'97 Ranger 2.3l misfiring after rebuild

[JC 97]

Just because the o2 has continuity does not mean that it is good.I would replace the up-stream o2 if it was my truck.

 

[chilsam]

Try uhooking it

We checked the upstream o2 sensor, and it had continuity when we tested it with a multimeter. Our idea to swap it with another one off my dad's truck (spare) fell flat because although they were the same part number, the connector was different. So, we still have the same upstream sensor installed, and we think that it works fine.

What about the egr valve? We were checking the vacuum coming from the hose that connects to the top of the egr valve, and the suction seems really weak. I know that the egr compensates for a cold engine somehow, so maybe the valve isn't opening when it's supposed to or there is another part where the egr goes into the manifold that is plugged up. The exhaust is always hot, so it should be doing its job when the engine is cold, but it's not and that might be why it misfires until its at running temp.

We also put on the 195 degree thermostat, we thought that the one that was in there was 180, but it was actually 192. So we have a new thermostat that will allow it to get a little warmer.

does it get better.worse or stay the same?

 

[hoppy]

same, (so this is hoppys dad)

so after reading the poorly written manual, it seems there is one sensor that may be a problem. the engine coolant temp sensor (ECT). It says "handle carefully when installing as this is an essential part of the FI and Emmissions system".
saturday as we were working on the o2 and the thermostat, we kept feeling the upper hose and as soon as it got hot and firm, the engine started running better and the 2 sensors in the 5/8 line running away fro the thermo housing obviously were seeing the same temp change we were.

So, there are two, on this 2.3 engine and they are 3 inches apart, I know one is simply for the temp gauge, the other for the PCM.

Will auto zone know which one is pcm related?

Or do we start it up. let it get warm and disconnect one at a time to see which one works for the dash gauge and if so, what happens when the other one is disconnected. OR does someone here know which is which, the manual says nada on this.

before even asking here i DID check the tech section of this site to see if there was a diagram of some sort. couldnt find one.

 

[hoppy]

attached is a pic of the egr. The hose that goes down to it, and connects there on the left of the circular part has little suction. Is this normal? When it is disconnected, the truck doesn't run any different.

 

[chilsam]

thats what id do

same, (so this is hoppys dad)

so after reading the poorly written manual, it seems there is one sensor that may be a problem. the engine coolant temp sensor (ECT). It says "handle carefully when installing as this is an essential part of the FI and Emmissions system".
saturday as we were working on the o2 and the thermostat, we kept feeling the upper hose and as soon as it got hot and firm, the engine started running better and the 2 sensors in the 5/8 line running away fro the thermo housing obviously were seeing the same temp change we were.

So, there are two, on this 2.3 engine and they are 3 inches apart, I know one is simply for the temp gauge, the other for the PCM.

Will auto zone know which one is pcm related?

Or do we start it up. let it get warm and disconnect one at a time to see which one works for the dash gauge and if so, what happens when the other one is disconnected. OR does someone here know which is which, the manual says nada on this.

before even asking here i DID check the tech section of this site to see if there was a diagram of some sort. couldnt find one.

on my 87 gauge sensor is in the head ECT is in the intake manifold between #2 & #3 cyl,probably in same location on your's "I'D THINK" if poss could you check for the colors of wires in wiring diagram and use them as a reference?

 

[chilsam]

yes

attached is a pic of the egr. The hose that goes down to it, and connects there on the left of the circular part has little suction. Is this normal? When it is disconnected, the truck doesn't run any different.

it should have vacuum.

 

[hoppy]

This ranger has 2 sensors, both seem to be of the sort that could be for the pcm.

Nowhere on the head / block etc is there a coolant temp gauge that screws in.

The ones on this Ranger are on the same section of coolant line towards the passengers side, slightly from the thermo housing.

 

[hellion]

The o2 sensors are not heated by engine coolant.They have a heating element in them.After the exhaust temp hits 600 degrees the o2 goes into closed loop mode.So if the heating element is bad, when cold the o2 could malfunction causing a mis-fire.After it gets hot enough it starts to work properly.

You misunderstood part of what i said, i wasnt suggesting the coolant heats the filamant lol.

 

[hellion]

We checked the upstream o2 sensor, and it had continuity when we tested it with a multimeter. Our idea to swap it with another one off my dad's truck (spare) fell flat because although they were the same part number, the connector was different. So, we still have the same upstream sensor installed, and we think that it works fine.

What about the egr valve?

Try plugging the hose, and use a piece of tubing to suck with your mouth, you should notice a change.
Personally it didnt make anything better.

 

[hoppy]

we have a vacuum tester with all the attachments so yes we can pull a vacuum on it and see what it does (or not).

thanks for the hint, we also have a strong vacuum source nearby we can tap into.

but my feeling is still strong on the coolant sensor(s) since it ran well as soon as the thermo opened up. its all like a mystery though.

 

[JC 97]

You misunderstood part of what i said, i wasnt suggesting the coolant heats the filamant lol.

My bad,I must of confused you and hoppy.

 

[hoppy]

we appreciate the hints and helpful ideas. we have gone from mad, to depressed to just curious about what the heck is going on here. probably a frayed wire somewhere.

 

[hellion]

we appreciate the hints and helpful ideas. we have gone from mad, to depressed to just curious about what the heck is going on here. probably a frayed wire somewhere.

The coolant temp sensor is one i havent tried before, i also know there reltively cheap,15$ im just happy someone else is havin the same problem as me! Lol sorry but at least im not the only one

 

[hellion]

My bad,I must of confused you and hoppy.

Or i wrote mine in a confusing way lol

 

[hoppy]

bump, we are going to switch out the coolant sensors next I believe