Author Topic: Missfire  (Read 1582 times)

Offline zoomered

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Missfire
« on: 27 February 2009, 17:49 »
Hi. Ive been having a missfire problem with my ADY. The car will run really rough at first start and won't idle. Once warm it idles but has a very slight missfire. When driving though it bogs down under acceleration and hessitates up through the revs really underpowered. It is an intermittent fault and will run good for a couple of weeks then play up... Had it on Diagnostics which brought up a speed sensor fault so replaced the crank sensor. Still brings up the same fault.
So far..

New Plugs
New leads
New Dis cap
New Rotar arm
Cleaned TB
New Small Vacuum hose
Plastic Dip stick tube
New Crank sensor
Checked Dis advance block values fine

Tomorrow its getting a new ecu temp sensor.

Anyone got any ideas?


Offline zoomered

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Re: Missfire
« Reply #1 on: 27 February 2009, 17:51 »
Forgot to mention Tried a coil of another car and it was just the same.
Also disconnected Maf and it ran pretty much the same, no better anyway.

Thanks

Offline boneybradley

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Re: Missfire
« Reply #2 on: 27 February 2009, 18:14 »
check the wiring to the sensor (any splits, cracks will show as a fault!)
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Offline zoomered

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Re: Missfire
« Reply #3 on: 27 February 2009, 18:31 »
aye the sensor wires are fine. Need to get in about it and trace them right back. Do you know where it earths? Anyone got wiring diagrams?

Offline Din

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Re: Missfire
« Reply #4 on: 27 February 2009, 18:38 »
Ok, just thinking outside the box slightly here, you say it seems to be temp related?

Ah hang on you just said it  :wink: coolent temp sensor will cause it to run rough as the ecu will have no idea what temp the engine is and will run on a set fuel map, so worth a go  :smiley:
You can test your old cts by  putting an ohm meter across the pins, then put a lighter or similer over the end of the sensor and watching the resistance drop as it heats up, thats because it an NCT sensor,
NCT = negative  temperature Coefficient, so as the temp rises the resistance drops .........

Er hang on, ive gone off on one here  :embarassed: oops.

And also sorry if im teaching you to suck eggs,  :grin:

Good luck with it anywho  :smiley:

On another note, hope your timing has not jumped a tooth  :undecided:

Offline zoomered

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Re: Missfire
« Reply #5 on: 27 February 2009, 18:53 »
Wouldn't be intermittent if timing was out. Just thought i would give the sensor a bash for 11 quid. Can't do any harm, least then i'll no its not that! Im a gas engineer and spend all day testing thermistors! Lol! Sometimes they can give you correct readings but its still the problem. Thought i might aswell chuck one on cause there cheap! Thanks

Offline Din

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Re: Missfire
« Reply #6 on: 27 February 2009, 18:55 »
Im a gas engineer and spend all day testing thermistors! Lol!

 :laugh: i had that coming tbh  :grin:

And i didnt read the intermitant bit... :embarassed:

Offline zoomered

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Re: Missfire
« Reply #7 on: 27 February 2009, 18:58 »
Nah i didn't know how to do that till a little time ago. Thanks anyway. Im sure there will be a few folk on here greatfull for the info.

Offline Andy-H

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Re: Missfire
« Reply #8 on: 27 February 2009, 19:01 »
Having the same kind of trouble meself.....

Where abouts is the sensor located??

Sorry for hijacking the thread   :embarassed:
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Offline harlemex

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Re: Missfire
« Reply #9 on: 27 February 2009, 21:45 »
Whats your oil and water like? Worth checking. I expect you already have, but thought id mention it just in case.