Coil / ign amp ???
Discussion
Was on the Tiffin run in North Yorks yesterday, parked up for dinner...came back, car wouldn't restart. Waited for 30 mins whilst doing some diagnostic work - took a plug out and couldn't see a spark.....suspected duff coil or ign amp ??? Tried again and engine started. Car ran for 50ish miles then died again...waited again for 1.5hrs this time whilst waiting for recovery geezer. Just as he turned up engine started again. He had brough another "sports" coil to try and after connecting it up engine ran for about 10 mins then failed again. He says he heard an electrical "crack" as it failed but no-one else heard this. I suspect the ign amp and am going to replace the coil with a Bosch anyway as it had the original coil on which is now 7 years old ( still not leaking tho ). I searched on the forums for past experiences and found GreenV8s's write-up on how to fault find this area and will try this out later today. Any further advice as to replacing the ign amp / coil, any thing I should watch out for ? Also where is the ign sensor and do these commonly fail too ? just any advice really.... the recovery geezer also did a weird thing of holding his finger on the LT side of the coil and then earthing his other hand and said he thought there was something else wrong coz he could feel HT in his finger....but as the field in the coil collapses this would surely induce HT into the LT side so you WOULD feel this anyway....is he talking cobblers ???
snorky said:
Was on the Tiffin run in North Yorks yesterday, parked up for dinner...came back, car wouldn't restart. Waited for 30 mins whilst doing some diagnostic work - took a plug out and couldn't see a spark.....suspected duff coil or ign amp ??? Tried again and engine started. Car ran for 50ish miles then died again...waited again for 1.5hrs this time whilst waiting for recovery geezer. Just as he turned up engine started again. He had brough another "sports" coil to try and after connecting it up engine ran for about 10 mins then failed again. He says he heard an electrical "crack" as it failed but no-one else heard this. I suspect the ign amp and am going to replace the coil with a Bosch anyway as it had the original coil on which is now 7 years old ( still not leaking tho ). I searched on the forums for past experiences and found GreenV8s's write-up on how to fault find this area and will try this out later today. Any further advice as to replacing the ign amp / coil, any thing I should watch out for ? Also where is the ign sensor and do these commonly fail too ? just any advice really.... the recovery geezer also did a weird thing of holding his finger on the LT side of the coil and then earthing his other hand and said he thought there was something else wrong coz he could feel HT in his finger....but as the field in the coil collapses this would surely induce HT into the LT side so you WOULD feel this anyway....is he talking cobblers ???
When replacing the amp, use heat conductig paste between it and the distributor body (or mounting plate depending on its location). The ignition sensor is inside the dustributor and relies on an electrmagnetic pulse. It should never need adjustment (hence it is under a plastic cap which reads 'do not remove'), but can benefit from a clean and the air gap resetting. If you reset the air gap you'll need to check/adjust the timing.
As Griffter says it still needs heat sink paste no matter where its mounted.. The new amp will have paste with it but this is a silicon based paste, under advisement from Griffter I did some research and found the silver base paste was better conductivity and temp range...Probably over the top but it certainly can't hurt!
I got my coil and amp from Tim at ACT recently, worth a call to him I think, super fast delivery and Bl**dy Nice Bloke.
I got my coil and amp from Tim at ACT recently, worth a call to him I think, super fast delivery and Bl**dy Nice Bloke.
If you get an unspecified 'engine cuts out'/'engine won't start' type problem, the first thing to check is whether the fuel pump is priming. You should be able to hear the pump run for a second or so when you switch the ignition on. If the pump isn't running then nothing else is going to work. Incidentally, these symptoms of running for 10-20 minutes and then cutting out intermittantly are typical for a failing fuel pump relay.
If the pump is making the usual noises then move on to the ignition, alarm etc. The best way I know to check the ignition is with a passive strobe light in series with one of the HT leads, you can see instantly whether you are getting a spark.
If the pump is making the usual noises then move on to the ignition, alarm etc. The best way I know to check the ignition is with a passive strobe light in series with one of the HT leads, you can see instantly whether you are getting a spark.
snorky said:
....but as the field in the coil collapses this would surely induce HT into the LT side so you WOULD feel this anyway....is he talking cobblers ???
You're quite right: that is exactly what would happen. In the days of mechanical points, the condenser was fitted to soak up this voltage rise and thereby stop a spark across the points, which would eventually burn them out. Whether or not this needs to be dealt with in an electronic system I don't know, but the fact he felt this high voltage would tend to indicate that the primary side of the coil is working. That in turn would indicate the ignition amp. is also working. However, as the problem is intermittent you can't really rule anything out.
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