Corsica misfiring after rain

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Bapsu
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Re: Corsica misfiring after rain

Postby Bapsu » Sun Sep 03, 2017 7:24 pm

Yeah well since the winter (or nowadays the salt/rain flow) is coming and its getting cooler i guess it might take some time I try to put the new ICM on its place, though its not that bad job after taking it apart couple of times. :D

This is what it looked like in the ecu wiring harness mount in the left corner:

https://imgur.com/ViYAIZj
https://imgur.com/uklAtuI

Luckily seems like theres still some healthy steel left, though it takes hours to sand all the rust and crap away. Also, the rust is living between the mounting lines of the body... and I can do anything for that rust.. Not gonna weld anything there.



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Re: Corsica misfiring after rain

Postby themixer » Wed Sep 06, 2017 10:19 am

i would use panel bond, this stuff is amazing


http://www.3m.com/3M/en_US/company-us/a ... 847&rt=rud



Bapsu
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Re: Corsica misfiring after rain

Postby Bapsu » Tue Oct 17, 2017 5:21 am

Well well, icm and coils put on place. No difference.

Car runs like a crap, running on 5 cyls sometimes etc. Luckily, I found something; opened the hood when it was dark and car running. Each of the plug wires were shooting thru the cable, I could see spark going from wires to radiator and valve cover. Specially the front plug wires were sparking thru the cable. Rear ones a bit also.

How the hell its possible that year old delcos premium silicone wires are acting like this? And that almost each wire is leaking.. lol. Plugs arrived from rockauto today, wires lying at germany still.



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Re: Corsica misfiring after rain

Postby GT_Indy » Tue Oct 17, 2017 9:34 am

The insulation gets old over time. Microscopic holes start getting big enough that the spark jumps.


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Bapsu
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Re: Corsica misfiring after rain

Postby Bapsu » Tue Oct 17, 2017 1:17 pm

I read a bit and many people said, that this kind of "glowing" effect isnt causing problems? But i.e for me I had wires that were sparking with each other. Its not a real, strong spark, but you feel the electricity with ur finger if you touch the wire. Not normal I suppose. I didnt find a real spark (the one snapping ur finger reaallly hard) escaping from wires.



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Re: Corsica misfiring after rain

Postby GT_Indy » Tue Oct 17, 2017 4:29 pm

Bapsu wrote:I read a bit and many people said, that this kind of "glowing" effect isnt causing problems? But i.e for me I had wires that were sparking with each other. Its not a real, strong spark, but you feel the electricity with ur finger if you touch the wire. Not normal I suppose. I didnt find a real spark (the one snapping ur finger reaallly hard) escaping from wires.


As far as I've always known the wires shouldn't be leaking at all. I've had many engines running at night and a couple with much higher voltage than these cars use and no light shows under the hood. Seeing the spark jump from the wire means you are losing potential and you get weaker spark on the plugs or no sparks on the plugs from it depending on how much is lost.

I would say the same for the glowing effect too. The only way that there will be light is if a spark jumps somewhere even if its behind something causing a glow.

Depends on the quality of the wires and the insulation. I assume a cheap set wont last long and will start grounding out to the engine sooner than a higher quality insulation and wire. I always buy the higher quality wires and replace them when needed (usually when I do the plugs) which is probably why I never see the insulation break down and spark or glow.

Some fun facts about sparks and stuff:
https://en.wikipedia.org/wiki/Dielectric_strength
And this:
https://en.m.wikipedia.org/wiki/Breakdown_voltage


Mint White 1990 Beretta GTZ Quad4 5-spd
Mint Yellow 1990 Beretta Indy 3.1 auto, Digital Dash, Sunroof.
Clean 1996 Beretta (Z26 swap) 3100 auto.

Bapsu
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Re: Corsica misfiring after rain

Postby Bapsu » Tue Oct 17, 2017 6:17 pm

GT_Indy wrote:
Bapsu wrote:I read a bit and many people said, that this kind of "glowing" effect isnt causing problems? But i.e for me I had wires that were sparking with each other. Its not a real, strong spark, but you feel the electricity with ur finger if you touch the wire. Not normal I suppose. I didnt find a real spark (the one snapping ur finger reaallly hard) escaping from wires.


As far as I've always known the wires shouldn't be leaking at all. I've had many engines running at night and a couple with much higher voltage than these cars use and no light shows under the hood. Seeing the spark jump from the wire means you are losing potential and you get weaker spark on the plugs or no sparks on the plugs from it depending on how much is lost.

I would say the same for the glowing effect too. The only way that there will be light is if a spark jumps somewhere even if its behind something causing a glow.

Depends on the quality of the wires and the insulation. I assume a cheap set wont last long and will start grounding out to the engine sooner than a higher quality insulation and wire. I always buy the higher quality wires and replace them when needed (usually when I do the plugs) which is probably why I never see the insulation break down and spark or glow.

