Little bit of help to understand coil signal??? negative ?

Ask for and share advice on using the PicoScope kit to fix vehicles here.

Re: Little bit of help to understand coil signal??? negative

Postby STC » Sat Jul 22, 2017 1:13 am

Debbie

Nice Nails :) :)

Moving on!

If you were to cable tie a 4 wire 02 into the exhaust, power it to temperature,close to manifold as you could achieve and scope that alongside the ignition and fuel delivery you would be both belt and braces on either fuel or ignition loss.

It would be additional verification to what you have already, correctly deduced ?

Lean would = Fuel Fault or Air Leak - ? Fuel F?low - Quality ... .... ...
Rich would confirm Spark not optimum ? Excess fuel, fuel pressure ... .... ...
User avatar
STC
TwoWaves
TwoWaves
 
Posts: 790
Joined: Sun Sep 13, 2015 4:10 am

Re: Little bit of help to understand coil signal??? negative

Postby DebbieSidera » Sat Jul 22, 2017 8:44 am

Technician wrote:You know what I find very interesting reading this thread!

This country, the UK (GB) we are told that our vehicles must reach high standards for emissions purposes, looking at zero emissions at the tail pipe and all this technology on our vehicles were we are told must be there to combat these emissions. We are a very small country compared to most other industry countries, yet reading this thread and other threads on other forums about their vehicles over the ponds, they all still have plug wires, distributors and carburetors, where we were told back in the late 1980's that carburetors throw petrol into an engine like throwing a bucket of water over the path when compared to electronic fuel injection, which I agree from an emissions point of view, but we are a very small fish in a very large ocean, why then are all these other big countries allowed to have dinosaur technology on their vehicles today and we have to have all this state of the art electronics?


As STC said, In California we have to most strictly emission standards in the world. All cars, including the carbureted ones have to pass all these tests (there are exceptions for vehicles that are older than 1974 and other diesel vehicles). Actually, a carbureted engines can be pretty well tuned if using correct procedures.
New technicians that work on 'generic' car dealers often forget about the carburetors. I work a lot on new engines too and I love them, however I feel that carburetors are more 'romantic'.
I'm attaching a picture of a seminar that I attended last winter of Sunoco and Shell fuels. The topic was about the fuels that are based on ethanol blends and how badly they effect the engines. Only in US there is +42 million vehicles running on carburetors.
Attachments
IMG_00000593.jpg
User avatar
DebbieSidera
OneWave
OneWave
 
Posts: 43
Joined: Mon Oct 21, 2013 2:39 am
Location: LOS ANGELES, CA

Re: Little bit of help to understand coil signal??? negative

Postby DebbieSidera » Sat Jul 22, 2017 9:11 am

STC wrote:Debbie

Nice Nails :) :)

Moving on!

If you were to cable tie a 4 wire 02 into the exhaust, power it to temperature,close to manifold as you could achieve and scope that alongside the ignition and fuel delivery you would be both belt and braces on either fuel or ignition loss.

It would be additional verification to what you have already, correctly deduced ?

Lean would = Fuel Fault or Air Leak - ? Fuel F?low - Quality ... .... ...
Rich would confirm Spark not optimum ? Excess fuel, fuel pressure ... .... ...


Yes, You are right. I would need two O2 sensors because the two separate exhaust. For now I try to solve one problem at the time. I think that last capture was a good found. I got to reproduce the same problem that customer was complaining over the bench (over 5400 RPM engine has a drop of power). Its clear that the ignition unit can't follow the breaker points (Actually I had to go up to 8800 RPM of the synchrograph before the breakers points floated). In Idle and lower engine speeds everything does very well.
If manufacture isn't willing to support or replace defective unit, probably I will recommend to the customer to go either back to the original one or a different electronic unit that I have been using for years without problems.
Then when the ignition is running well, I will check the fuel. Check carburetors jets with a gauge, and synchronize them with the mercury vacuum. Finally connect the 'smog' machine on tail pipe during a drive test.

The main reason I posted this thread was to find the way to reverse the negative coil signal (Thanks so much for the answer, I had it in the menu options in the front of my eyes but I didn't see it...).
And to get a better understanding of the wave of the coil signal during the burning time. I was wondering if rich mixtures are wider waves than the lean ones.

I'll keep you updated ;)
User avatar
DebbieSidera
OneWave
OneWave
 
Posts: 43
Joined: Mon Oct 21, 2013 2:39 am
Location: LOS ANGELES, CA

Re: Little bit of help to understand coil signal??? negative

Postby STC » Sat Jul 22, 2017 9:03 pm

I was wondering if rich mixtures are wider waves than the lean ones.


For sure Lean mixtures require more KV's to initially jump the gap, also on snap throttle you may see a double peak / High burn line. Richer mixtures require less KV s to jump the gap. More moisture in the cylinder makes for a easier, more conductive ionisation path in the plug gap I guess.

It should then follow that with a lean cylinder the spark line / duration will be shorter because more coil energy is used to start and sustain the spark

ScannerDanner has a good video on Spark Analysis.

It is quite clear you have this worked out, however please humour me as I am not following.

(over 5400 RPM engine has a drop of power). Its clear that the ignition unit can't follow the breaker points (Actually I had to go up to 8800 RPM of the synchrograph before the breakers points floated). In Idle and lower engine speeds everything does very well.


If it fails at 5400Rpm then the distributer will be spinning at Cam speed of 2700Rpm Right ? Wrong ?

If you are spinning the distributor at 8800 rpm (17,600 Rpm Crank speed) for it to fail ??

