1993 3.1 will not stay running

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90CamaroRS
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1993 3.1 will not stay running

Post by 90CamaroRS »

Alright guys, so my Beretta died on me Friday night after replacing the thermostat for whatever reason. Left me sit on the side of the road. Just shut off without warning and then started right back up, but then died again right away. Then it would not start when hot. Once I got it running, it made it about another mile and started acting like it was missing really bad and then would die again. Same thing, then wouldn't start when hot. Finally got home and checked things out. Here's a list of what I have recently changed on the car:

Throttle Position Sensor
Ignition control module
All ignition coils
Spark plugs (Gapped correctly)
Wires
Air filter
Oil and filter
Fuel pump
Fuel filter
Fuel Pressure Regulator
All injectors

After I redid the complete fuel system, it would prime to 42 psi, then today it was running on 35 psi, just like it was before. I let it idle until the fan came on and shut off, then when I went to take it for a ride, I had no brakes, broke a brake line getting the tank in and out so I have to fix that now too, but I let the car continue to idle while I was cleaning up, and it died again. Started right back up, ran for a few more minutes and died again. I have no fault codes or check engine light. Is there something that I'm missing?

I have put a lot of money into this car over the last few months keeping it going, I want to keep it going. Unrelated, but here are some other parts I have changed in the last 6 months

Front brake pads, rotors, calipers
Front struts
A-arms and bushings
Front wheel hubs
CV axles
Tires all the way around

What would keep shutting off the car? It seems like an electrical problem. Everything works as it should on the car, even the R12 A/C. Car is a 1993 Base Model 3.1 V6 Auto with 136,181 miles on it.

Looking for some ideas here guys, I need to get the car running again ASAP. Its either an electrical or fuel related problem.

I'm thinking either something is shutting the car off electrically, or its a fuel problem. As far as I know, the car is supposed to run 40-48 psi, and even after redoing the entire fuel system, it still runs on 35 psi, and when given throttle, the pressure drops.

I can't find any vacuum leaks or anything of the sort.

Any help is greatly appreciated!


2004 Silverado standard cab stepside 4.8 V8 Auto 4x4, 6" lift 35's
1993 Beretta Base 3.1 V6 Auto Z26 wheels, grille
1990 Camaro RS 355 TPI swapped LT4 hotcam
1979 K5 Blazer Restomod LSx swap body off frame underway
heavywoody
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Re: 1993 3.1 will not stay running

Post by heavywoody »

Crank Position Sensor in the back of the block, or the ICM under the coil packs. Those will work when cold and if they are bad, will fail when hot.


Geoff
95 Z26 Turbo 3400 5spd - R&D Project
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woody90gtz
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Re: 1993 3.1 will not stay running

Post by woody90gtz »

Are the MPFI cars vacuum referenced on the fuel pressure like the SFI cars? If so...43 with key on and 35 idling sounds about right. If you have the gauge on it you could stab the throttle quick to see if the fuel psi rises to 43 and then falls back down.

That test would help either confirm normal operation or possibly give you some new data for troubleshooting.

Speaking of data, do you have a code reader or laptop and cable you could hook up to see live info from the computer? That stuff can be invaluable in figuring this kind of thing out.


91 "SS" - WOT 3400/5spd - 13.29@101.6 - World's fastest N/A FWD Beretta
96 "T56" LS/6spd/8.8 RWD swap - 13.45@104.7 lol
GEARHEAD dezign youtube
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90CamaroRS
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Re: 1993 3.1 will not stay running

Post by 90CamaroRS »

Thanks for the replies but I was able to fix the car before moderator approved my post. I replaced both the ignition control module and the crank position sensor, and threw in a coolant temp sensor to be sure. I know a wacky CTS throws off a lot of OBD1 GM cars, including with my experience TPI and TBI. Even caused problems with the 3.1 in my Camaro.

On another note, what the correct way to bleed the brakes on these things? This is my first experience with the ABS module on these cars, and it seems like no matter what I do to try and bleed the front calipers, they always seem like they are dragging going down the road...


2004 Silverado standard cab stepside 4.8 V8 Auto 4x4, 6" lift 35's
1993 Beretta Base 3.1 V6 Auto Z26 wheels, grille
1990 Camaro RS 355 TPI swapped LT4 hotcam
1979 K5 Blazer Restomod LSx swap body off frame underway
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ifixalot
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Re: 1993 3.1 will not stay running

Post by ifixalot »

Since you were working with the thermostat, is it possible the wire to the temp sender is messed up or disconnected?
If it is off, would that cause the car to run real rich and die? Maybe pull a spark plug and see if it is dark from running rich.


