Injector Duty And Timing

[Room42]

Random knocks could be oil burning under load.

[_x_FiReStOrM_x_]

Checked valve timing? Cam may have slipped a tooth or two.

Best advice is to start simple... check ALL the basics, then if not resolved, start to dig deeper. If i could count the amount of times i've had cars brought in with random misfiring, which have been looked at all around town, and something as simple as spark plugs have been the issue.. i'd run out of fingers to count with.

Edited August 20, 2011 by _x_FiReStOrM_x_

[T.D]

Random knocks could be oil burning under load.

Hmmm, sounds interesting. Could you elaborate a bit more? I do notice my rocker covers are very hot after driving.

Checked valve timing? Cam may have slipped a tooth or two.

Best advice is to start simple... check ALL the basics, then if not resolved, start to dig deeper. If i could count the amount of times i've had cars brought in with random misfiring, which have been looked at all around town, and something as simple as spark plugs have been the issue.. i'd run out of fingers to count with.

Timing has been checked and even been as far changing the timing belt and the tensioners as well.

Car doesn't misfire at all, it just won't take any timing

So, what actually causes an injectors duty cycle to increase? Is it boost, timing or just power in general? Or is it a combination of all? Reason is, I can't figure out why injectory duty is up but boost levels are the same, but with less timing and ALOT less power.

[DVS JEZ]

More Airflow through the AFM should inturn use more fuel and more injector duty cycle.

Can u post up a pic of the spark plugs

[_x_FiReStOrM_x_]

More Airflow through the AFM should inturn use more fuel and more injector duty cycle.

Can u post up a pic of the spark plugs

Yep, generally air flow meter, coolant temp sensor, and TPS are the main sensors that affect injector duty cycle.

[_x_FiReStOrM_x_]

Is the coolant temp at the head normal? Also, how much carbon buildup in the cylinders? You could try a cylinder drop test to possibly find a weak injector?

[Room42]

I cant remember where I read it. It might have been in STATUS's link. It seems that if oil is getting in the cylinder it lowers the octane rating of the mix and causes knock. If its running very hot then it will knock easier. Mine has 10 to 15 knock on wot usually. After I gave it a hiding through 4 gears it went up to 35. And yeah if there is excess carbon it will glow and cause preignition.

[DVS JEZ]

If u get pre ignition there will be tears.

Post a pic of the plugs please

[Lithium]

It'd be interesting to know EGT/AFR variance across cylinders... probably not realistic in this diagnosis?

I've seen some pretty funky rpm signal stuff when an ignitor was playing up.

[T.D]

More Airflow through the AFM should inturn use more fuel and more injector duty cycle.

Can u post up a pic of the spark plugs

Alright then, I see. No worries mate, I'll try get some either later today or tomorrow and I'll post them up

Yep, generally air flow meter, coolant temp sensor, and TPS are the main sensors that affect injector duty cycle.

Coolant/water temp sits between 80-degrees and 83-degrees in regular traffic but when on the freeway doing 100km/h it sits at around 86-degrees and when cruising at 110km/h, it sits at around 88-degrees.

I'll post a pic up of the engine bay soon but on the topic of TPS, I have 2 plugs off the side of the T/B (for the TPS I'd say) and when installing the T/B onto the plenum, I had to stuff around with the TPS a bit so could a bad TPS be causing the weird issues I'm having? Or is that a bit too far fetched?

Is the coolant temp at the head normal? Also, how much carbon buildup in the cylinders? You could try a cylinder drop test to possibly find a weak injector?

The timing issue was present well before I got the temps from above. The temps used to sit around 81-84 degrees constantly, regardless of speed.

As for carbon build-up, not sure as we haven't cracked it open yet. Don't really plan to for another 12 months or so either, when I scratch some funds for a Spool 2.8 stroker hehe

I cant remember where I read it. It might have been in STATUS's link. It seems that if oil is getting in the cylinder it lowers the octane rating of the mix and causes knock. If its running very hot then it will knock easier. Mine has 10 to 15 knock on wot usually. After I gave it a hiding through 4 gears it went up to 35. And yeah if there is excess carbon it will glow and cause preignition.

I see. We had a comp test done and it was all very even across the board, with the lowest reading coming from cylinder 3, though it still wasn't too far off from the other so the mtoor is healthy. No oil/blow-by either.

It'd be interesting to know EGT/AFR variance across cylinders... probably not realistic in this diagnosis?

I've seen some pretty funky rpm signal stuff when an ignitor was playing up.

Yeah, I've toyed around with the idea of individual AFR/EGT sensors for each cylinder but lost interest as soon as I was told the massive costs involved LOL

[T.D]

Here are some photos of the spark plugs

Spark plug 1 (predominantly white):

Spark plug 2 (black but had some ash around it for some reason):

Spark plug 3 (black):

Spark plug 4 (black):

Spark plug 5 (black with minor white marks):

Spark plug 6 (light blck/dark grey):

And here's the engine bay, hoping someone can see something wrong with it that me and two mechanics/tuners can't? lol

Also, in the bottom left hand corner you can see one of the TPS plugs resting on top of the radiator hose (has a bit of foam wedged in between though). I tried to move the TPS but I ended up rounding the head for the screw cos it was that damn tight (FML) so I couldn't move it away from the hose. Any problems with it like that sitting on top of the hose?

