3.1 engine ignition(?) problem

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1988GTU
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Re: 3.1 engine ignition(?) problem

Postby 1988GTU » Sun Feb 08, 2015 8:30 am

Hopefully you figure it out before swapping. I agree with Jon.

Pull the rocker arm covers (front at least, preferably both) & pay attention to make sure all rockers exhibit correct fulcrum when rotating the engine's valve train a full cycle. If you have a dead or very little motion with a rocker arm or few, you have mechanical issues within the engine giving better reason to swap.


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Re: 3.1 engine ignition(?) problem

Postby michi » Fri Feb 13, 2015 1:52 pm

I know it would be stupid to swap engines just because of this but i thought if i get this engine i could later swap in it cause i always wanted a 3400 beretta. But after that guy isnt answer on my mails and calls i am going to ditch that swap for now and get my 3.1 running again.
I was pretty sick the last few days so i did nothing on the beretta... i am getting better already and see if i can check some more things on the car this weekend. Talked to my neighbor which has a car repair shop and hes helping me to check the fuel pressure of my car by next week or so. Im also looking if i can get some used injectors from a good runing engine to see if my injector(s) is the problem... first going to check harness, ecm and some more stuff also doing some more datalogs, then fuel pressure test and after that injectors.



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Re: 3.1 engine ignition(?) problem

Postby themixer » Fri Feb 13, 2015 6:44 pm

3X00-Modified wrote:
themixer wrote:https://www.youtube.com/watch?v=rUUgR94drxg

you could try something like this on them to see what kind of spray pattern you are getting and clean them at the same time.

I spent a lot of money attempting to find 3.1 injectors that were in good working shape, tried ebay auto parts stores, even had a chip burned to run 3100 injectors but never had any luck.

In the end I switched engines to a 3400, and it runs better and cost way way less money than I spent messing around with the 3.1.

Seeing the location you are in it's probably not so easy to find 3400 motors. If you could find a set of multec 2 injectors out of one and the connectors/injector harness, you could get a chip burned to run them in your 3.1.

If I could go back in time that's what i should have done to my own car.


Funny thing about that... I just grabbed an old set of 3100 injectors I had and slapped them into my Indy... Ran great going all the way to Tenn Bfest :) Never touched the chip.



Yes I remember you saying this, they are pretty similar in flow. In my area these older parts are pretty scarce, cannot even imagine being overseas looking for them. If you have another extra set of 3100 injectors, send them over to michi and help out!



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Re: 3.1 engine ignition(?) problem

Postby Money pit Beretta » Fri Feb 13, 2015 7:06 pm

I have a set of 150k 3100 injectors just sitting around. Not sure if they are any good. It ran rough, new 99 Venture van injectors didn't solve it so I blame piston slap.
If you need them Michi they are yours.


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Re: 3.1 engine ignition(?) problem

Postby michi » Sun Feb 15, 2015 1:28 pm

That sounds great, Thanks! Well at the moment someone from a austrian american car forum told me he has 3.1 injectors from a corsica laying around... im waiting for some pics he said hes going to take and maybe they are mine soon. If this deal fails i will get back to you! :)

Today i pulled the ECM, floor is all dry but found 1 corroded pin on first (yellow) connector... cleaned off the corrosion, put it back together and started the engine. It was idling pretty rough but reeved up just fine, shut it down, started it again and drove it out of the garage, it died when i took a turn, started again, parked it and let it idle then shut it down when it was running fine. Well fine... i mean just like it did before :D
Was a bit strange when it was running that rough after i put back in the ECM. First time i do this on 3.1... had my chip swapped on my GTZ and it didnt acted like that.

Cool thing was how i got a flashback today when i pulled the ECM. This car had a ECM failture about ~15 years ago when me and my parents were in holidays and the car struggled and didnt reeved up anymore on highway, so my dad(r.i.p) pulled it over, we pushed it some meters then parked it and waited for the car club to get the car towed. Went straight to a GM dealer where the car got a new ECM after 2 weeks. We got a rental car in holiday so we could continue and drove home after a few more days.
Thats one reason i love that car... so much memories.



