POP when turning ignition on (not cranking) and burned fuel smell
#62
I don't think injectors have anything to do with it. To me, this is clearly a function of MS1 firing the spark plugs. A leaky injector isn't gonna lite the mixture.
#63
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No question- the combustion event is caused by the fact that the plugs fire at powerup, which is a function of the output circuit design, not the CPU. The question is- where is the fuel coming from in the first place, and why do so many of us not have the issue? IOW: What's the variable? It certainly isn't the software or the circuit.
#64
The one thing that bothers me is the fact that my pop always happens 2 seconds after the key is turned on. I can change this by changing the "Fire priming pulse" option. If i change it to on power on, it happens almost instantly at key on. If it is set to after 2 seconds, it happens after 2 seconds.
Joe, these three people report that changing the injector fire time for the priming pulse "moves" the time when the pop happens. So that kinda rules out the plugs sparking at power up being the cause.
To me, it's obvious what's happening. What I can't tell you is why it's happening. Whenever MS decides to fire the injectors, it's triggering the coils. Probably triggering all of them such that the cylinder with an open intake valve is always fired. A timing light would verify this. Someone should kill the fuel pump to their car, put a timing light on a spark plug wire, set the priming pulse for say, 1 sec, and see if it fires the plug after 1 sec. Then change to two seconds and see if it now fires at 2 seconds. See if there's a correlation. I bet there is. It's obviously firing the plugs whenever it's priming. Of course it shouldn't, but it is.
More prone to happen at cold start? You spray more fuel for the priming pulse at cold start. See a correlation?
I don't think this has anything to do with leaky injectors. To me, it looks like MS is firing the plugs whenever it fires the injectors for the priming pulse. I hope somebody puts a timing light to it to see if what I speculate above is correct.
But alas I have this shitty EDIS that's overly complex and has no real benefits over letting MS control the ignition coils directly. But it works flawlessly.
Last edited by patsmx5; 11-27-2008 at 12:21 AM.
#65
To me, it's obvious what's happening. What I can't tell you is why it's happening. Whenever MS decides to fire the injectors, it's triggering the coils. Probably triggering all of them such that the cylinder with an open intake valve is always fired. A timing light would verify this. Someone should kill the fuel pump to their car, put a timing light on a spark plug wire, set the priming pulse for say, 1 sec, and see if it fires the plug after 1 sec. Then change to two seconds and see if it now fires at 2 seconds. See if there's a correlation. I bet there is. It's obviously firing the plugs whenever it's priming. Of course it shouldn't, but it is.
I think this is a direct result of leaking injectors. The MS is firing my plugs every time it gets switched on. The priming pulse and the ignition event are independent in my setup.
#66
Well, Wes65 said:
And then immediately proceeding this post, Spookyfish said:
Hence why I said he seems to have the same problem.
And I read your other talk about "testing" the fuel injectors for leaks. I can tell you if the car sits long enough, the pressure WILL go down. But of course it would be leaking back through the pump. Pretty sure this is normal. Hence why when you turn the key on, the pump primes for a couple seconds. Not really sure how to tell you to test for leaky fuel injectors.
I still find it "strange" that MS2 cars don't exhibit this problem but several MS1 cars do. And a few MS1 cars say that changing the priming pulse does move this pop around. I still think this is a function/problem with MS1, not leaky fuel injectors.
And finally, I think some of the people that say moving the priming pulse around moves the pop around should do the timing light thing to verify if MS is sparking when firing that priming pulse.
Had two different sets of injectors in my 99' with and w/o MS and never had this problem.
I'll close with a question: Does ANYONE who is not MS1 have "the pop"?
The one thing that bothers me is the fact that my pop always happens 2 seconds after the key is turned on. I can change this by changing the "Fire priming pulse" option. If i change it to on power on, it happens almost instantly at key on. If it is set to after 2 seconds, it happens after 2 seconds.
I'm pretty sure Sookyfish said the priming pulse did not affect the timing of the pop when he said:
I've noticed the same thing. My car pops the moment the ignition is switched on, regardless of settings.
I just did this. Timing light confirmed that there is a single ignition event right after I switch the key to run. Changing the priming pulse did nothing. No matter the settings, there is a single spark event once the MS gets power (or a fraction of a second thereafter). We knew this though. Also, there isn't another ignition event until cranking begins.
My priming pulse won't ignite even if I try. If I switch on the ignition, wait for the pulse, then switch off and back on again, it won't pop. It only pops after at least 48 hrs of non-operation.
I think this is a direct result of leaking injectors. The MS is firing my plugs every time it gets switched on. The priming pulse and the ignition event are independent in my setup.
I've noticed the same thing. My car pops the moment the ignition is switched on, regardless of settings.
I just did this. Timing light confirmed that there is a single ignition event right after I switch the key to run. Changing the priming pulse did nothing. No matter the settings, there is a single spark event once the MS gets power (or a fraction of a second thereafter). We knew this though. Also, there isn't another ignition event until cranking begins.
My priming pulse won't ignite even if I try. If I switch on the ignition, wait for the pulse, then switch off and back on again, it won't pop. It only pops after at least 48 hrs of non-operation.
I think this is a direct result of leaking injectors. The MS is firing my plugs every time it gets switched on. The priming pulse and the ignition event are independent in my setup.
