With misfire been a regular issue I have to deal with when a nice zed cam in last week that had just had the plenum off for rocker cover gaskets at another garage I half expected to find a loose or bad connection on an injector or coil pack. On arrival the owner gave me some more info, the garage had tried to fix the misfire and even replaced a coil pack connector and injector connector a coil pack and spark plug but could get nothing on cylinder no 4. When driving the car clearly was missing and popping on over run which as least suggested fuel was getting injected!!

 

So you can see from the picture a generally ok job from a non specialist garage doing the rocker covers and plenum pull, but letting it go with a misfire was somewhat remiss though, anyhow a quick look and could see the coil pack connector had been changed very poorly with twisted cables and rubbish insulation tape/

 

 

 

 

Looking closer the poor connection and even less than useful insulation take did reveal something though, the cable colour`s where wrong as is the cable size for the coil pack connection.

 

 

 

A few moments with a test meter and the problem was revealed, the coil pack connector and 02 sensor connection had been installed the wrong way around, the cable runs under the balancer bar and so had to be released to switch them back and sort out the dodgy connection, 10 minutes later and purring lovely, seen connectors mixed up before but cannot believe a garage could not trace it and then let the owner take it away....tut tut!!

 

 

 

 

Jeff TT

Sorry, just so I'm clear, the O2 sensor was plugged in the coil pack on cylinder 4 and vies versa?

Sorry, just so I'm clear, the O2 sensor was plugged in the coil pack on cylinder 4 and vies versa?

 

 

Yep!!

Yikes, that's an example of some utter crap workmanship there.:thumbdown:

Another great Doctor Jeff Diagnosis and fault find!.....really, do people pay the bills of these garages that get away with c**p like this?, I'd be back round to them in a misfire to arrange a refund!

Wow that was bad workmanship for a garage to do.

God damn! I HATE crap wiring, there's no excuse for it, but that is just ridiculous!

What a shit Idea that Nissan didn't make the connectors non-interchangeable!:ph34r:

Seriously, that work was carried out by a "professional" I've seen chav bodges better than that.

What a shit Idea that Nissan didn't make the connectors non-interchangeable!:ph34r:

 

Agree especially where connectors are close together, another common one I see wrong is the near side variable valve timing solenoid connector and the det sensor connector both two pin units with the same detent lobe and are clipped a few inches apart.

 

Jeff TT

Agree especially where connectors are close together, another common one I see wrong is the near side variable valve timing solenoid connector and the det sensor connector both two pin units with the same detent lobe and are clipped a few inches apart.

 

Jeff TT

 

ive made this mistake myself and easily done when your napping

Wondering what's worse, the colour coding on the engine bay or the incorrect coloured wires!

Even if Nissan had coloured coded them it would have made sense. My neighbour has a Morris and we had a look at it, checked the plug gaps etc, I left him came back and he had pulled the ht leads off. I asked did you pay attention to what order they were in, I knew the answer before I asked and sure enough the reply of no was given. A face palm moment and some consulting on the manual later it was sorted, funny firing order those engines. I think iirc they actually fire in order, which is odd. I recommended him to do what ive always done and write the cyl numbers on the dizzy and the leads. It's a job I need to do on mine, label each connection.