Jump to content
Sign in to follow this  
Ken Dunkley

VE numbers seem high at idle

Recommended Posts

Hi- With modelled fuel if the injector flow rate input into the ecu is higher than what they flow in reality would that effect the VE numbers I have to put into the fuel map? I have to put in numbers around 71 at the idle . The injectors I bought are bosch 1000cc and the flow rate given in the info was 1206cc at 400 kpa. If they are not what was advertised and flow less would this make the VE numbers seem high ? Much like the master fuel number in traditional mode ? A low number means higher numbers in the map and a higher number the reverse . Also I have a fuel pressure sensor input into AN 3 . Ive used a cal table to get it calibrated and reading correctly compared to the pressure gauge on the fuel rails . So my question is - is just having this sensor input into AN3 enough for the ecu to use this for fuel pressure corrections or do I need to do more for the ecu to do this ?

Share this post


Link to post
Share on other sites

Do you have the injector deadtimes correctly entered?

If the injector dead time was incorrect, then at very low pulse widths it might be showing that you need a whole heap of fuel... But in reality 3/4 of that time is just dead time. Hence the high numbers to get a "normal" AFR

Edited by Davidv

Share this post


Link to post
Share on other sites

The injectors did come with the deadtime info and I have entered this . They seem reasonable as the lambda reading is stable . Engine is on a test stand but starts and runs fine . I can get any A/F ratio I need so that part is good . Its just the high numbers that are confusing to me . I can only idle and free rev the engine on the stand so was just concerned that when its in the car and under load what will the VE numbers need to go to ? A lot higher I would guess .

Share this post


Link to post
Share on other sites

Thought id try and answer my own question . So I backed the whole fuel table down by 50% and the fuel injector flow rate by 50% and voila !  Same A/F Ratio with half the VE number . So yeah . I Been professionally ripped off by a company ! My 1200 cc @ 400 kpa injectors more than likely flow less than half this !  Still don't know about the fuel pressure input though .

Share this post


Link to post
Share on other sites

Hi Ken,

a trap to be very aware of and to all users, is the MINIMUM EFFECTIVE PULSE WIDTH VALUE.

Having this value incorrectly set will give strange readings and settings and I have also seen data logs where incorrect injector data loaded will show injector duty cycles of upto 150% etc even though the AFR is exactly correct and the engine runs fine and the injector used is a lot bigger than required to make the horsepower on that particular displacement engine.

Yes you have to create table for fuel temps or pressure differentials to work, this is not an automatic system.

Regards

Dave.

 

Share this post


Link to post
Share on other sites

Hi Ken,

The G4+ has an advanced injector test that can be used on Injector 1 output. This test gives you greater control and in conjunction with a pressure sensor/gauge and an accurate measuring cylinder you should be able to test the flow of your injectors. 

This is not going to give you all the data you need to setup the modelled fuel mode, but at least you'll know whether you got ripped off on your injectors.

Edited by Scott

Share this post


Link to post
Share on other sites

Hi - I had a fuel injector flow tested by a fuel injection specialist . I gave him the info sheet so he could do an apples to apples test (  full flow for 1 minute @ 4 bar ) . Yip sure enough they don't quiet flow the full 1200ccs . .... only 590 !  So my guess at half the advertised flow rate wasn't bad . Anyway the supplier says he will replace them bla bla - ill see I guess . So yeah ! only deal with reputable firms - Ill let you know if they turn up !  Thanks for your help .

Share this post


Link to post
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

Loading...
Sign in to follow this  

×
×
  • Create New...