I still find it "strange" that MS2 cars don't exhibit this problem but several MS1 cars do. And a few MS1 cars say that changing the priming pulse does move this pop around. I still think this is a function/problem with MS1, not leaky fuel injectors.
And finally, I think some of the people that say moving the priming pulse around moves the pop around should do the timing light thing to verify if MS is sparking when firing that priming pulse.
Had two different sets of injectors in my 99' with and w/o MS and never had this problem.
I'll close with a question: Does ANYONE who is not MS1 have "the pop"?
#68
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I have prime pulse always, then fire after 2 seconds....never hear the pop...only when I slightly flood the motor when I'm fooling around with stuff.
if you turn it the ignition to ON, then off....it will pop right? will it happen if you do that say two three times in a row?
if no, then turn the car to ON and let your fuel pump run for 5 minutes, then try it...does it happen then?
if you turn it the ignition to ON, then off....it will pop right? will it happen if you do that say two three times in a row?
if no, then turn the car to ON and let your fuel pump run for 5 minutes, then try it...does it happen then?
#72
So if the fuel injector leaks (fuel into the intake manifold) after sitting a few days it will pop.
But if you turn the key on after warm start and they injector sprays (fuel into the intake manifold) it won't pop.
And therefore it's a leaky injector? I don't buy it. Why would one fuel/air/spark combination ignite and another not?
But if you turn the key on after warm start and they injector sprays (fuel into the intake manifold) it won't pop.
And therefore it's a leaky injector? I don't buy it. Why would one fuel/air/spark combination ignite and another not?
#74
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So if the fuel injector leaks (fuel into the intake manifold) after sitting a few days it will pop.
But if you turn the key on after warm start and they injector sprays (fuel into the intake manifold) it won't pop.
And therefore it's a leaky injector? I don't buy it. Why would one fuel/air/spark combination ignite and another not?
But if you turn the key on after warm start and they injector sprays (fuel into the intake manifold) it won't pop.
And therefore it's a leaky injector? I don't buy it. Why would one fuel/air/spark combination ignite and another not?
When the injectors prime, however, there just isn't enough time for the fuel droplets to find their way into the chamber, much less vaporize.
#75
I will clarify myself:
This means just what I say.
However:
This means the problem is still there (either at 0s or 2s) and it does not solve the problem.
@wes65: I was observing the samen 0s or 2s delay. Maybe I should grab a timing light, turn the ignition on and see how many pulses I get and when... maybe that will tell me something.
However:
Tried the 'After two seconds', but that doesnt change the behaviour. Only takes longer to crank the car.
#77
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I didn't but I will if I get a chance here soon. I don't think that the injectors are going to specifically fire at power-off, as I'd expect that the +12v to drive them (on the white/red wire) will fall to zero much faster than the MS's internal Vcc, which has some reserve capacity in the form of the large electrolytic caps in the supply.
What I'm sure does probably happen from time to time is that at the instant you turn off the key, two of the injectors are squirting normally, however after you turn off the key, the associated spark event never happens, thus leaving fuel lying around. On a normal engine, I assume that said fuel winds up being cleared through the chambers owing to the fact that the engine continues turning (as a function of the momentum of the flywheel) for a short while after the key is switched off. I guess some day I should measure the amount it typically turns after power off- should be easy by scoping my VR sensor relative to +12.
What I'm sure does probably happen from time to time is that at the instant you turn off the key, two of the injectors are squirting normally, however after you turn off the key, the associated spark event never happens, thus leaving fuel lying around. On a normal engine, I assume that said fuel winds up being cleared through the chambers owing to the fact that the engine continues turning (as a function of the momentum of the flywheel) for a short while after the key is switched off. I guess some day I should measure the amount it typically turns after power off- should be easy by scoping my VR sensor relative to +12.
#78
What if the ignition outputs are momentarily interrupted with a normally closed double pole pushbutton?
For cold starts, the sequence would be: depress interrupt switch, turn on ignition, start cranking, immediately release switch.
Please tell me if this is super retarded.
It would take a bit of time to install and it’d be a bit of a nuisance at startup but it’d only be for cold starts, it’d only cost a few bucks, and it’d be easier/cheaper than sourcing new injectors…
For cold starts, the sequence would be: depress interrupt switch, turn on ignition, start cranking, immediately release switch.
Please tell me if this is super retarded.
It would take a bit of time to install and it’d be a bit of a nuisance at startup but it’d only be for cold starts, it’d only cost a few bucks, and it’d be easier/cheaper than sourcing new injectors…
#79
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What if the ignition outputs are momentarily interrupted with a normally closed double pole pushbutton?
For cold starts, the sequence would be: depress interrupt switch, turn on ignition, start cranking, immediately release switch.
Please tell me if this is super retarded.
It would take a bit of time to install and it’d be a bit of a nuisance at startup but it’d only be for cold starts, it’d only cost a few bucks, and it’d be easier/cheaper than sourcing new injectors…
For cold starts, the sequence would be: depress interrupt switch, turn on ignition, start cranking, immediately release switch.
Please tell me if this is super retarded.
It would take a bit of time to install and it’d be a bit of a nuisance at startup but it’d only be for cold starts, it’d only cost a few bucks, and it’d be easier/cheaper than sourcing new injectors…
:wtf: