'97 Ranger 2.3l misfiring after rebuild

[hoppy]

check out this article, http://www.therangerstation.com/tech_library/O2Sensors.htm

makes me pretty sure that it's not the O2 sensor.

Like what was mentioned yesterday (dad posted that one), we'll pull the coolant temp sensors next. What's weird is that nowhere in the manual or on autozone/napa parts catalog is there anything for 2 coolant temp sensors, BUT my truck looks like it has 2 of these sensors. We'll pull them, and see just how different they are and replace the one that autozone has in stock and I guess just hope that the 2nd one is the same...fingers crossed, but why would they install 2 of the same sensors into the coolant line coming from the thermostat?..one going to the ecu and one to the dash gauge? weird

 

[chilsam]

soild brass core

check out this article, http://www.therangerstation.com/tech_library/O2Sensors.htm

makes me pretty sure that it's not the O2 sensor.

Like what was mentioned yesterday (dad posted that one), we'll pull the coolant temp sensors next. What's weird is that nowhere in the manual or on autozone/napa parts catalog is there anything for 2 coolant temp sensors, BUT my truck looks like it has 2 of these sensors. We'll pull them, and see just how different they are and replace the one that autozone has in stock and I guess just hope that the 2nd one is the same...fingers crossed, but why would they install 2 of the same sensors into the coolant line coming from the thermostat?..one going to the ecu and one to the dash gauge? weird

one is the one 4 temp gauge on my 87 2.3.

 

[hoppy]

one is the one 4 temp gauge on my 87 2.3.

that's correct. Went to autozone on saturday and they only had the sensor for the gauge in stock, so I bought that and a new spark plug (just one). Installed the sensor and the new spark plug on the compression side.

Now normally when it would start up it would misfire and it was so bad that it was like it was running on 3 cylinders instead of 4. BUT this morning I started it up and it still misfires but not nearly as bad, and all 4 cylinders were firing.

I think we're getting somewhere. autozone has the other sensor in stock now, so I'll pick it up after work today and install it.

I'll let you guys know what's happening.

 

[hoppy]

the only thing that was different about those 2 sensors was the electrical connector 'groove'

the one going to the gauge, the groove on the plug is in the middle, and on the other sensor, the groove was a little to the left

 

[hoppy]

Now I have replaced both coolant temp sensors, replaced the one going to the gauge on saturday, replaced the one going to the ecu just yesterday and reset the computer yesterday.

After replacing the coolant temp sensor going to the gauge, it seemed like it ran better when cold, still misfiring but not like running on only 3 cylinders. After replacing the 2nd coolant temp sensor yesterday, and driving it this morning, it still misfires really bad and again like it's running on only 3 cylinders.

I still haven't replaced the upstream o2 sensor, so that's another thing I'm going to try. I'm still pretty certain that it's NOT electrical because it only misfires when it's cold, and it runs GREAT when it's up to operating temp. If it were electrical, then I assume it would misfire all the time, or at least more inconsistently. The misfire now IS consistent because it only misfires when it's cold.

 

[chilsam]

Ecu?

 

[hoppy]

maybe the ecu, my dad and I just talked about that...about a year ago I had my truck in the shop to have the heater core replaced, and I know that the ecu needs to be removed to get that job done so maybe those dumbasses at the shop dropped it or something.

How do I check to see if the ecu is malfunctioning, and would it give a code if it was? (I assume it would give a code if it was malfunctioning)

Also, how does that explain it running bad and misfiring when cold but running great when it's up to operating temp?

We're going to do a leak-down test, just to make sure that it's nothing mechanical. When we did the compression test to begin with, each cylinder had 150psi at least. Also, I'm just going to replace the upstream o2 sensor to eliminate that too.

 

[Captain Ledd]

Dang this sounds a LOT like the issues I was having after I replaced my timing belt (I know, already been covered).

Turns out I picked the wrong mark out of 3 possible ones on the idler/oil pump gear. I also had a spark plug that was missing it's electrode and had backed out a ways. But because my cam timing sensor was off it kept telling me it was on a different cylinder (THAT was frustrating).

It was the only time I've ever contemplated selling the thing, took me months to track down.

I hope you eventually figure it out. Good luck.

 

[Kenneth S]

Try running when the engine is cold at night time (the darker the better) with the hood open and look for any arcing from the ignition system to a gound somewhere.

 

[chilsam]

Run's in closed loop

maybe the ecu, my dad and I just talked about that...about a year ago I had my truck in the shop to have the heater core replaced, and I know that the ecu needs to be removed to get that job done so maybe those dumbasses at the shop dropped it or something.

How do I check to see if the ecu is malfunctioning, and would it give a code if it was? (I assume it would give a code if it was malfunctioning)

Also, how does that explain it running bad and misfiring when cold but running great when it's up to operating temp?

We're going to do a leak-down test, just to make sure that it's nothing mechanical. When we did the compression test to begin with, each cylinder had 150psi at least. Also, I'm just going to replace the upstream o2 sensor to eliminate that too.

mode till it warms up.

 

[hoppy]

mode till it warms up.

I thought it was the other way around. I thought it ran in open loop till warm and at wide open throttle.

 

[hoppy]

also, the next thing, just to eliminate it as a possibility as well is I'm going to replace the upstream o2 sensor. I need one for my wife's honda anyways, might as well make a party out of it

 

[hoppy]

I thought it was the other way around. I thought it ran in open loop till warm and at wide open throttle.

cause it's not in closed loop till the o2 sensor heaters get up to operating temp right?

 

[scotts90ranger]

basically, but it's not just the O2 sensor, it's the whole system, it should just go off of the coolant temperature. It'll be in open loop until it reaches a certain temperature, and pretty much all the time above 3000rpm

 

[hoppy]

basically, but it's not just the O2 sensor, it's the whole system, it should just go off of the coolant temperature. It'll be in open loop until it reaches a certain temperature, and pretty much all the time above 3000rpm

that makes sense. I replaced the coolant temp sensors just in case they were part of the problem, and it still runs the same: misfiring on 3 cylinders till it's warm, CEL on, code says mis in cyl 2. I know that the o2 sensors work with the coolant temp sensors which I replaced, and another part of the problem was the TPS sensor connector which we re-spliced and fixed. We don't know what else could contribute to the problem except for the ecu or the entire harness, but that still doesn't explain why it runs crappy when cold, but runs perfectly when at operating temp.

New idea, maybe it is some type of circuitry that is only used when it is cold, and when it gets up to operating temp, it switches over to using circuitry for when it is warm. I don't remember if it runs in closed or open loop mode when it's cold, but I'm pretty sure it's open loop, so what I'm trying to say is that maybe the wires or the part of the harness associated with this open loop mode are faulty which might cause a misfire, and the wires/part of harness associated with closed loop mode are just fine which allows it to run well.
What do you guys think?