'97 Ranger 2.3l misfiring after rebuild

[hoppy]

okay, so here's all that we have done, some things fixed 'part' of the problem, but it still misfires like it's only running on 3 cylinders until it's at operating temp..:


Things we have done:
New Cylinder head (1 year old)
Rebuilt engine: new pistons, rings
-checked compression @ 150+psi/cylinder
Rebuilt injectors
New clutch
New TPS
Replaced Throttle Position Sensor connector (spliced in new wires, plug)
Replaced Idle Air Control Valve
Replaced both O2 sensors
New Cat
Replaced BOTH coolant temp sensors
Fairly new plugs and wires
Swapped coils from t-bird, to ensure that those weren’t causing misfire (same part#)
Swapped plug wires on intake side coil to 1-3 and 2-4 to make exhaust stroke plugs fire on compression stroke

Our only other ideas are some type of short or frayed/broken wire somewhere in the electrical harness OR a malfunctioning ECU. I'll be posting a 'want' thread in the for sale section to see if anyone has an ECU with similar numbers.

 

[Kenneth S]

Maybe a bad wire in the harness for the injectors.

 

[hoppy]

Maybe a bad wire in the harness for the injectors.

all the connectors for the injectors looked good, and the wires looked good when we were working with them.

underlying question for this whole job is 'if ______ is the problem, then how is it that ________ causes it to misfire until it's at operating temp?'

my bet is on the ecu. i've been off-roading a lot, and I'm sure that type of vibration isn't the greatest for computer components.

 

[Kenneth S]

Heat can do funny things to the wiring over time, I'd try swapping out the injector harness if you have access to one from another engine, it couldn't hurt to try it before spending $$$ on a ecu.

 

[hoppy]

ECU's are cheap, $200 max, $149 from autozone, and next to nothing if I can find a used one. First thing is first: I'm done trying to figure this thing out on my own, so I'm going to take it to a local place that has free diagnostics and see if they think if it's an ecu or a harness or both....

 

[Insanejughead]

This has been an interesting thread to follow. I've been having some issues with my ranger and the biggest one turned out to be the TPS. I got a new one in today, and I'll see how it runs after it's installed.

 

[hoppy]

This has been an interesting thread to follow. I've been having some issues with my ranger and the biggest one turned out to be the TPS. I got a new one in today, and I'll see how it runs after it's installed.

good luck with the TPS! On mine it was both the TPS AND the TPS connector that was causing part of the problem. Luckily they're really easy to get to

 

[hellion]

good luck with the TPS! On mine it was both the TPS AND the TPS connector that was causing part of the problem. Luckily they're really easy to get to

Ok, so i know its been a couple months now, BUT! i need to know if you got any new words for us hoppy, its gonna be rain season soon and im an electrician with only a GSXR 750 as an alternate transportation lol. not easy to do EVERY day.

 

[hoppy]

Ok, so i know its been a couple months now, BUT! i need to know if you got any new words for us hoppy, its gonna be rain season soon and im an electrician with only a GSXR 750 as an alternate transportation lol. not easy to do EVERY day.

PM'd hellion

Got it fixed! I finally just took it to a mechanic, and 3 1/2 weeks and $650 later it ended up being a valve lifter in cyl. 2. We had never suspected anything with the cylinder head because it was brand new and complete as of a year and a half ago.

I have a guy coming to buy it today.

 

[hellion]

Sweet man, thanks
ANYWAYS, ill be checking into this myself soon, (Im currently painting the plastics on my motorcycle, so after thats done ill have an alternate mode of transportation lol) If i do it myself which i know i probably will. ill take lots of 8mp pictures (I forget easy) breaking down everything im doing. (NeverMind the beer cans) thanks for the heads up, i was suspecting something in the valves myself personally, it occured to me that the lifter might be "Sticking"