VEMS Community Forum

VEMS => Configuration => Topic started by: Tcal on October 22, 2007, 11:07:16 AM

Title: Cold start again.. And some other too
Post by: Tcal on October 22, 2007, 11:07:16 AM
IÃ,´m having some problems with that cold start. IÃ,´ve been trying to configure it for about three weeks now...
When cold (near zero degrees) car wonÃ,´t start so well. Those warm startÃ,´s are quite good..

My car is Calibra turbo, equipped with v3.3 management. ItÃ,´s running with 1.0.53 firmware.
470cc injectors, req fuel 4.4
And iÃ,´m having some problems too with those temp readings.
With 2252 256 hex loaded , reading is quite near in hot area, but when cold it shows about 10 degrees too much.

But hereÃ,´s one log when starting from cold. Outside temp was around 4 degrees celsius...
That log is missing 15 seconds at 163s.  for some reason? (my laptop perhaps)
http://www.box.net/shared/rklin4xove (http://www.box.net/shared/rklin4xove)
http://www.box.net/shared/q2pa43y6hp (http://www.box.net/shared/q2pa43y6hp)

Oops, somebody could move this into fuel injection area... ItÃ,´s the right place for this?

Title: Re: Cold start again..
Post by: hilly on October 22, 2007, 01:01:27 PM
What do you mean when you say it is difficult to start ?

Does it fire up then die, or is it difficult to get the engine to run at all ?

Hilly
Title: Re: Cold start again..
Post by: Tcal on October 22, 2007, 09:44:30 PM
Yes, it fires ok, revolutions might go to up to 1100, then dies. This happens right after cranking
On second try everything usually works better. No problems at all when warm..
Sometimes it cranks ok, revs go up and then drop to 400-500, and after few seconds itÃ,´s behaving as it should (cold idle).

You should see what i mean when you look at that log.
Title: Re: Cold start again..
Post by: [email protected] on October 23, 2007, 11:38:21 AM
Sounds like afterstart:
(http://www.vems.co.uk/VEMSUserManual/PrimingCrankingAfterstart.png)

Its getting colder now so you may want to increase the afterstart values and scale the 77degC amount accordingly.
Title: Re: Cold start again..
Post by: Tcal on October 23, 2007, 09:46:53 PM
Yeah, i know..
IÃ,´ve tried them alot..
IIRc today i tried with 130ASE and 8 scaling.. Same as always when cold.
I think, next time iÃ,´ll try  to start with pedal pressed about 3-4% to see if it needs more air.

How much scaling should be good if ASE is like 70%-90%'?
Title: Re: Cold start again..
Post by: [email protected] on October 23, 2007, 10:22:00 PM
It's tricky to say, the rule of thumb is that you need to stick a hell of a lot more fuel in as it gets colder.
134 seems a hell of a lot mind... I wonder if we're looking at this the wrong way round - if its too rich now its getting colder.
Title: Re: Cold start again..
Post by: Tcal on October 23, 2007, 10:30:54 PM
Could you recommend any reasonable values on those..
Maybe ASE 80%
Scaling ??? How much?
Title: Re: Cold start again..
Post by: Tcal on October 24, 2007, 09:37:07 AM
Tried this morning with throttle 4% opened. It got worse.
Title: Re: Cold start again..
Post by: [email protected] on October 24, 2007, 10:12:39 AM
So that does suggest that you need to consider a load more fuel, what are your warm-up enrichments like?  The ASE sits on top of those. So it may be worth setting your ASE back to where it was and increasing the warm-up value at the temperature point you're now at.
Title: Re: Cold start again..
Post by: Tcal on October 24, 2007, 10:42:11 AM
Does Warmup change anything when problem is happening at ASE?
Or is ASE and Warmup calculated together and then scaled within clt?


For example:
If ASE is like 200% and Scaling is 10, WhatÃ,´s the temp when that 200 is applied? -40c or perhaps something else?

Well for tonight i thought iÃ,´d try 90% and 18 scaling..

