Lots of cranking needed to start when warm
Discussion
Got new plugs on the way, Will do: leads appear to be new Magnecor jobs, plug extenders are I think the original Beru items but appear in good condition, it has a special A&R Power Amplifier for the coil (so not original). Don't know anything about coil just yet.
Yes, I'm going to check these things first (once I figure out how to). Can resistance be checked on the plug extenders to check their condition? What about the coil?
Yes, I'm going to check these things first (once I figure out how to). Can resistance be checked on the plug extenders to check their condition? What about the coil?
The ignition system certainly needs to be tip top on these.
The leads and power amp you have are not well regarded here tbh.
An article worth reading, im not a fan of the ceramic ended leads they recommend though.
https://www.google.com/url?sa=t&source=web&...
The leads and power amp you have are not well regarded here tbh.
An article worth reading, im not a fan of the ceramic ended leads they recommend though.
https://www.google.com/url?sa=t&source=web&...
Edited by Belle427 on Tuesday 19th December 07:33
The A& R amp is not ideal, you are better off with the Lucas unit if it's still fitted as the Lucas unit is very finely balanced for the requirement of a short dwell on a V8 engine, something the A&R actually makes worse at higher engine RPM. On the HT side this weather is ideal as it's so cold and damp. Go and look at the HT leads in the dark and any tracking or breakdown will be seen by the blue glow around any weak bits as it tracks to earth.
PreCat Griffith said:
Pre-cat Griff takes a lot of cranking to start when warm (but fine when cold); what are the usual suspects?
I also have a misfire at idle (even to my untrained ear) which may or may not be related, and sooted up plugs. Drives well though.
Sooted plugs are not ignition related as it's a pre cat engine. You are likely looking at over fuellng caused by the AFM voltage being out of spec' or failed water temp sensor. I also have a misfire at idle (even to my untrained ear) which may or may not be related, and sooted up plugs. Drives well though.
Same AFM test process as this post.
https://www.pistonheads.com/gassing/topic.asp?h=0&...
Edited by blitzracing on Tuesday 19th December 20:19
blitzracing said:
The A& R amp is not ideal, you are better off with the Lucas unit if it's still fitted as the Lucas unit is very finely balanced for the requirement of a short dwell on a V8 engine, something the A&R actually makes worse at higher engine RPM. On the HT side this weather is ideal as it's so cold and damp. Go and look at the HT leads in the dark and any tracking or breakdown will be seen by the blue glow around any weak bits as it tracks to earth.
Thank you. So if a lead has broken down, it's spark still has to go somewhere, and if it's not going to the spark plug, it'll be arcing somewhere? I have checked for this at night in the garage with light off but not seen any arcing; I'll double check.blitzracing said:
Sooted plugs are not ignition related as it's a pre cat engine. You are likely looking at over fuellng caused by the AFM voltage being out of spec' or failed water temp sensor.
Same AFM test process as this post.
https://www.pistonheads.com/gassing/topic.asp?h=0&...
I suspect you're right; my engine oil does smell of fuel. Might leaky injector also be the culprit? I'll give all that testing a go when I get a chance. Thanks for your help.Same AFM test process as this post.
https://www.pistonheads.com/gassing/topic.asp?h=0&...
Edited by blitzracing on Tuesday 19th December 20:19
What rubbish advice. An oil change and a run are not going to solve a poor starting issue when hot! What has oil got to do with how a car starts?
It isn't getting the right fuel/air mixture, or a big enough spark. You need to look at the causes of those issues, and they certainly are not oil or giving it a run related!
If the car has vapour lock issues, which sounds probable, then getting it really hot after a run will just make it worse! There probably isn't enough fuel pressure when it is hot, probably because the injectors need replacing.
It isn't getting the right fuel/air mixture, or a big enough spark. You need to look at the causes of those issues, and they certainly are not oil or giving it a run related!
If the car has vapour lock issues, which sounds probable, then getting it really hot after a run will just make it worse! There probably isn't enough fuel pressure when it is hot, probably because the injectors need replacing.
It's unlikely all the injectors are leaking if all the plugs are sooty as it will be one thing common to all 8 if all are black. Have you checked the CO trim voltage? It's a hex screw on the side of the AFM and is like a mixture screw on a carb. It controls the mixture up to about 3400 RPM. There is no reason for this to be wrong unless it's been fiddled with
Setting The Air flow Sensor Applicable to NON catalyst cars only. Using a voltmeter between red and black wire and blue and red wire check the voltage with the ignition on, but the engine not running. Recessed Hex head screw allows you to set the carbon monoxide base line with these voltages. NOTE these are base settings ONLY. Turn the adjustment screw clockwise to richen the mixture, and anticlockwise to lean the mixture. The screw has multiple turns, that will go from 0 volts to over 3.5 volts.
This unit has 4 connections:
Red/Black Ground
Blue/Green Air flow signal- should be .3-.34 volts (no air flow).
Tick over on the 3.9 is about 1.7 volts
Brown/Orange +12v
Blue/Red CO trim value. Non cat cars are in the range of 1-1.5 volts, typically about 1.2 volts Lower voltage is leaner.
