Faulty Fuel Injector causing mis at startup?

[rusty ol ranger]

The new oil flows better then the old oil so its eaiser to pump, but since the old oil probably hadnt broke down enough to lose viscosity yet the thickness stayed the same so pressure did it. Cause the pump is weak

The fact the oil turned black that fast though could very well point to a fueling issue, but personally i think you got bigger fish to fry first

 

[eightynine4x4]

The new oil flows better then the old oil so its eaiser to pump, but since the old oil probably hadnt broke down enough to lose viscosity yet the thickness stayed the same so pressure did it. Cause the pump is weak

The fact the oil turned black that fast though could very well point to a fueling issue, but personally i think you got bigger fish to fry first

It all makes sense. I buy the theory! I’ll plan to do the pump swap soon. I’m a little weary of the cost and time of doing the peripheral pieces required to install an HV pump, especially since this is not a guaranteed solution. But I’ll continue scoping to see if I can find the right set of pieces. Of course, if it works out, any reasonable price will be well worth it.

As for the fuel causing oil to go black… Are you referring to unburnt fuel resulting in soot buildup in oil? Not sure how that works but have found it mentioned elsewhere. But, it would confuse me to hear that that’s the case, given that my ECM is giving a lean code. Wouldn’t unburnt fuel mean that I’m running rich?

And on that note, I think I should install higher quality spark plugs. Assuming it’s not snake oil, it would probably be good to put some in that provide as strong of a spark as possible. The ones I’ve used are pretty basic.

Also.. I’m wondering if there’s a way to measure spark performance.. be it current or voltage. I would really like to confirm that my ECM and wiring and coil and distributor and plugs are sending the right amount. Given that I still have misfire type behaviors, it would be good to check that off the list.

 

[rusty ol ranger]

You could send the oil out for analysis. That would give you a major clue as to if you have internal bearing damage that the pump alone wont solve. You could also cut open the filter and check for shavings.

As far as plugs, you dont need the fancy ones, just run the motorcraft copper cores. These trucks dont make hot enough spark to make the fancy 4 prong iridium things worth it.

As for the rich and lean...the ECM is getting a lean signal from the O2, so the ECM is dumping in fuel trying to richen itself up. But its doing all it can, evidenced by your adaptive fuel code.

As for spark condition, best way i know is to pull a plug with the wire attached and have someone crank it over. (Unplug fuel pump relay first and start it till it stalls before you do it, so it dont start during test).

You want a sharp blue spark.

 

[eightynine4x4]

Ok gotcha. Well the Bosch 9657 seems to get some good reviews from 80’s ranger owners. I guess due to quality of windings? Don’t know much about it. I’ll hold off for now.

I just ordered the Lisle 20610 inline spark tester. Very cheap and it’s dead easy and I just want to take a look at spark of each cylinder while the engine misfires and wobbles. Hopefully I can recreate the problem enough to go through all 6 lines and see. If the spark for some cylinder is stopping or weakening during the misfire shakes, then I know I have some issue upstream or from ECM. Seems unlikely, but for 10 bucks I’m gonna give it a go and at least rule that factor out.

Not sure what to do about the O2 sensor. I could just try replacing it again. Can test for continuity of wires too. Would really like to functionally test the sensor but can’t think of a way other than maybe attempting to take DC voltage readings from its putout connector in bay? Would need to figure out which wires sends the supply / reference voltage and which is the return, and measure the return. Engine would have to be hot. Maybe I can build a splitter into the return wire and leave a DC voltage meter hooked up in cab and always be able to monitor rich / lean. Once it’s all working I mean. But at least for now I could monitor if the sensor is sending signal. Trouble is, if I’m always WAY lean right now, the sensor won’t send anything I guess, right? So if I’m truly running lean, and the sensor is fine, I’ve then got to figure out why im running so lean.

The check engine light seems to be from specifically this issue, since it takes a long time for the light to appear. I know that the ECM is expecting the sensor to start becoming active with signal after the exhaust reaches 600 degrees, and it’s probably waiting long enough and the indicating that it isn’t ever getting signal.

 

[rusty ol ranger]

Check for contunuity in the wires. Im no wireing expert but it sounds like thats the O2 issue. Since the HEGO and switching is throwing codes.

There is a way to test it...i tested mine. Im trying to remember exactly how i did it, i think you remove it and use a torch (propane or mapp) to heat it and read readings...but im not sure.

@RonD can help with that possibly.

 

[eightynine4x4]

Check for contunuity in the wires. Im no wireing expert but it sounds like thats the O2 issue. Since the HEGO and switching is throwing codes.

There is a way to test it...i tested mine. Im trying to remember exactly how i did it, i think you remove it and use a torch (propane or mapp) to heat it and read readings...but im not sure.

@RonD can help with that possibly.

Ha! That’s classic. Would be fun.
As for the wiring…
Looking at the diagrams, apparently there’s a couple of places that the signal could be failing getting to and from the O2 sensor. And I hadn’t realized that there is a fuse involved, and it appears to be the supply voltage to the sensor. I’m gonna track that fuse down and test it. Damn that would be a very convenient fix.

 

[rusty ol ranger]

Ha! That’s classic. Would be fun.
As for the wiring…
Looking at the diagrams, apparently there’s a couple of places that the signal could be failing getting to and from the O2 sensor. And I hadn’t realized that there is a fuse involved, and it appears to be the supply voltage to the sensor. I’m gonna track that fuse down and test it. Damn that would be a very convenient fix.

I was totally unaware of a fuse for it.

 

[eightynine4x4]

I was totally unaware of a fuse for it.

Comparing to versions here... https://www.therangerstation.com/tech/1983-1992-ford-ranger-fuse-box-diagrams/
I'm having trouble pinning down how mine should be hooked up, and if anything might be missing or in the wrong spots.
Here's mine below. I've only checked the 10amp fuse on the right so far, thinking that's the one for HEGO. But I'm still not certain.

 

[rusty ol ranger]

Comparing to versions here... https://www.therangerstation.com/tech/1983-1992-ford-ranger-fuse-box-diagrams/
I'm having trouble pinning down how mine should be hooked up, and if anything might be missing or in the wrong spots.
Here's mine below. I've only checked the 10amp fuse on the right so far, thinking that's the one for HEGO. But I'm still not certain.


View attachment 90466

Good luck lol. But if it is a blown fuse somethin caused it to pop

 

[eightynine4x4]

Good luck lol. But if it is a blown fuse somethin caused it to pop

THIS would do something haha. I just detached the O2 sensor wires to test them and found next to it a totally loose orange wire with a mount terminal, dangling completely down towards transmission.
This wire looks like it’s supposed to have been mounted to ground point on back of plenum. When I did my plenum uninstall, I noted only two items back there and reinstalled accordingly later. I suppose it could be my fault and that I missed this, but I don’t think so. I remember counting two items, not three. And I’ve had all these issues for a while now.
Looking at diagrams, it appears to be how the ECM receives the ground half of the signal for the O2 input. There are at least 3 other grounds hitting different ECM pins, so I think it’s just for the O2. But I suppose it could be for more than just the O2 and that this impacts the ECM’s communcations with the engine in more ways. Would need to look at ECM schematics themselves to figure that out.
Gonna hook it back up to plenum but also test the remaining O2 wires before starting up truck again.

 

[RonD]

O2 sensors are heated, a fuse for the O2 would be just for the internal heater

O2 "sensor" part generates its own voltage using a chemical reaction, 0.1v to 0.9v, after it is heated above 600degF, by exhaust and internal heater

Pre-1995 O2 heaters were just grounded to battery
1995 and up had the new computers(104 pin) and each O2 heater was grounded by the computer, this was to make sure each O2s Heater was working

Yes, you could test if the sensor part was generating voltage by heating it with torch, but it wouldn't tell you if it was "working" as an O2 sensor to set correct fuel trims

 

[SenorNoob]

It is possible to see an O2 sensor "switching" with nothing more than a cheap voltmeter. It'll swing pretty steadily once it warms up. I've probed right into the ECU connector.

