Brandon
New member
- Joined
- Mar 1, 2008
- Location
- Essex Junction, VT/Boston, MA
So, I've had poor gas mileage issues for a while on my 240. It's even at the point where it smelled rich at idle or if you were near the car while it was running. It's a 1976 240 but K-jet is gone and the car was swapped to a JY LH 2.0 and B23F set-up. The car was later repinned to LH 2.2 AMM/computer so I could have more easily accesible AMMs. The swap was done by Andysbeta and is thorough, correct, etc. When I picked up the car it was running wonderfully and returned great gas mileage on my drive all the way back from California, so I'm not worried about some sort of parts non-compatibility there.
Of course I did a basic tune-up (cap, rotor, wires, plugs) and that didn't do much. Checked all my vacuum lines, replaced most, and no real change. The car has always been hard to start cold (cold as in it hasn't been running, the ambient temperature seems to have no effect) so my next thought was the CTS. I pulled that out, checked the wiring and connector and everything checked out good there. I pulled the sensor, tested resistance at different temperatures; that also checked out fine. I checked the signal at the wire side of the ECU, and that was fine too.
So, with the CTS ruled out, I'm a little lost. O2 sensor? I've swapped a few different ones in from various other Volvos with no luck. I've also checked and at idle I was able to have the O2 sensor swing from .1-.8 (normal, right?). I've got an interesting 3 wire set-up, standard fare for LH 2.0, that has one black signal wire and 2 white wires that I assume go to the heater circuit. My AMM came out of a well running 740, so I don't have any reason to believe that's the culprit either. Is there any good tests to do for the AMM other than swapping another one? Or do you guys have any suggestions for what else I should try testing? Any help here would be appreciated, the gas mileage is killing me on this car.
-Thanks, Brandon
edit: Now, here's a kicker. I've got this sensor AND a connector that are unhooked under my intake. It's very possible that either of these could have something to do with it, but from what I can tell I've never been the one who unhooked this (accidentally or on purpose), and it very well may have been some sort of left over cast-off from the K-jet system and that sensor could have simply been used to plug a hole. It looks to be some sort of knock sensor? But it's a B23F engine and to my knowledge those never had knock sensors. The interesting part is these two things (the connector and the sensor in the head) are both male connectors, so it doesn't appear that these will go together, which once again leads me to believe that these are simply castoffs from the previous engine management system. Anyway, I'm just rambling now. For reference, that's the front-most coolant temp sensor (the gauge one) that this mystery sensor is below and those two orange wires are the connector i'm talking about.
Of course I did a basic tune-up (cap, rotor, wires, plugs) and that didn't do much. Checked all my vacuum lines, replaced most, and no real change. The car has always been hard to start cold (cold as in it hasn't been running, the ambient temperature seems to have no effect) so my next thought was the CTS. I pulled that out, checked the wiring and connector and everything checked out good there. I pulled the sensor, tested resistance at different temperatures; that also checked out fine. I checked the signal at the wire side of the ECU, and that was fine too.
So, with the CTS ruled out, I'm a little lost. O2 sensor? I've swapped a few different ones in from various other Volvos with no luck. I've also checked and at idle I was able to have the O2 sensor swing from .1-.8 (normal, right?). I've got an interesting 3 wire set-up, standard fare for LH 2.0, that has one black signal wire and 2 white wires that I assume go to the heater circuit. My AMM came out of a well running 740, so I don't have any reason to believe that's the culprit either. Is there any good tests to do for the AMM other than swapping another one? Or do you guys have any suggestions for what else I should try testing? Any help here would be appreciated, the gas mileage is killing me on this car.
-Thanks, Brandon
edit: Now, here's a kicker. I've got this sensor AND a connector that are unhooked under my intake. It's very possible that either of these could have something to do with it, but from what I can tell I've never been the one who unhooked this (accidentally or on purpose), and it very well may have been some sort of left over cast-off from the K-jet system and that sensor could have simply been used to plug a hole. It looks to be some sort of knock sensor? But it's a B23F engine and to my knowledge those never had knock sensors. The interesting part is these two things (the connector and the sensor in the head) are both male connectors, so it doesn't appear that these will go together, which once again leads me to believe that these are simply castoffs from the previous engine management system. Anyway, I'm just rambling now. For reference, that's the front-most coolant temp sensor (the gauge one) that this mystery sensor is below and those two orange wires are the connector i'm talking about.
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