Lumpy Idle, cutting out while driving diagnostics.
#1
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Well I've had six months trouble free wafting about in my £400 eBay bargain, but that came to an end on the way back from work where dear old Rupert cut out twice and rolled to a halt.
It also now having trouble starting. And has to crank for a while.
Then it settles into a bit of a lumpy idle.
The bracket that holds the crank angle sensor had bust so I replaced that.
![](https://lh3.googleusercontent.com/CpxYr1chQkXYB8Ug6XR9kNjyyftMjeQFbyuTO_KnM-6K=w1440-h810-no)
And also the Crank Angle Sensor for a known good one, but no improvement.
I checked the Throttle Position Sensor by jamming a couple of pins in the back of the plug and going at it with the multi-meter.
Got a nice smooth increase in voltage as the throttle spindle turns. 0.39v to 4.07v which I hope is close enough to the shop manual range of .5v to 4.5v seems fine....
![](https://lh3.googleusercontent.com/99O6a4y18Bi74XII171OvHMfhkPElW1QVgioTXOEVWBj=w1440-h810-no)
I also pulled all the plugs, but they looked absolutely fine, except that 2 & 3 had oil above the washer, maybe the cam cover gasket has failed?
I changed them as I had a spare set.
1.003 Kohms coolant temp sensor after engine running, about right.
Forgot to write this down but I think the MAF was giving .11g/s to .3g/s either way it was a nice smooth increase as the accelerator is pressed.
0.6 / 0.7 kOhms resistance all coilpacks, pulled each one at a time with the engine runnning and all made it far worse/stall.
It does have one Fault code P1621. Which comes back when you clear it. I've read a few threads about this... Possible failing ECU or Coil packs, not convinced and there seems to be no definitive answer.
Some odd things:
This wire (which looks to have been repaired), is not attached to anything and I cant find a single orange wire on the wiring diagram.
![](https://lh3.googleusercontent.com/ezMICEQIHF9jhdn5_52Rv7ZRnNg1CvepjC7bx4W_KFJR=w1440-h810-no)
![](https://lh3.googleusercontent.com/f1D1KEG7xZDq5maWyiU5biUKoAUwoKBrs8d-Kdg-9bo3=w1440-h810-no)
And this plug laying by the abs again has no home and i cant find on the wiring diagram.
![](https://lh3.googleusercontent.com/Ne-l0Fv5eIF1NAqoloYGBJW49UpyLBcPIC_2DH6y76jo=w1440-h810-no)
Any help, thoughts on what to check next would be much appreciated.
It also now having trouble starting. And has to crank for a while.
Then it settles into a bit of a lumpy idle.
The bracket that holds the crank angle sensor had bust so I replaced that.
And also the Crank Angle Sensor for a known good one, but no improvement.
I checked the Throttle Position Sensor by jamming a couple of pins in the back of the plug and going at it with the multi-meter.
Got a nice smooth increase in voltage as the throttle spindle turns. 0.39v to 4.07v which I hope is close enough to the shop manual range of .5v to 4.5v seems fine....
I also pulled all the plugs, but they looked absolutely fine, except that 2 & 3 had oil above the washer, maybe the cam cover gasket has failed?
I changed them as I had a spare set.
1.003 Kohms coolant temp sensor after engine running, about right.
Forgot to write this down but I think the MAF was giving .11g/s to .3g/s either way it was a nice smooth increase as the accelerator is pressed.
0.6 / 0.7 kOhms resistance all coilpacks, pulled each one at a time with the engine runnning and all made it far worse/stall.
It does have one Fault code P1621. Which comes back when you clear it. I've read a few threads about this... Possible failing ECU or Coil packs, not convinced and there seems to be no definitive answer.
Some odd things:
This wire (which looks to have been repaired), is not attached to anything and I cant find a single orange wire on the wiring diagram.
And this plug laying by the abs again has no home and i cant find on the wiring diagram.
Any help, thoughts on what to check next would be much appreciated.
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#2
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Humm, sounds like your on the right track for trouble shooting this issue. On the rough starts, you might have to replace the starter. This is what i did when i was having the rough starter issues. Core packs replacement might be needed to help on the idle, replace the boots on the core packs first to see if this helps.
#3
The following users liked this post:
Don B (07-17-2015)
#4
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The small plug looks like Temp Sensor connector. There are two sensors on the thermostat housing. The one nearest the valve cover has a single plug with an orange wire.
The larger plug is likely for Traction Control unit - so if you don't have that then it will just be floating around near the ABS unit.
I'd look next at fuel pressure regulator. Not easy to test but see if it can hold vacuum. You can find used ones on ebay for about 15 pounds so may be worth a gamble - it's a good part to have spare for diagnostics anyway.
The larger plug is likely for Traction Control unit - so if you don't have that then it will just be floating around near the ABS unit.
I'd look next at fuel pressure regulator. Not easy to test but see if it can hold vacuum. You can find used ones on ebay for about 15 pounds so may be worth a gamble - it's a good part to have spare for diagnostics anyway.
#5
#7
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Looks like your "oil cooler bypass" fixture is leaking as well, which is a common but simple and cheap problem to remedy. That is a simple o-ring replacement from what I hear.
The part I'm talking about is the "U" shaped fixture directly under the oil filter held on with a single bolt. There are a couple O-rings inside that eventually leak.
.
The part I'm talking about is the "U" shaped fixture directly under the oil filter held on with a single bolt. There are a couple O-rings inside that eventually leak.
.
The following 2 users liked this post by al_roethlisberger:
Don B (07-17-2015),
littlelic69 (07-07-2015)
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#8
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Hi all, had some more time to work on the car.
I have cured the lumpy idle, one of the coil packs was cracked and as I lifted it it was sparking out of the side of the case and earthing to the head. New coil & lumpy idle and intermittent stalls are now cured!
Presumably every so often the coil sent a jolt back up the earth that the ECU didnt appreciate and knocked it out until I turned it off and on again.
The orange wire remains a mystery, yes I have oil pressure on the gauge with a yellow wire running from the sender, that works fine, although the Oil pressure sender is leaking a bit. New one on order.
However it still is a pain to start, but having read through a few forum posts I'm thing Cam Angle Sensor has failed/gone out of alignment so its relying on the Crank Angle Sensor.
Guess that's next.
Thanks for all the pointers. Nice to find a forum full of useful posts & people.
Cheers
Maff
I have cured the lumpy idle, one of the coil packs was cracked and as I lifted it it was sparking out of the side of the case and earthing to the head. New coil & lumpy idle and intermittent stalls are now cured!
Presumably every so often the coil sent a jolt back up the earth that the ECU didnt appreciate and knocked it out until I turned it off and on again.
The orange wire remains a mystery, yes I have oil pressure on the gauge with a yellow wire running from the sender, that works fine, although the Oil pressure sender is leaking a bit. New one on order.
However it still is a pain to start, but having read through a few forum posts I'm thing Cam Angle Sensor has failed/gone out of alignment so its relying on the Crank Angle Sensor.
Guess that's next.
Thanks for all the pointers. Nice to find a forum full of useful posts & people.
Cheers
Maff
The following users liked this post:
Don B (07-17-2015)
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