That would at least let you know if the computer is getting any kind of reading...

 

[rusty ol ranger]

THIS would do something haha. I just detached the O2 sensor wires to test them and found next to it a totally loose orange wire with a mount terminal, dangling completely down towards transmission.
This wire looks like it’s supposed to have been mounted to ground point on back of plenum. When I did my plenum uninstall, I noted only two items back there and reinstalled accordingly later. I suppose it could be my fault and that I missed this, but I don’t think so. I remember counting two items, not three. And I’ve had all these issues for a while now.
Looking at diagrams, it appears to be how the ECM receives the ground half of the signal for the O2 input. There are at least 3 other grounds hitting different ECM pins, so I think it’s just for the O2. But I suppose it could be for more than just the O2 and that this impacts the ECM’s communcations with the engine in more ways. Would need to look at ECM schematics themselves to figure that out.
Gonna hook it back up to plenum but also test the remaining O2 wires before starting up truck again.

View attachment 90467

IIRC that grounds on the side of the plenium. Or is that the green wire im thinking of?

 

[eightynine4x4]

O2 sensors are heated, a fuse for the O2 would be just for the internal heater

O2 "sensor" part generates its own voltage using a chemical reaction, 0.1v to 0.9v, after it is heated above 600degF, by exhaust and internal heater

Pre-1995 O2 heaters were just grounded to battery
1995 and up had the new computers(104 pin) and each O2 heater was grounded by the computer, this was to make sure each O2s Heater was working

Yes, you could test if the sensor part was generating voltage by heating it with torch, but it wouldn't tell you if it was "working" as an O2 sensor to set correct fuel trims

Thank you Ron!

Well so below is the diagram showing the orange wire I just reconnected to the plenum. In my 89 2.9, it comes from pin 49 of ECM, and gets grounded. I can only hope that this is part of the way that the ECM receives info from O2.

There are 3 other wires, in the O2 connector of course. One is coming from the fuse box but has 1500 ohms between it and the fuse box box. I cleaned all connections/points, and it’s almost exactly 1500. There must be some kind of current limiting resistor in line somewhere. It is Grey/Yellow, which is unexpected. But the other side of that fuse is fed by the Org/Blk Run Hot In wire. So that is the upper part of the O2 connection in diagram.

Then there is a blk/ltgrn ground wire in the connector, which I beeped out to the battery negative and which in the diagram shoots over to the left and hooks directly to battery not some ground. And finally there is the green/purp wire which has to be the voltage signal sent from O2 sensor to ECM.

So my thinking is that since the blk/ltgrn wire within connector is illustrated as going to the actual battery, then that is the O2’s heater wiring ground for its higher current. That would then mean that the loose orange wire that I discovered, is the ground portion of the O2 DC signal INPUT for the ECM, and it being disconnected means the ECM was never seeing any signal. This is my hope, anyways.

The only thing I haven’t tested is the green/purp signal wire to the ECM pin 29. If I drive the truck and still get a check engine light and the codes show no/low O2 signal, or running lean, I’ll open up the ECM and poke around for continuity throughout all of it and of course check that wire.

Haven’t fired it up yet but am looking forward to it.

 

[RonD]

If that's the correct Year diagram then the 2.9l would have Orange as a ground and no connection to pin 49 on PCM

Orange/black wire would show 12v with key on

Those are the 2 heater wires

The sensor wires are pin 29 green/purple
And "black"/green? can't see where it goes but most likely a reference ground, pin 46, this pin is connected to several sensors, grey/red wires