Jump to content

Welcome to the brand new 205GTIDrivers.com website! We hope you'll enjoy it! Read the full notice here.

  • Welcome to 205GTIDrivers.com!

    Hello dear visitor! Feel free to browse but we invite you to register completely free of charge in order to enjoy the full functionality of the website.

Telf

Idle control on cold start

Recommended Posts

Telf
Posted (edited)

Post my car being converted to an Emerald ECU its become apparent that cold start idle is a problem.

 

The SAD isn't installed so the idle is awful when cold, particularly in really cold weather. Once warm after a minute or two of driving its rock solid at 950Rpm.

 

So any suggestions on how to solve this?

 

My initial thought was reinstall the SAD and rig some power control to heat and close it. Then I am aware the MI16 has some sort of load control valve but I've not looked closely at that. 

 

Anybody rigged up a solution? Car is 8V standard 1.9. Its on an Emerald  ECU with the original throttle inlet etc.

 

 

 

Edited by Telf

Share this post


Link to post
Share on other sites
DamirGTI
Posted (edited)

Surely the ECU can be tweaked for the cold start/warm up period ? must be something there to set up .

 

Few more degrees of the ignition advance @ the cold start will do the job , and some increase of the injector pulse/fueling as needed (cranking enrichment %) .

 

 

D

Edited by DamirGTI

Share this post


Link to post
Share on other sites
petert

You could use an A/C idle up solenoid. They screw into the throttle body and would be a lot neater and easier solution.

Share this post


Link to post
Share on other sites
SRDT

You need more air when cold but then without a SAD, IAC or other gizmo your warm idle won't be at 950 rpm.

Share this post


Link to post
Share on other sites
Telf
10 hours ago, petert said:

You could use an A/C idle up solenoid. They screw into the throttle body and would be a lot neater and easier solution.

I take it this screws into the throttle body in place of the air screw? I like the idea of this seems simple 

Share this post


Link to post
Share on other sites
Telf
15 hours ago, DamirGTI said:

Few more degrees of the ignition advance @ the cold start will do the job , and some increase of the injector pulse/fueling as needed (cranking enrichment %) .

Ill have a look in the manual and see - this is probably programmable. I'll check

 

Share this post


Link to post
Share on other sites
petert
Posted (edited)
3 hours ago, Telf said:

I take it this screws into the throttle body in place of the air screw? I like the idea of this seems simple 

No, in addition to the air bleed screw.

Screen Shot 2021-01-02 at 11.12.35 pm.png

Screen Shot 2021-01-02 at 11.13.09 pm.png

Edited by petert

Share this post


Link to post
Share on other sites
welshpug

you'll need an appropriate throttle body to take one of those, there aren't any threaded ports on most uk throttle bodies.

Share this post


Link to post
Share on other sites
petert
13 hours ago, welshpug said:

you'll need an appropriate throttle body to take one of those, there aren't any threaded ports on most uk throttle bodies.

Probably easier to just adjust ignition vrs coolant temp map then.

Share this post


Link to post
Share on other sites
Telf

Well I spent i few hours following the document but to no avail. Engine stone cold but regardless of what I do it just will not cold start and idle. 

 

I live adjusted the injector trim  and the advance.  No difference. 

 

Increased the % of fuel on crank. Nothing.

 

Increased the number of engine turns it counts . Nothing.

 

ECU is showing it reading 1 to maybe 3 engine turns and it dies.

 

If I start it and manually hold the throttle it idles at 950rpm after about 2 mins. Solid idle no drama.

 

So that makes me think it must be a air issue rather than a fuel or advance issue?

 

The emerald manual says the warm idle must be correct before the cold start is adjusted for. So in terms of the prerequisites its fine. The car idles spot on when warm.

 

Bloody annoying as hell!

Share this post


Link to post
Share on other sites
petert

Advertise on Aussiefrogs for a throttle body and valve. Every 205 sold in Australia had A/C.

Share this post


Link to post
Share on other sites
SRDT

950 rpm must be too low. As for the throttle body maybe you just have to drill and tap the port.

Share this post


Link to post
Share on other sites
welshpug

no, they will idle at 900 fine when in good health, 850-900 is the figure specified for xu5 and xu9.

Share this post


Link to post
Share on other sites
Telf
16 hours ago, opticaltrigger said:

run it in place of the SAD and have your ECU drive it in step with CLT.

That might work quite well,I wonder if it might provide too much air? I was thinking I could probably wire the SAD back in , ill have to look up how its connected as I've forgotten. 

