Corsica misfiring after rain (nowadays problem with IAC valve)

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Bapsu
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Re: Corsica misfiring after rain (nowadays problem with IAC valve)

Postby Bapsu » Wed Jun 20, 2018 7:29 pm

Money pit Beretta wrote:It is a normal start, but when it does fire off it is like it has lost a cylinder or two.
Just bought a GM sensor and put it in. That day it ran fine, then sat for a day and on Monday it would not start. Put the old one(BWD) back in and it still would not start. What's the problem? All I can say is that the wires were bare at the plug for the crank sensor. The strands were loose too. No sign of something chewing on them(still have not ruled that out). Got to go to the junkyard to find the wires on a 3400. They go from the ICM straight to the crank sensor.
What do you have to take off to get to the crank sensor? Nothing. Can say that it is easy to see between the engine and the transmission. To get your hand in there is not easy at all. You must go over the transmission a work your way around. It will cut your hands up pretty good. Hands: need the right one to get the bolt off with a 1/4in ratchet and a deep well 10mm. The left one works well for taking the bolt out or putting it back in.
A very long flat blade screw driver is great for getting the "plug"(or connector) off. That can be done between the engine and the transmission. At least you can see what you are doing on that. Was able to see the ratchet and get it on the bolt(it was tough though).
As a side note: the bolt is very long on the 2.8/3.1L, the 3100 has a much shorter bolt.
So now it wont randomly start at all? When it doesnt crank do you see crank on the rev meter? If the rev meter is dead the problem is indeed on the crank signal. If you see rev meter bumping during cranking your problem is something else.

Been working on that second Corsica, so far i have removed steering rack/pinion, brake booster, wipers motor, blower motor housing and both bulkhead connectors from firewall. Looks quite empty now, time to start scraping off the sealants and sand the rust & paint & seal. That car is a goddamn construction site...



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Re: Corsica misfiring after rain (nowadays problem with IAC valve)

Postby Money pit Beretta » Wed Jun 20, 2018 8:15 pm

You are doing something I really wish there was time for. That would end the water leaks for sure.

Never looked at the Tach when cranking. Did use the old scanner and found a history code. It said signal loss for 3x crank sensor. Think that about covers it. As long as it doesn't get hit where it is parked now I'll go to the junkyard this weekend. Oh sorry.... cranks just fine, just no start. Even tried it today just to be sure.

Got my other car running. Lucky for me the Theft Lock didn't set, that would have been a pain. That leaves another car not running(crank sensor or ECM) and another that needs struts(just put rear brakes and shocks on it). Nice to have one car that doesn't need anything(less tires from sitting too long). The others are not mine, but I must fix their little problems. Girlfriends car is the one not running, struts are for her dad's car(that she is driving). Her mom's car is ok for now.
Not sure when it happened.....now there is a fleet of cars to take care of. Getting to old for this crap.


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Re: Corsica misfiring after rain (nowadays problem with IAC valve)

Postby GT_Indy » Wed Jun 20, 2018 9:31 pm

If you go to replace the crank sensor it will be hard to remove.
Lots of lube and pull evenly to not break the plastic while rotating to help it come out. One broke on me once but a bendable drill end and an easy out let me get the bottom half out without having to remove the oil pan.
There is a single bolt that holds it down as well.


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Re: Corsica misfiring after rain (nowadays problem with IAC valve)

Postby Money pit Beretta » Wed Jun 27, 2018 6:40 pm

"New" replacement wires for the crank sensor from a 3400 and my car is on the road again. Feels weaker, but it could be learning.


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Re: Corsica misfiring after rain (nowadays problem with IAC valve)

Postby Bapsu » Tue Aug 14, 2018 3:05 pm

Update:

Firewall sanded, painted and sealed. Put back steering rack, brake booster and blower motor housing. Looks good so far.

Gonna hit up that sensor tomorrow, lets see what kind of show it is to replace that...



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Re: Corsica misfiring after rain (nowadays problem with IAC valve)

Postby Bapsu » Thu Aug 16, 2018 7:41 pm

Crank sensor replaced. Quite a pita.

If someones heading to the operation: take look from under the car to see where the sensor itself is located. Then hit up the sensor from above the car. Screw is 8mm. Sensor came out without pain, as the new one also went to its place.

Both sensors had ohms around 900. Never had chance to crank the car and see what kind of signal the old one was pushing out, since i got the car apart for firewall repairs. Still betting that the culprit to no crank signal in tach meter was the crank sensor.

Going to get an answer tomorrow, going to hit all the wires on their places and fire the car up for test.



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Re: Corsica misfiring after rain (nowadays problem with IAC valve)

Postby Bapsu » Sat Aug 18, 2018 6:40 pm

Ok, still not starting. No crank on the tach meter (its not jumping while cranking the car, as its supposed to do). Checked crankshaft position sensor voltage while cranking, 0.2-0-5v coming to the icm while cranking. 12v coming to icms power input connector. So icm is getting everything it needs.

I guess its time to swap icm tomorrow to spare one i got and see whats happening after that.



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Re: Corsica misfiring after rain (nowadays problem with IAC valve)

Postby Money pit Beretta » Tue Aug 21, 2018 7:11 pm

Hoping that the ICM solves the problem.
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Re: Corsica misfiring after rain (nowadays problem with IAC valve)

Postby GT_Indy » Tue Aug 21, 2018 7:50 pm

Money pit Beretta wrote:Hoping that the ICM solves the problem.


