Discussion
The car was running great. Thursday was oil & coolant change & new front pads. Friday was MOT passed no adviseries.
Saturday was head for the hills for a run out. Well untill the coughing spluttering misfiring started. It was missing when accelerating then picked up.
It felt that both banks where missing & slow traffic made it worse.
Turned round & headed home. It felt electrical, so when the car had cooled i had a look.
The coil was very warm, the dizzy & leads looked fine.
So i ordered an ignition amp & coil from a rover dealer PRC 6574 & STC 1184G.
Started the car parked in the garage. Ticking over nicely & no sign of trouble.
Will try the ignition amp first.
Is there any thing else i need to check before going for a drive.
Saturday was head for the hills for a run out. Well untill the coughing spluttering misfiring started. It was missing when accelerating then picked up.
It felt that both banks where missing & slow traffic made it worse.
Turned round & headed home. It felt electrical, so when the car had cooled i had a look.
The coil was very warm, the dizzy & leads looked fine.
So i ordered an ignition amp & coil from a rover dealer PRC 6574 & STC 1184G.
Started the car parked in the garage. Ticking over nicely & no sign of trouble.
Will try the ignition amp first.
Is there any thing else i need to check before going for a drive.
Are you still using the spark plug extenders? They can often come a bit loose, resulting in them turning on the plug, this can result in a lead touching the manifold, especially cylinders 7 and 8.
My car developed a misfire when hot and high revs, and then after a month or so, ran on 7 all of the time. In this case, it was one of the extenders breaking down and not provided a circuit.
I've now removed them from cylinders 1 and 2, providing a spare. 
Only the old Beru ones seem to last.
My car developed a misfire when hot and high revs, and then after a month or so, ran on 7 all of the time. In this case, it was one of the extenders breaking down and not provided a circuit.
I've now removed them from cylinders 1 and 2, providing a spare. Only the old Beru ones seem to last.Check connections are nice and tight at the coil but it could be any of the components in the ignition circuit really.
Extenders are common as are coils and modules.
Try to change 1 item at a time so you know what's failed.
Aftermarket coils and modules quality wise can be hit and miss too so don't throw away known good original parts.
Extenders are common as are coils and modules.
Try to change 1 item at a time so you know what's failed.
Aftermarket coils and modules quality wise can be hit and miss too so don't throw away known good original parts.
rigga said:
My experience of a failing ignition amp (two) is a sudden cut of ignition, rather than a missfire , so engine dies, then comes back in with a bang.
This ^ and you cant tell if HT leads are good by just looking at them if you dont know their history swap them out or at least try a king lead 1st (from coil to dizzy cap) systematically going through the HT parts first gets my vote I put a new dizzy & rotor arm on from the distributor doctor 4 years & 14K miles ago along with HT leads.
I thought it was a lot less than that. So time for a change. Strange how your memory plays tricks on you.
I got rid of the extenders 5 years ago & use angled leads & socks except on No 8 where the extender stays.
https://www.textiletechnologies.co.uk/products/sil...
The manifold is far to close for even angled leads to work.
I will try the new ignition amp ( when i have a new clip ) then the coil first. I still have an old good set of leads so thats next.
Then if that fails the old but good dizzy & rotor arm. I would like to find which part is at fault so one step at a time.
I thought it was a lot less than that. So time for a change. Strange how your memory plays tricks on you.
I got rid of the extenders 5 years ago & use angled leads & socks except on No 8 where the extender stays.
https://www.textiletechnologies.co.uk/products/sil...
The manifold is far to close for even angled leads to work.
I will try the new ignition amp ( when i have a new clip ) then the coil first. I still have an old good set of leads so thats next.
Then if that fails the old but good dizzy & rotor arm. I would like to find which part is at fault so one step at a time.
There is an old saying that if an engine has problems and you suspect it is electrical chances are it will be fuel ( and vice versa).
I experienced very erratic running years ago and traced it to only one bank firing and running on 4 cylinders it was due to a poor connection on the ECU plug/socket.
Have you checked that all the injectors are receiving pulses? a NOID light is the easiest way without hassle.
I experienced very erratic running years ago and traced it to only one bank firing and running on 4 cylinders it was due to a poor connection on the ECU plug/socket.
Have you checked that all the injectors are receiving pulses? a NOID light is the easiest way without hassle.
Loubaruch said:
There is an old saying that if an engine has problems and you suspect it is electrical chances are it will be fuel ( and vice versa).
