cj.surr
Well-known member
This engine is an AHU that has been put in a Volvo 240. The car had no problems starting and running for the first few hundred miles. Then, I would sometimes have a hard starting issue. Either it would take several seconds to start or would start and run really rough <500 RPM. If it was running rough, I would usually turn it off and upon restart it would run normal. These conditions would happen when the engine was warm or cold, but seemed to occur more often when cold.
Today the car would not start at all. Several long cranking sessions would not get it to start, although it would sometimes fire. My first guess was that there was air in the lines. I don't have any clear fuel lines, so I filled the feed line and fuel filter. I also tried to use a vacuum pump to pull fuel from the pump return fitting, but it was unable to pull much fuel at any rate. After hours of attempted starting after bleeding was unsuccessful, I started it by pulling it in 3rd gear with a truck. Once it started, it ran normal. I drove it around for a few miles but during that drive another issue started,
The engine would run fine shifting through the gears, but if you let off the throttle with it in gear, and it went into deceleration fuel cut (0% load on the OBD2 software), returning to throttle would be a mess. Returning from fuel cut, load could be at 50% but the engine was still decelerating. This could last for seconds, and smoke would come out of the tailpipe during this (I even heard it backfire through the exhaust a few times which was very surprising). Eventually it might bang back to life and run normally, but it would start all over again if I let off the throttle. If I were driving in gear and toed the throttle down to 1%, and it did not enter fuel cut, it would run completely fine, full power. Also, if I went from a fuel cut deceleration to idle (push the clutch in) it would run fine also, never encounter the hesitation. The hesitation would only occur if I tried to return from deceleration fuel cut out at higher RPM (2000+).
Once I turned the car off, it went back to no-starting. I have a clear fuel line in there and I can see that it is primed. I am not sure about the injector lines themselves as I haven't tried to bleed them (since it's not running). However, this seems to be an electrical issue to me, because of how systematic it is.
The only relating code I got was the "N108 short or open to ground". I think this was because I had unplugged it at one point with the ignition on while I was trying to bleed. regardless, I tested it. With KOEO, 12v on the harness side, 15ohm on the sensor side. So it seems to be fine.
Also, I checked the timing of the camshaft and fuel pump, and they are both in line.
I hope this explanation makes sense. It seems like a very strange issue to me but I am new to electronically controlled diesel. Hopefully someone can suggest another area to check.
Thanks in advance.
Today the car would not start at all. Several long cranking sessions would not get it to start, although it would sometimes fire. My first guess was that there was air in the lines. I don't have any clear fuel lines, so I filled the feed line and fuel filter. I also tried to use a vacuum pump to pull fuel from the pump return fitting, but it was unable to pull much fuel at any rate. After hours of attempted starting after bleeding was unsuccessful, I started it by pulling it in 3rd gear with a truck. Once it started, it ran normal. I drove it around for a few miles but during that drive another issue started,
The engine would run fine shifting through the gears, but if you let off the throttle with it in gear, and it went into deceleration fuel cut (0% load on the OBD2 software), returning to throttle would be a mess. Returning from fuel cut, load could be at 50% but the engine was still decelerating. This could last for seconds, and smoke would come out of the tailpipe during this (I even heard it backfire through the exhaust a few times which was very surprising). Eventually it might bang back to life and run normally, but it would start all over again if I let off the throttle. If I were driving in gear and toed the throttle down to 1%, and it did not enter fuel cut, it would run completely fine, full power. Also, if I went from a fuel cut deceleration to idle (push the clutch in) it would run fine also, never encounter the hesitation. The hesitation would only occur if I tried to return from deceleration fuel cut out at higher RPM (2000+).
Once I turned the car off, it went back to no-starting. I have a clear fuel line in there and I can see that it is primed. I am not sure about the injector lines themselves as I haven't tried to bleed them (since it's not running). However, this seems to be an electrical issue to me, because of how systematic it is.
The only relating code I got was the "N108 short or open to ground". I think this was because I had unplugged it at one point with the ignition on while I was trying to bleed. regardless, I tested it. With KOEO, 12v on the harness side, 15ohm on the sensor side. So it seems to be fine.
Also, I checked the timing of the camshaft and fuel pump, and they are both in line.
I hope this explanation makes sense. It seems like a very strange issue to me but I am new to electronically controlled diesel. Hopefully someone can suggest another area to check.
Thanks in advance.
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