Same, there is also the possibility the CPS is defective out of the box, I've encountered that before which is horrible because a new CPS is hard to pull out once its tightened down.


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Re: Corsica misfiring after rain (nowadays problem with IAC valve)

Postby Bapsu » Wed Aug 22, 2018 7:57 pm

GT_Indy wrote:
Money pit Beretta wrote:Hoping that the ICM solves the problem.


Same, there is also the possibility the CPS is defective out of the box, I've encountered that before which is horrible because a new CPS is hard to pull out once its tightened down.
Yup. ICM was it. Swapped the spare one and had crank signal.

However, crank signal was intermittent; sometimes when i cranked, no signal at all, sometimes it was bumping to 500rpm on tach, even though the engine was cranking just normally below 200rpm. Sometimes it showed accurate crank reading on the tach and engine stumbled few times like it was trying to fire up.

I came to the conclusion that new standard motor products crank sensor was somehow defective, gotta ask refund/replacement from rockauto. Swapped the old (working one) back. Engine fired right up and runs like a clock for now.

Since firewall is now repainted and resealed and everything back except carpets and seats (gonna pull red ones from usa imported corsica lol) i guess things are quite well for now. Still have to do brake line, front brakes and check some rust spots at the bottom before inspection.



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Re: Corsica misfiring after rain (nowadays problem with IAC valve)

Postby GT_Indy » Wed Aug 22, 2018 9:14 pm

Bapsu wrote:
GT_Indy wrote:
Money pit Beretta wrote:Hoping that the ICM solves the problem.


Same, there is also the possibility the CPS is defective out of the box, I've encountered that before which is horrible because a new CPS is hard to pull out once its tightened down.
Yup. ICM was it. Swapped the spare one and had crank signal.

However, crank signal was intermittent; sometimes when i cranked, no signal at all, sometimes it was bumping to 500rpm on tach, even though the engine was cranking just normally below 200rpm. Sometimes it showed accurate crank reading on the tach and engine stumbled few times like it was trying to fire up.

I came to the conclusion that new standard motor products crank sensor was somehow defective, gotta ask refund/replacement from rockauto. Swapped the old (working one) back. Engine fired right up and runs like a clock for now.

Since firewall is now repainted and resealed and everything back except carpets and seats (gonna pull red ones from usa imported corsica lol) i guess things are quite well for now. Still have to do brake line, front brakes and check some rust spots at the bottom before inspection.


I forgot to mention, I believe there are 2 different part numbers for the CPS for the 2.8/3.1 v6's, and I believe it is also true for the 3100/3400 engines.
The numbers are the same, but one has an added letter at the end where as the other does not. I don't remember which one is the correct one and which one is the incorrect one.
Its been a long time but I'm pretty sure I measured different resistance between the two versions.

I remember going on a trip after fixing my 88 GT 2.8 v6 and I had to swap the CPS in a parking lot because the one in the car was causing issues for me. Its tach signal sometimes cut out or was weak, similar to what you describe.
I do remember finding a tall curb and getting the front wheels on it so I could get under the car and fix it because I didn't have a jack with me. lol
Car ran fine after, never had issues after that.


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Re: Corsica misfiring after rain (nowadays problem with IAC valve)

Postby Bapsu » Thu Aug 23, 2018 8:00 pm

Okey, gonna check those numbers also...

Meanwhile, had to replace my corsicas heater core. What a pita! Not disassembly, but putting it back together arrgh.

Succeeded in everything, except the last box containing heat passages. Spent around 3hrs trying to get it on place properly. Cannot still get those rear seat heat passages on place. Gonna take center console away tomorrow, that should fix the problem.

Btw, anyone here got good hints for removing dash? There was few posts somewhere, but not too much. Is that also a pita?



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Re: Corsica misfiring after rain (nowadays problem with IAC valve)

Postby Money pit Beretta » Sat Aug 25, 2018 5:07 pm

Damn good news that it running again. This time for sure!
The dash? Last I remember reading it took like six hours to do. It was said that there are a few screws that are hard to find/get to.


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Re: Corsica misfiring after rain (nowadays problem with IAC valve)

Postby GT_Indy » Sun Aug 26, 2018 12:48 am

Money pit Beretta wrote:Damn good news that it running again. This time for sure!
The dash? Last I remember reading it took like six hours to do. It was said that there are a few screws that are hard to find/get to.


I think the heater core has to come back out as well if the whole dash assembly is being removed.

If it is just the cosmetic cover over the plastic shell then its easier. A few screws and it slips off like a glove.


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Re: Corsica misfiring after rain (nowadays problem with IAC valve)

Postby Bapsu » Sun Aug 26, 2018 6:29 pm

Yeah took the dash out today.In case someones heading to same operation:

One nut at both sides, other near glove box and the other near fuse panel. Four screws just near windshield wheres the blower grill. Two nuts inside dash.

Things to be taken away;
Radio
AC-panel
Steering wheel, unbolt if from the dash and open the clamp holding it on the steering rack near firewall.
Take out cluster aswell. wiper controls and headlight switch also.

After removing those, unbolt and unhook the wiring harness going behind the dash. You really cant see much there, you just gotta feel it by hand where are the nuts and holders. Take all wirings out of the dash, disconnect heating hoses going to side vents. Pull dash out.

Not rocket science, did it myself first time on this car, took around 4hrs. Also, no need to deal with heater core!




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