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Old 3rd August 2011, 12:52   #1
ratc69
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Default Mil Codes P0172 & P0300 Plus misfire

Hi if you have been reading i have had a few problems with my MG ZT 2.5 160.

I have codes P0172 & P0300 and have a misfire on Cyl 1,3,5 between 1500 & 2000 rpm and clears after 2000rpm.cyl 3 & 5 are worse than cyl 1. I have put another inlet manifold on recently and also 2 recondition vis valves.
This is what i have done so far.
Changed Plugs & leads.
Swapped coil packs between Cylinder 1 & 5 but no change.
Checked that there is a good earth inc from the coil packs.

Any help and info would be great as dont know what else to do.

Many thanks

Rob
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Old 3rd August 2011, 14:00   #2
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See Post 2 Entry 62, Parts 1,2,3, etc. for a generic codes listing.
Click: http://www.the75andztclub.co.uk/foru...ult+codes+list

These will not include the bespoke MGR codes which requires a T4 or similar to interpret properly.

Yours are:
P0172 System Too Rich (Bank 1)
P0300 Random Misfire Detected

Which may or may not help.

TC
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Old 3rd August 2011, 14:37   #3
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Quote:
Originally Posted by T-Cut View Post
See Post 2 Entry 62, Parts 1,2,3, etc. for a generic codes listing.
Click: http://www.the75andztclub.co.uk/foru...ult+codes+list

These will not include the bespoke MGR codes which requires a T4 or similar to interpret properly.

Yours are:
P0172 System Too Rich (Bank 1)
P0300 Random Misfire Detected

Which may or may not help.

TC

Hi T-Cut i know what the code mean's i am looking for anyone with any info to what a cure could be. like i said i got a misfire on Cyl 1,3,5 so this is to do with the P0300 code but i can't seem to find why it is doing it. Also been told i am getting the 2 fault codes as they could be link so looking for some advice where to go from here as i have change, swapped the things i could do.

Cheers, Rob
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Old 3rd August 2011, 19:58   #4
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Hi, well P0300 Random Misfire Detected can some times be down to worn plugs but you changed these it cant be this, have you checked the wires to all 3 coils maybe damaged?
P0172 System Too Rich (Bank 1) Maybe a air leak on the inlet manifold?

If not any of above may be fuel injectors?
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Old 3rd August 2011, 21:42   #5
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If you got a multable missfire code whiuch you do have then it will flag it as running rich as it is putting unburnt petrol down the exhaust. So you missfire is on bank one looking at it
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Old 4th August 2011, 06:52   #6
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Default misfire

Quote:
Originally Posted by ratc69 View Post
Hi if you have been reading i have had a few problems with my MG ZT 2.5 160.

I have codes P0172 & P0300 and have a misfire on Cyl 1,3,5 between 1500 & 2000 rpm and clears after 2000rpm.cyl 3 & 5 are worse than cyl 1. I have put another inlet manifold on recently and also 2 recondition vis valves.
This is what i have done so far.
Changed Plugs & leads.
Swapped coil packs between Cylinder 1 & 5 but no change.
Checked that there is a good earth inc from the coil packs.

Any help and info would be great as dont know what else to do.

Many thanks


Rob
Rob,

Does the car mis-fire all the time? I know you say ok above 2000.....
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Old 4th August 2011, 07:58   #7
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Rob, have a word with Jake ( reg sec ) his blue zt is/was suffering the same missfire on the front bank, not sure if he has cured it yet, we were looking at changing coil packs and leads to the front bank.
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Old 4th August 2011, 09:02   #8
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Quote:
Originally Posted by Hogwarzt View Post
Rob,

Does the car mis-fire all the time? I know you say ok above 2000.....
Yea it is ok above 2000 rpms. we put it on a machine with live data and we watch all 6 banks and you see the misfire on 1,3,5. but only between 1500 & 2000 rpm's

Quote:
Originally Posted by stocktake View Post
Rob, have a word with Jake ( reg sec ) his blue zt is/was suffering the same missfire on the front bank, not sure if he has cured it yet, we were looking at changing coil packs and leads to the front bank.
Cheers and will do. we have changed the plugs leads and changed the coil packs around to no luck.

Quote:
Originally Posted by eurorover View Post
If you got a multable missfire code whiuch you do have then it will flag it as running rich as it is putting unburnt petrol down the exhaust. So you missfire is on bank one looking at it
Yea the only problem is on bank 1.

Cheers for all your input.

Rob
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Old 4th August 2011, 09:05   #9
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Quote:
Originally Posted by Simon.h View Post
Hi, well P0300 Random Misfire Detected can some times be down to worn plugs but you changed these it cant be this, have you checked the wires to all 3 coils maybe damaged?
P0172 System Too Rich (Bank 1) Maybe a air leak on the inlet manifold?

If not any of above may be fuel injectors?
Hi Simon we recently fitted a new intake manifold so will look to see if that has been fitted ok and we check the earth wire to see if we was getting a good earth on bank 1 and that is fine. will look at injectors next.

Also if there was a leak on the inlet manifold would this cause a misfire on bank 1??

Cheers

Rob
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Old 4th August 2011, 16:28   #10
Simon.h
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Also if there was a leak on the inlet manifold would this cause a misfire on bank 1??
No! it would just over fuel!

I been thinking about your misfire, sometimes other things like water/oil can get into the pistons and cause a misfire but they will not be picked up by the ecu and be in form of a fault code! Also lack of fuel will cause a misfire, i had this on my ZT with a lpg faultly injector which i got a fault code which states 'misfire due to lack of fuel'
So you can not have any of the above!

So as yours is getting codes its got to be on the electric side, so check the wiring/earths going to the 3 coils.

Is there anyone near you who you could swap coils with just to try?, but its got to be around the same age V6 because around 2003 onwards the coil are different and dont have spark plug leads.
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