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Re: 3.1 engine ignition(?) problem

Postby Berry » Sun Feb 15, 2015 4:09 pm

hi michi
do you remember? last year my car had big idling-issues (in the beginning only with warm engine, later always) and you helped me finding out the reason why. my ECM had corroded pins too, cleaning off the corrosion didnt help, I had to replace the ECM. since then my beretta has no problems.
I dont believe that the injectors are bad when all 6 spark plugs together are black. It's rather a bad o2 or temp sensor, a burnt cable in the harness or the 15 years old ECM, I bet it's a timeworn electronical part. typical beretta-issue ;) how old is the cool temp sensor?
and yeah how about testing the o2-sensor with a propane burner like rettax3 suggested? but I suppose after 2 years the o2 should still be ok.
I hope u 'll find out the reason for the problems soon, good luck and keep us posted!


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92 GT 3.1 MPFI auto 57K white

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Re: 3.1 engine ignition(?) problem

Postby michi » Sun Feb 15, 2015 4:42 pm

Your right berry, just havent thought about the ECM first but after i saw a corroded pin(just a little bit) i was a bit worried... too bad i dont got another ECM laying around :/
Coolant temp sensor should be the original one, lol. O2 should be okay since it doesnt threw me any codes but then again i had a O2 sensor failture on my old 92 GT, the car ran in loop mode and mega rich and couldnt even idle in neutral(auto).



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Re: 3.1 engine ignition(?) problem

Postby Berry » Sun Feb 15, 2015 5:13 pm

me too, I havent got any spare ecm laying around...is there no an other beretta near you for a short ecm-borrow-action only to check out if it's a bad ecm or not? my car is in spain, otherwise I would do a short trip to austria


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Re: 3.1 engine ignition(?) problem

Postby 1988GTU » Sun Feb 15, 2015 9:55 pm

I know rockauto is uber slow for you, but they have the ECU and at the time I was looking, they had stock ECM's packaged with reman ECU's for a fair price.

Food for nom


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Re: 3.1 engine ignition(?) problem

Postby michi » Mon Feb 16, 2015 3:55 pm

Yeah i have seen that rockauto sells them and for a good price.
Pulled the ecm again and checked the connectors so everything is clean there and also disconnected the battery. After putting these together i did an idle relearn, a testdrive and let it idle for couple minutes after that. I thought it was a better till it started to rumble just a little bit more but not that worse as it did before. I will be sure after emission test this week.. my neighbar got such a tester so we will see if theres any better or not, also trying to get the fuel pressure tested when where already at it.



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Re: 3.1 engine ignition(?) problem

Postby michi » Tue Feb 17, 2015 3:42 am

Guys, i noticed that my idle video on youtube was "privat" so i guess you couldnt see the video. Now turned it to public. Check it out, maybe you get an idea with that idle. http://youtu.be/kA25Wo8wFE4



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Re: 3.1 engine ignition(?) problem

Postby ifixalot » Tue Feb 17, 2015 10:05 am

Yes, it was private but it's short and doesn't help much.
Did you ever check the ohms of the injectors?
An injector is an electric controlled valve.
Pass electricity through a coil of wire and it becomes
a magnet. In this case, it pulls open a plunger and lets
fuel flow. If it is short circuited, it won't have the same
strength as a good coil. It has to pull against fuel pressure.
So even if it clicks why dry, it may still be bad. The only way
to tell is measure the ohms.
I told you that I had a 92 Buick V6 that ran rough and blackened
the plugs. I think one was lighter but I'm not 100% sure of that.
I told you one injector measured 4 ohms and the others 11-12
ohms. These injectors have a history of going bad. After I swapped the
4 ohm injector the car ran much better. I also told you that I think
the ECM sees the lean pulse from the cylinder which gets no fuel
and richens the mixture to the others trying to average out.
This is my theory based on the experience of what I found
and what happened after I changed that one injector.
If you don't want to buy or borrow an ohm meter, I don't have any more
suggestions for you except keep changing parts, you may eventually
find the problem.



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Re: 3.1 engine ignition(?) problem

Postby michi » Tue Feb 17, 2015 1:48 pm

Yeah my bad i didnt checked the injectors before i put them back in. After it still wasnt running right I thought im going to get another set and just put them in and be good but i havent got ones yet so i am going to pull them tomorrow and ohm them out. Lets see what will happen.
Thanks :good:



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Re: 3.1 engine ignition(?) problem

Postby michi » Wed Feb 18, 2015 12:02 pm

Here we go.... meassured them out and we have one bad injector here. One is 5,5ohms and the rest 12,3-12,5.



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Re: 3.1 engine ignition(?) problem

Postby 3X00-Modified » Wed Feb 18, 2015 12:07 pm

On a 3.1MPFI engine that will kill or screw up an entire bank of injectors when it's trying to run.




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