One more thing about flooding!
Discussion
My old XJ 8 used to flood? Coil packs the lot, problem is it soaks the bores, washes oil away loosing compression, if you have proper flooded, disconnect fuel pump( not sure on the tiv) then floor it, only way on the jag, I spent an hr once,even had inlet tract off, thank god, flame and bang would have destroyed it! Must have been 2 ft high gee! So yes it will need a long turn on the key to BUILD UP the compression needed to fire. Shoot me down if I'm wrong. My main point is many of the V8 engines can suffer, starting from cold then stopping engine soon after is not good! Bout a gallon in there! Lol
Not sure if the 14 cux is the same as most ecus but when you first turn the key the ECU sends a priming pulse of fuel to coat the inlet tract, it only does it once, but if you turn the key to the off position then on again it will send another priming pulse,potentially flooding the plugs compounded with trying to pump the throttle.
The trick to cold starting is not to touch the throttle and release the key on the starter so all the current goes to the plugs giving a better spark if it doesn't start first time don't turn the key off but use short bursts of the starter, if it still won't start check your ignition system
The trick to cold starting is not to touch the throttle and release the key on the starter so all the current goes to the plugs giving a better spark if it doesn't start first time don't turn the key off but use short bursts of the starter, if it still won't start check your ignition system
Discopotatoes said:
Not sure if the 14 cux is the same as most ecus but when you first turn the key the ECU sends a priming pulse of fuel to coat the inlet tract, it only does it once, but if you turn the key to the off position then on again it will send another priming pulse,potentially flooding the plugs compounded with trying to pump the throttle.
The trick to cold starting is not to touch the throttle and release the key on the starter so all the current goes to the plugs giving a better spark if it doesn't start first time don't turn the key off but use short bursts of the starter, if it still won't start check your ignition system
Almost- the pump priming only pressurises the fuel rail in prepartion to start and clear any air locks- the injectors are still shut until the engine starts to crank. At this point the ECU picks up the engine rotation, and a set amount of fuel is injected with a fixed injector pulse for a couple of seconds. The engine should then fire, and the AFM reading is then taken into account to set the required fueling. Im not sure if the engine does not start if the ECU tries to read the AFM after a couple of seconds, or if it sticks with the fixed injector pulse width- certainly the latter would flood the engine pretty quickly.The trick to cold starting is not to touch the throttle and release the key on the starter so all the current goes to the plugs giving a better spark if it doesn't start first time don't turn the key off but use short bursts of the starter, if it still won't start check your ignition system
blitzracing said:
Discopotatoes said:
Not sure if the 14 cux is the same as most ecus but when you first turn the key the ECU sends a priming pulse of fuel to coat the inlet tract, it only does it once, but if you turn the key to the off position then on again it will send another priming pulse,potentially flooding the plugs compounded with trying to pump the throttle.
The trick to cold starting is not to touch the throttle and release the key on the starter so all the current goes to the plugs giving a better spark if it doesn't start first time don't turn the key off but use short bursts of the starter, if it still won't start check your ignition system
Almost- the pump priming only pressurises the fuel rail in prepartion to start and clear any air locks- the injectors are still shut until the engine starts to crank. At this point the ECU picks up the engine rotation, and a set amount of fuel is injected with a fixed injector pulse for a couple of seconds. The engine should then fire, and the AFM reading is then taken into account to set the required fueling. Im not sure if the engine does not start if the ECU tries to read the AFM after a couple of seconds, or if it sticks with the fixed injector pulse width- certainly the latter would flood the engine pretty quickly.The trick to cold starting is not to touch the throttle and release the key on the starter so all the current goes to the plugs giving a better spark if it doesn't start first time don't turn the key off but use short bursts of the starter, if it still won't start check your ignition system
Key on - injectors pulse for a predetermined number of milliseconds - inlet manifold wetted in preparation for start.
This is different to, and should not be confused with the fuel pump being run for 2-3 seconds when you turn the ignition on, it's completely different & unrelated.
When you hear the fuel pump buzz, it's not the injectors opening, the noise is just from the fuel pump priming the fuel rail up to pressure, but the two do occur at the same time.
Key on - key off again = a second priming pulse & so it continues - this may result in flooding just as Discopotatoes has indicated.
Priming pulse is typically active or inactive dependant on a set coolant temperature value.
But hey, that's just what I was told.
But given his background I'm inclined to trust the information provided by the man that told me
Flooding during cold start on TVRs equipped with the 14CUX is very common & can have many root causes, but there is one place to always start & that's not the fuel side.
It's actually the ignition.
Our cars have very poor ignition at the best of times, for example if you ditch the distributor in favour of wasted spark you will see immediate benefits.
This is clearly a rather costly solution & to be honest the distributor & coil system should be perfectly adequate.
