Hey all,

I have a 96 Disco SE7 with 160k on it. I’ve had it for about 7 months now and have been fixing it up. I use it as a daily driver. The nagging issue that I am dealing with is loss of power on acceleration over 2500rpm. If I’m going up a hill, it goes under load, lose power, sporadic misfire, and I have no throttle response no matter how far I push down. Eventually the speed will come down far enough to where I can regain response. I can get the thing up to 50 or 55mph with me being easy on the throttle but it starts to act funny after that.

New plugs, wires, TPS. Fuel pressure is good. Coils have been replaced and no change. One thing I did notice is that my freeze frame data shows the RPM’s at 1660 and my speed at 40mph at idle. I thought this was a VSS problem after reading through other posts so I unplugged but this didn’t change anything. It continued to struggle if I tried to give too much throttle. Any suggestions?

Here are the current codes that I have: P1193, P0150, P0300, P0304, P1316, P1313, P1314, P0340

 

95 D1 isn't OBD2 so how did you get those codes? 14CUX will have a code reader built in under the passenger seat and it displays 2 digit fault codes one at a time. P0300 fault = multiple misfires, P0301-P0308 = misfire for the appropriate cylinder. P1193/P0150 = O2 sensor fault, but your problem without a doubt = P0340 Cam/Crank Position Sensor fault. Either your Crank Position sensor is bad, or the wiring is shorting out (insulation is known to get brittle and fall off leaving the wires touching). I would inspect the wiring harness to the sensor itself, and if that looks good replace the Crank Position sensor.

 

typo! 96! My bad. And okay, thanks for the reply. It gives me something new to look at.

 

If you have the OBDII port, you can do a live data and monitor the VSS data. it should stay pretty steady within a few MPH. when they act up, speed will drop to around 30-35 mph and then speed up until it errors out again.

 

P0340 is a dead give away, it will cause all the other fault codes due to misfires. When the CPS goes or the wiring falls apart and shorts = ECU can't properly produce spark/fuel to the correct cylinder and the correct time. Inspect wiring harness and replace the CPS. It could be either the cam/crank sensor, but usually it's the Crank Position due to it's location by the exhaust and the wiring insulation cracks due to the heat.

 

I’ve read that a lot of people with a bad CPS, their rover won’t start which I never have had an issue with. So this could just be a matter of faulty connection? Why do you think the rover does fine until there is a greater amount of throttle put on the engine? I guess my questions revolves more around as to why this only acts up as the engine is told to move faster? I haven’t gotten a chance yet to get under the rover and inspect. Hope to soon!

 

The ECU is trying to tell you P0340. That is CPS related either wiring harness or sensor plain and simple.

 

When I had a similar problem and it ended up being my VSS, I did not get an error code pointing directly at the CPS.

 

I'm very familiar with this issue. I had a friend recently purchase a sweet 99 D1 SD in near flawless shape that sat for god only knows how long. My friend was able to get it running, but it would not go any faster than 20MPH and the RPM's acted like it was dying out anything above 2K. He had it towed home and he pulled the codes with his bluetooth OBDII device. It pointed toward a MAF, and emission codes. We swapped out the Chinese made MAF and it helped, but on a 20 mile trip it went back to doing the same thing. I came out the following weekend with a Lynx scantool and P0340 popped up. We immediately started looking at his CPS. First we found it without a cover, then it was loose and wiggled, then we found the wiring harness to the CPS had brittle insulation, and someone had twisted it the wiring upon trying to mess with the CPS in the past (causing the wires to be shorted in 3 places). We repaired the CPS harness, installed a new CPS (spare was in the glovebox), and we secured the CPS (had to install a spacer to compensate for the CPS cover which was missing). Fired it up, and now his 500.00 D1 runs flawless. His only fault codes now are Emission related which is nothing.

So trust me when I say the D1 is trying to tell you to check the CPS wiring harness, the CPS sensor, and to make sure it's mounted securely and not damaged. P0340 is a big clue. My friend originally missed that because his OBDII scantool didn't list it as a CPS fault.

When a VSS acts up usually the first sign of any problems = speedo bounces or surges.