2nd Hand Bf Xr6t Engine Vct Issues

[eblis]

Hi there,

After blowing up my 52000km old BF XR6T motor I picked up a 2nd hand BF F6 motor (2000km old apparently). Swapped it over and it started ok and was running smooth. On the first road test the engine reached normal operating temperature then started to miss at low revs a stalled when stationary in drive. Engine was hard to restart and the brakes were poor (manifold pressure related it think). Engine check light came on so parked it up.

Started car in the morning, was still hard to start but came right after 10 seconds of idling and ran like a champion again. Got the car back to the workshop and plugged in a scan tool to find the following codes:

P1381 VCT OVERADV I6 IN

P1386 VCT OVRADV I6 EX

P1383 VCT OVRRETARD I6 IN

P1388 VCT OVRRETARD I6 EX

After speaking to the local Ford service manager it was recommended to try an engine oil flush then and manually pulse the VCT solenoids while holding 2500rpm to try and clear blockages in the oil galleries to the VCT phasers. Tried this without much success. Also swapped over the VCT solenoids with the ones from my old engine but this made no difference.

Monitoring the cam timing via the scan tool I can see each cams timing and the amount of error and the VCT solenoid valve duty cycle. When cold everything is normal with both cams timing changes with low error and low duty cycle, but when the motor warms the exhaust cam ends up with 25 deg retard (30 deg error at idle) with no duty cycle and the motor runs like a pig. This only comes right if the motor is left to cool down then is started and all returns to normal within 10 seconds.

The last run I tried the inlet cam stayed locked at -5 deg retard while the ECU was trying to retard it with 98% duty cycle.

Have tried running with VCT solenoid wire plugs off to try and prevent ECU from changing cam timing but the exhaust cam timing still ended up at 25 deg retard when the engine warmed up.

Starting to think the phasers are faulty, may look at swapping them with the ones from my old motor.

Any one here had experience with fault finding on the VCT side of things? Any suggestions of what I could test before swapping the phasers over would be greatly appreciated.

Cheers

Chris

[senna_T]

I can't say I've heard of many VCT issues in the Barra motor, but I think your trial and error approach with swapping the phasers over is worth the time.

On a side note, what killed your original motor?

[RSWEPN]

NO idea about your problem, but does anyone know what the cam timing sits at when the vct is disconnected?

[eblis]

The number three piston/rod let go and put a couple of holes through the engine and sump (Jan 06 BF, BA type rods).

When I first installed a PW kit (plenum/piping/IC 350rwkw) ran it hard with 1/4 tank of gas and it fuel surged, since then it had a slight tap once fully warmed up - must have been a bent rod. Anyway traveled 20,000km/11 months on the motor like that and it finally let go. The tapping noise didn't get any worse prior to the failure and was I wasn't driving hard when it let go either.

[Martman]

Has been a while since we were working with the XR6T engine,

but from what I can remember there were some wee filters built into the VCT controls area?

Cant remember if they were in the vavles or the head,

but there was no mention of them in any service manual at ford,

just like the one inside the banjo bolt that feeds oil to the turbo,

no mention of that anywhere either.

[eblis]

Turns out the engine had low oil pressure, about 9psi at idle / 25psi at 2000rpm when hot. This had the effect of making the VCT phasers lose control of the cams when the engine oil got hot, wouldn't have been good for the engine lubrication in general either. I'm surprised at how low an oil pressure these engines can run without the oil light coming on, will be getting an oil pressure gauge shortly.

Anyway will never find out what was causing the low oil pressure as the engine was exchanged and the replacement is all good (FYI 40psi at idle when hot).

Chris