Starting problem
Discussion
My '97 Griff 500 has never had problem starting until now. Symptoms are starter motors turns over fine but it struggles to fire up. After about 3-5 seconds of the starter motor turning over, just about catches at very low revs and strong smell of petrol. A few pumps on the gas gets it running. It then continues to run fine. Any suggestions what to check?
You'll probably find you've had the fault for a lot longer than you realise but it's only become a starting issue since we've been enjoying this hotter weather, this is because the required ratio of air and fuel to achieve an effective start is super critical and it changes dramatically with temperature. The cranking mixture required to start a cold engine on a cold day is very different to the cranking mixture the engine needs when starting from hot, or even cold starting during the warmer months.
As a first test try cracking the throttle slightly before cranking, hold the throttle pedal in that position as you attempt the start to see if the engine starts better like this..... I suspect it will
Your symptoms indicate one or more of the following:
1. The engine is getting too much fuel
A faulty coolant temp sensor, faulty fuel temp sensor, sticky injector, grounded injector wire holding it open, ect, ect would all cause over fueling. If your engine coolant and or fuel temp sensor is out of range then the ECU may well be over dosing the engine, plugging in RoverGauge will show you the values the ECU is seeing from these sensors.
2. The engine is not getting enough air
If your idle valve (stepper motor) is stuck closed, you have the incorrect base idle screw setting, an incorrectly adjusted throttle butterfly, ect ect your engine will not be getting enough air. The system may well be applying the correct amount of fuel but if the engine is just not receiving sufficient air you'll have starting issues, the important point here is you need the right ratio of air and fuel so the effects of insufficient air are the same as excessive fuel ie the rich condition you describe.
3. The engine is failing to effectively burn the air and fuel
Failed plug extender, fouled spark plug, failed HT lead, ignition coil breaking down, ignition amp failing ect ect. Do look at your plugs, if you're still running the inappropriately cold and shrouded electrode B7ECS specified by TVR I strongly recommend you replace them with a set of BPR6ES plugs or better still a set of BPR6EIX iridium plugs. The ignition elements should not be overlooked because you may of course be applying the correct amount of fuel and air but an ignition fault would mean your engine is failing to effectively burn that correct air/fuel ratio, if thats the case you would also get a smell of fuel as raw unburnt fuel finds it's way through the combustion directly into the exhaust.
The final cause of your fault would be a mechanical one, a broken rocker, a burnt or stuck valve, poorly sealing piston rings ect ect will result in poor combustion and bad starts but I'd work your way through points 1,2 &3 before getting involved in a compression test as a mechanical fault is far less likely than a fueling, air or ignition issue.
TBH if you systematically work your way through points one, two and three..... the inevitable and unavoidable outcome will be to find your fault.
As a first test try cracking the throttle slightly before cranking, hold the throttle pedal in that position as you attempt the start to see if the engine starts better like this..... I suspect it will
Your symptoms indicate one or more of the following:
1. The engine is getting too much fuel
A faulty coolant temp sensor, faulty fuel temp sensor, sticky injector, grounded injector wire holding it open, ect, ect would all cause over fueling. If your engine coolant and or fuel temp sensor is out of range then the ECU may well be over dosing the engine, plugging in RoverGauge will show you the values the ECU is seeing from these sensors.
2. The engine is not getting enough air
If your idle valve (stepper motor) is stuck closed, you have the incorrect base idle screw setting, an incorrectly adjusted throttle butterfly, ect ect your engine will not be getting enough air. The system may well be applying the correct amount of fuel but if the engine is just not receiving sufficient air you'll have starting issues, the important point here is you need the right ratio of air and fuel so the effects of insufficient air are the same as excessive fuel ie the rich condition you describe.
3. The engine is failing to effectively burn the air and fuel
Failed plug extender, fouled spark plug, failed HT lead, ignition coil breaking down, ignition amp failing ect ect. Do look at your plugs, if you're still running the inappropriately cold and shrouded electrode B7ECS specified by TVR I strongly recommend you replace them with a set of BPR6ES plugs or better still a set of BPR6EIX iridium plugs. The ignition elements should not be overlooked because you may of course be applying the correct amount of fuel and air but an ignition fault would mean your engine is failing to effectively burn that correct air/fuel ratio, if thats the case you would also get a smell of fuel as raw unburnt fuel finds it's way through the combustion directly into the exhaust.
The final cause of your fault would be a mechanical one, a broken rocker, a burnt or stuck valve, poorly sealing piston rings ect ect will result in poor combustion and bad starts but I'd work your way through points 1,2 &3 before getting involved in a compression test as a mechanical fault is far less likely than a fueling, air or ignition issue.
TBH if you systematically work your way through points one, two and three..... the inevitable and unavoidable outcome will be to find your fault.
ChimpOnGas said:
As a first test try cracking the throttle slightly before cranking, hold the throttle pedal in that position as you attempt the start to see if the engine starts better like this..... I suspect it will
Sorry. Very rude of me not replying/thanking you sooner. You were spot on. "Cold start" on a very hot day!
TvrIanD said:
ChimpOnGas said:
As a first test try cracking the throttle slightly before cranking, hold the throttle pedal in that position as you attempt the start to see if the engine starts better like this..... I suspect it will
Sorry. Very rude of me not replying/thanking you sooner. You were spot on. "Cold start" on a very hot day!
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