Can an engine ping under medium load even if it doesn't ping under heavy load?

[WHITCHY]

Sorry if this sounds like a weird question, but I am running a 100kw 4age with quads and a microtech, and at light throttle it is normal, but when I am on about half throttle there is a noise that sounds very much like loud pinging? But when I put my foot flat to the floor it goes away?
if I start going up a hill and put it in 4th or 5th and put load on the engine with my foot flat to the floor it doesn't ping, but as soon as I start to lift my foot of the gas at around the 50%throttle point it starts making the noise? so is this noise just something to do with the quads, or is it possible that it is pinging?

I went and visited a mate before and he hooked the microtech up to his laptop and checked out the air/fuel mix and it was running lean at the point where it sounds like pinging, so he put some more fuel in and it is still making the noise?

Its really annoying trying to drive either with light throttle or flat out, cause I really don't want to blow this motor up just yet!

Thanks in advance for any info!
Cheers.
-Whitchy-

[Draven]

with an aftermarket computer it is very easy to ping under medium load and not heavy load - the solution is to either put more fuel in at the designated mapping points (which you've done) or take out some timing... perhaps that could be the next step? Also, depending on your mate's tuning competency, it might be worth taking it to someone who knows how to tune a microtech and get them to check your map

[sideshow]

checking air fuel on a laptop is not right

u need a proper air fuel ratio meter worth anywhere over 500 bucks up to 2000 bucks

just spend the money get it tuned by a proffesional

have you had it tuned properly or are you running on the tune it came with or have you tuned it roughly by driving it

cause if you ahvnt done it on a dyno or with a good air fuel meter then yr an idiot just like alot of other people i have done microtechs for

[Billzilla]

Can an engine ping under medium load even if it doesn't ping under heavy load?

Yep.
(10 chars)

[ViPeR_NiPPleX]

My engine pings under load with its current vacuum leak. Medium throttle up hills seems to set it off, planting the foot puts it back right

[Fattony]

How can you know if it is running lean at the load points on 50% throttle without the use of a proper wide band AFR meter? If your car has been tuned, it sounds like your car has spent most of the time getting the tune done at WOT, which is what quite a few tuners do. Id suggest you get the car on the dyno, get a proper AFR meter onto the car with a decent knock sensor and try to replicate the condition. If at that point you are running proper AFR's pull some timing out,

Secondly does it happen when you suddenly when you sharply change throttle position to that 50% and go away? Could be a case that you require a little more acceleration enrichment.

[1jzracing]

also if its got quads and running load from TPS its easy to get cylinders filling clost to wide open situation when the throttle is only half open (and only half way up the load scale) at mid revs and if this is close to the rpm that max torque is produced then the timing will need to be pulled back a bit lower in the load band than you would usually think

once you mash the throttle the load band shoots to the top and the timing should be less (and as sugested fuel should be more) you will get better economy from removing timing rather than adding fuel to fix it and no less power

id be dropping a few degrees out at a time in the area its pinging untill it goes away

[WHITCHY]

Sorry I should have mentioned that! we had a wideband AFR sensor plugged into the exhaust!
I am just running the tune that the ECU came with, which is for the same motor the only difference being extractors.
The noise happens no matter if I slowly get to that 50%ish mark or if I get to it suddenly.

I don't want to spend the money getting it tuned on the dyno yet as I have some bigger cams I want to put in first. I just wanted to know if the noise could be pinging so I can avoid med throttle untill I get the cams set up!

Thanks for all the info!
Cheers.
-Whitchy-

[Cuzzo]

Im getting the impression with a smallport on standard ecu compared to standard ecu on bigport, the smallport pings a bit more on meduim load.

Is this possible with the difference betweent two?. Could it be a smallport issue?

[KGB]

Hmm think about oil in the intake only takes a small bit .... had a 5m doing this ....um is your breather runing to inlet manifold ..... something to check & try takeing some timing out at said point ....

@2C Keith:

[Draven]

also different extractors put your power in different areas... 4-2-1 will give you meatier mid range, 4-1 better top end at expense of mid-range (or the other way around - different anyhow)

edit: and I don't know how microtech stock tunes are these days, but when I bought mine many years ago they were considered a "get you to a tuner" map by many

[TurboRA28]

Mate I reckon the base timing must be wrong.
Mixtures & timing were fine on ECU. But if base timing is out then what we are seeing on the ECU in regards to timing could be all wrong.

Organise a weekend when you can come up and we'll work through it.

Cheers
Joel

[myne]

Does it sound exactly like pinging?

Can you reproduce this sound by free-revving the motor at a certain rpm?
If you can, then odds are it's piston-slap or mild bearing wear in the bottom end.

A while back I inspected a corolla a mate was considering, moved the throttle by hand, and slowly increased the revs. At about 3500rpm the piston slap (loud metallic rattling not too dissimilar to pinging) must have come into its natural frequency because it was much louder than the rest of the rev range.

Ofcourse, it could simply be the tune, and will not show up while free revving, but others have covered that.

[StuC]

could it be something rattling? Ive had similar noises pop up in certain areas that sounded so much like pinging it wasnt funny. Turned out that it was just some things rattling around at certain revs -harmonics etc etc...... But i agree to go and get it tuned ASAP and if you want the cams in, put em in, tow the car and get it tuned then.

[WHITCHY]

nah it doesnt make the noise in neutral, its just at that certain throttle point, I was playing with it more today and it does it wether there is heavy load on the engine or very little, so even if Im coasting down a hill in gear and i get the throttle to that point it still makes the noise!
Joel, I have blown all my money on this LSD setup, gimme a week to save to get these cams in, and then another week to save some more coin so I can feed u pizza and booze and fill your wallet up a little! oh and there is a massive credit card bill due somewhere between there as well! and some rent!
As soon as all my debts are taken care of I'll be down at yours! unless you wanna sort out some payment plan? only 99 weekly payments of $99.95 + $14.95 postage and handling!
Cheers.
-Whitchy-