engine pinging

FS5 · 10-05-2006, 04:52 PM

i just found out yesterday that my engines been pinging or detonating .it gets thins strange sort of pinging rattling kind of sound when i rev it over 4500rpm.i always thought it was the cat convertor crapped itself.its only done this with the ported head we fitted. it might explain why i lost power after putting it on.
it dosen't do it all the time it must be the fuel i'm putting in or something.i had it tuned to run on 98 octane last time it was tuned.so maybe one of the servos i'm going to is selling crap fuel.
do think it maybe just a crap tune?

jimt3te50 · 10-05-2006, 04:55 PM

yeah it could be that or maybe the chambers are smaller or the head deck milled and the compressions up a bit too high........

just a thought- do you know what work was done to the head?

FS5 · 10-05-2006, 05:01 PM

yeah it only had 12 thou shaved off it

jimt3te50 · 10-05-2006, 05:17 PM

Quote:

Originally Posted by FS5

yeah it only had 12 thou shaved off it

I'd say that would be it- .012" would be enough to bring the chamber sizes down a fair bit (lower cc's = higher compression). I could be wrong but I reckon that's your probelm.

It might be something you could sort out with a piggyback or even better the EDIT and custom tune. Be a $1000-1500 job though.

Keep us posted though.....

xr8ute · 10-05-2006, 05:21 PM

Could be oil getting into the combustion chamber air-fuel mix.

Has been known to increase the likelyhood of detonation, and with the leakdown figures you posted in the other thread is a definite possibility for those cylinders (#1 and #5..?)

XR6-VCT-2000 · 10-05-2006, 05:32 PM

i wouldn't be suprised if its just crap fuel , if its that annoying to you but its only very light pinging and only now and then , then maybe depending on what grade oil you use now , maybe go another grade thicker ..maybe - but if crap fuel is effecteing it that much then it sounds like the tune you got is right on the edge on set to run 98 octane and not a drop less ! . usually with the timing being to advanced or retarded will cause pinging .

SIKSIX · 10-05-2006, 05:35 PM

try adding that el cheapo octane booster mid tank to the same batch of fuel, to see if the fixes it.

XR6-VCT-2000 · 10-05-2006, 05:44 PM

Quote:

Originally Posted by SIKSIX

try adding that el cheapo octane booster mid tank to the same batch of fuel, to see if the fixes it.

Thats a very good point ! - crap fuel in ya car or not a can of that octane boost should at least bring it back to a 98 octane rating if thats what you originaly filled ya car with in the first place . Lest you will know then if it was a bad batch of fuel you got . gl

**Stav** · 10-05-2006, 07:05 PM

Listen mate..it is the tune or the unichip may be playing up.

It sounds like the car is running too lean.The chip needs retuning.Not the engine work or any of that. Mine is doing the same thing..a tad to lean up top and yes its been verified...pinging

kc_ksom · 10-05-2006, 07:26 PM

I think it is fuel pressure, I had the same thing happening with my car, it is the fuel pump or filter. with mine it was the filter that was fairly hard to blow through, but you still could blow throw it.
Try that 1st.

Casey

XR6-VCT-2000 · 10-05-2006, 07:32 PM

Quote:

Originally Posted by kc_ksom

I think it is fuel pressure, I had the same thing happening with my car, it is the fuel pump or filter. with mine it was the filter that was fairly hard to blow through, but you still could blow throw it.
Try that 1st.

Casey

Nice way to introduce yourself to the forums ! - for a first time poster - welcome - i'll leave it at that for now .

FS5 · 10-05-2006, 07:56 PM

Quote:

Originally Posted by xr8ute

Could be oil getting into the combustion chamber air-fuel mix.

Has been known to increase the likelyhood of detonation, and with the leakdown figures you posted in the other thread is a definite possibility for those cylinders (#1 and #5..?)

thats what i was thinking to ,but you think it would be blowin oil smoke.

it could be running lean , but when i got tuned for the gnd cam last time ,i asked them if it was leaning out or if the injectors were maxing out and they said the afr's were fine and the injectors weren't maxed out either. the fuel filter could be due for a change its done nearly 40000 k.

GK · 10-05-2006, 08:59 PM

Quote:

Originally Posted by XR6-VCT-2000

usually with the timing being to advanced or retarded will cause pinging .

Advanced = pinging (I agree)

Retarded = pinging (I wouldn't have thought)

GK

JC · 10-05-2006, 09:06 PM

You can't change the timing on an AU, so it won't be that.

