Corsica misfiring after rain

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Bapsu
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Re: Corsica misfiring after rain

Postby Bapsu » Sat Nov 04, 2017 6:40 pm

Whoorray. Shes running again. And runs great. I think it's never been running that well over the time I have owned this Corsica. Looks like wires were bad and als many plugs looked really bad, one plug had corrosion on its boot.

Ok, now the car runs very well and feels powerful. Starts great when its cold. When the car warms up, theres still the hard start issue. Looking foward to iac now.

Today it hard started, turned car off, took iac partially out (so the engine could suck air from the hole left between iac and throttle body. Started right up. Then putted iac back on its place with gasket. Kept starting good. Iacs connector was unplugged during my little investigation. Looks like the iac is not adjusting itself as it should and prevents enough air entering the engine to start smoothly? Is this scenario possible?

Havent done the idle relearn yet tho, but i took the valve apart from iac motor, so im afraid iac might not work properly anymore (couldnt adjust valve by hand, its so stuck again...)



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Re: Corsica misfiring after rain

Postby GT_Indy » Sat Nov 04, 2017 9:56 pm

Bapsu wrote:Whoorray. Shes running again. And runs great. I think it's never been running that well over the time I have owned this Corsica. Looks like wires were bad and als many plugs looked really bad, one plug had corrosion on its boot.

Ok, now the car runs very well and feels powerful. Starts great when its cold. When the car warms up, theres still the hard start issue. Looking foward to iac now.

Today it hard started, turned car off, took iac partially out (so the engine could suck air from the hole left between iac and throttle body. Started right up. Then putted iac back on its place with gasket. Kept starting good. Iacs connector was unplugged during my little investigation. Looks like the iac is not adjusting itself as it should and prevents enough air entering the engine to start smoothly? Is this scenario possible?

Havent done the idle relearn yet tho, but i took the valve apart from iac motor, so im afraid iac might not work properly anymore (couldnt adjust valve by hand, its so stuck again...)


Yah, that happened to me, IAC valve quit working, I moved it manually to make it half work then eventually replaced it.
Just gotta watch, I had went through many IAC valves New In box and failed in box before I got a new one that worked. lol 30 dollars a piece too, no returns on electrical items where I live. That was my 96 Beretta Z26 swapped car, 3100 SFI motor.

They can fail the same way on the 3.1's.


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 » Sun Nov 05, 2017 5:16 am

This one is somehow broken coz couldnt adjust it by hand at all lol. Damn, delcos iac at rockauto is quite expensive but i think i gotta go with it to make things sure.

Yeah, the old wired and plugs seemed to cause the old hard start and running with 5 cylinders at cold, now she fired up right on tho it was -5. Last winter it was -25°, didnt have block heater, still started up right on! Damn, never seen any car start that easily on -25°.



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ifixalot
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Re: Corsica misfiring after rain

Postby ifixalot » Mon Nov 06, 2017 9:18 am

Check the connector to the ECM. I had a 90 Beretta with a cowl leak on the passenger side which caused moisture in that area of the ECM.
The corrosion caused intermittent contacts, the IAC would not close and caused a really high idle (2K). I think it possible that corrosion could also cause the IAC not to open for starting.
Look for green corrosion on the pins. Clean with a small wire brush and WD-40. Use a similar size drill bit to the pins and use the blank side in and out of the female connector to clean that.



Bapsu
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Re: Corsica misfiring after rain

Postby Bapsu » Mon Nov 06, 2017 4:57 pm

I already took the ECM connector out last summer (still havent put that thing back together). Connector looked good, though I noticed there has been water coming through the hole where wiring harness bypass firewall. Actually that hole was two times bigger it was supposed to be.

I'll finish that operation in few weeks, guess gonna post some pics to others for note, that this are doesnt like water at all... also its one hell of a mess to sand the rust off, tear down half of interior to access there, and painting sucks also. :(



Bapsu
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Re: Corsica misfiring after rain

Postby Bapsu » Wed Nov 08, 2017 10:04 pm

Hmmm... Can anyone give me a little hint? The ecm connector, theres two vacuum lines going with the wires with the connector, right? Ok, I managed to put one of them to the pink vacuum line going to AC control panel. This vacuum line is responsible for blowing directions. But, where is the other one going? I cant even seem to find whats its purpose, since everything seems to work (at least with ac panel)? lol

Theres picture of those vacuum lines with the connector: https://imgur.com/a/yejqj



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Re: Corsica misfiring after rain

Postby GT_Indy » Thu Nov 09, 2017 12:34 am

I know there is one that goes under the dash for HVAC on the passenger side. And a larger hose on the driver side for the brake pedal and cruise control vacuum switch.

I never remembered seeing more than one there.
Are you able to follow it to see whee it goes under the dash and under the hood?

I know there is a second MAP under the dash for atmospheric pressure, but there shouldnt be any vacuum lines going to that sensor.


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 » Fri Nov 10, 2017 7:55 pm

Well the question where its supposed to go under the dash, since i had to take apart the passengers side harnesses and interior to repair the ecm hole at firewall. These two vacuum lines come with the ecm wiring harness bundle at the passengers side, other one goes to the HVAC line on AC panel. But the other one, no clues so far.

