HT lead / coil pack resistance values? ECU reader?
Discussion
Hi All,
3 weeks in and another issue has raised it's head - misfiring around 1800 to 2200 revs and then a backfire! A great spectacle but it is only going to get worse! She starts with a little splutter and struggles a little under load - typical Ignition issues.
Anyone know the resistance values of the HT leads and coils so that I can check them before replacing? Should I invest in the RS/AJP diagnostic App or will this just state the obvious? I have regularly used an ELM327 reader with the TORQUE App on my other cars and it has been very useful. Sometimes though the fault is obvious.
Thanks.
3 weeks in and another issue has raised it's head - misfiring around 1800 to 2200 revs and then a backfire! A great spectacle but it is only going to get worse! She starts with a little splutter and struggles a little under load - typical Ignition issues.
Anyone know the resistance values of the HT leads and coils so that I can check them before replacing? Should I invest in the RS/AJP diagnostic App or will this just state the obvious? I have regularly used an ELM327 reader with the TORQUE App on my other cars and it has been very useful. Sometimes though the fault is obvious.
Thanks.
Thanks for the quick replies fellas.
Will "rip Em out" and test at the next opportunity. I might attempt the job without removing the fuel rail this time.
Which leads are now recommended as all the posts I have found are easily a few years old? The blue TVR? I will maybe put a layer of something to shield from the heat if possible?
I have not heard of the EvoIi APP and having searched cannot find any reference either - probably my terrible search skills as I always end up looking through the whole of Pistonheads!
I'm annoyed I left an XP laptop in Aus when I moved back a couple of months ago as I think this might have been handy.
Will "rip Em out" and test at the next opportunity. I might attempt the job without removing the fuel rail this time.
Which leads are now recommended as all the posts I have found are easily a few years old? The blue TVR? I will maybe put a layer of something to shield from the heat if possible?
I have not heard of the EvoIi APP and having searched cannot find any reference either - probably my terrible search skills as I always end up looking through the whole of Pistonheads!
I'm annoyed I left an XP laptop in Aus when I moved back a couple of months ago as I think this might have been handy.
It's EvoOlli, I've used it on a laptop running windows 7 and it worked ok. Here's a link to his software http://www.pistonheads.com/gassing/topic.asp?h=0&a...
LincsCerb said:
It's EvoOlli, I've used it on a laptop running windows 7 and it worked ok. Here's a link to his software http://www.pistonheads.com/gassing/topic.asp?h=0&a...
Apologies for the trypo.It helps if someone spells a name correctly when you are trying to search!
1.Has the issue started since you did the oil pressure switch?
2. Does the mil light come on when it backfires?
Don't just start replacing stuff without 95% sure, then test drive before
Changing something else.
Some poor quality 'new' components for cerb can cause more trouble than the parts they replace.
Good news is we're here to help
(Best thing I did to help performance on my car was to replace badly corroded fuel pump terminals!)
2. Does the mil light come on when it backfires?
Don't just start replacing stuff without 95% sure, then test drive before
Changing something else.
Some poor quality 'new' components for cerb can cause more trouble than the parts they replace.
Good news is we're here to help

(Best thing I did to help performance on my car was to replace badly corroded fuel pump terminals!)
This is a good example of what to look out for while diagnosing....
http://www.pistonheads.com/gassing/topic.asp?t=141...
http://www.pistonheads.com/gassing/topic.asp?t=141...
Thanks for the replies fellas. The comedy of errors begins.
Decided to check resistance of the leads as tick over was ok, just started to struggle under load which often signifies ignition issues. Then the coil packs if all ok.
First lead to be pulled was No.8 and a right pig. Ended up leaving the metal connector on the spark plug as it was that tight. They all seemed very tight (compared to any previous leads I'd dealt with on any car). Great start! Then having pulled it off the spark plug I managed to drop it on the engine, it bounced to the front of the car and rolled down the cover before the fan and then inside the fan itself! Jeez this was not a good start! Having searched for the lead end for an age I realised now needed to pull the radiator as the fan nuts are spinning! This was not going well.
I decided to carry on with the leads first and the rest of the "even" side were all the same resistance at about 3.34k ohms.
Pulled # 7, then realised that #5 was loose, way too loose. #5 had worked its way off the plug and was sitting on it. This I think is the misfire reason.
In hindsight I should have just checked all of the leads for "tightness" before starting any pulling. As it seems with this car though, there is so much to do before that point that I completely forgot about the basics.
So now I'm one lead broken and have to get into the fan to fish out the lead end in case it damages the fan. Whilst trying to locate the part at the base of the radiator I have also noticed what seems like a very large bolt end is loose. More investigation needed with the radiator off.
A lesson in how something so minor as a loose lead can develop into more unnecessary work. To add, no one seems to make individual leads anymore - only sets are sold. Quoted £75 by a TVR dealer and £46 online with 3/4 days wait. Whatever happened to the rack of individual HT leads enabling the suspect lead to be replaced rather than replacing the rest of the good leads? Madness.
I hope I made somebody else giggle at my expense?
Decided to check resistance of the leads as tick over was ok, just started to struggle under load which often signifies ignition issues. Then the coil packs if all ok.
First lead to be pulled was No.8 and a right pig. Ended up leaving the metal connector on the spark plug as it was that tight. They all seemed very tight (compared to any previous leads I'd dealt with on any car). Great start! Then having pulled it off the spark plug I managed to drop it on the engine, it bounced to the front of the car and rolled down the cover before the fan and then inside the fan itself! Jeez this was not a good start! Having searched for the lead end for an age I realised now needed to pull the radiator as the fan nuts are spinning! This was not going well.
I decided to carry on with the leads first and the rest of the "even" side were all the same resistance at about 3.34k ohms.
Pulled # 7, then realised that #5 was loose, way too loose. #5 had worked its way off the plug and was sitting on it. This I think is the misfire reason.
In hindsight I should have just checked all of the leads for "tightness" before starting any pulling. As it seems with this car though, there is so much to do before that point that I completely forgot about the basics.
So now I'm one lead broken and have to get into the fan to fish out the lead end in case it damages the fan. Whilst trying to locate the part at the base of the radiator I have also noticed what seems like a very large bolt end is loose. More investigation needed with the radiator off.
A lesson in how something so minor as a loose lead can develop into more unnecessary work. To add, no one seems to make individual leads anymore - only sets are sold. Quoted £75 by a TVR dealer and £46 online with 3/4 days wait. Whatever happened to the rack of individual HT leads enabling the suspect lead to be replaced rather than replacing the rest of the good leads? Madness.
I hope I made somebody else giggle at my expense?
I know your pain, I am in the process of a rebuild at the moment. I can sympathise rather than laugh, as I know EXACTLY how you feel!
When the car is done, there will be a write up and I think it may make for an interesting read so I wont bore you just yet. But I think we are all int eh same boat here, and it just keeps sinking!
When the car is done, there will be a write up and I think it may make for an interesting read so I wont bore you just yet. But I think we are all int eh same boat here, and it just keeps sinking!
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