Share this post


Link to post
Share on other sites
Telf

If I recall correctly its wired into a 12v supply but I can't remember what cuts the power to it. The SAD eventually closes due to engine temp heating it doesn't it?

Share this post


Link to post
Share on other sites
DamirGTI

On a 3 wire ISCV , two pins are earths and one 12V supply .. two earths are controlled by the ECU , which by earthing one or another path opens the valve clockwise or anti-clockwise . 

 

SAD needs to be bolted up near the heat source (thermostat housing) , but it also needs 12V supply to the heater element in order to fully close after warm up period . 12V supply to the heater needs to be present only while engine runs , thus commonly taken from the fuel pump relay output .

 

D

  • Like 1

Share this post


Link to post
Share on other sites
welshpug

sad is easy, 12v ignition switched live, earth.

  • Like 1

Share this post


Link to post
Share on other sites
opticaltrigger
5 hours ago, Telf said:

That might work quite well,I wonder if it might provide too much air? I was thinking I could probably wire the SAD back in

Hi Telf,

I cant see that to much air will be a problem as it's a dedicated ISCV with a motor drive. I supose it's possible that it wouldn't seat completely when closed, but I'd be supprised.

 

The only problem that I see with the OEM SAD in your application is that it's not a device that has any real resolution to it really.. Bit of a blunt instrument.

Your ECU is all geared up to run an ISCV in trim with CLT and therefore maintain a smooth idle, but it needs an actuator with some degree of accuracy and resolution to do it.

 

All the best,

O.T.

  • Like 1

Share this post


Link to post
Share on other sites
Telf
On 1/7/2021 at 9:06 PM, opticaltrigger said:

Your ECU is all geared up to run an ISCV in trim with CLT and therefore maintain a smooth idle, but it needs an actuator with some degree of accuracy and resolution to do it.

 

Ok I see, I was thinking this was just an open or closed device similar to the SAD. So  ill need to have a look in the manual and see how i could set this up.

 

What i dont understand is why altering values in the MAP - advance etc seems to make no difference. Its weird Emeralds own literature states you must have a stable warm idle before setting up cold start. It has this so they obviously did a good job at Emerald but beyond that the cold start is just a joke.

Share this post


Link to post
Share on other sites
petert

Is there a zero throttle ignition map, in addition to the main ignition map?

Share this post


Link to post
Share on other sites
Tom Fenton

Why make it difficult, reinstall the SAD.

Share this post


Link to post
Share on other sites
Telf
3 hours ago, petert said:

Is there a zero throttle ignition map, in addition to the main ignition map?

im not sure tbh!

 

2 hours ago, Tom Fenton said:

Why make it difficult, reinstall the SAD.

I might Tom I'm just looking for suitable options, after all the faff of turning it into a (relatively modern) Engine management I'm trying to proceed in the same spirit.

Share this post


Link to post
Share on other sites
opticaltrigger
1 hour ago, Telf said:

after all the faff of turning it into a (relatively modern) Engine management I'm trying to proceed in the same spirit.

Hey Telf,

Yeh,,, stick with it, you've done all the hard bits already, this is just the nice bits to bring it all together.

You can definitely get this last bit with the idle control sorted out.....

 

I'm not super up on the Emerald specifically but mostly all ecu's follow the same basic path with this.

Generally, modern ISCV'S come with PWM control or steppers and your ecu almost certainly supports both.

To get this idle of your's really under proper control, your definitely going to need to introduce some kind of ISCV in there somewhere. Then the software functions can come into play better. The niceties of all the cold start and idle control functions the ecu offers will only work at there best when the appropriate hardware is in place. You could rig the SAD back up i guess, but it would be nice to just replace it with a modern motor driven unit. When you have the option for full control, not to incorporate the idle would be a shame. Your only really replacing one part for another, plus a few wires, and a few settings on the computer..... ( plus all the headaches of course. )

Doing this will allow you to have the full and proper use of all the ecu's cold start functions and achieve perfect idle at all temperatures.

By the way, that link I put above is just an example of a standalone ISCV, there's lots out there in both stepper and pwm. It's just, that one looked at a glance like it would go rite in place of the OEM SAD as a straight swap almost.  

Once you get this last bit sorted out Telf, you'll be there, with full modern engine control.... Excellent... Stick with it mate, it's worth it.........

 

All the best,

O.T.

 

Edited by opticaltrigger

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now

×