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3.1 Multiport FI...


ninjee

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My gas gauge quit working (i think the floater got stuck :/), and anyway, the car ran out of gas. Put 3 gallons of gas in it from a gas can and tried to start it after letting the fuel pump pressurize the fuel system. It started, ran doggy, and as soon as i hit the gas, it would die. I figured it was air in the line so i kept doing this for about a half hour. Finally i gave up and had it towed home. Went out the next morning to see what it would do and it fired right up, ran ok. Went to go to the store and got about 1/2 way there via the highway, and the car died. Same situation, starts up, runs doggy, dies. Its not giving me any error codes OTHER than a rich exhaust. I know it cant be the catalytic converter because i did away with it a long time ago (glass pack cherrybomb). It blows black smoke when you give it alot of gas, and it seems to be lacking power.

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check the basics, spark plugs, spark plug wires, coils, fuel pump, fuel filter.

 

I just replaced the plugs and wires. The fuel system is saying its at 40 PSI at the schrader valve...

 

40 is a little low, most multi port systems need 53-57 psi. sounds like your fuel pump is losing pressure after it operates or heats up for a bit. Running out of gas could do this, the pump uses fuel to cool it.

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Did you check the pressure with it running or off?

 

I checked it with the engine off, key in the "on" position. Im starting to wonder if the reason for it running rich might be an injector. I was going through checking the 4 fuses for the injectors, and i pulled one and the black smoke / rich exhaust problem went away, so im wondering if one of the injectors is stuck running "open" and dumping fuel when it shouldnt be..

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  • 4 weeks later...

Sorry to bump my old dead thread, but i finally got it running again today. Havent had much time to work on the car since ive been working. anyway, onto the good news:

 

 

About a week ago i took the plenum off and decided i would check the injector's. well, once i got the egr valve, air intake, plenum, fuel rail, etc.. off, i got to looking at the injectors. 3 out of the 6 injectors had carbon deposit's built up. I was going to just get 3 new injector's from autozone, but it would have cost me almost $200 :shock: . I got to looking around online and found this site: Linder Tech. They sell refurbish'd injector's in a set of 6 for $199. I went ahead and ordered them. Last night they came. Replaced all 6 injector's and started to re-assemble. got the injector's in, mounted the fuel rail, and went to attach the vacuum lines to the fuel pressure regulator. Somehow one of the plastic vacuum lines got snagged and i didnt notice it, went to pull it over to the fuel pressure regulator and *snap*. vacuum line broke. this was around midnight or so, so i just left it be and quit for the night. Got up this morning to finish everything up. Got a new vacuum line and put her all back together. I pulsed the injectors a few times to let fuel get back into the system and get everything pressurized. Hit the key and it fired right up, ran really rough, then died. :x This is at least better than what i had before which was: hit key, start, instant death. Im not sure why, but i decided i would check the spark plugs. The damn things were burnt BLACK and wreaked of gas. Im guessing the bad injectors were dumping gas into the cylinders. Anyway, replaced the plugs, and tried again. fires right up and purrs like a kitten. Ive spent the last 2 or so hours just driving around. God i love having my cutty back.

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GM Fuel Systems should be at 44psi (and ford at 35 for those who care)

 

so 40 psi is good still. Having too little fuel in the tank can cause the pump to heat the fuel and then further heat it in the rail before sending it back to the tank, causing a "vapor lock" condidtion, this happened all the time on my 88 regal when I was under 1/8 tank.

 

what I'd probably do if I were in your situation tho, is I'd replace the pump, strainer, filter, and the fuel level sending unit - fix all those problems, then fill 'er full, and go from there.

 

--Dave.

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