Mk 3 Cavalier 2.0i auto 1990, getting fuel (so not relay)& spark but it just won't start. I've tried 2 different ECUs from the scrapyard, checked and WD40'd all the connectors I can find, distrubutor cap etc cleaned, plugs & leads ok, new air filter, tried with no air filter, earths ok, battery fully up. Started as an intermittent fault but rapidly got terminal.
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Starting with some obvious points. When you say it is getting fuel do you mean through to the plugs? Are the plugs wet with petrol with all that cranking and no starting? Similarly I assume you've checked each plug is actually sparking by holding plug against the engine block while someone cranks over the engine? If not, insulate yourself from plug - use well insulated pliers or similar to hold plug. Be careful not to shock yourself!
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I assume you've checked each plug is actually sparking by holding plug against the engine block while someone cranks over the engine? If not, insulate yourself from plug - use well insulated pliers or similar to hold plug. Be careful not to shock yourself!
I've heard using this method can damage the ecu, so beware.
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Not being up to speed with ECU controlled cars (carbs seem OK to me!), how is this method of testing a spark plug by touching the plug against the engine block externally different from the circuit created when the plug is actually screwed into the block? How should you see if plugs are sparking on ECU equipped car without a diagnostic setup & computer?
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Agree with DD that IIRC the Haynes manual for these Vauxhalls warns against using the spark plug against the block method. The only reason I can think of is maybe that using this method the ground connection between the plus & ECU is broken when you remove the plug from the block, and the ECU may not like this.
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Victorbox,
Firstly, electronic ignition *bites* a lot more than the older points/condensor setup, should you inavertantly ground yourself to a HT lead.
Secondly, the ignition coil or amplifier module could be damaged.
Never try to diagnose misfires by pulling off one HT lead at a time. Note also that the ECU is at risk if the system is triggered with an open (ie, not properly earthed) HT circuit.
Remember also that removing a HT lead while the engine is running will cause unburnt fuel to leave the combustion chamber and enter the cat convertor - which won't do it a lot of good.
(some of the above quoted from a Haynes manual for the mk3 Cavalier)
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Crumbs! Thanks DD. Thank goodness my Mk 3 Cavalier has a carb. and no cat. converter or ECU but it does have an amplifier module for the ignition so your point on this is noted.
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>>Started as an intermittent fault
was that just bad starting or did you have any other problems.
ie poor acceleration after starting/running rough-missfire.
the fact you have a spark won`t mean the coil is working perfectly.let me know
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Thanks. A few times it cut out suddenly then started again after a couple of minutes. I've double-checked the coil with our other Cavalier - it works. I'm pretty sure there is some simple but vital earth or other wiring failure, but of course finding its's another matter.
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Had same problem on a 1.8 G reg.turned out to be a Vacuum pipe
split on the inlet manifold.replaced pipe and all is well.
Just a possible.?
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Right, remove a spark plug and see if it is wet. If not it is likely that the injectors are not opening. The injectors require a 12v feed from the fuel pump relay. Although the fuel pump is running the second output from the relay may not be connecting which is a known problem. To check this you will need to gain access to an injector plug and with either a low wattage bulb or preferably LED tester check for battery voltage at either of the terminals of the plug. If the plug is wet you will need to check for a spark at the plug. Leave the existing plugs in place and connect a spare into one of the plug leads leaving the others connected. Lay the plug on the cam cover and briefly crank the engine looking for a healthy spark at the plug tip. You will not damage anything doing this. It will only cause a problem if the pluglead is open circuit and the spark jumps from the coil tower to the lt terminal to escape.
Good luck
Andrew
Simplicate and add lightness!!
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