"mystery misfire"

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"mystery misfire"
#1
2nd time it's happened.
same as previous trip.
on the way back from Surrey, joining the crawl past Heathrow, engine attempts to go into what I can only describe as like 'limp mode'.
picks up again quickly after.
only info I can offer is water temp normal, oil temp was hot, varying between 100 & 130+ in the stop start driving.
Ambient air temp 14c
decided to run from Uxbridge to Oxford with heat full on & windows down to see if that would help.
Expect everything will be back to normal again tomorrow.
journey down was totally trouble free.

<puzzled>
It goes, it stops (as reqd). Makeup
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#2
What are you reading the oil temperature from? As these don't have a dial for oil temperature... What do you describe as limp mode; loss of power, smoke, engine light lit, misfiring, etc?
306 HDi Deathtrap - 130bhp / 220lbft
...UPGRADING...



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#3
I fitted a pressure & temp gauge via a sandwich plate.
no fault lights, no smoke, did see brake lights were flickering (wired a tell-tale into the window unit, pointing at the interior mirror).
defo was a brief loss of power, but would pick-up again with welly.
stopped to chat with a friend back in the village, fired up motor again and oil temp had by then cooled to 'normal'.
will check for codes with my cheapo reader later (after brekkie)
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#4
sounds very similar to our car, see Tesco fuel thread.  Tank level is low today as we have been burning off the fuel so I can inspect the tank internals, for dirt water and anything else........tank level nearly in the red but no low fuel warning light on yet ( if it works that is ?? ) .

happen this morning after roundabout and slight up hill section, seemed to loose power for a second or 2 ( limp mode ??? ) .

have pulled back the mat just in case its under the throttle pedal, and been more careful as some times I seem to touch the brake pedal when throttling up....!! which don't help lol!

the last trip it did this the tank was never below about half full.

car wass great yesterday with no hint of a problem.......100 miles plus....

car VOR as of when I get home, tank pump out is the first job......

will report back with findings.......I wish I had pp so I can see data on the lap top, anyone help with that?? please please please...
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#5
I dont think limp mode just comes and goes? Once it's there it'll stay until a restart I believe, but can't think I've ever had limp on a 306. So the power loss is more likely a lack of fuel pressure for some reason.

I have PP but you're too far unfortunately lol.
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#6
Quote! did see brake lights were flickering (wired a tell-tale into the window unit, pointing at the interior mirror).!
As you said this also happens when the car is playing up i wonder if its worth checking all the earth leads etc in the engine bay etc just to rule out low battery voltage etc goint to to ecu etc causing this fault your having
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#7
thank Vincent, often the brake light is cos the switch has moved position slightly. (another task today)

(03-10-2015, 10:48 AM)Toms306 Wrote: I dont think limp mode just comes and goes?  Once it's there it'll stay until a restart I believe, but can't think I've ever had limp on a 306.  So the power loss is more likely a lack of fuel pressure for some reason.

I have PP but you're too far unfortunately lol.

how can I got hold of PP? (once ive fixed my other laptop)
It goes, it stops (as reqd). Makeup
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#8
could be a wire problem as it happens after a sharp corner..... may be 2 seconds or so after a sharp corner, or could be fuel sloshing in the tank, air pick up as fuel sloshes to side then back again, but looking at the fuel pick up pump in the tank it seems to have a "well" to prevent this from happening.......?

hope it just crap in the tank, but how did it get there?? problem has happened after Tesco fuel, normally use shell at the same pump and site, used morrisons prior to this and fuel site when went down to the smoke during the summer ( and last summer ) ........
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#9
I think i'll go with wire problem to begin with.

today, 1st am, I finally had the 'engine' light come on. Will hazard a guess it'll say TPS (again)
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#10
Ah ok, that'll be it, did wonder lol. Sounds a lot like an earthing problem if you've got other electrical faults popping up at the same time, might be worth checking over the earths in the engine bay and around the interior.
306 HDi Deathtrap - 130bhp / 220lbft
...UPGRADING...



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#11
yep, plugged in my cheapo, code P0220 - reset - hunky dory.
think i'll run a temp cable from engine to bat -ve, for elimination process.
brake light is cos it jiggles in the pita mount. I've thought up a mod for that.
+, I've still got the original TPS (I think), so I could strip, clean & Vaseline that as a back-up
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#12
any test procedure for the tps unit, still not sure how it works ? 2 off set metal segments ? are they magnetic ??

so works by inductance or change in frequency or hall effect array ?   rather than 2 "pots", one going up in resistance and the other going down ?

all info greatly appreciated.....
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#13
sadly, like you, I have no idea Undecided
I did see a thread here somewhere on how to strip, clean & 'lube' one
It goes, it stops (as reqd). Makeup
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