most of you have read my previous threads and are aware of my situation and problem with my car and it's mysterious pinging....

i took it to the dyno yesterday and all that i got was that when it pings black smoke comes out of the exhaust yet the AF's are at approx 10.9:1 and dont move at all, nothing on the graph moves mind you....

everyone thought it was the weirdest sound they have heard and the mechanic who was running the dyno said it didnt sound as if it was "pinging" or "detonating"....

a friend of mine was there who knows a fair bit about RX7's and had said that if it was indeed pinging that it would come from the left side of the motor closest to the plugs, while everyone ( approx 15 people ) said it sounded as if it was comming from near my turbo....

not sure what else i can tell you guys, i did a whole grounding kit and it helped with my idle and such, the TPS is spot-on and the timing is at top-dead-center or however they had said 'cept for the fact that the trailing is off a degree or 2....

people suggested that there is a good chance that it is my turbo, inwhich i just got a new one in mint condition that will be going in eventually....

my current turbo is going and you can hear the compressor wheel scraping the housing in 1st and sometimes when you boost it....

if there are any other details i will be informing you guys asap, my friend has a vid of the dyno and i'll try to get him to post it in here....

thanx for your help guys, hopefully soon i can enjoy this thing....

 

Pull the spark plugs - what color are they?
You might be running too rich, and the "pinging" is actually the spark plugs misfiring?
Try and back off the fuel to see if this helps?


-Ted

 

it was running high 9's for AF before and never pinged....

i'll check the spark plugs on my next day off....

i also added more fuel to the points where it did ping and it didnt help at all, at around 6000rpm where i added fuel it refused to revv past 6000rpm until i took some fuel out....

 

change the spark plugs.

 

Yep, I encountered this problem a while ago. I was getting misfiring, and I put my LM-1 on and saw that the pinging would start at around 10.5 or so. I leaned back out to about 11.3 and the pinging dissappeared. I even made some posts about it.

Food for thought..

Rat

 

i leaned it out to 11.6:1 aswell and it still does it, but this is the weird part, i got one or 2 pulls in WITHOUT it doing it, and the rest it did....

the spark plugs were just changed aswell....

 

Are you saying that it didn't ping on the 1st 2 runs, and then it did on the later runs once the engine, oil, and coolant are overheated???
You need to monitor your coolant and oil temps to see IF it starts happening at a certain temp and if a simple cool down prevents it.

 

when it does this pinging, does it jerk?

edit: also, do you have access to any racegas? like 110 octane or so. try putting some of that in (hell, even some 100 octane) and see if it still does it.

if you put some high octane gas in there and it stops, the problem is probably detonation. you're running 93 octane right?

 

Why dont you get rid of that crapped out turbo first, then try to troubleshoot?

 

I have 3 videos of his car on the rollers. 1 was successful and 2 were non-successful and you can hear this 'pinging' noise.


Im having some trouble converting the files to smaller ones, but it will be on putfile as soon as I get it converted.

 

i'm running 94octane yes, the pinging does NOT go away in the later pulls, my first pull was not sucessful, the second was, and so forth....

yep i thought i would ask you guys what you thought but i will change the turbo and go from there....

when it "pings" it jerks slightly....

 

dont hammer on it til you do a little more research.

also, do you have access to any racegas?

also#2, try retarding the timing and see what happens.

 

i havent hammered on it since it made the noise the first time, scares the **** outa me....

there is no change on the dyno chart, the AF stays the same, power stays the same, etc etc....

the car's probably going to be parked soon, but how would i retard the timing a little...?

 

Dude, pinging would be readily apparent on the Dyno (loss in power) sheet AND the AFR tracking. Sounds to me like you need to remove/replace the turbo and do it FAST.

 

i got a mint S5 stocker sitting downstairs on the bench....

i hope it's just the turbo....

 

I agree.
If it is detonating, it would be very obvious on the dyno graph.
Can you post it?

It sounds like you might have something loose banging around?
Loose heat shield or exhaust leak can sometime sound and feel like a "ping".


-Ted

 

i dont have a cam so i couldnt take a pic of the graph, but it's constant and normal even when it pings....

no change in AF, RPM or power....

i just hear the noise and get off the gas instantly....

 

- Dyno Clip -


Here's the clip guys, download it here:

http://members.shaw.ca/matrix9eleven/Badrun1.divx


You'll need this to view it:

http://www.divx.com/divx/play/download/



Although you might be able to get away with it and play it in Windows Media Player....

Thanx Guys!, tell me what you think....

Everyone said it was comming from near the turbo....

 

Man... What that sounds like to me... since it's under boost when it does it... is the turbine wheel actually hitting the side of the housing. Because if you say it can scrape the side of the housing, then I would imagine that even if it spins freely, at some point the centrifugal forces of tens of thousands of RPMS would make that out of balance shaft move a bit and slam that wheel into the housing.

Think of it like your motor, what happens if you try and spin your motor up to like 16,000 RPMS? Well, the eccentric shaft is balanced so at normal RPMs its ok, but at that kind of speed it will give a bit, maybe even enough to let your rotor tips smash into your housings. Now imagine if your eccentric shaft weren't balanced, or was bent, or the bearings were shot. That should give you an idea of what your turbo's going through.

Have you looked at the fins on the turbo impeller? I wonder what's left of them...

 

havent looked at the turbo at all, but i've refrained from doing anything that would cause the motor to make such a noise....

my car's going into the shop friday to get the oil changed....

last time it was making this noise i got the mechanic to check the oil for pieces of metel, thankfully nothing showed up....

but it makes sence that the turbo would do that, it would spool fine until i go WOT, then it makes that noise....

 

Uhhhhh.....your compressor wheel is scraping against the compressor housing. This wheel is spinning at 75k rpm +. You do know what happens if a compressor blade seperates and where it is going ? If a small piece comes off the imbalance could take the rest with it.

You must not care about your engine But rock out on that oil change

The noise might be a rich misfire?

James

 

Sounds like a compressor problem... Usually pinging comes in groups. If you were pinging that audibly, your car would already be toast.

 

Compressor bearing wear usually first gives the siren of death scream when the wheel first starts to hit the housing.

Did I hear what sounded like 2 sharp ticks?

I'm thinking pre-ignition more than detonation.
Like maybe from the hot corner of a carbon flake on the rotor face.

A spark leak can also sound like that.. Just a thought. Naa.

 

I am sticking to my original statement. Sounds more mechanical then anything else.

 

is that what ping sounds like?

i thought it was more like popcorn/crunching sound

u know it reminds me of 2 billard ***** hitting each other... very echo'y also...

if the compressoer blad was hitting the housing.. wouldn't the sounds be much "closer" together it almost sounds like something is "bouncing"