As part of a thorough ignition service I strongly recommend removing the shrouded type NGK B7ECS spark plugs & replacing them with NGK BPR6ES (or better still NGK BPR6EIX).
Although the 14CUX provides a huge dollop of fuel on cold start you should find the improved combustion from your new projected electrode plugs helps to burn this fuel more effectively.
ERGO - no more flooding on cold start
Edited by ChimpofDarkness on Tuesday 12th February 12:43
Chimpo what's the difference between the two plugs you mention, heat? Projected tip, forgot to mention I LPG' ed the Jag and had iridium plugs fitted, car always started on petrol regardless of engine temp, never ever flooded on start up again. I'm not suggesting LPG for the Chim, not at all but I'm sure the plugs fitted helped. Does that make sence, posts are great thanks. Can't bloody remember plug No, but it did have a split tip. If were using an old stock plug if seems daft considering we get better Cams etc!
Alun450 said:
Chimpo what's the difference between the two plugs you mention, heat? Projected tip, forgot to mention I LPG' ed the Jag and had iridium plugs fitted, car always started on petrol regardless of engine temp, never ever flooded on start up again. I'm not suggesting LPG for the Chim, not at all but I'm sure the plugs fitted helped. Does that make sence, posts are great thanks. Can't bloody remember plug No, but it did have a split tip. If were using an old stock plug if seems daft considering we get better Cams etc!
The number 7 on the plug dissipates more heat than the 6, the P stands for protruding which gets the spark into the mixture much better, I'm using BPR6ES and it runs and starts like a dreamDiscopotatoes said:
Not sure if the 14 cux is the same as most ecus but when you first turn the key the ECU sends a priming pulse of fuel to coat the inlet tract, it only does it once, but if you turn the key to the off position then on again it will send another priming pulse,potentially flooding the plugs compounded with trying to pump the throttle.
The trick to cold starting is not to touch the throttle and release the key on the starter so all the current goes to the plugs giving a better spark if it doesn't start first time don't turn the key off but use short bursts of the starter, if it still won't start check your ignition system
Is this the reason why the RV8 does not fire instantly when ignition key is turned? I have to wait 2 -3 seconds before firing. My old 200K petrol Toyota Land Cruiser fires instantly.The trick to cold starting is not to touch the throttle and release the key on the starter so all the current goes to the plugs giving a better spark if it doesn't start first time don't turn the key off but use short bursts of the starter, if it still won't start check your ignition system
My understanding was that the delay is deliberate to get the oil moving a bit before the stress of ignition. Mines goes for 2 seconds when cold before starting. Not when warm though.
I believe most cars have a flood clear feature, i.e full throttle while cranking will not add any fuel, allowing the fuel to air ratio to get back to norm.
I'm on Mark Adams map if that makes any difference.
I believe most cars have a flood clear feature, i.e full throttle while cranking will not add any fuel, allowing the fuel to air ratio to get back to norm.
I'm on Mark Adams map if that makes any difference.
977 said:
My understanding was that the delay is deliberate to get the oil moving a bit before the stress of ignition. Mines goes for 2 seconds when cold before starting. Not when warm though.
I believe most cars have a flood clear feature, i.e full throttle while cranking will not add any fuel, allowing the fuel to air ratio to get back to norm.
I'm on Mark Adams map if that makes any difference.
Thank's David. That's two of us with the same. Not sure about wide open throttle to start. Will this cause flooding if it does not fire after 2 seconds? I do not wish to try in case it happens. We often hear of tivs and the AA churning away to try and start, wearing away the piston rings and bores with petrol wash!I believe most cars have a flood clear feature, i.e full throttle while cranking will not add any fuel, allowing the fuel to air ratio to get back to norm.
I'm on Mark Adams map if that makes any difference.
Edited by EGB on Thursday 14th February 09:24
Alun450 said:
Chimpo what's the difference between the two plugs you mention, heat? Projected tip, forgot to mention I LPG' ed the Jag and had iridium plugs fitted, car always started on petrol regardless of engine temp, never ever flooded on start up again. I'm not suggesting LPG for the Chim, not at all but I'm sure the plugs fitted helped. Does that make sence, posts are great thanks. Can't bloody remember plug No, but it did have a split tip. If were using an old stock plug if seems daft considering we get better Cams etc!
You make a good point Alun, initiating combustion with LPG is significantly more difficult than with petrol.It's why iridium plugs are often used when a car is converted to LPG, just like your Jag.
I took this common knowledge and applied it to my petrol Chimaera.
What I found after fitting NGK BPR6EIX were immediate & noticeable improvements in idle quality, throttle response & cold start performance.
I was still running the the 14CUX & distributor at the time, the effects of the iridium plugs was almost as good as when I moved to the Canems engine management system with wasted spark.
Honestly it was that good!
The NGK BPR6EIX are a bit more expensive but they last more than twice as long.