Nice fight with oil pressure sender today. I tried to put the last and lowest nut back to icm, and managed to lose it somewhere under the icm. Couldnt find it anymore. In addition to that, while searching for nut decided to pull oil pressure senders connector out. Well, half of the sender came with the connector lol. Couldnt get it working anymore. Luckily the pressure sender itself seem still to hold the oil in, opposite to what the original one did at spring; blowed 4 liters of oil to the streets. Feels damn good to change oil pressure sender 2 times in 5 months. And I need to order that stuff from rockauto also... another month to go.



GT_Indy
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Re: Corsica misfiring after rain

Postby GT_Indy » Fri Nov 10, 2017 8:03 pm

Bapsu wrote:Well the question where its supposed to go under the dash, since i had to take apart the passengers side harnesses and interior to repair the ecm hole at firewall. These two vacuum lines come with the ecm wiring harness bundle at the passengers side, other one goes to the HVAC line on AC panel. But the other one, no clues so far.

Nice fight with oil pressure sender today. I tried to put the last and lowest nut back to icm, and managed to lose it somewhere under the icm. Couldnt find it anymore. In addition to that, while searching for nut decided to pull oil pressure senders connector out. Well, half of the sender came with the connector lol. Couldnt get it working anymore. Luckily the pressure sender itself seem still to hold the oil in, opposite to what the original one did at spring; blowed 4 liters of oil to the streets. Feels damn good to change oil pressure sender 2 times in 5 months. And I need to order that stuff from rockauto also... another month to go.


That bolt/nut might be between the block and the starter motor on the top of it behind the solenoid part. Sometimes those oil senders fail and leak, sometimes they fall apart. I've always been used to them not working until my Quad4, if that sensor ever goes bad I replace it instantly on that engine.


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 » Fri Nov 10, 2017 8:24 pm

Yah, not nice to drive without pressure gauge working. Yeah saw the nut between block and starter, tried to get it and managed push it even further to somewhere i cant reach with my hands (im 2 meters tall almost and got long hands lol) Maybe I'll find it when its daylight.

What brand IAC u would recommend using (meaning what brand you used with success)? Delco (most expensive) or do some other brands make the job also?



GT_Indy
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Re: Corsica misfiring after rain

Postby GT_Indy » Sat Nov 11, 2017 12:36 pm

Bapsu wrote:Yah, not nice to drive without pressure gauge working. Yeah saw the nut between block and starter, tried to get it and managed push it even further to somewhere i cant reach with my hands (im 2 meters tall almost and got long hands lol) Maybe I'll find it when its daylight.

What brand IAC u would recommend using (meaning what brand you used with success)? Delco (most expensive) or do some other brands make the job also?


I used one of my extending magnets last time I dropped a bolt there. I couldn't even reach it either. lol
I feel like any IAC is hit or miss, I've never had a new one simply work out of the box the first time without having to buy more than one at like 30 dollars a piece.


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 » Sat Nov 11, 2017 2:34 pm

Lol,

Lets see, played with iac today whether it had any effect on the starting problems. Ran the engine when iac was loose mouted on the tb. Engine started misfiring again slightly... then put iac back properly mounted but still had slight misfire. I think i messed up something with iac and now ecu dont know hows it working. Gonna pull battery out and take look what happens.

If the misfire still isnt solved I think its quire near that this car becomes spare part car and its time to invest on new corsica...



GT_Indy
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Re: Corsica misfiring after rain

Postby GT_Indy » Sat Nov 11, 2017 4:41 pm

Bapsu wrote:Lol,

Lets see, played with iac today whether it had any effect on the starting problems. Ran the engine when iac was loose mouted on the tb. Engine started misfiring again slightly... then put iac back properly mounted but still had slight misfire. I think i messed up something with iac and now ecu dont know hows it working. Gonna pull battery out and take look what happens.

If the misfire still isnt solved I think its quire near that this car becomes spare part car and its time to invest on new corsica...


Yah if you pulled or pushed the IAC center rod in or out at all, theres a good chance that broke it. lol


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 » Sat Nov 11, 2017 7:29 pm

Actually the center rod of IAC is completely stuck nowadays :D, couldnt move it any way anymore.

Seems that mounting iac valve loosely to throttlebody acted like vacuum leak, since engine misfired a little bit after that.

Pulled battery off again today and let it ran for 30mins, no misfires (although couple of little puff sounds from tailpipe, few times, but that puff wasnt that loud when it misfired with the old wires and plugs). Idle going up and down but the car otherwises runs well and feels powerful. Found little thing also; when iac was stuck and engines idle was sometimes too high and sometimes too low; when idle was high (iac stuck open), around 1k rpm, engine started right away. When idle was very low (iac stuck almost closed) engine hard started. Gonna fill the tank tomorrow and bring him to hwy for test drive.



Bapsu
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Re: Corsica misfiring after rain

Postby Bapsu » Sun Nov 12, 2017 2:24 pm

Ok seems to run ok. Now it seems like we can concentrate on tcc solenoid. Never had any probs with tcc. Today driving to work 80km/h revs went between 1800-2000rpm when tcc was supposed to be locked. Felt slight jerk when this happened. I guess its the solenoid or might something else be related to that?

Upper water hose leaked straight on top of the trans and pissed coolants around tcc connector, guess gotta take look there first...




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