Car Reading Knock On Startup...

[SargeRX8]

I don't know why but my car is reading 56 knock on the PFC when it starts up as soon as it turns over. It happened after I got the car tuned and we suspected the faulty fuel pump could be causing the issue. Ive got a GTR fuel pump and it looked fine for about a week until it done it again yesterday. Does anyonje know if this is normal? Could this cause any damage? I ran this power FC in the car for a month or two on its previous tune and have never detected any knock at all(only one time of about 45 but not during startup).

Also the car was tuned and payed for in full. Is it fair that I have to pay again for the tuner to tidy up the tune again and fix these little issues? If the fuel pump was failing, they should have told me and not taken my money (700+) and given me a messy tune... It makes the power, it doesn't knock much at all(apart from the 54 - 56 reading on startup and the odd 28 during driving which rarely happens) but startup the car is spluttering and shitting all over the place and because the pump was failing, low down rpm, cruising rpm, is too lean and too rich at the same time so I get my AFR gauge hitting rich, then dropping to lean, then rich and lean and so forth.

I really don't feel like giving them more money to fix this as its not really fair on me.

Can anyone here tidy up the tune? I'd be happy to give someone here some $. Its mainly startup which is of a concern and low cruising rpm. If I do fit on a higher pressure actuator later on I'm going to need a retune for the higher boost.

Cheers

[Hanaldo]

Not sure about the start up issue, but as far as paying for a dodgy tune goes I would agree with you. It is really up to how ethical the tuner is I guess. When I first got my car tuned, I had a terrible fuel economy issue (was getting about 160kms to a tank, driving sedately). My tuner told me to bring the car in straight away, got it on the dyno and found that I had bumped one of the sensors while I was working on the car, unplugging it and sending the tune into the knock map. He reset everything and even altered the fuel map a little to give me better fuel economy, didnt charge me a cent even though it was my fault.

[R31Nismoid]

What 'AFR' gauge are you talking about?

If its one that uses the factory O2 sensor then ignore it as it'll never read correctly and you wasted your cash on it.

As for start-up it could be anything. Starter motor might be loose, cam cover perhaps? Knock sensor just on start-up can be many things unrelated to the tune.

And of course if you up the boost, you'll need to change the tune.

[SargeRX8]

I just went to move the car into the drive way. Won't even start today. My luck with this car is amazing. It started and sounded like it was misfiring running on 3 - 4 cylinders. Now it wont start at all. I drove home last night from work, quietly, parked the car. Now it doesn't even start. I never had a single issue with this car until I put the pfc in and got it tuned. I even put my old coil packs in thinking my yellow jackets are ruined and no luck still won't start just turns over and pops every now and then.

I am sick to death of having to fix shit on this car.

AFR gauge was just one of those needles which moves up and down so nothing special or expensive.

[R31Nismoid]

Well take the AFR gauge out, it won't give you useful information and anything it does tell you will be wrong.

Sounds like its not tune related, more so mechanical.

Put a stock ECU in, if nothing changes then its 100% not tune related.

Do you have spark? Fuel pressure?

guessing you purchased a 2nd hand GTR pump? If so id start there, probably failed/failing. Kinda made your own bed if you installed a used pump

[Rolls]

Sounds like fuel pump, take the fuel line off and try priming the pump to start, see if anything comes out, if it does it could still be faulty, but if it is so bad it won't start I would say it isn't pumping at all. If this isn't the issue then get a consult cable and check all the fault codes.

Cars are expensive, skylines especially, be prepared to fix things on it from time to time.

Edited July 9, 2011 by Rolls

[boostn0199]

Welcome to the troubleshooting world of mOdifications lol. But yeah personally parts like afm coilpacks injectors fuel pumps i would never buy 2nd hand or cheap options there important parts so i believe get the best since alot of problems come back to parts like these.

[SargeRX8]

Well take the AFR gauge out, it won't give you useful information and anything it does tell you will be wrong.

Sounds like its not tune related, more so mechanical.

Put a stock ECU in, if nothing changes then its 100% not tune related.

Do you have spark? Fuel pressure?

guessing you purchased a 2nd hand GTR pump? If so id start there, probably failed/failing. Kinda made your own bed if you installed a used pump

The AFR gauge thing is just more for the looks than anything. It reads just above rich when giving it, around stoich rich when cruising and lean when off the throttle. I'm not using it as anything definitive but its doing what it should.

Stock ECU won't be good if I put it back in as the injectors are Nismo injectors. Fuel pressure was the first thing I checked. The line was pressurised so it was a sign I had some pressure, took the line off the filter and put it in a bottle. Squirted out alot of petrol so that was working fine. Pin pointed the problem to cylinder 1 and cylinder 4. Changed all coils back to standard, no luck. Tested each line with one of my spare coils and a spark plug and was getting spark the whole way. My brother said I flooded the engine with fuel so we removed all the spark plugs and they were soaked and black like ive never seen before. The engine is rich as f**k. I dried off all the plugs and cleaned off the carbon and still had the same issue with 1 and 4 so I used two old plugs and the problem is now gone. Its quite a surprise to see these fail and only after 2000km of use... With my old ECU and power fc(pre tune) my old plugs were near perfect on removal(I made a thread about it). With the tuned power fc and only after about 500km after the tune, these are black as shit. This tune is definately richer than it should be.

