i have no pill in the vacuum hose and my boost sensor is broken. could this be part of my shitty gas mileage? i'm sure its not helping my idle problem either. where can i get a pill?

 

What's broken about the boost sensor? Also, is this a turbo or NA?

If it's a turbo, do NOT boost around until you get it replaced - I popped my first motor when the vacuum hose to the boost sensor popped off.

The pill helps smooth the car out a bit, that's all.

Dale

 

yeah its an 87 T2. and i think that pill may be what i need to get a smooth idle cause we cant find any vacuum leaks. where can i get a new boost sensor?

 

The pill has absolutely nothing to do with the idle....it simply "shields" the pressure sensor from pressure waves (rapid, short pressure bursts). This last part sounds hard to believe....but according to Ted (very knowlidgeable), fuel ratio is not affected by the pressure sensor (maybe the timing is????). He ran a test and found that there was no change in the pulse width to the injectors as pressure to the sensor was increased. So.....I don't know what a broken boost pressure sensor would do.

Todd

 

well, i'm just going by what i heard; that unplugging that air hose from the boost sensor makes you run really rich. anyone else know anything about this?

 

so far, the only thing that the pressure sensor has done is make my boost gauge not work.

 

Idling rough is a hard thing to figure on the web because we can't see/hear the motor. On a 87 you have a variable resistor euphemistically called the rich/lean screw. It is a pot and has a screw that turns approx 180 degrees. It functions only at idle. Try slowly turning it clockwise to enrichen the mixture at idle and tell us if this helped.

You've looked for air leaks for sure, but try some starter fluid around the air inlet ducts, bac, just spraying around the back of the throttle body, and the best you can under the intake manifold where you are trying to aim at the injectors. If the injectors rubber sealing *gaskets*at the base, have hardened, you can and will get air leaks there.

Theres some unlikely places that WILL leak and you won't ever think of them of hand. While the acv on the whole does not inject air into the intake manifold, it does at certain times. That time is during deceleration. The antiafter burn valve that is a part of the acv does this. Its diaphram may be busted and leaking air. Spraying a touch second dose of starter fluid into the airpumps inlet hose will result in a pickup of rpm if that is the case.

Another place is the EGR being stuck and letting unauthorized exaust air to mix with the intake air at the wrong time.

Try the variable resistor first then spray with starter fluid.

And like someone will want to write, the duct from the afm to the turbo inlet has a bad habit of cracking where the clamp attaches the duct. TAke that duct off and do a visual on the clamp area.

 

I think the pressure/boost sensor DOES have a direct effect on the amount of fuel going into the engine. Haliers has a sheet out of the FSM that shows that it does. Thats probably why fuel cut hits at 8.6 psi (which is bad).

 

Attached is a relationship chart for a 89 model. I didn't answer direct about the pressure/boost sensor because you seem to have a idle problem. But......Pleasse don't disconnect it. You need it. The ECU needs it. Why not take the vac hose off the manifold and with the vac hose still connected to the sensor, suck on the vac hose. If the thing will hold a vacuum, at least you know the diaphram is ok. I can't figure why you think its broke. Does the boost gauge make any movement when your boosting?

The chart , attached, shows, as Akegeals mentioned, the timing is effected by the sensor. When boosting, I believe the timing is retarded at high boost. Just what I've read on this forum. No retardation equals maybe some knocking, which we know is not good.

The chart also shows that your fuel resistor relay is effected, mabe meaning that you will not get fully voltage to the fuel pump, which in turn means low fuel pressure, which in turn means detonation, which means...........but then again, you always wanted to rebuild a rotary motor. humor.

EDIT: OOOPS, that chart says FUEL INJECTION TIMING. Not what I wrote above. sorry 'bout that.

 

i have a similar problem, my turbo isnt boosting fully, might have something to do with that pill..anyone knwo where to find it? im noob

 

you can pick one up at checkers auto parts

 

Hey,
What is it called? You got one from Checkers????

 

It's an orifice and has a Mazda part number or you can make one. https://www.rx7club.com/showthread.p...hlight=ORIFICE

Won't help with any of your listed problems. NEEDS to be there though.