1st Gen R53 Cooper S Engine Pinging on acceleration at high rpms + engine running lean

So...

you have a 17% pulley and what else? When the tune was put on your car, how was this done? Just a plug and play tune or one done on a dyno with some data logging?

The fact that it's at high RPM at WOT (Wide Open Throttle) sounds like it's a fuel issue. These are classic symptoms of not enough fuel for what your car needs. But before you go changing stuff, it's best to know more about the before and after.

In your post you say that "ever since" your tune in May.... So did it start exacly when you got your tune? If so, it's the tune isn't well matched to what your car is doing. If it's a canned tune that works on other cars with the same mods, then it's possible something on your car isn't doing well.

Fuel pressure regulators, spark plugs, injectors etc can all make this happen.

If the connections on your coil were cleaned, it should be good. What did you do about the connections on your plug wires?

There's really not enough information here to say what is causeing your problem. Give some more details (how was the car tuned, what else is on your car etc) and maybe some of us can help. If there is a problem with your fuel regulator, then just slapping on 550 cc/min injectors (and getting a retune) is a very expensive fix that masks the true cause of the issue.

Matt

 

Don't forget...

the wires. The corrosion on the coil terminals means the plug wires are corroded as well.

Mynes does thier stuff pretty well. Give them a call as well, as they'll know what they did with your car.

Matt

 

I would definitely recommend one-step colder than OEM plugs (BRK7) with a 17% pulley...

Define "high RPMs" - did Mynes raise the rev limit with the tune? Approximately what RPM does the pinging start?

380 (JCW) injectors should be plenty unless the rev limiter is REALLY high, or unless you plan to add other mods (head, cam, etc.)

But I agree with the doctor... understand what's happening before you start throwing parts at it.

If it was a dyno tune, they should have seen any AFR issues when they did the tune... unless they tuned it really close to the edge in cooler temps, and the higher temps during summer are exacerbating the issue.

 

It seems unusual that Mynes would tune your car with stock injectors and then tell you that you need larger injectors to work with their tune. Did you tell them that you plan to install larger injectors so they tuned close to the AFR edge knowing you would install larger injectors?
+1 on different spark plugs and checking both ends of corroded connections.

 

Just adding a pulley

won't make the car run bad. Thousands have added just the pulley and been fine. You are running awful short on fuel, but others have run what you're running without the knock...

Matt

 

Sorry - forgot you said it's an auto (so is mine) so rev limiter doesn't come into play - in fact you'll never get the car over about 6700 RPMs... which really isn't THAT high. When we usually think about tuned cars doing weird things at high RPMS, we're thinking over 7000 - but you won't ever get there.

Where are you located? What are the temps like? Does it do the same thing in the cool of night as it does during the heat of day?

If Jan saw it that low on fuel at upper RPMs, seems like SOMETHING is making issues in your fuel system... because even the stock injectors shouldn't be that lean on an auto if tuned correctly. Fuel filter? Fuel pump? Pressure regulator? Clogged / dirty injectors? Something is up IMHO.

 

Guys, one thing to consider is he has an automatic transmission WITH his 17% pulley.

I'm in the same boat as you. 17% pulley. And colder plugs. Plus a tune. On a dyno. Ran fine for the dyno pulls but immediately started pinging once I was on the road with it.

So we change to a different style of plugs and go to JCW injectors. Another tune. HARD tunes this time. No pinging on the dyno.

Back out on the street the pinging starts again.

Then talked to some other folks. They're recommending 550 injectors and another tune. Plus more dyno time.

I'm in complete agreement but don't have yet another grand to throw at it.

And of course, there's always removing the 17% and going down to a 15% pulley.
But I'm stubborn. So no undersized pulley.

And this was all on a late model with low low mileage on the clock.
My thoughts are that the automatic does play a factor in how the engine performs, and of course, one size does NOT fit all.


I'd think that 550s trimmed properly to idle well and tuned well will help eliminate my issues. But these days I'm pretty much over it.

I should have gone with what my previous car experiences were telling me out of the gate, rather then listening to others.

Did I mention I'm stubborn? Know it all? Not at all, but as much as things change, some things also stay the same.

 

I'm running:
MCS automatic
17% pulley
Thumper TPR-1 head
RMW/Newman cam
RMW street header
JCW exhaust
JCW intake
ported intake manifold
stock intercooler
380cc JCW injectors
RMW tune

No pinging. Ever. Even with the meth turned off.

550's just seem like huge overkill on the automatic with a stock head.. If you're turning 8000RPMs with a big valve head... sure, you can use lotsa fuel flow...

 

If I was having your issues, I'd do the following:

1) have the dyno tune validated
2) have someone do a fuel pressure test
3) installed colder plugs and JCW injectors (or get my injectors tested/cleaned)

 

This...

could be something as simple as a dirty fuel filters.

To start this, check fuel pressures at load. You may need some help with this, but basically, you hook a fuel pressure gauge to the shrader valve fitting at the end of the fuel rail, and take the car out and drive the snot out of it. See if you're getting a fall off in fuel pressure. If you are, you're check that side of the system first. So that's the pressure regulator, the fuel filter, the fuel pump. If you're not then you attack the fueling side: Injectors! There are lots of places that can clean and measure injectors, I've used WitchHunter Performance - Injector Cleaning & Flow Testing Services as they are on my coast, and are fast and relatively inexpensive. A dirty injector can make one of the cyliders run lean...

Anyway, I'm still a fan of proper diagnostics before I spend more on parts.... Unless they are really cool parts, then sometimes I just get the stuff anyway...

Matt

 

Spooky! Matt and I agree on something else... :lol:

 

I would get whatever your tuner recommends. But if you get anything larger than 380's the car will probably run like crap (if at all) without a retune. Most folks installing the high flow injectors actually do it when the car is at the dyno waiting for the tune. I don't think you NEED anything larger than 380's with the automatic. But some tuners like to have the larger injectors to play with.