68jimmy

Happy Thanksgiving weekend! I'm having an issue with my '89 4Runner after I swapped out a few coolant hoses. Over the past few weeks I had a coolant leak from the rear of the motor which finally ended up being the small u-shaped coolant bypass. Well since then, I've started to experience an issue during the first 10 or 15 min when the engine is still warming up and idling higher. Normally I start the engine, let it idle until the fan speed reduces which is around 2min, then start driving. The problem is when starting from a stop where the engine seems to be getting too much fuel and nearly dies out. Only by feathering the clutch and accelerator can I get to get going without stalling. Once going and shifting to 2nd or 3rd the engine will have flat spot. Only once has it completely stalled and it was a b*%th to get it started, seemed as though it had flooded.

Now, once the engine has come up to temperature, the engine temp gauge is reading just below the middle and its idling around 800rpms, the truck runs fine, no flat spots or hesitation. As for troubleshooting, I read quite a bit on this forum and others and narrowed it down to the Coolant Temp Sensor... I ran to Napa this morning, purchased a new sensor ($27), swapped it out and started the engine. Well, the same problem is still there.

Now here is where I need your help please. Any ideas on what I should be checking or replacing?

Thanks in advance.
donovan

Charchee

Do you have a check engine light on? You had your hands all over those 27 year old sections of the harness where the coolant temp sensor is located while you were working on that coolant line.. The wires could have been brittle and you may have damaged one of them beneath the insulation. Every time I work on something in that area of the truck I have issues with my temp gauge which is right back there too. I go under the hood and wiggle the wire until my gauge starts working right again and then try and tie it down in that position until the next time.

68jimmy

Thanks Charchee, no CEL. I was wondering if the CSI time sensor could be the culprit, although I'd rather not spend another $20+ and it not be the issue.

d.

myredyota

Mine does the same thing. Being in CO, it sucks. Hopefully there are more suggestions because my temp gauge works fine. Mine has done this for several years and drives me nuts. I have checked everything, except the culprit...

Charchee

Unplug the CSI and try it. It will start warm without it.

Also, just to clarify, the issue I had was with the gauge sensor that will not affect performance. There is a sensor that sends temp data to the ECM right there in the same area. That would be the one to check. I was just giving an illustration of how you might tweek a sensor wire while working in that area of the engine / firewall.

myredyota

Thanks Charchee. This give me something to play with!