Warmup is:

-40 180
-29 175
-18 160
-7   145
4     134
16   127
27   114
38   108
54   105
71   100

That -18 and colder is ???  ... IÃ,´m using engine heater when temp is -5 or colder.

Hope you understand my writings, I havenÃ,´t used english so much. There might be some words or some spelling(?) chosen wrong.
Title: Re: Cold start again..
Post by: cliffb75 on October 24, 2007, 12:29:00 PM
Quote from: Tcal on October 22, 2007, 09:44:30 PM
Yes, it fires ok, revolutions might go to up to 1100, then dies. This happens right after cranking
On second try everything usually works better. No problems at all when warm..
Sometimes it cranks ok, revs go up and then drop to 400-500, and after few seconds itÃ,´s behaving as it should (cold idle).

You should see what i mean when you look at that log.

That description suggests the cranking pulse is too smal - i.e. the fuelling on the first attempt is too lean.

Because of the failed start, the residual fuel is then added to the fuel being delivered on the re-start, so the engine runs.

Consider using larger cranking / priming values to estabilish the port wall film more aggressively.

Also, how is your fuel delivery system put together. Do you get full fuel pressure on the first crank? I have had problems with this on 'key through' starts on cars in the past, especially at cold temps.
Title: Re: Cold start again..
Post by: Tcal on October 24, 2007, 10:00:28 PM
Hmm, i try tomorrow with longer Pump on after powerup time..
What does that pump on after inactivity mean?
They both have same time now (2.1)
And iÃ,´ll try with longer primepulse, and longer crank pw...
Title: Re: Cold start again..
Post by: Tcal on October 25, 2007, 08:28:31 AM
Tried again with smaller Ase.
HereÃ,´s the log http://www.box.net/shared/3ttve1avcq (http://www.box.net/shared/3ttve1avcq)
setup http://www.box.net/shared/cpmx10psrj


Looks like that lambda is on lean but i think itÃ,´s running too rich on ASE because PW drops from 4.4 to 2.1 when ase ends?
Why that RPM signal is at 122 after first attempt, MAP is as it should when not running????


Title: Re: Cold start again..
Post by: Tcal on October 27, 2007, 08:21:01 AM
I was wondering that itÃ,´s now running wasted spark and injectors are in two banks. ?

Divider 1
Alternate from 3..0

I have that cam trigger installed, but itÃ,´s not in use. Would that help anything if itÃ,´s fully sequential?
I bought the car with vems installed so these trigger things are bit unknown to me.
I know itÃ,´s 60-2 VR and cam should be Hall...
Engine is Vauxhall/Opel C20LET, but i think C20XE triggersetup should be same

And maybe i should use newer firmware (now running 1.0.53)

Title: Re: Cold start again..
Post by: [email protected] on October 27, 2007, 09:16:18 AM
You have the injectors setup sequentially as you're alternating from 3..0 - as long as your H[0] table is setup correctly.
Title: Re: Cold start again..
Post by: Tcal on October 27, 2007, 09:35:11 AM
It looks like this:
h[0]=02 08 04 01 10 20 40 80

But should  that camtrigger be in use when sequential?
Title: Re: Cold start again..
Post by: [email protected] on October 27, 2007, 10:12:42 AM
No you can inject sequentially without the secondary trigger.  You know TDC and BDC position, but not the engine phase, so when the engine is at TDC either 1 or 4 will be firing and the other will be on its exhaust stroke, if you inject 1 or 4 at this point then it will be on a closed valve.  Injection starts on the trigger tooth so the start point will be roughly around 60deg BTDC (or BBDC).
Title: Re: Cold start again..
Post by: Tcal on October 27, 2007, 12:47:20 PM
So if i enable that camtrigger it knows straight whatÃ,´s the next cylinder to inject?

WhatÃ,´s the best WORKING firmware you could recommend? 1.0.73?
IÃ,´m running on CopÃ,´s.
Planning to use boostcontrol in future too.
Title: Re: Cold start again..
Post by: [email protected] on October 27, 2007, 07:00:16 PM
It will know within two crank revolutions which cylinder to inject - but its not so much about injection but ignition for direct fire of COPs.

