Author Topic: v3.8 Primary Trigger problem - engine won't run - pls check logs  (Read 4847 times)

Offline SPatrickB

  • Jr. Member
  • **
  • Posts: 39
  • BHP: 0
After fixing the sensor gnd to power gnd problem, my 3.8 now gets primary VR trigger signal but it is ugly. The engine will not idle for longer than a couple of seconds, even though it has equivalent config (1.2.23) to my v3.6 config (1.2.11) on which it can drive.

Could someone please take a look at the trigger log and make any suggestions?

Is the problem because of the changes found in the 3.8 vs 3.6 primary trigger circuit?
...or have I killed components with the gnd problem?

3.8 trigger log with a few failed running attempts:
http://www.vems.hu/files/PatrickB/3.8PriTrigProb/FOMOFO_3.8_FailedStartAttempts.triggerlog

3.8 VEMS Log with failed running attempt (in case it's needed):
http://www.vems.hu/files/PatrickB/3.8PriTrigProb/FOMOFO_3.8_Wont_Run.vemslog

3.8 VEMS Config just in case it's needed. Note: I pulled a lot of fuel out of the map to reduce the violent startups and prevent engine damage.
http://www.vems.hu/files/PatrickB/3.8PriTrigProb/FOMOFO.vemscfg

Working 3.6 trigger log for comparison:
http://www.vems.hu/files/PatrickB/3.8PriTrigProb/FOMOFO_3.6_Working.triggerlog
« Last Edit: January 02, 2015, 03:55:13 pm by SPatrickB »

Offline MWfire

  • Hero Member
  • *****
  • Posts: 721
  • BHP: 35
Re: v3.8 Primary Trigger problem - engine won't run - pls check logs
« Reply #1 on: January 03, 2015, 11:43:48 am »
Cranking enrihchment is wrong
put 500% at 0deg, 300% at 20deg

Also look like you have problem with sec trigger. What is sensor type?

Offline NenadNR

  • Jr. Member
  • **
  • Posts: 3
  • BHP: 0
Re: v3.8 Primary Trigger problem - engine won't run - pls check logs
« Reply #2 on: January 03, 2015, 03:04:36 pm »
 In v3.8 log you don`t have RPM readings at all. Disable fueling until you get RPM readings and good trigger log because engine won`t work without it. Only thing I can recommend is to trace trigger signal with oscilloscope on v3.6 an compare it with v3.8.

Offline SPatrickB

  • Jr. Member
  • **
  • Posts: 39
  • BHP: 0
Re: v3.8 Primary Trigger problem - engine won't run - pls check logs
« Reply #3 on: January 03, 2015, 11:25:57 pm »
Secondary trigger is Hall. It's a Ford OEM style Cam Sync distributor plug.

Offline SPatrickB

  • Jr. Member
  • **
  • Posts: 39
  • BHP: 0
Re: v3.8 Primary Trigger problem - engine won't run - pls check logs
« Reply #4 on: January 03, 2015, 11:57:35 pm »
I had uploaded the wrong VEMS log, sorry. The correct one is now in place.

Offline SPatrickB

  • Jr. Member
  • **
  • Posts: 39
  • BHP: 0
Re: v3.8 Primary Trigger problem - engine won't run - pls check logs
« Reply #5 on: January 04, 2015, 12:22:41 am »
This is what I've worked out so far:

The trigger log shows that when the engine starts to fire, two things happen;
One is the primary trigger signal line shrinks down to a small length.
Why is this? What does the length of the trigger line represent?

Two is there appears another very, very short primary trigger signal line about 3ms after the correctly placed one. This equates to the sudden jump from 300 to 5000 rpm that is seen in the VEMS log which causes the sec errors and crazy fueling (5000 rpm worth of fuel at 300 rpm = violence).
What could this extra signal be? As my config uses Rising edge, it looks like it could be the Falling edge of the signal. Is this possible?

Offline MWfire

  • Hero Member
  • *****
  • Posts: 721
  • BHP: 35
Re: v3.8 Primary Trigger problem - engine won't run - pls check logs
« Reply #6 on: January 04, 2015, 11:49:55 am »
Lenght=distance between two signlas, less distance more rmp. So that is normal.

you have problems with sec trigger, try to add capacitor to sec trigger to ground, around 10-220nF.

Offline SPatrickB

  • Jr. Member
  • **
  • Posts: 39
  • BHP: 0
Re: v3.8 Primary Trigger problem - engine won't run - pls check logs
« Reply #7 on: January 25, 2015, 02:07:09 pm »
Added 100nf cap but it did not help.
I had already added a filter cap to the primary trigger input (as I had needed in v3.6), so I tried removing that and bingo...it now works fine.  :)
I think this cap in the v3.8 circuit set up some kind of oscillation.

I have left the sec trigger filter cap in place for now.