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Rizzo80

EPC & Check Engine

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So ive changed map sensor oxy sensor ht leads & plugs. Still running rough and showing missfire cylinder 1 & 4 😬😬😬 any ideas ? But no EPC light anymore yaaaaaaaaaaaaaaaay FML

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Cam or crank sensor.

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More money 😫

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Have you tried the green temp sensor yet?

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No not yet, its on the possible list. Could this be a problem ?

20181110_153509.jpg

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Nah.

Try the crank and cam sensor tests. Now you have the diagnostics thing and you can clear faults, do the old school trick of disconnecting sensors while the engine is running. If the engine note changes or kills it, sensor is probably ok... engine 'can' run on either cam or crank alone, but ideally needs both. So run with one disconnected then start it (if you can) and disconnect the other, and then switch round.

There's some very clever software in them ECUs, which means it will always try to keep the engine going to get you home even if there are multiple faults. Older ECUs just gave up and you were left stranded by the side of the road for the tiniest of faults. But cars still have only one ECU... no redundant systems like in an aircraft. And now new car steering and brakes are controlled by that one ECU while you're charging down a motorway. I don't like it.

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I used to have an e32 750, that had two ECUs.

Edited by Rich

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That's a new one on me. Both for engine? Like one being redundant, complete with two sets of sensors....?

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A twelve cylinder operating as two six cylinders.

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Uh, ok. I guess they ran out of injector drive circuits. When i worked on a V12 jag, the brits managed everything on one ECU, but it didn't have sequential injection. 4 banks of 3 or 3 banks of four. Can't remember...

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The Brits don't make cars.

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Because they did silly things.

Doubling the management (Bosch) was clearly the way for a twelve but then this was an 87

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So after new leads plugs map sensor still a missfire. But ive found sone concerning pipes. So the bottom one is a vacum pipe right ? So that has elec tape on it . So surely that must be it now ? Still showing P0106 MAP whuch is part of the vacum ?? And the red tape. Is that why the brakes are **** ?

20181114_195124.jpg

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You could be onto something here.

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There was a recall for cracked vacuum brake pipe ends... across the entire vdub range around '99 era i think (found out a year ago). If air is being sucked in elsewhere, a map/maf sensor will give a correct reading, but obviously wrong.... 

on a mk2 i once had a misfire, but at idle only. Drove me nuts.  Ran sweet as most of the time. The vacuum pipe to the brakes was on cyl 4 inlet duct. No problem. But in this case the short rubber hose joining the vacuum pipe to the manifold had a tiny almost invisible split. This allowed air in, which dliuted down the mixture to cyl 4. So no. 4 misfired because there wasn't enough fuel in the mix which entered the cylinder. Too lean..... but once the manifold pressure rose, under load, the tiny amount of air made no difference, since 99% of the mix came from the carb. All the symptoms suggested headgasket failure, leaky exhaust valve or a hot running spark plug (it was paler than the others).

Edited by mk2

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So what part is this, having a hard time trying to find the pipe that connects to it

20181114_204801.jpg

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Looks like a breather vapour separator, but not sure as i haven't worked on this model... @Rich what d'ya reckon?

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Stupid one way valve, I like it as I once had a non starting car and someone had spun it 180.

Shame I was so far into stripping it for another theory when I noticed otherwise quick money maker.

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No idea.

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