Hey guys,

1. What are these for?
http://img7.imageshack.us/img7/8984/1020707a.jpg
2. Does the wear/age of them matter, should they be replaced at some point?
http://img197.imageshack.us/img197/3982/1020708.jpg
3. Est price if need replacing?

Sorry for having such little 'technical' knowledge of an engine, I know computers not car engines.

Thanks a bunch in advance.

Cheers!

are you refering to the injector harness? a current is sent down those wires, firing the fuel injector, for duration and timing of the pulse
thats just insulation tape, its no biggy, just wrap some more over it if your worried.
if the spark plug leads, lower down the pic, (the solid black ones) looked like that, then yes you would need to change them

are you refering to the injector harness? a current is sent down those wires, firing the fuel injector, for duration and timing of the pulse
thats just insulation tape, its no biggy, just wrap some more over it if your worried.
if the spark plug leads, lower down the pic, (the solid black ones) looked like that, then yes you would need to change them

Thanks for the info, just recently had the sparky leads done, was making sure these weren't important either.

Err. Thread closed?

Well, lets assume that you are referring to the little orange things in the pics, which have a grey electrical connector clipped to them, with two wires each.
THOSE there, would be your injectors - one per cylinder.

They accept fuel from the high pressure fuel-rail (the alloy thing in your pics) and have a solenoid which is controlled by the ECU (see? COMPUTERS! you should excel here!) The solenoid in the injector allows fuel to flow for just the right duration at the precise time required - all worked out by the ECU. The piece of injector which "pokes in" is a nozzle, so the high-pressure fuel is atomised - squirts in like a fine spray or mist and mixes with the rush of air coming from the air intake - you can see bulges in the large alloy casting in the pics which are the air passages.

Injectors can "wear out" or more likely become a bit dirty and clogged with residues from the fuel - may become like a varnish etc. However, they are not a regular service item, they last a long long time usually and any decline in their performance is usually very gradual and not noticed. That said, it IS possible for one to fail - jam open or closed - but that'd be rare.

Servicing of injectors - possibly a huge money-making enterprise for dealers/mechanics. It is fairly common to be "suggestive sold" some kind of injector cleansing regime when having a car serviced..... in my opinion this is almost always not needed, and unlikely to be truly effective. You can buy bottles of "injector cleaner" off the shelf, which you just tip into the fuel tank when you fill up....... many folks like to use this occasionally, and just as many (including respected mechanical members here) think its basically crap. The true, useful, best-practice way for injectors to be cleaned involves removing them from the car, ultrasonically cleaning them, flow-testing them individually for performance and then refitting. I think it would be unusual for a basic dealer or mechanic to do this way in a usual car-service "upgrade", but specialist businesses exist where you can have it done, or pull your own out and take them there.

As for suggested replacement duty-cycle, and cost of replacement - to be honest I don't know. If you car idles smoothly and drives normally with reasonable power delivery - then I'd be tempted to leave them alone...... and refuse any "would you like fries with that?" extras involving them if you are offered this. Others opinions may vary!!

sorry to hi jack
my second car seems to miss a little and somtimes its ok other times pretty bad i have changed the leads and spark plugs and maf sensor cleaned still no joy can the injectors cause this problem and how do i find out if it is thanks
cant remember what its called but the thing that adjusts the idle stuffed up mechanic replaced that and siad the o ring seal had a split could this cause the problem
i was on the lines that it would just let more air through and make rev higher

Well seeing as there is still convo here, for a start, thanks for extra info Elwyn, quite useful..

I've noticed sometimes when I put my foot down there is a slight delay before the engine seems to really kick in, or if I'm accelerating hard the engine revs will sort of pause before continuing up - any ideas on this?

Cheers.

@ Robceline,

I'd chase-up a replacement for the split o-ring - if a part is not up to spec, get it right (esp as o-rings are hardly big-budget items). The air-intake and fuel supply systems are designed to give good performance, air leaks etc can upset the metering or "mislead" the ECU, thus affecting the air-fuel mix delivered.

Fixing your o-ring may not solve the problem you have - but it just might!! Do we know if it is the idle-speed motor (ISC) or an idle adjustment screw which has the broken o-ring??

