1988 Beretta misfire when cold and random acceleration

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JackTheFox
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Re: 1988 Beretta misfire when cold and random acceleration

Postby JackTheFox » Wed May 23, 2018 5:51 pm

Hello. Thank you for the advice, i didnt see those two bolts because of the aftermarket radio brackets. They connected cables the wrong way, this was the reason for the radio resetting each time after ignition got turned off, thats fixed now.

Alright, too bad that there is no other way to bleed the cooling system, but now i understand why. I installed a new thermostat today (the preowner removed the thermostat completely, not a surprise that it didnt get up on temperature), and replaced the coolant temp sensor just as precaution since i had a new one anyways. As soon as you fill the thermostat housing full with coolant, because of the height it gets pushed back into the reservoir. I guess it just needs the bled out like it happened with the Corsica.

The shipping to Germany makes the Monitor 2000's very expensive unfortunately. Also i couldnt exactly find ones for a 88 Beretta. Only "89 GM Models".
I didnt know that the TPS was always on tension when it gets installed. So i just lined it up with the edges of the throttle body housing, like the other one was. I am not sure if thats very correct, and i'd prefer to sort of check the value in % of how its set and how it needs to be set. Is it possible to maybe read out those values with a GM OBD I adapter to OBD 2 ?

The IAC valve seems to be working. I cleaned it and where it seats up with a dremel tool.

Today i also checked the whole system with my fog machine for vacuum leaks and found exaclty 4 leaks. 1 fixable, the other 3 i am not sure about:
Exactly the same thing happens on my Corsica, steam is coming out where the rod on the EGR valve goes up to the membrane. Is that normal when the engine isnt runing?
And the other two leaks are in the throttle body housing, actually exactly on the rod of the throttle. So fog comes out between the TPS and throttle body housing, and on the opposite side between the housing and the throttle cable. I dont think this one is fixable without disassembling the whole throttle body, so i'd probably just leave that as is. But the thing with the EGR valve i am curious about?!

Also another question. On my digital instrument panel the display for mileage etc wasnt working, it looked like the lines didnt show up as they should. Since i had a half pulled apart digital cluster, i just swapped over the display. Its still showing up the lines etc badly as before. Are those displays known to go bad, or is that an issue in the whole motherboard of the instrument cluster?
Also is the mileage saved in the ECM or the digital cluster?

Greetings :)



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Rettax3
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Re: 1988 Beretta misfire when cold and random acceleration

Postby Rettax3 » Wed May 23, 2018 6:16 pm

Mileage is stored inside the cluster. Supposedly a removable chip, but I have never tried to swap them. The clusters are pretty durable, sometimes you need to remove the grey conductor strips (carefully!) and clean them and the surfaces on the glass displays and boards with isopropyl alcohol. Also, make sure all of your back-light bulbs are working, or certain areas will be dark. Verify all of your power supply wires are actually working too (there is a keep-alive battery+ wire going to it for the tripometer memory). I do have a pinout diagram for it here somewhere... Let me look for it.


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Re: 1988 Beretta misfire when cold and random acceleration

Postby GT_Indy » Wed May 23, 2018 11:46 pm

As long as the egr functions properly when the engine runs I wouldnt bother with it.
But there should be a return on it so it closes when not under demand.
You have the round vacuum controlled eye right? You can move it by hand and see if its still spring loaded, if so its probably fine. No need to remove it to do so. Just make sure its not hot.

Yah I forgot to mention the tps normally has some tension on it when installed. Its been a long time since I had one apart on a 2.8/3.1 engine.

Where are the other 3 leaks? Under the top intake?
Ideally there sbould be 0 leaks. These engines dont like vacuum leaks. lol

There is also the datalogger cable from Moates.net that can work with tuner pro.
The ads file for tuner pro to read your data and tuner pro are both free on the tuner pro web page.
Might be an option if you were interested in reading about it. Then you can view live data from your engine as it runs.


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Re: 1988 Beretta misfire when cold and random acceleration

Postby Bapsu » Thu May 24, 2018 9:11 pm

Do you guys have had any problems with the engine while its idling i can almost always feel little shaking or stumbling on the streering wheel and seat? It is really slight, but its unstable, not like normal idling vibrations coming from engine.

