Was having a look round a new owners car the other night and the exhaust seemed to be blowing on the passenger side. Anyway, he said its been misfiring etc. Anyway, to cut a long story short, I think the injector is back in cylinder number 2 (passenger side).

 

Pulling the coil pack plug on the cylinder and there was no drop in revs. Timing etc was perfect. I tried it with a screwdriver on the back of the injector and couldn't feel the pulse. Pulled the spark plug and the guy said it was getting spark in the side of the plenum. But a SMALL puff of white smoke came out of the cylinder (I didn't see it).

 

S I'm gonna mind my multimeter to test the injector, but I just wanted to ask:

1 - can you simply replace 1 injector or do you need to do them all

2 - can/should you use a secondhand good one?

3 - should we be concerned with this tiny puff of smoke? As in, could there be a gasket problem?

You can change just one injector, i did this a while ago, however before you start use the multimeter on the pins of the injector to see what ohms it is reading, should be between 10-14 ohms, if its out of that range, then its duff, clean the connector terminals anf the injecotr terminals first of any corrosion, as it may be a simple case of green gunk causing the lack of signal

Will give it a go first. Can you use second hand injectors though?

Also, does the plug just pull off?

Bear in mind injectors don't necessarily just stop working at all. To my understanding it's simply a valve, it opens and closes as controlled by the ecu, the signal controls how much it injects. They can fail either way, jamming open or closed, equally they could run out of spec say it won't inject the full amount or won't inject a low enough amount that would cause poor running. Anyway that's neither here nor there, what you need to check is that,

A. Power is supplied to the injector, think dirty or broken connections.

B. The "health" of injector so to speak, by checking the resistance in ohms your checking the valve is happy. As Groover says 10-14 ohms, I think 12.5 is perfect as such.

The smoke well that could be simply unburnt fuel evaporating. If you definatly have a working injector and spark, it may be a sensible step to start looking at other more sinister causes such as compression. 9 times out if 10 the injector plug is shitty or the injector itself is green. They get manky quite easy and the heat makes the connections brittle and prone to failure.

Also, does the plug just pull off?

 

The injector plug itself may have a metal clip holding it on.

The injector will be a pita to get out, you will likely need a damn good screwdriver or impact driver to remove the pesky buggers. Even then they are still quite in there. Be careful to not damage the fuel rail during removal and ensure you lubrucate the seal on replacement or you will pinch it and flood the cylinder with fuel.

I use a biggish flat blade screw driver to lift the plug upward, the clip will naturally open to allow it to come off, but do it slowly and have a magnetic pick up tool handy as the clip can ping off. To refit simply prefit the clip so the legs sit on the outer rim of the plug and push down firmly and it will clip back into place.

As Steve said the bit of smoke could be unburnt fuel if the injector is getting an intermittent signal or dead, i would say 9 times out of 10 you have green corrosion on the terminals, hopefully :thumbup1:

Will have a look at them. If nothing else it'll be worth giving them a clean anyway. Should probably check mine :-)

 

What would you use to clean the rubber seal?

It's the contacts inside you need to clean not the rubber.

Sorry, I meant lubricating the seal

get some dielectric grease to fill the plug around the terminals, are you talking about the injector seals, when/if you take them out? use a little vaseline or oil on the injector O rings if replacing the injector

I have 6 spare std injectors here if required mate

Thanks all. Got another question - O2 related, if they're unplugged, what will the conzult/data scan show for them when looking at the dials screen? From memory, they were just sitting at 32 or 35 and not moving

An artists impression of how I got my injector out!

Thanks all. Got another question - O2 related, if they're unplugged, what will the conzult/data scan show for them when looking at the dials screen? From memory, they were just sitting at 32 or 35 and not moving

 

From your other thread:

Unplugged O2 sensors: ECU sees a constant voltage of 0.31v

Thanks mate, what does that mean it'll show on the data scan?

Could an injector read 57??? I've got the multi meter set on 200 and not sure if I'm reading it wrong

If the resistance is 57ohms it's out if spec.

Could an injector read 57??? I've got the multi meter set on 200 and not sure if I'm reading it wrong

 

57Ω is way out of spec. ~12Ω for high impedance injectors.

If it's reading a resistance of 50+ ohms does that mean it's failed open? With lower than 10 being too lower resistance ie it's closed? Do I understand that correctly?

The screwdriver on the back feels very very weak

Just checking.... You didn't measure the impedance with the connector still in place did you?

Well it was unplugged. Could you even do it with the plug still on? Lost the retaining clip like and took donkeys to get it out lol

Well it was unplugged. Could you even do it with the plug still on? Lost the retaining clip like and took donkeys to get it out lol

 

Yeah, the probes are pointed for that exact purpose.

Yeah, the probes are pointed for that exact purpose.

 

I don't get how I'd check it with the plug still on???

I don't get how I'd check it with the plug still on???

 

Pushing the pointy probes into the back of the connector. It doesn't matter, it's not important :D