[Beer Baron]

this might seem obvious but have you considered that the problem is the new plenum and intercooler? car was running fine before them. you may also have an injector problem as well but generally when stuff goes wrong you need to go back to what you changed last. in this case plenum and cooler.

[Room42]

Is it just me or do those plugs look lean as a bastard? Lean means hot and knocking. Either that or only run for a very short time. Check this link out. http://www.denso.com...Used-Spark-Plug

[T.D]

this might seem obvious but have you considered that the problem is the new plenum and intercooler? car was running fine before them. you may also have an injector problem as well but generally when stuff goes wrong you need to go back to what you changed last. in this case plenum and cooler

Yeah, I've considered that actually haha but my first recordings of extremley high knock levels (120+) appeared well before the plenum and cool went on. I have a strong feeling something shat itself around that point and the timing issue was only diagnosed after the plenum went on and it went in for a tune

Not sure if this is related, but I saw high knocks not long after I removed the charcoal cannister. I plugged up the line that goes to the throttle body (and the stock manifold at the time) so is there any way that an incorrectly removed cannister and fuel lines associated with it cause knocking?

Is it just me or do those plugs look lean as a bastard? Lean means hot and knocking. Either that or only run for a very short time. Check this link out. http://www.denso.com...Used-Spark-Plug

I thought they were lean as shit too, but the insulator is actually white from factory (NGK 7-heat range, gapped to .6mm) so if anything, they look like the second diagnosis with the link you provided (i.e carbon build-up, pointing to rich conditions). Any ideas on that?

[T.D]

Anyone able to help, given the new bit of information from the above few posts?

Should also add, if I give the car a quick 2nd gear pull (i.e drive normally 1st gear, fang 2nd gear and then just drive normally through the rest of the gears) and then cruise around for 5-10mins, the hot side of the intercooler end tank becomes warm and the cold side end tank is still relatviley cool. Does that mean the air is superheated and possible cause of timing issue?

Edited August 24, 2011 by turbodragon

[Room42]

Anyone able to help, given the new bit of information from the above few posts?

Should also add, if I give the car a quick 2nd gear pull (i.e drive normally 1st gear, fang 2nd gear and then just drive normally through the rest of the gears) and then cruise around for 5-10mins, the hot side of the intercooler end tank becomes warm and the cold side end tank is still relatviley cool. Does that mean the air is superheated and possible cause of timing issue?

My intercooler is exactly the same after a bootfull. If its coming out the other end cold then its not an issue. Maybe a pressure test either side of it is in order. Make sure its not blocked. Unlikely tho. Beer Baron is on the money. It was fine before and not now. There wouldn't be a huge change in the tune before and after so it seem like its time to rip of the new bits and thoroughly sus them out. Put the old bits back on and see if the problem is still there. I wouldn't worry about carbon build up cos that crap takes a hell of a long time to build up enough to get hard and stay there. It usually get vibrated/burnt loose and comes out the back. You can spray atomized water through the throttle body when the car is idling and it will soften it up and break it loose also.

Edited August 24, 2011 by Room42

[T.D]

Ahh I see. I'm going to hook up a temp gauge on either end of the 'cooler so I'll know the exact tempereture that's going in and out fo the core

Nah, I don't think it's any carbon build-up as it's far too sudden to cause an issue like this.

One thing that has been mentioned to me by Plazmaman though is to check the TPS. If the TPS is responsible for the issues, I wouldn't be surprised as I did attempt to mess around with it when fitting the throttle body onto the plenum.

Basically the bottom plug (grey) was getting pushed and resting on top of the radiator hose so I tried to move it by undoing the 2 screws holding the TPS in place. I did not succeed in this as I rounded one of the screw heads.

How can I check that the TPS is in working order? I checked it with the hand controller of the PFC but I'm not sure I believe it as another time I unplugged the VCT plug but the hand controller was telling me it was still working lol

Also, I heard that manual S2 R33s only use one plug for the TPS, with the grey one as a spare and not having any wires from it. My grey one has wires connected to it though. Anyone shed some light on this?

Edited August 25, 2011 by turbodragon

[Don Dada]

Automatic trans use the second plug

Maybe your car was auto that was converted to manual

[T.D]

Automatic trans use the second plug

Maybe your car was auto that was converted to manual

I'm pretty sure my car has been a manual all along though. Dash cluster is a manual one, the stock ECU that came out was a manual one and there was only one other owner of the car before me. Weird.

I know that when I unplug the brown plug, the idle changes. But is there any way of checking the TPS?

[Don Dada]

Ign on engine off

HC> etc> sensor/sw check> thro

Should be around 0.4v without mashing and 4v to the floor