My both corsicas seem to have same feature...



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Re: 1988 Beretta misfire when cold and random acceleration

Postby GT_Indy » Thu May 24, 2018 11:12 pm

Bapsu wrote:Do you guys have had any problems with the engine while its idling i can almost always feel little shaking or stumbling on the streering wheel and seat? It is really slight, but its unstable, not like normal idling vibrations coming from engine.

My both corsicas seem to have same feature...


Like when its idling smooth but there is 1 subtle off beat tone every so often?
I've had that before on a couple 2.8 and 3.1 engines.

I think its just aged electronics and maybe a pinhole vacuum leak in an aging hose. My current 3.1 a 94 sunbird sometimes sounds that way, but I know my coils and tps need replaced.


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JackTheFox
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Re: 1988 Beretta misfire when cold and random acceleration

Postby JackTheFox » Sat May 26, 2018 5:41 pm

Hello.
I might try to swap the digital clusters out, just to see if its the whole thing thats broken, or if just the mileage display is broken. Since i just replaced all the bulbs i am very sure that its an hardware issue.

I will look into the datalogger cable from Moates.net a bit more, i might give that one a try.

The last time i was driving my Corsica i had a check engine light coming up for a few seconds now and then. Independent of how i was driving, it didnt matter if i was just rolling or accelerating. It appeared 3 times for just a few seconds over a timespan of two hours.
Today i was able to check the code, and it threw the code 13 which is supposed to mean "02 sensor or circuit". The O2 sensor is brand new though, i just replaced it as precaution. Before i replaced it, the check engine light never showed up for me. Since its always just for a few seconds (Like 20 or 30) does it mean that the new O2 sensor is broken?

Greetings



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Re: 1988 Beretta misfire when cold and random acceleration

Postby Bapsu » Sun May 27, 2018 8:12 pm

JackTheFox wrote:Hello.
I might try to swap the digital clusters out, just to see if its the whole thing thats broken, or if just the mileage display is broken. Since i just replaced all the bulbs i am very sure that its an hardware issue.

I will look into the datalogger cable from Moates.net a bit more, i might give that one a try.

The last time i was driving my Corsica i had a check engine light coming up for a few seconds now and then. Independent of how i was driving, it didnt matter if i was just rolling or accelerating. It appeared 3 times for just a few seconds over a timespan of two hours.
Today i was able to check the code, and it threw the code 13 which is supposed to mean "02 sensor or circuit". The O2 sensor is brand new though, i just replaced it as precaution. Before i replaced it, the check engine light never showed up for me. Since its always just for a few seconds (Like 20 or 30) does it mean that the new O2 sensor is broken?

Greetings
You also might have problem with the wiring. Check the wire for cracks and the connector itself that it is well seated and there is no corrosion.

Theres also quite high possibility that your o2 might be broken out of box (not first time).
WhiteGTZ wrote:
Bapsu wrote:Do you guys have had any problems with the engine while its idling i can almost always feel little shaking or stumbling on the streering wheel and seat? It is really slight, but its unstable, not like normal idling vibrations coming from engine.

My both corsicas seem to have same feature...


Like when its idling smooth but there is 1 subtle off beat tone every so often?
I've had that before on a couple 2.8 and 3.1 engines.

I think its just aged electronics and maybe a pinhole vacuum leak in an aging hose. My current 3.1 a 94 sunbird sometimes sounds that way, but I know my coils and tps need replaced.
Yes, you got my point perfectly, every now and then theres one "beat" which breaks the rhytm. I have been thinking aged electronics also and more likely vacuum leak... I think I should replace those vacuum lines around tb.



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Re: 1988 Beretta misfire when cold and random acceleration

Postby GT_Indy » Sun May 27, 2018 9:57 pm

Yah sometimes (often where I live) the TPS, IAC, and O2 are bad when new in box. I had three IAC valves in a row that never worked new and there is no return on electronic parts where I live. lol. I thought that something else was wrong with my 96 Beretta but the IAC valves were just junk.


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