Won't stay running..

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AeraBell
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Won't stay running..

Postby AeraBell » Sat Sep 16, 2017 11:06 am

My 91 beretta gt won't stay running. I'll turn it over and it dies out within 15 seconds tops! I've replaced the map because it was showing codes for 33 and 33 then it showed nothing until about 3 days Ago now it's just 34.. ran on after unplugging map and turning over then plugging it back in, for a day. Now same regardless.. any ideas?



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Re: Won't stay running..

Postby Money pit Beretta » Tue Sep 19, 2017 6:57 pm

Will it stay running with your foot on the gas?


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Re: Won't stay running..

Postby GT_Indy » Tue Sep 19, 2017 11:09 pm

I'd start by pulling the vacuum line on the fuel pressure regulator and see if it squirts gas out when the key is turned to run and the pump primes.


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.

AeraBell
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Re: Won't stay running..

Postby AeraBell » Sun Sep 24, 2017 7:57 pm

Adding gas kills it quicker. Every so often you can catch it good enough for it to run smoothly but pretty much once you turn it off and try again, same thing. And the pump is definitely priming. We even checked the fuel rail and fuel pressure. Thinking it may be throttle position sensor? It's running lean..



AeraBell
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Re: Won't stay running..

Postby AeraBell » Mon Sep 25, 2017 1:36 pm

It dies quicker if you add any gas..



AeraBell
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Re: Won't stay running..

Postby AeraBell » Mon Sep 25, 2017 1:37 pm

Where is the fuel pressure regulator?



Bapsu
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Re: Won't stay running..

Postby Bapsu » Tue Sep 26, 2017 7:35 am

But where is that vacuum line? Been looking for that from the + marked thing near intake but I only can find two fuel lines (metal ones) going to it? And mines 3.1 mpfi.

Been wondering why i need to crank for 5-10s before it starts and it seem to be a fuel problem.



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Re: Won't stay running..

Postby GT_Indy » Tue Sep 26, 2017 9:18 am

See the small left most vacuum line?
There is a T fitting if you look close just under the 3.1 intake.
Carefully pop the T fitting off the fuel pressure regulator and see if fuel comes out the regulator vacuum port.
Also, does it stay running if you keep your foot on the gas?
Attachments
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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: Won't stay running..

Postby Bapsu » Fri Sep 29, 2017 6:54 pm

Ah thanks my friend, now i got it. :)

Gonna take look to it, im experiencing very hard starts, only time it dont hard start if i immidiately start after i turned off the engine. So i guess fuel is draining (leaking) from somewhere... Before hard start thingy I gotta sort that misfire out..



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Re: Won't stay running..

Postby GT_Indy » Fri Sep 29, 2017 10:54 pm

Did you connect a fuel pressure regulator to see if you have proper fuel pressure after prime and during running?
Possible causes of low fuel pressure: failed fuel pressure regulator, leaking fuel injector(s), plugged fuel filter, weak fuel pump.

Also, check your plastic vacuum lines. It may be possible they are cracked or fully broken under or behind the intake causing incorrect MAP readings.


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: Won't stay running..

Postby Bapsu » Sun Oct 01, 2017 8:21 pm

How I connect a fuel pressure regulator? :Yahoo!:

I havent used pressure tester yet, but from the pressure relief valve, theres barely any pressure left after the car has been shut off. I mean if u tap that with screwdriver etc. fuel just flows out, doesnt come out with pressure as it should?

Other thingy, managed to locate that vac line you talked about (vac lines are ok btw) and pulled it off when car was sitting and was doing some rust jobs (almost ready!). I didnt find any fuel from that line, BUT the vac line going to fpr was smelling for fuel... So looking foward to get the car running and see if theres fuel in the vac line while engine runs... But I guess that line shouldnt smell for fuel, right?

Gotta sort that misfire out soon also, just have to order few parts.



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Re: Won't stay running..

Postby GT_Indy » Tue Oct 03, 2017 12:25 am

Yah I meant fuel pressure tester. lol

Yes there shouldn't be any fuel smell in the vacuum lines.

Fuel can squirt out of the test port even if its low pressure. The fuel system should prime to 46 PSI and hold it for a while, and hold 46 PSI while running at idle in park.

Here is a video of my QUAD4 Beretta with a bad fuel pressure regulator:
https://youtu.be/Bl-Rp8ZYONs

I had hard starts and misfire under higher rpm's and under loads. You should see about 46 PSI on the v6 3.1 engine as well. And you should see it hold the pressure longer than mine. If it drops like mine did that is not good.
I say 46 PSI, but I think 44-46 is acceptable, I forgot what the GM service book says.


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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Posts: 38
Joined: Mon Aug 14, 2017 4:05 pm

Re: Won't stay running..

Postby Bapsu » Thu Oct 05, 2017 6:13 pm

Hmm theres light smell in the line, but when i fired up the engine and pulled the line off, it remained dry. Maybe I should take a drive with that line unplugged.

Dont have fuel pressure tester so not sure atm what I do with this starting problem. Also still havent sorted out the misfire (dont have parts) caused propably by faulty icm, I guess icm would be one more box causing hard start also.



GT_Indy
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Re: Won't stay running..

Postby GT_Indy » Thu Oct 05, 2017 6:43 pm

It needs the line connected to get proper vacuum reading for your MAP sensor as that T fitting goes to your throttle, your MAP and your FPR.
If you smell fuel, there could be an external leak somewhere else on the rails/injectors, or injectors may have leaks and you smell vapor from the intake.

A fuel pressure tester will show right away if were on the right track for fixing your engine.
If you have a camera, do a recording like I did, turn the key and let it prime, do it a couple times. Then show the pressure while it runs/revs.


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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Posts: 38
Joined: Mon Aug 14, 2017 4:05 pm

Re: Won't stay running..

Postby Bapsu » Thu Oct 05, 2017 9:25 pm

Yeah, gotta look for the pressure tester if new icm wont fix that hard start issue as well. Its winter coming here for now, so I wont be driving my chevy in next 6 months anyway. Neither fixing too much. :D I just will try to get rid of the misfire in few weeks as i got some freetime finally.




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