If its definitely a "missing" scenario - have you worked out which plug is not firing, and have you checked the spark plugs? If an injector wasn't delivering fuel properly, then that cylinder wouldn't fire well. Worse, if an injector delivers too much fuel, that cylinder has excess petrol "washing" and affecting lubrication by diluting the oil - can lead to excessive wear. Same thing can happen with normal fuel delivery but electrical/spark issues causing lack of detonation consistently in one cylinder - the fuel is not burned, it dilutes the film of oil lubricating the cylinder/rings/piston and lack of lubrication leads to wear.

@ Oxidious, could be multiple causes and might even be normal. Do you have mates or other members near by with similar vehicle, so you can seek opinion or do a comparison? Fuel supply, air intake and spark are the basic ingredients to getting petrol exploding in your motor when its needed. Might be a good idea to search forums for similar issues in the past OR find the "workshop manual" thread and download a Mitsi factory Workshop manual as PDF file - these have good troubleshooting flowcharts in some chapters - which dealer service staff would use to trace problems..... they give common and easily-fixed possibilities first and lead-onwards towards more obscure possibililties..... perhaps you could have a read of those in fuel / air / ignition chapters and see what is suggested.

If you have a mechanic's stethoscope, you could try listening to each injector to see if you can hear a consistent "clicking" indicating that the solenoid is at least functioning enough to make a noise.

@ Oxidious, could be multiple causes and might even be normal. Do you have mates or other members near by with similar vehicle, so you can seek opinion or do a comparison? Fuel supply, air intake and spark are the basic ingredients to getting petrol exploding in your motor when its needed. Might be a good idea to search forums for similar issues in the past OR find the "workshop manual" thread and download a Mitsi factory Workshop manual as PDF file - these have good troubleshooting flowcharts in some chapters - which dealer service staff would use to trace problems..... they give common and easily-fixed possibilities first and lead-onwards towards more obscure possibililties..... perhaps you could have a read of those in fuel / air / ignition chapters and see what is suggested.

If you have a mechanic's stethoscope, you could try listening to each injector to see if you can hear a consistent "clicking" indicating that the solenoid is at least functioning enough to make a noise.

Cheers for the reply - first of, isn't 'normal' only started recently, It's a 97 TF Magna, mate has a 98 model and it doesn't do it.

Second - just had plugs and leads replaced + full injector workover so that would leave air intake? Checked air filter - it's relatively new, gave it a bit of a shake and replaced - same same.. anything else I could do?

Thanks for the suggestions about the manual, I remember seeing one on the forums before.

Cheers!

Just a quick note on the topic of injector cleaning - I had also thought this was a somewhat unnecessary procedure that doesn't give big results. I've had this done recently though, and boy - was I wrong!

When I got the car, it was running a bit sluggish and I felt it idles a bit rough also. Just didn't quite feel 100% healthy. My mechanic charged me $250 to drain the tank and clean all residue from the bottom then flush the fuel lines and the injectors. The car runs MUCH smoother now, and perfomance has noticeably increased. The car is more responsive now, and fuel economy has also improved (dropped by an average of 2L/100km).

Thought I'd share that, if anyone else is considering the treatment.

My TW Magna is dual-fuel, and I usually run it on gas. But a few weeks ago I switched it back to petrol and it ran like a dog, esp. at and just off idle. Was surging and chugging, quite rough, at idle.
I put a $9 bottle of injector cleaner in the tank and ran it on petrol for a while, and after about 200km it was absolutely fine.

Yeah, I actually don't mind putting the occasional bottle of injector-clean thru - but have never noticed much difference.

However, I ALWAYS refuse any "upgrade" when getting car serviced - cos they never would tell me precisely what they would do for the money - which was substantial. Other specious "upgrades" were also suggested and refused.

This was the local Misti dealer - no longer stand-alone but merged into the Holden dealership and working out of the Holden service area...... You can no longer explain things to the actual mechanics, they have a few robotic staff at the counter who look spiffy but talk crap. End result for me is that I will never take either of my cars there unless its something that only Mitsi dealer could do - eg coding of new key, etc. Even then, if that need arises, I will possibly drive to a nearby town to avoid that dealership.

If I want injectors cleaned beyond tipping a bottle into fuel myself, I'll remove the injectors and get them cleaned and flow-tested by a specialist.