I stick with 1.0.73 for 36-1, 60-2 etc, and 1.1.18 for the Nissan triggers.

Boost control is available in both those releases, hopefully by the time you're ready to use it the 1.1.29 version will be tested and released.
Title: Re: Cold start again..
Post by: Tcal on October 27, 2007, 08:25:18 PM
So if i upgrade to .73 iÃ,´ll need to change that h2 table
from h[2]=05 04 05 04 01 03 01 03
to    h[2]=50 40 50 40 10 30 10 30
Right? Anything else?

I downloaded that .73 and it looks ok..
WhatÃ,´s the difference between generate-config and generate-configwithdefaults??
I looked that Primary trigger settings there are some difference to .53 version, what do i need to change there?

Title: Re: Cold start again..
Post by: [email protected] on October 28, 2007, 08:30:31 AM
generate config with defaults uses two files to set some specific settings in the config, one blitzes the ALS settings to make sure its turned off, the other ensures that the factory wideband settings are in place.

There shouldnt be anything to change regarding the trigger settings, the extra items only relate to you if you have some of the special filters enabled.
Title: Re: Cold start again..
Post by: Tcal on October 28, 2007, 08:46:43 AM
So will i need to leave those 4 to zero or what does they mean??
I have now in .53
Tooth relation normal 181
Tooth relation missing 118

I opened latest msq with that .73 MT and there were next values.
Tooth normal relative min 31
Tooth normal relative max 169
Tooth missing relative min 200
Tooth missing relative max 338

They arenÃ,´t correct if i understand them right?

Does that crank min. period effect how to starting, itÃ,´s now setted to 1280
I have not tried to upload that firmware yet.

Played with those ASE values today, now having ASE 30% and scaling 70..
LetÃ,´s see tomorrow how will that effect..

I did try that Idle PID controller too, for some reason i didnÃ,´t get any changes to idle ,when i played with those values.
Should it usually be enabled, or is it just for stepper iac or something.?
Title: Re: Cold start again..
Post by: [email protected] on October 28, 2007, 06:29:36 PM
Leave the values as they are, although they're not used its better to leave them well alone.
Crank min period is related to the rev limit of the engine, its calculated by the number of teeth on the trigger * max rpm/60
Its a filter to reduce potential noise problems - if a trigger happens before minimum trigger period then its clearly noise and should be ignored.
If you set it to zero then it turns the feature off.

Rob
Title: Re: Cold start again.. and some other
Post by: Tcal on October 29, 2007, 05:42:06 PM
Hmm. I did find something interesting today.
ItÃ,´s about that IAC valve. When i turn ignition on and look in the valve itÃ,´s closed ,but not always..
If i knock that IAC a bit, it releases that valve to open. and then it moves ok..
If i move that valve with my finger when itÃ,´s powered and closed, i can feel that something is blocking it to start move freely, but again when itÃ,´s moved a bit itÃ,´s okay again.

If IAC is unpowered then thereÃ,´s nothing blocking it when moving that valve by hand.

ThatÃ,´s could explain my coldstart issue quite much...

IÃ,´m thinking that there could something between that magnet and armature that blockÃ,´s valve movement when powered...
Or could it be that thereÃ,´s not enough power to start moving that valve.. Hmm no.. it shouldnÃ,´t be possible...

That IAC valve (2-wire) is made by BOSCH and itÃ,´s part number ends 516, itÃ,´s quite common in motronic equipped vehicles.
iÃ,´ll start to hunt for a better one...
Title: Re: Cold start again.. And some other too
Post by: Tcal on October 30, 2007, 04:40:19 PM
AARGH !!. Just solved that iac problem.. And probaply that cold start issue too...
There should be an brass bolt holding that valve almost closed when not powered.
and if that iac has failured  so  engine is still running on raised idle.

Somebody has changed that brass bolt to steel one for some reason.
Valve were stuck in the bolt because itÃ,´s magnetic .
When bolt was off valve moved perfectly.

So when ignition on, valve was closed because of that.
First start attempt when cold, not enough of air (valve closed)
That unsuccesful start released valve from bolt.
Now valve  opens as it should .