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Flooding
Topic Started: Oct 26 2017, 10:14 PM (485 Views)
freegeo
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suzukitom
Oct 27 2017, 08:49 PM
freegeo
Oct 27 2017, 08:29 PM
I guess it depends on what you consider floor clear mode , or clear flood mode to be. If just pressing the gas pedal to the floor and cranking it over is flood clear mode than that's fine. Me personally I considered it to be the injector being shut off with the gas pedal fully depressed. At least on a car with electronic fuel injection.

Fixkick (A Suzuki tech) described it as the ECU suppressing fuel injection whenever TPS voltage is 4V (WOT) and engine is cranking, not yet running).

I don't know how it works personally but I'd like to do the noid test you suggest this weekend. Not sure if I can realistically simulate a flood condition unless i have some excess residual gas in the TB or intake manifold.
Quote:
 
I don't know how it works personally but I'd like to do the noid test you suggest this weekend. Not sure if I can realistically simulate a flood condition unless i have some excess residual gas in the TB or intake manifold.


Why would you need to simulate a flood condition? The ecm/pcm has no idea if the engine is flooded or not while it is cranking over. I think it is a good idea for you to try the noid light and see what results you get.

I looked through the fixkick website a little but didn't see a reference to the 4 volt. I will have to look at it some more.

We have kinda gotten off track on this thread.
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suzukitom
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Tom

Quote:
 
We have kinda gotten off track on this thread.


Agreed. Plus we seem to be all responding to what the op described as flooding symptoms. After reading post #1 again, it sounds like hard starting... followed by a surging idle.. it would be good to know if the op can verify what the injector spray pattern looks like during cranking.. and whether it looks like it is dripping fuel when switched off.
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Woodie
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suzukitom
Oct 27 2017, 11:44 PM
After reading post #1 again, it sounds like hard starting... followed by a surging idle.. it would be good to know if the op can verify what the injector spray pattern looks like during cranking.. and whether it looks like it is dripping fuel when switched off.
I'm with you on this. Leaky injector usually won't cause a problem on a cold start, cold engine loves to be rich. It's usually when you try to start it again ten minutes after shutting it off.
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MR1 Kingsbury
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Exp. builder/rebuilder

An old or failing injector may have developed additional resistance, limiting cold fuel delivery.... after dozens of tries, the device warms up and lowers electrical resistance? thereby allowing signal to fully open (or stay open) to fuel pressure?

Just guesses based on knowledge of electricity and OP's description... disabling the FI then warming up the engine with the starter... plug it back in and you get maybe enough fuel to start?
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suzukitom
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Tom

I did a cranking test at WOT using a Noid light directly connected to the fuel injection wire connector. This confirmed that at WOT, which the scanner reported as 76% throttle..., the fuel injection continued to pulse during cranking...

This seems to confirm that a 'Flood Clear' mode where fuel injection does not occur at all when the gas pedal is fully depressed, is not present on a 2000 Metro 3/5.

What I don't know yet is whether the PCM might be doing something equivalent to cutting injection, such as leaning out the A/F ratio so that it doesn't add too much more fuel to an engine that might be flooding. :hmm

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Attachments: noidtest_metro_wot.jpg (163.25 KB)
Edited by suzukitom, Oct 30 2017, 10:48 PM.
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freegeo
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Glad to see you did the test and found out results for yourself.

Quote:
 
What I don't know yet is whether the PCM might be doing something equivalent to cutting injection, such as leaning out the A/F ratio so that it doesn't add too much more fuel to an engine that might be flooding. :hmm


You would need to use your scope for that one.

How would the PCM know the engine is flooded while cranking?
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suzukitom
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Tom

freegeo
Oct 30 2017, 11:07 PM
Glad to see you did the test and found out results for yourself.

Quote:
 
What I don't know yet is whether the PCM might be doing something equivalent to cutting injection, such as leaning out the A/F ratio so that it doesn't add too much more fuel to an engine that might be flooding. :hmm


You would need to use your scope for that one.

How would the PCM know the engine is flooded while cranking?
I am speculating that instead of a fuel cut strategy, Suzuki might have chosen to use an A/F leaning strategy, whenever the PCM receives a WOT signal from the TPS when other inputs tell it the engine is not yet running.

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freegeo
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suzukitom
Oct 30 2017, 11:15 PM
freegeo
Oct 30 2017, 11:07 PM
Glad to see you did the test and found out results for yourself.

Quote:
 
What I don't know yet is whether the PCM might be doing something equivalent to cutting injection, such as leaning out the A/F ratio so that it doesn't add too much more fuel to an engine that might be flooding. :hmm


You would need to use your scope for that one.

How would the PCM know the engine is flooded while cranking?
I am speculating that instead of a fuel cut strategy, Suzuki might have chosen to use an A/F leaning strategy, whenever the PCM receives a WOT signal from the TPS when other inputs tell it the engine is not yet running.

Quote:
 
I am speculating that instead of a fuel cut strategy, Suzuki might have chosen to use an A/F leaning strategy, whenever the PCM receives a WOT signal from the TPS when other inputs tell it the engine is not yet running.


Sounds like a possible theory. You would have to test it to see if it is true or not. That's what I did to see how something works.
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suzukitom
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Tom

Well. That was embarrassing.. the fuel injector connector worked loose enough to cut out on the drive home..

I think the next test will be to warm up the engine till it's in closed loop. Then I will pull the injector connector and repeat the cranking test at WOT with my OBD2 scanner recording STFT data.. I'm not sure if these data parameters are available and can be captured or be meaningful, during a cranking test of maybe 6 seconds in duration.

My thinking is that while the O2 sensor is still hot enough to be active, any STFT numbers might show if the PCM is commanding fuel to be removed...




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freegeo
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suzukitom
Oct 31 2017, 12:10 AM
Well. That was embarrassing.. the fuel injector connector worked loose enough to cut out on the drive home..

I think the next test will be to warm up the engine till it's in closed loop. Then I will pull the injector connector and repeat the cranking test at WOT with my OBD2 scanner recording STFT data.. I'm not sure if these data parameters are available and can be captured or be meaningful, during a cranking test of maybe 6 seconds in duration.

My thinking is that while the O2 sensor is still hot enough to be active, any STFT numbers might show if the PCM is commanding fuel to be removed...




Please let us know what the results are when you are done.
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