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90CamaroRS
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Re: 1993 3.1 will not stay running

Post by 90CamaroRS »

I actually have a lot of things going on with the car this week...

So now that its warm out again, I can confirm that the A/C clutch is no longer working.

The car runs hot. To the point today that it was damn near hitting the red on the gauge when driving home in traffic on I80 in New Jersey.

The way that I got past the issue last summer was running the A/C constantly, just to keep the fan on and help keep the engine cool. Now with the A/C not working, when the fan finally does come on, it can't cool the engine fast enough, its a run away hot until I get rolling again.

Since I already cut the wires for the A/C high pressure switch, I jumped them so that the fan will come on when I turn the HVAC to an A/C selection and trick the computer into giving me the fan.

I have also pulled out a third gen Camaro trick and made a lower air dam for the radiator. This works by creating a low air pressure behind the radiator that in turn forces more air through the radiator.

But these are just bandaids. Even after replacing the thermostat, the engine runs hotter than ever. The radiator is much newer (Date code April 2006 on it) so that leaves two other things.

1) The belt is skipping on the water pump pulley
2) The water pump is going out

How common is water pump failure on the FWD 3.1 LH0? I have never had to replace a water pump in anything.

I also tried to bleed the brakes again tonight, but the brakes continue to stick on, they are simply set too tight. How do you go about getting the brakes to back off? They are brand new calipers, so they should be releasing just fine. I'm convinced that the problem is the ABS solenoids applying too much pressure. How do I get the ABS set right with the new calipers? Its a major annoyance, and forcing the car to work much harder to go down the road.

Thanks guys!


2004 Silverado standard cab stepside 4.8 V8 Auto 4x4, 6" lift 35's
1993 Beretta Base 3.1 V6 Auto Z26 wheels, grille
1990 Camaro RS 355 TPI swapped LT4 hotcam
1979 K5 Blazer Restomod LSx swap body off frame underway
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woody90gtz
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Re: 1993 3.1 will not stay running

Post by woody90gtz »

I have seen people replace the water pumps on these, but I think it's usually due to leaks...no diminished flow. I couldn't tell you for sure though. They are super simple, at least, and I would guess pretty cheap.

I haven't heard of your ABS problem. Have you tried unplugging the module to see if that does fix it? That could probably rule out the solenoids. If you unplug it and slam on the brakes that should have enough pressure to move a de-energized solenoid back home.


91 "SS" - WOT 3400/5spd - 13.29@101.6 - World's fastest N/A FWD Beretta
96 "T56" LS/6spd/8.8 RWD swap - 13.45@104.7 lol
GEARHEAD dezign youtube
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90CamaroRS
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Re: 1993 3.1 will not stay running

Post by 90CamaroRS »

woody90gtz wrote:I have seen people replace the water pumps on these, but I think it's usually due to leaks...no diminished flow. I couldn't tell you for sure though. They are super simple, at least, and I would guess pretty cheap.

I haven't heard of your ABS problem. Have you tried unplugging the module to see if that does fix it? That could probably rule out the solenoids. If you unplug it and slam on the brakes that should have enough pressure to move a de-energized solenoid back home.
That's exactly what I did. Drove it for a day with the solenoids unplugged, then bled them with it unplugged, plugged them in, bled them once more. Got A LOT more air out of the system and now appears to be working as it should.

As for the overheating, I replaced the belt with a Continental one, took the glazing off of the water pump pulley with scotch brite, and now as soon as the engine speed is increased, it starts cooling right away.

The third-gen Camaro makeshift air dam is also working as soon as vehicle speed is pushed pasted 40 mph or so, and I jumpered the A/C line pressure switch to operate the fan with the HVAC controls since the compressor clutch has apparently stopped working and on a digital infrared thermometer with the fan running, lower rad hose temps are around 165 while upper temps are around 185. Fan doesn't kick on until 245 automatically though.


2004 Silverado standard cab stepside 4.8 V8 Auto 4x4, 6" lift 35's
1993 Beretta Base 3.1 V6 Auto Z26 wheels, grille
1990 Camaro RS 355 TPI swapped LT4 hotcam
1979 K5 Blazer Restomod LSx swap body off frame underway
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woody90gtz
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Re: 1993 3.1 will not stay running

Post by woody90gtz »

Yeah, I swapped the 195 tstat in mine for a 180 and reduced the kick on temps in the tune by 15 degrees. But I did it more as insurance against knock since I've been playing with the fuel and spark tables.


91 "SS" - WOT 3400/5spd - 13.29@101.6 - World's fastest N/A FWD Beretta
96 "T56" LS/6spd/8.8 RWD swap - 13.45@104.7 lol
GEARHEAD dezign youtube
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