With all the symptoms of the engine between the two threads, I would say it's oil contaminating the fuel, lowering the octane rating and causing the pinging.

kc_ksom · 10-05-2006, 10:13 PM

If it is the oil that is causing this problem then there would be more problems then just pinging I can tell you.. Look for fuel problems 1st. The oil thing is going a little over the top. besides that, were not talking about a finely tuned top fueler, so a minimal amount of oil in the chamber is going to do jack SH&T to compressions, you would instantly smell the oil burning anyway.... just my opinion.

This guy hasnt complained it is using oil either, so start with basics 1st, work from there...

Casey

JC · 10-05-2006, 11:42 PM

He has actually - 3 litres in 8000km, but that info is in a different thread. He's effectively running a two-stroke!

I6corp · 10-05-2006, 11:51 PM

Quote:

Originally Posted by JC

He has actually - 3 litres in 8000km, but that info is in a different thread. He's effectively running a two-stroke!

: I wonder what the problem is then?

**Stav** · 11-05-2006, 08:27 AM

The car is running too lean. Simple.We have a knock sensor which pulls out more and more timing with more pinging.If you are pinging then the car is extremely lean.Otherwise you need some nulon octane booster.When the cars tune is set up so lean the tuners are aiming for max power.Most probably on the day you had a good tank of fuel and it was ok.However less octane fuel and the fact that it is so lean makes it knock/ping when the fuel isnt as good.So you have to see if it will continue withthe nexttank full of fuel.If it does then take it back to G&d and ask them to check the ratios.

FS5 · 11-05-2006, 05:39 PM

its not doing it so much now ,i have a tank of optimax in it .i'm just going to take it easy in it for a while untill get the bottom sorted out and get it all retuned at once .i going to try and get back over to CnJ and have a chat about what could be causeing it

GK · 11-05-2006, 05:41 PM

Quote:

Originally Posted by useless

The car is running too lean. Simple.We have a knock sensor which pulls out more and more timing with more pinging.If you are pinging then the car is extremely lean.Otherwise you need some nulon octane booster.When the cars tune is set up so lean the tuners are aiming for max power.Most probably on the day you had a good tank of fuel and it was ok.However less octane fuel and the fact that it is so lean makes it knock/ping when the fuel isnt as good.So you have to see if it will continue withthe nexttank full of fuel.If it does then take it back to G&d and ask them to check the ratios.

I always thought that out of the factory the AU ran too rich. I also thought that if cars were tuned lean, it was for economy not for power!

GK

4.9 EF Futura · 11-05-2006, 05:49 PM

Quote:

Originally Posted by GK

I always thought that out of the factory the AU ran too rich. I also thought that if cars were tuned lean, it was for economy not for power!

GK

The factory tune on most cars is on the rich side of ideal performance. Lean the mix out a little and you will see an increase in power... until the point where it pings, which kills power.

Oh - it also kills engines. Any loss of compression in the motor may be a result of a lot of pinging.

Too lean and or too much timing advance will cause this. Both of which are possible if the tune isnt right...

Get it sorted tho - nice way to destory an engine...

**Stav** · 11-05-2006, 05:53 PM

Quote:

Originally Posted by GK

I always thought that out of the factory the AU ran too rich. I also thought that if cars were tuned lean, it was for economy not for power!

GK

The au sixes run airfuel ratios run really rich from around roughly 70 kays to 140 kays then start to lean out at around 150kmph.

The lean tuning is done to optimise best lean torque and power. The problem is if you use an interceptor and something changes in the car the result can be too lean at wot. I retarded my cam and so did FS5.Typically this may make the car run too lean up top and then pinging.Exactly as mine did.By running my car richer at the moment I can gain 3 -5 rwkws more. But its a pain in the butt having to retune the car not to mention the cost.I hoped that the tune would make up for the lack of power in my car..but it cant. A better engine combo is the key here.

GK · 11-05-2006, 07:08 PM

Quote:

Originally Posted by 4.9 EF Futura

Too lean and or too much timing advance will cause this. Both of which are possible if the tune isnt right...

This is what I was getting at, I guess I didn't express it. I had an 89 Laser and advancing the ignition (because it was sluggish) certainly picked up power and response, but i went too far and it was pinging like the Alpha attack subs in the Hunt for Red October! LOL!

Thanks for helping me understand a lot better fellas!

GK