Some fun facts about sparks and stuff:
https://en.wikipedia.org/wiki/Dielectric_strength
And this:
https://en.m.wikipedia.org/wiki/Breakdown_voltage
Yeah mate. Still waiting for the wires. Plugs are here waiting for the friday. :)

I am now also voting for the plugs and wires, since, as my topic said; the misfire mostly occured after rain at summer. It went almost completely away by driving daily. Now the car has been sitting for months and its misfiring like mad. I also guess that worn plug wires are prone to moisture... and if the moisture gets into the wires, problems will occur. And yeas, I have also had my corsicas hood open at night and never seen that kind of effect around plug wires.

Its wonderful to see how lively and well supporting this board still is, though not so many of us playing here anymore heh. :good:



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Re: Corsica misfiring after rain

Postby GT_Indy » Tue Oct 17, 2017 6:22 pm

Its all good.
Since facebook most people don't visit the forums much, they are all in the facebook group.


Mint White 1990 Beretta GTZ Quad4 5-spd
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Clean 1996 Beretta (Z26 swap) 3100 auto.

Bapsu
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Re: Corsica misfiring after rain

Postby Bapsu » Wed Oct 18, 2017 1:28 pm

Yeah, seen that here also.

Btw, the car has developed another problem during few months; sometimes when I start the car, it wont stay running. It runs just as long I hold the gas.

After holding the gas around minute the car will run itself. Might iac being stuck cause this? I am almost sure that iac:s valve isnt moving as it should.



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Re: Corsica misfiring after rain

Postby GT_Indy » Wed Oct 18, 2017 2:40 pm

Bapsu wrote:Yeah, seen that here also.

Btw, the car has developed another problem during few months; sometimes when I start the car, it wont stay running. It runs just as long I hold the gas.

After holding the gas around minute the car will run itself. Might iac being stuck cause this? I am almost sure that iac:s valve isnt moving as it should.


Its possible the IAC is dirty and sticking. Probably just needs cleaning out. How far down do you have to hold the pedal? Shouldn't be much to get idle air past the throttle.
Does it only happen on cold starts or every time you turn it off and on again?


Mint White 1990 Beretta GTZ Quad4 5-spd
Mint Yellow 1990 Beretta Indy 3.1 auto, Digital Dash, Sunroof.
Clean 1996 Beretta (Z26 swap) 3100 auto.

Bapsu
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Re: Corsica misfiring after rain

Postby Bapsu » Wed Oct 18, 2017 6:26 pm

Seem to happen every now and then, never happened cold though.

It will run just fine with around 1000rpm (lowest engine speed u can have with the pedal). So I can almost let the pedal up, but not fully, until I wait some time. And even then it might not run itself.

I am quite sure the iac isnt dirty since i cleaned it some time ago (and the hard start symptom went away). When hard start came back after idle relearn, I pulled iac out again and took the valve out completely (should've never done that). Managed to get it back, somehow but it felt like harder to move than before. So I am afraid the little motor inside the iac wont be able to move the valve well anymore... just didnt manage to get the valve on its place anymore.



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Re: Corsica misfiring after rain

Postby GT_Indy » Wed Oct 18, 2017 6:37 pm

I've pulled the thing out the center myself before. I think that breaks them as they always stopped working for me whenever I did it (I did it twice lol).
Sometimes they can be moved in and out carefully although some are stiff enough that this won't work and they pop apart. I sometimes question if this also breaks them. lol

When I had a bad IAC on my 96 it did two things: it wouldnt run unless I kept my foot on the gas or it would rev to 3000 rpm and I had to turn the car off and cycle the key a few times to get it to close again. Its possible you have a similar issue.

If you did decided to replace the IAC valve, I'd try to find one that is a reliable brand. Where I live there is no return on electrical items and these are basically 30 dollars a piece for me and I kept getting new ones that didnt work, 4 valves later and I finally got a good one.


Mint White 1990 Beretta GTZ Quad4 5-spd
Mint Yellow 1990 Beretta Indy 3.1 auto, Digital Dash, Sunroof.
Clean 1996 Beretta (Z26 swap) 3100 auto.

Bapsu
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Re: Corsica misfiring after rain

Postby Bapsu » Thu Oct 19, 2017 7:14 pm

Yeah, I also got feeling that IAC isnt operating well anymore. Do you have experience if iac broken / stuck can cause this hard start issue I have been suffering for loong time now. Since it seems like the cleaning helped with the issue..

Replacement, I would got with delco...



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Re: Corsica misfiring after rain

Postby GT_Indy » Thu Oct 19, 2017 7:26 pm

Bapsu wrote:Yeah, I also got feeling that IAC isnt operating well anymore. Do you have experience if iac broken / stuck can cause this hard start issue I have been suffering for loong time now. Since it seems like the cleaning helped with the issue..

Replacement, I would got with delco...


Not sure, when mine was idling at like 400 rpm and needed the gas to stay on, I used to have to apply some pedal to start it, but that was about it.


Mint White 1990 Beretta GTZ Quad4 5-spd
Mint Yellow 1990 Beretta Indy 3.1 auto, Digital Dash, Sunroof.
Clean 1996 Beretta (Z26 swap) 3100 auto.

Bapsu
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Re: Corsica misfiring after rain

Postby Bapsu » Thu Oct 19, 2017 8:47 pm

Yeah, maybe its the plug wires causing it then... Hopefully.




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