I experienced very erratic running years ago and traced it to only one bank firing and running on 4 cylinders it was due to a poor connection on the ECU plug/socket.
Have you checked that all the injectors are receiving pulses? a NOID light is the easiest way without hassle.
And also the least likely cause of a misfire on the RV8 with the Hotwire/Lucas system but a possibilty nonetheless I experienced very erratic running years ago and traced it to only one bank firing and running on 4 cylinders it was due to a poor connection on the ECU plug/socket.
Have you checked that all the injectors are receiving pulses? a NOID light is the easiest way without hassle.
fieryfred said:
Thanks for the tips. Back on the job in the morning.
I dont have a noid light but i know a local indy that does if i need one.
Saw a yellow Stag today & thought they where bad new & thoughtgood job i have a TVR.
I'd still love a Stag, one of my favourite cars.I dont have a noid light but i know a local indy that does if i need one.
Saw a yellow Stag today & thought they where bad new & thoughtgood job i have a TVR.
There is a lovely looking orange one near me that will be seen out now and again in nice weather.
When i first got the car i noticed a lump covered in insulating tape near the coil.
So as you do i took the tape off to reveal 2 fuses with spades direct to the fuses.
I had no idea what they were but put them in a proper fuse holder & mounted them above the coil.
I did a quick sketch & put it down to when i get aroundtuite.
With the coil off & new amp fitted i had a closer look. I am no auto electrician, but could not see what the fuses where protecting or what purpose they served.
Looked at Steve d wiring diagrams & no fuses.
So i took them off & put a 2 into 1 in place. I will also replace all spades to the coil.
Took the car for a 140 mile jolly & all is well. Might have been the odd fuse arrangement or the Amp.
I dont know if an auto electrician has been at work or a well meaning owner.
When i had the dash off i took some photos, that will be another thread to keep Penny / Poly happy.
The sketch from the loom should read white blue, white black. Well it was mucky at the time.
So as you do i took the tape off to reveal 2 fuses with spades direct to the fuses.
I had no idea what they were but put them in a proper fuse holder & mounted them above the coil.
I did a quick sketch & put it down to when i get aroundtuite.
With the coil off & new amp fitted i had a closer look. I am no auto electrician, but could not see what the fuses where protecting or what purpose they served.
Looked at Steve d wiring diagrams & no fuses.
So i took them off & put a 2 into 1 in place. I will also replace all spades to the coil.
Took the car for a 140 mile jolly & all is well. Might have been the odd fuse arrangement or the Amp.
I dont know if an auto electrician has been at work or a well meaning owner.
When i had the dash off i took some photos, that will be another thread to keep Penny / Poly happy.
The sketch from the loom should read white blue, white black. Well it was mucky at the time.
Im guessing somebody has removed the 2 resistors that should be in place but god knows why 2 fuses were added.
See below for some info, ignore the fact someone calls them tune resistors.
I didnt think the car would run properly without them.
https://www.pistonheads.com/gassing/topic.asp?t=20...
See below for some info, ignore the fact someone calls them tune resistors.
I didnt think the car would run properly without them.
https://www.pistonheads.com/gassing/topic.asp?t=20...
Edited by Belle427 on Saturday 3rd June 20:49
The Resistors in question normally live near the coil not in the footwell.
The tune resistor as it’s known lives in the footwell but this isn’t anything to do with your problem.
You could examine the wiring near the Ecu for any modifications but my guess is someone has just removed them thinking they were rusty inline fuses and replaced them, but that’s just a wild guess.
There isn’t an easy way to test really, maybe a continuity from coil to ecu will show you the circuit resistance.
The tune resistor as it’s known lives in the footwell but this isn’t anything to do with your problem.
You could examine the wiring near the Ecu for any modifications but my guess is someone has just removed them thinking they were rusty inline fuses and replaced them, but that’s just a wild guess.
There isn’t an easy way to test really, maybe a continuity from coil to ecu will show you the circuit resistance.
So i just need a skinny resistor wrapped around the wire & soldered into place.
What power rating do i need 0.25W or higher.
https://uk.rs-online.com/web/c/passive-components/...
These are cheap i dont know why some one would cut it out rather than replace.
Had a look in the footwell & this little resistor showed up.
What power rating do i need 0.25W or higher.
https://uk.rs-online.com/web/c/passive-components/...
These are cheap i dont know why some one would cut it out rather than replace.
Had a look in the footwell & this little resistor showed up.
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