Have I got those numbers correct ?
User avatar
STC
TwoWaves
TwoWaves
 
Posts: 790
Joined: Sun Sep 13, 2015 4:10 am

Re: Little bit of help to understand coil signal??? negative

Postby DebbieSidera » Sun Jul 23, 2017 8:09 pm

STC wrote:(over 5400 RPM engine has a drop of power). Its clear that the ignition unit can't follow the breaker points (Actually I had to go up to 8800 RPM of the synchrograph before the breakers points floated). In Idle and lower engine speeds everything does very well.

If it fails at 5400Rpm then the distributer will be spinning at Cam speed of 2700Rpm Right ? Wrong ?

If you are spinning the distributor at 8800 rpm (17,600 Rpm Crank speed) for it to fail ??

Have I got those numbers correct ?


I always was talking on engine speed, Crank Rpms. A Dino would never go up to 17k, lol.
I should have specified it.
User avatar
DebbieSidera
OneWave
OneWave
 
Posts: 43
Joined: Mon Oct 21, 2013 2:39 am
Location: LOS ANGELES, CA

Re: Little bit of help to understand coil signal??? negative

Postby STC » Sun Jul 23, 2017 9:39 pm

Debbie
I always was talking on engine speed, Crank Rpms. A Dino would never go up to 17k, lol.
I should have specified it.


Indeed, at 17k Rpm we are in F1 territory and not 40 year old cars. Humour me some more !

The Dino starts to "wobble" at 5500 rpm and then recovers at circa 4500 rpm (all RPM figures quoted as crank speed)

Now if you cannot make that unit fail at 5500 - 6500 rpm then I see no issue. Then by pushing it to 8800 RPM Crank Speed you can make it fail.

IF my statement, figures & comprehension above are correct then you have "Created a Fault" not "Found a Fault"

Are you asking it to perform outside of its designed comfort zone - Or do I have something to learn :D :D
User avatar
STC
TwoWaves
TwoWaves
 
Posts: 790
Joined: Sun Sep 13, 2015 4:10 am

Re: Little bit of help to understand coil signal??? negative

Postby DebbieSidera » Wed Jul 26, 2017 4:51 pm

STC wrote:Now if you cannot make that unit fail at 5500 - 6500 rpm then I see no issue. Then by pushing it to 8800 RPM Crank Speed you can make it fail.
if my statement, figures & comprehension above are correct then you have "Created a Fault" not "Found a Fault"
Are you asking it to perform outside of its designed comfort zone - Or do I have something to learn


I didn't create any fault, car is not accelerating properly to the 'redline'. The cylinder compression is correct and very even in all of them.

The unit fails only over 5400 rpm. not following the breaker points.
The ignition breaker points starting to float over 8800 rpm.
This engine should go up to +7000 rpms no problem if everything was correct.

I did not work on it yet, only I reported the problem. Now, the car owner is asking for a unit replacement. The readings that I captured with the pico were enough to get the Perma-tune support.

best
Debbie
User avatar
DebbieSidera
OneWave
OneWave
 
Posts: 43
Joined: Mon Oct 21, 2013 2:39 am
Location: LOS ANGELES, CA

Re: Little bit of help to understand coil signal??? negative

Postby DebbieSidera » Wed Jul 26, 2017 4:58 pm

STC wrote:
ScannerDanner has a good video on Spark Analysis.


Yes, I like the his videos. Last weekend I have been watching some of them and I ended buying his book.
User avatar
DebbieSidera
OneWave
OneWave
 
Posts: 43
Joined: Mon Oct 21, 2013 2:39 am
Location: LOS ANGELES, CA

Re: Little bit of help to understand coil signal??? negative

Postby STC » Thu Jul 27, 2017 11:37 pm

Debbie.

Sorry to bang on about this but I'm not getting this, perhaps I need to learn something here ?

The unit fails only over 5400 rpm. not following the breaker points.
The ignition breaker points starting to float over 8800 rpm.


There is a huge difference of 3400rpm there !!!

If the Dino engine will redline at 7500 rpm then for that unit to fail on the bench at 8800 RPM is not necessarily a fault in that application ???

Either I am being thick ?? missing something ??

The only explanation I can see is that the unit fails at lower rpm in the car due to extra heat, vibration etc. If that is the case then your diagnosis has room for error because you have no evidence to support what impact that heat vibration etc. has on that component ??

The best test bench for that component is on the vehicle, I'm sure we have all read that some place, why go to the trouble of doing such a test off the vehicle. Can it not be done in Situ ?
User avatar
STC
TwoWaves
TwoWaves
 
Posts: 790
Joined: Sun Sep 13, 2015 4:10 am

Re: Little bit of help to understand coil signal??? negative

Postby FioranoCars » Sun Jul 30, 2017 9:02 pm

Hi Debbie
Maybe I'm a little late to the party, but missed this till now. All the Dino's we've had have been twin points, so sadly no direct experience of you single setup, but have a seen quite a few of these over the last 20years!

One thing that comes to mind is "bounce" of the points? have they been changed? Do you have another set you can put in?
Is the advance exceeding the 30° Max at 5400rpm (if that's the same for your model)?

The snail CAM on the carbs have a nasty flat spot, but don't think this is related, especially as you've been testing on a rig off car, but worth mentioning (not found a better cam to use, it's a "live with it" issue).

Have overhauled the dissy? weights etc ?

The dinoplex is pretty solid, not stunning, and reliable, no idea of your system, but the fact that the points fail on the bench would lead me to look at rotational play, excessive wear etc, although a redline in the high 7k means testing beyond 8k is moot, stressing it see how it fails off the car can highlight visually or from vibration the root source?

Very interested to hear how this one ends

Many thanks
Richard
User avatar
FioranoCars
TwoWaves
TwoWaves
 
Posts: 377
Joined: Thu Dec 13, 2012 1:26 pm
Location: London, UK

PreviousNext

Return to Diagnostic discussion

Who is online

Users browsing this forum: No registered users and 0 guests