There are no mechanical issues. Think of it like this. You got a switch, on and off there is no inbetween. The day I came out of the tuner, problems started with the car not starting, fuel pump failing, spark plugs turning black and fouling. The car was driven on the new turbo for quite a while before it was tuned and everything was fine(I didn't fang it around).

I got the GTR pump cheap and Ive got a brand new 040 here. Only reason I put the GTR pump in there was because the 040 was delayed in post by 4 days and I needed the car ASAP so I was able to source, fit and drive the car in one day after finding the pump.

Sounds like fuel pump, take the fuel line off and try priming the pump to start, see if anything comes out, if it does it could still be faulty, but if it is so bad it won't start I would say it isn't pumping at all. If this isn't the issue then get a consult cable and check all the fault codes.

Cars are expensive, skylines especially, be prepared to fix things on it from time to time.

It was funny watching it prime. Was a fountain of fuel squirting everywhere. But yeah this was the first thing I tested. Little things like this I don't mind fixing, its just diagnosing which is a pain.

Welcome to the troubleshooting world of mOdifications lol. But yeah personally parts like afm coilpacks injectors fuel pumps i would never buy 2nd hand or cheap options there important parts so i believe get the best since alot of problems come back to parts like these.

Yeah, I got new coil packs, new fuel pump ready to go. The AFM I bought was from the US and very new.

Anyway I have narrowed the problem down to the spark plugs, replaced them with some oldies for now and the problem which started today is now gone.

[blue_vl_t]

Sounds like the tune is too rich, he may have tuned the car on the dyne and not on the road, so light throttle maps could be rich. Some tuners do this, hence make sure you know what your having done. It makes it hard these days, I rarley trust anyone with my car and if I have a tune done I usually drive and they tune. Not I tune most of it myself, just use a dump for a tune tidy up and so your not speeding on the road to tune. Get a proper wide band sensor if you want to check your af ratios or have it done for you.

[SargeRX8]

It was all dyno tuned, the low down afr are rich to lean, not only by reading my gauge, but the graph he showed me at the shop. He couldn't get a straight line and he doesn't know why. When we found out about the fuel pump, that could have caused many problems. It may have ran fine on tune day but maybe the pump was running at 60% and now with a fully operational pump, the fuel map may be unsuited...

[Beer Baron]

Firstly forget about reading your afrgauge. It only reads one point of afr. On the gauge 14:1 is the min it reads and 15:1 is the max. So any far out of that range (which it will be most of the time) is not shown. It should of course be showing "rich" just about any time you so much as touch e throttle as all that means is it's richer than 14:1. And of course it goes lean when you're off the throttle. They are useless. You may as well pay a psychic gypsy to predict your afr for you as reading a gauge hooked up to the factory narrowband sensor. It's only purpose is form the ecu to read it and target a stoich afr under light throttle low rpm cruise conditions. And that's all it should be used for. Using it as a gauge input is a waste of time. It's just confusing things.

Get the tune checked on the dynon and they'll check the afr with a proper wideband meter and the can plot it against the graph.

[Rolls]

Sounds like it might be the start which is overly rich and not the rest of the tune.

Who tuned the car? I would take it back and say it is fouling plugs and not running properly and it wasn't doing it before, points to the tune is at fault, be polite about it and I'm sure they will fix it up for cheap.

Though if you are changing the fuel pump I would just do that first and take it back for 1 hour of touch ups, shouldn't cost much. The last 20% of the work takes 90% of the time, like everything complicated.

Edited July 9, 2011 by Rolls

[SargeRX8]

Is it worth investing in a wideband just to keep track of things my self?

Can anyone explain why my plugs failed so quickly?

[Rolls]

Is it worth investing in a wideband just to keep track of things my self?

Can anyone explain why my plugs failed so quickly?

Missing at startup will foul them very quickly. You will probably be getting mixtures lower than 5:1 when the engine finally fires. Was it hard to start always?

The plugs could also be the heat range, what are they marked as? Usually any carbon and soot will get burnt off as soon as you give it a good flogging.

Edited July 9, 2011 by Rolls

[SargeRX8]

The amount of black shit which came out of the exhaust when I got it started was amazing. I was cleaning the car behind me, the gate, the fence and hosing the ground. They are BCP7RES. Ive always used these plugs in both my skylines. This is the second set I have used in this car. First set came out and read perfect. These ones here are black as shit. It only became hard to start after the tune... I hate it when people are telling me its not the tune when it was perfect before the tune on PFC...

[Rolls]

So take it back to the tuner

[Beer Baron]

Is it worth investing in a wideband just to keep track of things my self?

Can anyone explain why my plugs failed so quickly?

Up to you. They are a good tool but you need to understand how to interpret the readings for it to be really usefull. Otherwise it'll just cause worry over potentially nothing.

It sounds like the tune may need some work. Once it's sorted there's no real need to watch the afr all the time.