Setting The Air flow Sensor Applicable to NON catalyst cars only. Using a voltmeter between red and black wire and blue and red wire check the voltage with the ignition on, but the engine not running. Recessed Hex head screw allows you to set the carbon monoxide base line with these voltages. NOTE these are base settings ONLY. Turn the adjustment screw clockwise to richen the mixture, and anticlockwise to lean the mixture. The screw has multiple turns, that will go from 0 volts to over 3.5 volts.
This unit has 4 connections:
Red/Black Ground
Blue/Green Air flow signal- should be .3-.34 volts (no air flow).
Tick over on the 3.9 is about 1.7 volts
Brown/Orange +12v
Blue/Red CO trim value. Non cat cars are in the range of 1-1.5 volts, typically about 1.2 volts Lower voltage is leaner.
PreCat Griffith said:
Thank you. So if a lead has broken down, it's spark still has to go somewhere, and if it's not going to the spark plug, it'll be arcing somewhere? I have checked for this at night in the garage with light off but not seen any arcing; I'll double check.
Any leakage is bad but it may not be as obvious as a blue spark but just a pale blue flash around any weak areas.LucyP said:
What rubbish advice. An oil change and a run are not going to solve a poor starting issue when hot! What has oil got to do with how a car starts?
It isn't getting the right fuel/air mixture, or a big enough spark. You need to look at the causes of those issues, and they certainly are not oil or giving it a run related!
If the car has vapour lock issues, which sounds probable, then getting it really hot after a run will just make it worse! There probably isn't enough fuel pressure when it is hot, probably because the injectors need replacing.
It hasn't, but if you'd read the post that response was to instead of your usual jumping in feet first, the OP admitted his oil smelt of fuel. This needs changing because it's degradation will quickly damage the engine.It isn't getting the right fuel/air mixture, or a big enough spark. You need to look at the causes of those issues, and they certainly are not oil or giving it a run related!
If the car has vapour lock issues, which sounds probable, then getting it really hot after a run will just make it worse! There probably isn't enough fuel pressure when it is hot, probably because the injectors need replacing.
blitzracing said:
PreCat Griffith said:
Pre-cat Griff takes a lot of cranking to start when warm (but fine when cold); what are the usual suspects?
I also have a misfire at idle (even to my untrained ear) which may or may not be related, and sooted up plugs. Drives well though.
Sooted plugs are not ignition related as it's a pre cat engine. You are likely looking at over fuellng caused by the AFM voltage being out of spec' or failed water temp sensor. I also have a misfire at idle (even to my untrained ear) which may or may not be related, and sooted up plugs. Drives well though.
Same AFM test process as this post.
https://www.pistonheads.com/gassing/topic.asp?h=0&...
Edited by blitzracing on Tuesday 19th December 20:19
The car starts up from cold and sounds good while idling from cold. Once it's warm though I think I hear it running on not the full 8 cylinders, though it's still smooth. No sign of any arcing under the bonnet in the dark though.
I'm next going to investigate the fuel pressure and injector bank resistance at the ECU loom plug as per: http://www.britishv8.org/Articles/Rover-14CUX-EFI.... Could do with a more explicit guide on where and how to connect the pressure gauge to the fuel rail, so will start searching.
If this yields nothing I think I'll take the plunge and fit BP6ES plugs and replace the coil for one of these: https://simonbbc.com/Viper-Dry-Ignition-Coil-Sport...
And if that fails, I'll replace the ignition amp (although it already has some special RPI Engineering Power Amp). And last resort I'll take the injectors out and see about testing them. Maybe check the earths? Then I'll give up.
Edited by PreCat Griffith on Friday 29th December 13:42
I had a similar problem, turned out to be the ignition amp. It came with the car ( good opportunity for LucyP to stick her motor mouth in )
I did change leads plugs etc over the years & the ignition amp was the last item. Well hidden & easy to forget. I caught it before it became a problem.
Over to LucyP to have a go at me Attack Attack.
I did change leads plugs etc over the years & the ignition amp was the last item. Well hidden & easy to forget. I caught it before it became a problem.
Over to LucyP to have a go at me Attack Attack.
He has the Rpi magical A&R power amp but i would agree about going back to a standard module, problem is you cant buy original any more so are never quite sure what your getting.
The green boxed lucas stuff you see for sale is junk.
I believe old stock good lucas has the white lettering on it as below.
https://www.ebay.co.uk/itm/133318230946?hash=item1...
The green boxed lucas stuff you see for sale is junk.
I believe old stock good lucas has the white lettering on it as below.
https://www.ebay.co.uk/itm/133318230946?hash=item1...
gruffalo said:
Worth checking the fuel temp sensor, when mine went faulty i had exactly this issue started fine from cold lots of cranking when hot.
Tested the resistance of both Coolant and Fuel temp sensors at 11C and they were both around 1500Ohms; since they are both the same resistance at the same temperature, I'm thinking they are both OK.Gassing Station | Griffith | Top of Page | What's New | My Stuff