Misfire - suspected coil packs
Discussion
I think I may have a bad coil pack - here is the description of the symptoms.
I was driving my purple Cerbera tonight and it just didn't sound quite the same, no pops or bangs and not as raspy. It also was running quite rich and smelt very fumy.
After about 6-7 miles it developed a hesitant spot around 2.5K RPM so I turned around and headed home. A few miles from home the car became very lumpy and was missing between 2-3K RPM like it was running on 6 (or less) cylinders.
It idled normally and above 3-3.5K RPM the engine came back to life.
When the car was recommissioned it has new leads and plugs but I didn't replace the coil packs (I wish I would of now) as it was running fine.
The car has been out in three heavy thunderstorms between the previous drive (when the car was fine) and today so it could be water related too.
The car has a fuel pressure gauge and that was reading a steady 900PSI so I think it is more spark related than fuel.
It feels like a coil pack on the way out to me as the car was getting worse by the time I got home so unless anyone has any other ideas I am going to replace them.
Before I order the packs can I also confirm the the 4.5 part is INTERMOTOR 12613. I know some poeple say the 4.5 has a higher output pack than the 4.2 but I don't know if that is true. If anyone knows of an upgraded pack which will last a bit longer I would also be interested to hear from you.
Thanks.
I was driving my purple Cerbera tonight and it just didn't sound quite the same, no pops or bangs and not as raspy. It also was running quite rich and smelt very fumy.
After about 6-7 miles it developed a hesitant spot around 2.5K RPM so I turned around and headed home. A few miles from home the car became very lumpy and was missing between 2-3K RPM like it was running on 6 (or less) cylinders.
It idled normally and above 3-3.5K RPM the engine came back to life.
When the car was recommissioned it has new leads and plugs but I didn't replace the coil packs (I wish I would of now) as it was running fine.
The car has been out in three heavy thunderstorms between the previous drive (when the car was fine) and today so it could be water related too.
The car has a fuel pressure gauge and that was reading a steady 900PSI so I think it is more spark related than fuel.
It feels like a coil pack on the way out to me as the car was getting worse by the time I got home so unless anyone has any other ideas I am going to replace them.
Before I order the packs can I also confirm the the 4.5 part is INTERMOTOR 12613. I know some poeple say the 4.5 has a higher output pack than the 4.2 but I don't know if that is true. If anyone knows of an upgraded pack which will last a bit longer I would also be interested to hear from you.
Thanks.
gruffalo said:
Lambda sensors also cause this symptom.
If you can plug the car in to a PC then look at the ignition traces, if both smooth then it is not the HT side of the coil packs, if they are spiked then yep you coil packs are FUBAR.
Thanks - I did think about Lambda sensors but I thought that the MIL light comes on if a lambda goes down. The MIL is off once started.If you can plug the car in to a PC then look at the ignition traces, if both smooth then it is not the HT side of the coil packs, if they are spiked then yep you coil packs are FUBAR.
I may have to find a lead to plug the ECU in. Does anyone on here make them or do I need to make my own?
The leads are available online if you do a google search, I forget where I saw them? May have evn been ebay?
On the coil pack front, also check the four wire connector that goes to each pack and ensure the real thin wires (4 to each) have not broken down in the connector. This was the issue with mine. The plugs are numbered at the connectors 1, 2, 3, 4 which correspond to a signal to send to each HT lead via the coil. YOur could could infact be fine, so worth a check of these first.
I ordered two new connectors from Vehicle Wiring Products and extended each of the cables while I was at it. It only cost a few quid and sorted me right out!
I will dig out some pics...
On the coil pack front, also check the four wire connector that goes to each pack and ensure the real thin wires (4 to each) have not broken down in the connector. This was the issue with mine. The plugs are numbered at the connectors 1, 2, 3, 4 which correspond to a signal to send to each HT lead via the coil. YOur could could infact be fine, so worth a check of these first.
I ordered two new connectors from Vehicle Wiring Products and extended each of the cables while I was at it. It only cost a few quid and sorted me right out!
I will dig out some pics...
No worries. I did actually swap my coils over at the same time as the fix. They are not expensive and while it was apart I thought it a worth while service.
I had one wire that was loose in its spade connector that would rattle about and cause the misfire and one cylinder not to fire. It was intermittent due to actually still being in the connector, but just free to work loose.
This is how it looked when I found it...
I had one wire that was loose in its spade connector that would rattle about and cause the misfire and one cylinder not to fire. It was intermittent due to actually still being in the connector, but just free to work loose.
This is how it looked when I found it...
Tim, I would also check the engine wiring loom. I had exactly the same symptoms as you describe about 2 weeks ago, mine was also cutting out if I dipped the clutch from high revs and struggling to hold tick over when cold, over 3k the thing pulled like a train though and was not lumpy. I was convinced it was my coil packs but as it was booked in for a service at APM I thought I'd hold of buying them until Andy has seen it.
I described the symptoms and said I think it needed new coil packs. Andy dismissed the coil packs almost immediately (shows what I know). After investigation it turns out it was a fault in the engine wiring loom causing the car to only run on half a bank under 3000rpm (under 3k the lambda sensors control the mix, over 3k it hands over to another ecu apparently).
Now its fixed and feels like a totally different car to drive. Pick up from tick over is so smooth, the pops and bangs are now even louder and I have no smell of petrol.
Just another possibility to confuse matters, sorry.
I described the symptoms and said I think it needed new coil packs. Andy dismissed the coil packs almost immediately (shows what I know). After investigation it turns out it was a fault in the engine wiring loom causing the car to only run on half a bank under 3000rpm (under 3k the lambda sensors control the mix, over 3k it hands over to another ecu apparently).
Now its fixed and feels like a totally different car to drive. Pick up from tick over is so smooth, the pops and bangs are now even louder and I have no smell of petrol.
Just another possibility to confuse matters, sorry.
Yes - that's what I am worried about. If it was just a coil pack breaking down that is easy enough to fix but if it is a wiring issue somewhere else then that can be a real ballache to find.
I am going to try plugging in the ECU first to see if any issues are reported or if a lambda is down but failing that then I will replace both coil packs. I have a couple of Cerberas now so even if it turns out not to be coil packs this time having a spare set will come in handy at some point in the future I'm sure.
I am going to try plugging in the ECU first to see if any issues are reported or if a lambda is down but failing that then I will replace both coil packs. I have a couple of Cerberas now so even if it turns out not to be coil packs this time having a spare set will come in handy at some point in the future I'm sure.
Sounds quite similar to mine when the water temp sensor was failing ,in the end it stank of fuel & used to refuse to start when hot. Put it on the laptop & make sure this is giving a true reading Tim or it will be running rich & help towards your symptoms.
Does the other Cerb seem quaint up to the purple monster performance wise ?
Does the other Cerb seem quaint up to the purple monster performance wise ?
Tirus said:
...
Does the other Cerb seem quaint up to the purple monster performance wise ?
When the purple monster was running right - yes, a little. My 4.5 runs great, totally smooth through the rev range and pulls like a train. It has whirlwind short induction and a short induction map so I expect it will make health numbers. Does the other Cerb seem quaint up to the purple monster performance wise ?
But...it is no match for the purple monster. I haven't run the NOS yet - I haven't felt the need. I don't know if it is the fact it is a 4.7, the custom head porting, the custom induction, the custom mapping but whatever it is, is it a different league. It just flies and it feels effortless when it goes up the revs.
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