P0378 & P0778 Help Please....!

bkwa

FIRSTLY, MY CAR STALLED 1 WEEK AGO AND THEN IT HAS NOT STARTED SINCE.

I have an OBDII reader and have got the above codes. Have read a few posts on here and there are lots of different views on these codes. I think i know what the codes mean (P0378 Timing Reference High Resolution Signal “B” Intermittent/Erratic Pulses / CRANK SENSOR ? !) Also (P0778 Pressure Control Solenoid “B” Electrical / MAP SENSOR ?! )

I also read that the timing chain should be ok because i have good compression. I also have New platinum spark plugs & juice in the tank.

Should i change the crank sensor ? & maybe the map sensor ?

Kind regards

Wayne

vocky

I would still whip the cam cover off and check the chain is ok, it may have jumped a tooth and that could be causing the timing error code

crank sensors are very good and seem to last forever, duff map sensor would stop the engine running though, try and borrow one from another member to test

bkwa

Would removing the cam cover effect the compression though ? Cheers Vocky.

MikeS

you remove the cam cover to check the timing is oki

worth clearing the codes down and trying again though

bkwa

i have removed tghe cam cover now. how do i check the timing by eye ? thanks.

nickgb

Hi, did you resolve this problem?

I have similar symptoms on our 2002 Zafira 2.2.

Car started to run rough, parked it up at home and now it turns over but won't start at all. ECU codes P0378 and P0778 showing.
Swapped the coil pack - no change (checked both coil packs outside the engine and they make sparks).
checked the Crank Sensor and wiring - looks OK, no open/shorts and reasonable signal when the engine is turned over.
After some bodging got a pressure reading on the fuel rail of 3.7BAR (book says 3.8 is nominal) so looks like the pump and fuel regulator are OK too.

What next? Any Ideas?

Recent history: The car was in the dealer a few months ago because I noticed the timing chain rattling so it got replaced (and I'm now down 1 arm and 1 leg 🙁 )

Update 24th October:
Just picked the car up from the garage having had it towed down there a week ago after checking the compression in each cylinder at between 50 and 70 PSI.

It now runs like a dream. The engine warning light is off (after three years - don't know what it is). It no longer hesitates at low RPM / high gear. It does not rattle (garage could not find anything at previous service). The petrol smell which has been coming in through the air grill for 6 months is now fixed (they changed the return pipe which did little to fix the problem about 6 weeks ago). In fact all the problems which never got fixed when I asked for them to be investigated at services are now gone. If it weren't for the dirt the car could be new.

What the garage charged for was changing the rocker cover and sump gasket because they were leaking. Their explanation was there was no oil in the engine so the compression was low. What confuses me is there was enough oil to trip the sump float and cranking the engine produced enough pressure to turn off the oil warning light. If a lack of oil was the cause then I would have expected either badly scored bores or broken rings before the compression got that bad.

I don't have the energy to demand more detail from the garage but if anyone can shed light on this either confirming the garage explanation or offering a different one I'd be interested.