

Look at the Flash Pro help - there is amore detail - why didnt your tuner tune your start?

great how-to