They are a direct replacement to the rather outdated & inefficient NGK B7ECS fitted by TVR, just dont be tempted to try and gap the iridiums when you fit them.
Simply remove from the box, & fit, that's it.
Being the slightly hotter running 6 heat range they are also less susceptible to fouling than the cooler shrouded original 7s.
This is just want you want, the 6 heat range was used by Land Rover for years in their Rover V8 engined cars as it's a far more suitable heat range for a road car than a 7.
Don't worry about the "R" in your new plugs either, "R" stands for RESISTOR, contrary to internet forum folk law a resistor wont reduce the intensity of your spark one bit.
All that will happen if you fit resistor plugs is your radio reception will be better, & that's very welcome in a TVR.
Some people will tell you iridium plugs fail causing catastrophic engine failure, but I can assure you this is complete hog wash.
But I'm sure you know this already having owned an LPG Jag fitted with iridium plugs.
I encourage you to add your experiences of iridium plugs to this post:
http://www.pistonheads.com/gassing/topic.asp?h=0&a...
Best regards, Dave.
ChimpofDarkness said:
blitzracing said:
Discopotatoes said:
Not sure if the 14 cux is the same as most ecus but when you first turn the key the ECU sends a priming pulse of fuel to coat the inlet tract, it only does it once, but if you turn the key to the off position then on again it will send another priming pulse,potentially flooding the plugs compounded with trying to pump the throttle.
The trick to cold starting is not to touch the throttle and release the key on the starter so all the current goes to the plugs giving a better spark if it doesn't start first time don't turn the key off but use short bursts of the starter, if it still won't start check your ignition system
Almost- the pump priming only pressurises the fuel rail in prepartion to start and clear any air locks- the injectors are still shut until the engine starts to crank. At this point the ECU picks up the engine rotation, and a set amount of fuel is injected with a fixed injector pulse for a couple of seconds. The engine should then fire, and the AFM reading is then taken into account to set the required fueling. Im not sure if the engine does not start if the ECU tries to read the AFM after a couple of seconds, or if it sticks with the fixed injector pulse width- certainly the latter would flood the engine pretty quickly.The trick to cold starting is not to touch the throttle and release the key on the starter so all the current goes to the plugs giving a better spark if it doesn't start first time don't turn the key off but use short bursts of the starter, if it still won't start check your ignition system
Key on - injectors pulse for a predetermined number of milliseconds - inlet manifold wetted in preparation for start.
This is different to, and should not be confused with the fuel pump being run for 2-3 seconds when you turn the ignition on, it's completely different & unrelated.
When you hear the fuel pump buzz, it's not the injectors opening, the noise is just from the fuel pump priming the fuel rail up to pressure, but the two do occur at the same time.
Key on - key off again = a second priming pulse & so it continues - this may result in flooding just as Discopotatoes has indicated.
Priming pulse is typically active or inactive dependant on a set coolant temperature value.
But hey, that's just what I was told.
But given his background I'm inclined to trust the information provided by the man that told me
Flooding during cold start on TVRs equipped with the 14CUX is very common & can have many root causes, but there is one place to always start & that's not the fuel side.
It's actually the ignition.
Our cars have very poor ignition at the best of times, for example if you ditch the distributor in favour of wasted spark you will see immediate benefits.
This is clearly a rather costly solution & to be honest the distributor & coil system should be perfectly adequate.
As part of a thorough ignition service I strongly recommend removing the shrouded type NGK B7ECS spark plugs & replacing them with NGK BPR6ES (or better still NGK BPR6EIX).
Although the 14CUX provides a huge dollop of fuel on cold start you should find the improved combustion from your new projected electrode plugs helps to burn this fuel more effectively.
ERGO - no more flooding on cold start
Edited by ChimpofDarkness on Tuesday 12th February 12:43
This is really interesting.
Bought a 450 Chim yesterday, my first TVR and it started on the button throughout the test drives and the drive home.
This evening, after it had been sitting all day, I flooded the engine trying to start it. Took me a good 10 mins to get it going by using a WOT to clear the fuel.
It was certainly my mistake. It didn't start within a second (which I am used to) so I put my foot on the throttle a bit to help it get going. What I didn't realise is that its normal for it not to fire immediately and I was just chucking more fuel into those cylinders.
NO THROTTLE TOMORROW.
Bought a 450 Chim yesterday, my first TVR and it started on the button throughout the test drives and the drive home.
This evening, after it had been sitting all day, I flooded the engine trying to start it. Took me a good 10 mins to get it going by using a WOT to clear the fuel.
It was certainly my mistake. It didn't start within a second (which I am used to) so I put my foot on the throttle a bit to help it get going. What I didn't realise is that its normal for it not to fire immediately and I was just chucking more fuel into those cylinders.
NO THROTTLE TOMORROW.
Gassing Station | Chimaera | Top of Page | What's New | My Stuff