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Discussion Starter · #1 ·
I'm totally confuzed. When engine starts O2 voltage goes to .05V. When O2 warms up and engine goes idle voltage drops to .052V . But when I'm driving voltage ranges from .055(Closed) to .35V(WOT). Is it normal ?
 

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Discussion Starter · #2 ·
123

Ok sorry that was wrong dial on voltmeter. Votlage is .055V on idle and from .05V to .30V on the run. Do I need a fuel regulator?..
 

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Do you have a GT? How many wires on the O2 sensor?

How warm was the engine during these readings? How long had you been driving when you recorded the numbers?

(I didn't know what to say about that 2.5V reading 8O I'm glad you checked it again)
 

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Pull out a couple spark plugs. If they're white ashy looking on the electrodes, chances are you're running pretty lean. Make sure that your fuel pump is getting the proper voltage and that your fuel pressure reg isn't shot. 0.03 is extremely lean. Chances are you're detonating and the ECU is implimenting anti-knock because leanness runs hot cylinder temps (which makes your plugs white like that)...

Chances are you aren't reading it correctly. At WOT the ECU will make the engine run rich... lol, well I guess 2.5 is pretty rich :)
 

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When it warmed up, WOT should be about .9 maybe 1.
when your just cruzing around it will bounce around, and when your slowing down it can drop all the way down.
As long as your fuel pressure is 32 psi, and 40psi @WOT than your fine.

You might just need a new O2 sensor, they should be changes every 60k.
 

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Discussion Starter · #6 ·
123

It's 1.9L LX
Actually it's almost new O2 sensor. What else..hmm.. ECU gives out "lack of HEGO switches...lean" error code. Mods done to the engine.. full ram air. TB from Tbird. Larger MAF housing form newer LX. Also ECU was swapped as well from the same newer LX. Ported Intake manifold. Port and polished head. larger camshaft.
But overall performance of engine is good. Even with those voltages.
I'll try to swap my old O2 sensor and see what it'll give me.
 

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Discussion Starter · #7 ·
123

It's 4 wire one with a heating coil. Becuz of the that O2 heats up in like 20 sec. My voltmeter is hooked all the time.
 

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Next time your taking a reading, just put it in second or third and floor it (once it fully warmed up).
If your lower than .8 you'v got problems, and you better fix it.

The base fuel presure is 32psi @ idel, should be 40 @ WOT. A adjustable FPR set up a tad should give you the fuel you need, it thats the case.

Read your plugs.
 

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Discussion Starter · #9 ·
123

Ok slowly I'm getting there. Today I swapped larger injectors 19lb(insted of stock 13lb) from 5.0L Mustang. Voltage is .37v now. Car runs so much stronger. Still needs a fuel preasure regulator. to get it up to .5v.
 

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Re: 123

AleX said:
Ok slowly I'm getting there. Today I swapped larger injectors 19lb(insted of stock 13lb) from 5.0L Mustang. Voltage is .37v now. Car runs so much stronger. Still needs a fuel preasure regulator. to get it up to .5v.
Escorts have'nt used 13# injecotrs since the 80's?
Stock 1.9 are 19#'s
I think your MAF is screwed up, if you really did jump up a size in injectors your car would idel like crap. and run super rich until WOT.
 

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Discussion Starter · #11 ·
123

It's 1.9L. Yeaps you're right 91 LX used 13-14lb injectors. 92-96 used like 15lbs. Why I'm doing it. I just need more fuel. :) Turn out that 02 sensor was right and I was running lean.
 

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Re: 123

AleX said:
It's 1.9L. Yeaps you're right 91 LX used 13-14lb injectors. 92-96 used like 15lbs. Why I'm doing it. I just need more fuel. :) Turn out that 02 sensor was right and I was running lean.
Were are you getting your injectors sizes from? I allways thought that the 91-96 1.9's use 19#er's.

Your car should now idel poorly because the PCM thinks there is a smaller injectors that what ther really are.
Any time the O2 see's far off reading it spits out a CEL.
What do your plugs look like, now and before the change.
Would'nt it be a better A/F ratios to just bump up the fuel pressure from a A-FPR instead of going to the next size injector?
 

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I know this is going to the start of the discussion but when I was calibrating my rx-7 VAF (which I got rid of by the way - too much headache -- and the guys at Aspec recommonded against it), the voltage, using the stock VAF, on my O2 sensor was 0.250 V.

When I reved the engine, then it went up to 0.80 and higher.

However when I put the rx-7 vaf on, before calibration, it was 0.050 V.
 

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RX7 Vaf's are a PITA!!! i keep trying to tell people that it is not the best of ideas and that the (oh so minumal) gains only occur above the 6000rpm mark.

as for your issue with fuel delivery pull the vaccum line off of your FPR and smell it. if you smell gas you need a new one.
 

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Sajeevan said:
I know this is going to the start of the discussion but when I was calibrating my rx-7 VAF (which I got rid of by the way - too much headache -- and the guys at Aspec recommonded against it), the voltage, using the stock VAF, on my O2 sensor was 0.250 V.

When I reved the engine, then it went up to 0.80 and higher.

However when I put the rx-7 vaf on, before calibration, it was 0.050 V.
The ony way to get a reliable O2 signal is at WOT W/ load. At any other time the signal just kinda wanders around.
 

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Sajeevan said:
The ony way to get a reliable O2 signal is at WOT W/ load. At any other time the signal just kinda wanders around.
What does WOT W/load mean. I don't know what WOT stands for.
WOT= Wide Open Throttle.
W/ Load means actullly going down the road, not just flooring it in nutrial.
 
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