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Junkyard 240 stumping stupid.

brickb!tch

Member
Joined
May 8, 2020
So I bought a 240 blind from the JY because the body was in great shape and was told it "started right up". I have been trying to get it to run decently for the last few days and am wondering if any of you had any insight into what might be causing it to run so rough. The car in question is a 1992 240 with a b230 engine being controlled by LH 2.4, and EZK ECUs. The issue at hand is that the car will barely idle, stumble, pop, and shake, and that is with my foot depressing the gas pedal. With AMM unplugged it will oscillate from almost dying to 1500 RPMS. I am getting 2 codes, 123 AND 224, both indicative of bad temp sensor, but would that really make the car run so horribly?

Things I have checked:
Fuel pump relay (I can hear fuel pump activating with key in pos II)
Compression was 115, 115, 120, 120 from cyl 1 to 4, this was on a completely cold engine
swapped AMM with a known working one from my 940
Checked for vac leaks and found none
checked for fuel at rail and pressure seemed okay
Coil is producing spark
Wires seem okay

I know there is more to test, but I have never seen a 240 run this poorly, and I was honestly expecting some kind of compression issue given the horrible sounds it makes. Maybe one of you has some kind of insight that could help me get this car running again.

Thanks!
 
It could be many things....

You could unplug the coolant temp sensor, the rear one! Inspect for corroded, spread, backed out terminals. It's possible the wrong connector was plugged in to the sensor too! (Cold start injector or EGR temp)
 
Yes, it will run like crap with a bad temp sensor, it’s one of the most important inputs for the ECU. If it’s throwing codes for it I’d start there. Might be a good time to check and make sure the connectors under the manifold (IAC valve, knock sensor, coolant temp) are all in the right places, I know a couple of things in that area use the same style of connector and it will mess things up if they’re swapped.

e: whoops zvolv beat me, oh well
 
Thanks for the responses. After getting the car to run for a bit I lifted the oil cap and found a milkshake like substance. I am now leaning towards thinking it's a blown headgasket and maybe the car overheating fried the temp sensor. Why would the car have decent (relatively) compression if coolant is getting into oil?
 
Thanks for the responses. After getting the car to run for a bit I lifted the oil cap and found a milkshake like substance. I am now leaning towards thinking it's a blown headgasket and maybe the car overheating fried the temp sensor. Why would the car have decent (relatively) compression if coolant is getting into oil?

Head gasket can blow between an oil and coolant passage without affecting compression.
 
Thanks for the responses. After getting the car to run for a bit I lifted the oil cap and found a milkshake like substance. I am now leaning towards thinking it's a blown headgasket and maybe the car overheating fried the temp sensor. Why would the car have decent (relatively) compression if coolant is getting into oil?

You can get a milkshake from starting the engine multiple times without letting the oil get up to operating temperature. I wouldn't worry too much about that just yet.
 
I'd worry if it was milkshake on the dipstick, not so much if it was just on the cap. That's just the coolest part of the engine, where water vapors (possibly from leaking coolant, but also from combustion products in blowby) will tend to condense until the whole motor gets well warmed up for a decent amount of time.
 
spark plug wires hooked up correctly?
I checked all wires and their orientation.



I don't know how I missed this when I first looked over everything, but the oil is very watery and light in color. It drips quite easily off of the dipstick. I am totally prepared to replace HG and have the head machined with a proper valve job, but should I be worried about a cracked block? I wish there was an easier way to test and see if the doing the HG is even worth it.
 
Does the dipstick smell like gas?

Have you done a pressure test on the cooling system?


I have not, I guess I could just rig something up with a bike pump and spare reservoir cap. The oil smells weird and "fishy". Not a hint of fuel smell, really.
 
For the price I paid I don't mind too much. These cars are getting harder and harder to find in my area and for $700 I could have the car up and running with a nice machined head. Thanks for the help!
 
It could be many things....

You could unplug the coolant temp sensor, the rear one! Inspect for corroded, spread, backed out terminals. It's possible the wrong connector was plugged in to the sensor too! (Cold start injector or EGR temp)


Did you unplug it and recheck?

Sounds like you have gassy oil. Change it.
 
Does it have the correct AMM? I think 92 still used 016. Does it have the correct ECU? Not sure what number was used that year. Maybe swap the temp sensor with your 940 to rule it out????
 
Out of curiosity, how did you check for vacuum leaks? These 2.4 systems are pretty reliable (well, the first few years had crap ECU's!), so there isn't too much to fail really.
 
Hey everyone, it turned out to be a burnt up sensor that seems to have met it's demise during an extended amount of time being driven overheated! I am purchasing a b230ft and will pop it in. Thanks for the replies!
 
Does it have the correct AMM? I think 92 still used 016. Does it have the correct ECU? Not sure what number was used that year. Maybe swap the temp sensor with your 940 to rule it out????

Swapped the temp sensor with my 940's and it ran better. Tons of white smoke out the exhaust and bubbling over coolant tank.
 
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