Roberto Tschen

i have a problem with my pro 1991 1.8L DOHC. i drive like grandma and it's consuming in the city 20 mpg and it doesn't have power and from the exhaust i see black smoke (not white smoke like it was burning oil).
i think that it is very rich the air/gas mixture.

1. can it be a problem with the fuel pressure regulator?

2. the fuel pressure regulator has a screw or something to adjust?
thanks!!

ghettopro

If it is smoking alot I would say piston rings thats was the prob with mine....and thats the only thing I can think of with it burning alot of gas....O YEAH my bro says his 1995 Explorer has been burning ALOT of gas and he says it is his fuel injectors and things in that area so yeah it probably is.....................the piston rings are the only thing I can thnk of for the smoking...

ghettopro

and I would say it is probably the pressure regualtor also thats what he says is his prob may be yours also...

midnightblue97

You're running rich, it isn't necessarily the rings. Is there a check engine light on??
I'd guess that your O2 sensor is bad. You should get that **** fixed before you plug your cat, and have to spend more money.

Roberto Tschen

that`s an other problem because the engine light doesn`t light on when I turn the key to acc or on position, I dont know if the light burns or it doesnt work... How can i xheck the O2 sensor?

1ofdfew323

Ur better off replacing the 02 sensor cuz most likely you will need to replace it when its time for smod check + you will need a tool
( I forgot what its called) to check the voltage of it flactuating from .02-.08mV.

Check the resistance with a voltmeter of your VAF and make sure its in spec.

Check the spark plugs, wires, caps and rotor.

Check the vacuum hose line on your press. gauge. Make sure its connected.

gasgoblin87

I had a problem with my fuel pressure last month, it wasn't getting enough gas, but now the pressure is back at 100%, it was the problem the whole time.

midnightblue97

What exactly was the problem??

Roberto Tschen

when I buy the car I find that it has two solenoid valve,
1. is from the pressure regulator
2. from the VICS (variable intake control system)
but these to solenoids where disconnected from the plenum and here on the internet I found a diagram for the vaccum routing system and I connect these solenoids to its original place but I didn't feel any inprovment. Anyway has two electric connector to the solenoids but, who goes were? The diagram doesn't tell me who goes where. With the engine started at idle, one has 12volts but the other one has 0v.

I guess all this **** has something to do with it, the vaccum chamber and the shutter valve are working fine but with the problem of the connectors I don't know, even the pressure regulator.

I know my question is stupid but I'm not clearly, Waht's the VAF?

midnightblue97

VAF= Vane Air Flow meter.

kcidmil

First of all, white smoke is from water in your system, black smoke is a rich mixture, and blue smoke is from oil being burned.

macdaddyslomo

You beat me to the punch...Mazda's always seem to run rich as hell...first things first...do a COMPLETE tune up...air filter,cap,rotor,plugs,wires,timing adjustment(with a timing light too, not by ear)...new fuel filter,egr valve,pcv valve....also get a compression checker..if your compression is still good i doubt the rings are the problem

Roberto Tschen

thanks, but I all ready change some things and the car respond a little better, well beter, but I steel don't get it way is burning a lot of fuel and doesn't run like it should, I haven't check the timing; it is burning black smoke. it has 120K miles.

Sorry for the question but what is egr valve?

I all ready change the plugs, air filter, gas filter, oil and wires.

i don't know how much the pro 1.8L DOHC runs. With what car can I conpare? But I don't think it is normal to burn between 18 to 20 miles per galon.

macdaddyslomo

Exhaust Gas Recirculation....not exactly sure on the BP where it is....what about cap and rotor on the disty ?? change that yet?? what about the compression checker..they are only like $25 at auto parts store