I just spent over a month going through the engine in a 1997 XK8 I bought. It had dropped two exhaust valves and put a hole in the piston. I replaced the block, head, two pistons, connecting rod bolts, plugs, water pump, hoses, knock sensors, ect. After getting the engine back in I started it up and it has great oil pressure but it runs like crap! won't idle, shakes, erratic rpms, codes P1000, P0333 knock sensor, P0328 knock sensor. both knock sensors are new! Really frustrating, any ideas?
Thanks,
Jay111

 

Jay111,
My initial take on your problem, is that the OBD2 DTC show both Knock Sensors (KS) problems and the engine runs badly. P1000 is nothing to worry about (failure to run long enough to sort out emissions tests). So your KS problems are probably related to either bad wiring or bad/wrong new KS parts.

The former is probably a good place to start as you've obviously done a major overhaul of the engine and know your stuff. As you probably know, the knock sensors are behind the Thermostat tower, in the V of the head, so it'll be a pain to get to but I would first carefully check the connectors there and trace the wiring all the way to the ECM. It may be dirty connectors (easy fix) or a pinched short to ground somewhere (considering the work you've done).

Big question - how did you set the timing during your overhaul? Lots of problems if you didn't fix it properly as the AJ engines don't have Drop Dead Centre marks and use specific tools/procedures for the job.

Are there any other DTCs? You haven't mentioned dash messages such as the CEL or "Restricted Performance" etc. Did the engine run for a period of time and settle down, or does it misbehave constantly despite a period of time running.

You didn't mention the engine, so for a 1997, I presume it's a AJ26, where KS problems can also be related to fuel rail pressures, bad air/fuel mixtures causing bad detonation, injector problems, ignition coils. NB: You cannot simply put a different AJ27 in for a AJ26 (it can be done and lots of info here how to do it)

Need a bit more info on your situation, as you obviously know your stuff.

 

If the replacement head was from a later AJ26, note also that the 97 had different exhaust cams (timing).

 

I used the original cams.
Jay111

 

Got it running ok there was a vacuum line not attached but it still shows ABS/ stability and traction control fault and P0328 and P0333 knock sensor high input. Any ideas to fix this, not noisy and seams to run good, oil pressure good, temp. good, charging good.
Thanks for your help,
Jay111

 

jay111,

Well done. Fantastic result for a month’s effort.

Hopefully you just need to drive around the block to get some data through the ABS wheel speed sensors and the ABS warning will just go off. If not you have the usual cleaning job of wheel speed sensors, check wiring (front 2 wiring are known to break due to steering) or you have the ABS module internal solder job on the pins. I always go for the potential easy fixes first before going down the list.

For the knock sensors, see my thoughts above - check connectors, wiring and other fuel/air problems that could be leading to bad detonation. Hopefully the new KS parts are correct.

 

I store my '97 for 6 months during the winter. The ABS / traction control warning light comes on after initial start up in the spring and after 20 or 30 km of driving goes off and doesn't reappear for the rest of the summer.