I have a Vectra 1.8 1997P with a similar fault to that described on the archive dated Sept 01 by Peter Bowman.
A couple of miles into a run, the engine hesitates and the rev counter dips to zero. Afterwards the engine management light comes on and remains on. When this first happened, switching the engine off and restarting would clear the fault, but in the past few days it refuses to restart. It can be restarted after cranking for about eight seconds, after which the engine coughs and splutters, then runs reasonably but with the engine management light on.
The HJ archive leads me to suspect either the camshaft sensor or crankshaft sensor, though it has been suggested to me that the difficulty in restarting points to the crankshaft sensor as the most probable cause. Before I start buying sensors on a trial and error basis, would anyone have an opinion? Also, is there any way of doing an electrical test on the sensors?
Incidentally when I first examined the crank sensor, it wasn’t even bolted in but just pushed into place, not fully home and at 90 degrees to its correct orientation. The 6mm thread in the block was dry and rusty and I expect had been so since it left the factory. I cleaned and refitted it properly, but still have the problem.
I’ll be grateful for any guidance.
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I'd suggest your best plan is to have the fault code memory read before you start renewing parts.To test the crank sensor you need a fairly high end oscilloscope and the self diagnostic codes are quite reliable on this system.Also cam belt problems can cause fault codes for the cam and crank sensors to be generated.If you get fault codes for either of these the ideal repair is to renew them both and service the cam belt at the same time.
David Davies (Tune-Up Raglan)
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You can check for fault codes yourself on Vectra's. Codes are a four digit number.
1. Switch off ignition.
2. Using a piece of wire through a 5A or less fuse (for safety) bridge terminals 5 & 6 of the diagnostic plug under the handbrake lever.
3. Switch on ignition.
4. Count number of flashes of Engine Management Lamp. ie. 10 flashes = 0, 1 flash = 1, 5 flashes = 5, etc. There will be a short pause between each digit of the code. And each code is repeated three times. You may possibly have more than one code stored, so on the fourth repeat you can be sure you only have one code. You should end up with something like '0135'. This is quite long winded but you will get there.
5. If you have 1.2. repeating, you have no fault code stored.
When you have done this, post again and I'll tell you what fault code you have logged in your ECU.
Bear in mind that you cannot carry out actuator tests like the dealer can using diagnostic equipment, this is just for identifying the fault code/s.
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Many thanks for the inputs and the welcome to the club. I’ve been on a steep learning curve re fault codes….I didn’t realise I could read these myself.
I have two codes: 0335 and 0110 which I understand from onboarddiagnostics.co.uk are “crank sensor circuit malfunction” and ”Intake air temp circuit” respectively. These were the only two connectors I pulled the last time I ran the engine, so I’m fairly sure I introduced these codes by doing that.
My next plan is to erase the fault log, then run the car again until the problem reappears (about 10 minutes by recent experience) then re-read the codes. I thought the fault log was erased by switching the ignition on and off 25 times, but this had no effect.
Please tell me what I’m doing wrong!
John
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I thought the fault log was erased by switching the ignition on and off 25 times, but this had no effect.
The log will only be erased if the fault is no longer there. I believe it's actually 14 to 20 times of switching on/off the ignition, not 25, but I think it depends on which ECU you have fitted.
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Hello John
Welcome to the club! Strongly suggest you read the code as suggested. If you are unsure as to pin numbers etc, there is a device you can buy from Halfords known as the Gunson Code reader which costs £18. This is really a lot of money for a switch and two leads, however, they give you the codes you require plus diagrams of the socket and its still cheaper than paying a garage . My problem back in Sept 01 was the crankshaft sensor and your symptoms sound very much like mine at that time. Ironically I changed the camshaft sensor first (not having benefit of the code reader then). Recently I suffered similiar management light problems again and my code reader told me it was the camshaft sensor, the very last thing I would have suspected as it had seen little more than a years service. Fortunately I had not thrown away the old one so for once I enjoyed a very cheap repair.
Best of Luck
Peter Bowman
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Having failed to clear the fault log, I decided to drive the car to see if any further codes were generated. Sure enough, about 10 minutes into the run the engine hesitated and the light came on. I continued to drive for a further 30 minutes with the light on before switching off and reading the codes.
The codes were unchanged at 0335 and 0110.
I note the code explanations state “Circuit malfunction” in each case, rather than a specific condemnation of the sensors themselves.
I’m tempted to change the crank sensor as the next step, but what do you think?
Regards
John
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You can clear the fault codes by disconnecting the battery and joining the terminals (NOT BATTERY POSTS) together for a couple of minutes. This will discharge all capacitors. NB. you may erase all radio stations meaning you will have to re-programme them.
Check the Crankshaft Position Sensor for resistance at the 3 pin plug at the top of the timing cover by using a ohm meter across terminals 1 & 2. Disconnect it and check at the sensor end of the plug connector. Terminal 3 is a screened earth, so check that for resistance to battery -. You should read about 500-1500ohms. Flex the cable, particularly around the crankcase area where it bends and see if the resistance alters. If it does you may well have found your problem. If it doesn't then the CPS is unlikely to be at fault. Then check it for AC voltage output also at terminals 1 & 2. Crank the engine and you should measure >0.5V AC.
Check the Air Temperature Sensor for resistance also. As it warms, it's resistance should decrease. Check this by touching it with your hand or breathing on it to warm it up. Check also for continuity between these components and the ECU.
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Eureka!
The intake air temp sensor resistance was 3 Kilohms at ambient, falling to 2 Kilohms when breathed upon. The crankshaft sensor read open circuit between pins 1&2, and checked dynamically for AC output gave no discernible signal. Off to the Vauxhall dealer for a new sensor, which I resistance checked on their counter …..my meter read open circuit, but the parts guy said “They’re not the same as the Cavalier ones, you know”. I took it home, fitted it and the car ran perfectly (and has continued to do so). For my future reference, I measured the AC output at cranking speed to be 0.025v
My grateful thanks go to David Davies, to Railroad, to Superannuated Rocker and to Dynamic Dave for their invaluable help in guiding me along the path of enlightenment!
With best wishes
John
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just to let you know have just done 97 vecta 1.8 with good driveabilty but stalling and misfire at high revs. engine management light on. found breathers blocked rocker cover gasket leaking oil on to plugs and camshaft speed sensor. sensor and gasket replaced ecu interrogated fault was only intermitant so was not logging in fault memory just when running car with sykes acr on car. also found exhaust manifold gasket split. local vauxhall dealer caffyns said sell loads of these gaskets. replaced breather pipes also as all rot. and this was main dealer serviced only one year ago! granted a lot could of happened since then but it shouldnt deterioate this quick.
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