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Discussion Starter #1
I replaced a blown cylinder head gasket after the aux belt snapped and overheated engine. I changed timing chain and valve seals while I was at it. When I started engine it ran once but had to use throttle to keep it running. Tried to start it again and no go. Pedal test shows p0100. Checked wiring to maf sensor, got 12v, 5v and a ground on 3 of the pins so I replaced maf sensor with a used 2nd hand one. Same problem, after putting in safe code after battery had been disconnected for 20mins, engine eventually started with throttle and would rev OK with high revs but then die. It wouldn't restart. Same pedal fault code p0100.
I've run out of ideas, I'm sure if I disconnected battery it would start once again but still run erratically, but not start a second time. Don't really want to scrap the car (140k) after I've done so much work on it, just annoyed I'm so close to fixing it! Any ideas of what to try?
 

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Discussion Starter #4
Disconnected battery for 3/4 hour, removed maf connector and unfortunately still the same problem, started a couple of times but would only run lumpily if revved. Cuts out as soon as foot taken off accelerator. Eps light is always on. Funnily enough no pedal fault codes with connector removed (continuous flashing lamp)
 

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Discussion Starter #6
I cleaned throttle body as it was quite oily and tried again. Engine started after many turns and it revved nicely and it now ticks over. But then couldn't start it again. Cleaned the new plugs which were all sooty, and tried to start again. Took a very long time to fire, then the engine died when I tried to put in gear.
So now it seems to take ages to start, when it usually starts right away.
No pedal faults now and all warning lights out when it's running. Any ideas regarding the starting issue please? Many thanks for your help so far.
 

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What to do is check for oil in the loom at the ECU, then check the resistance of the crankshaft and camshaft sensors. Then make sure the fuel pump is priming
 

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Discussion Starter #8
Wiring loom was oil free. Measured camshaft sensor, open circuit across coil. Noticed end of sensor cap was scuffed. When I replaced cam chain, I got camshaft sensor fault. Realised there were 2 washers in the kit which I heard online were to put between chain sprocket and sensor vane so that the vane is closer to the sensor. I put one washer in and although the vane was now very close to the camshaft casing, it cleared enough but the vane probably touched the sensor sensor and killed it. So I bought another sensor, supposed to be for my car but I had to file the body a bit to get it to plug in to the chassis. Although it wouldn't go fully home, the seal was in enough so I tightened it down so it maybe protruded about 3mm outside the casing. Thought that would be OK and the sensor was about 3 to 4 mm away from the vane so guessed it would be OK. Engine started and ran well. Tried to restart and no go. Now get p0340 twice with pedal test (camshaft position sensor)
Measured sensor and its open circuit.
So looks like the sensors gone again so should I now replace with a Bosch part? And what about the washer, should it be there or should the sensor work if the vane is further away (the washer thickness is 5mm)?
This is so near yet so far, any further help would be greatly appreciated!
 

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Discussion Starter #11
I removed sensor from engine casing and checked voltages, 5v across pins 1 and 3 and either 2 v or 0v on pin 2 when I put metal near the sensor head. So looks like the sensor I modified and a new Bosch sensor I've just purchased are ok. The original sensor was 0v only on pin 2 so must be dead. Fitted the new Bosch sensor which fits properly in the chassis and same problem, engine wouldn't start. Changed wet plugs, still won't start. Pedal test shows P0340, P0340 and P0335 (crankshaft position sensor A circuit). Checked wiring loom, wiggled it but still the same. Not sure how to release connector at ecu to check cable continuity yet, but if cable is OK that just leaves the ecu?
Is this the case and is there anything else I can check please? Cheers.
 

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Discussion Starter #13
When I cut the signal wire from the sensor to the ecu, the ecu pin is sitting at 2.4v, so the sensor will pull it down to 0v when near metal, but I don't ever see a 0v to 5v swing. The cable is clean, no oil near connectors, so does this mean it's the ecu that's faulty?
 

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Sounds like a faulty sensor. The 5v is fine from the ecu. Have you checked 5v and ground with the sensor plugged in. If they are still good then the sensors at fault. All tests should be performed with sensors plugged in.
 

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Discussion Starter #15
I replaced the sensor, no fault codes now but engine still won't start. Checked compression, all cylinders between 4 and 7 bar and I've got a spark. Plugs were damp so think I've got fuel.
Any ideas what to check next?
 

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Discussion Starter #16
Also when I try to start the engine, rev counter moves slightly, only about100 revs, and the engine light goes out eventually, only the eps light is continually on.
 

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How old is the fuel in the tank? It won't really matter as the engine should still run but it does have an effect on my classic minis.
 

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Discussion Starter #19
Thanks but fuel is only 5 weeks old. I'm going to check if the fuel pump is priming z
You have low compression. It should be 12 bar +. Check the timing
You have low compression. It should be 12 bar +. Check the timing
The camshaft sensor phase disc positioning tool would line up with two of the slots on the phase disc might I of picked the wrong one to line up?
 

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Is piston 1 at tdc though. I'd throw no more parts at this until you found what the issue is with compression. I had a astra a few months back with same issue and low compression like your and it had been cranked that long it had washed the bored down. Had to pour a load of oil down each cylinder and turn it by hand with the plugs out. Then suck as much oil as I could before refitting the plugs. Make sure plugs are bone dry. Heat the tips over a flame to dry them. One refitted it went first go. It was unreal. Never seen borewash drop compression to less than 5 bar. The cars still running fine today and compression was later checked and all had returned to over 13 bar.
 
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