Does a large plug gap really cause pinging?

99FiveOh · Sep 3, 2009

I've been battling a pinging issue on a car that runs relatively well, but has high mileage. No engine codes at all and 9~10* base timing on a new balancer. Running 89 octane. 93 octane will clear it up, but I'm not going to spend the extra money on it.

My EGR is non-functioning; though it is still there, just blocked off with a penny. But it was pinging before I took the EGR offline.

I read on a couple threads that larger plug gaps "could" cause this problem, but I didnt' see anyone confirm this.

Now, I've owned a few Foxes and a few SN's in my time and my Fox cars NEVER pinged, even on the hottest day with 14* timing and 87 octane.. well, maybe a ping here or there if it was crappy gas

So, one of the big differences in these cars is plug gap. I believe Foxes ran somewhere in the low 30's and our cars want like a 55 gap IIRC.

Could it be that simple? Anyone with first hand experience battling a pinging problem confirm this?

revhead347 · Sep 3, 2009

My car pings like an Asian Whore in the summer at mid throttle and low rpm. It's so weird, wide open, no problem. Never been able to get it to stop completely, but putting a oil/air seperator on the PCV line helped a little bit. I also don't have an EGR. I'm not sure how much difference the plugs make, but you can try? It doesn't take long to pull them out.

Kurt

GDTrumbo · Sep 3, 2009

Try this. Clean the MAF sensor, temp sensor (use MAF cleaner only!) and TB out. Set the plug gap to spec's and hook the EGR back up. Disconnect the battery for 15 min's & let the PCM reconfigure itself and drive it again.

The EGR actually helps reduce cylinder temps as well as help with emissions. Higher cyl. temps help induce "pinging". Contrary to popular belief, removing it does not produce more power. It usually just causes the PCM to throw codes.

GT

99FiveOh · Sep 3, 2009

But removing the EGR does help with the expensive EGR tube that BBK want's for their headers!

I just installed a pieced-together CAI yesterday and while I was in there I cleaned the MAF and the ACT was spotless! I can feel a HUGE improvement in power just with the CAI, but it still pings. I'm been around these cars for a long time and have tried pretty much all the rememdies accept regapping the plugs. I'm going to try that and see what happens.

revhead347 · Sep 3, 2009

The_Mustang said:
But removing the EGR does help with the expensive EGR tube that BBK want's for their headers!

I just rebent the stock tube on the 94' Cobra I just did. It took maybe 15 minutes to get it to fit. It's not too bad.

Kurt

HISSIN50 · Sep 3, 2009

Aero foxes and our cars run the same 0.052-0.056" gap.

You could try running one range colder if you want (i.e. Autolite 24's).

947166 · Sep 4, 2009

+1 for colder plugs.

I have a 94 that is basically stock except for underdrive pullies, CAI, high flow cats and Flowmaster cat back exhaust. It pinged a lot under load, I changed the plugs to 1 heat range colder and the pinging went away completely.

99FiveOh · Sep 4, 2009

Really??!! And how much timing is it allowing you to run now? Any side effects to performance or SOTP feel?

HISSIN50 · Sep 5, 2009

No side effects with one range colder. The colder plugs help more with preignition than detonation (regarding your timing advance question).

Though it might have had some detonation with the EGR functional, having the EGR gasses blocked while still having the EGR electronics thinking it's functional cannot help the issue.

You could try locking the timing if you want.

99FiveOh · Sep 5, 2009

Or I could throw a Fox puter in there and have some fun for a change. I remember having "FUN" with my fox cars, throwing all kinds of mods at em without much regard to the "tune". Don't get me wrong, I love our SN95's, I can never get used to having a box on wheels again.

Since so many people want Fox (A9x) drivability out of our cars, why can't someone put out a chip that will basically turn our computers into Fox computers? Ours are supposed to be more advanced, correct? So it's not difficult to emulate a slower computer with a faster one.

HISSIN50 · Sep 5, 2009

final5-0 · Sep 5, 2009

revhead347 said:
My car pings like an Asian Whore in the summer at mid throttle and low rpm. It's so weird, wide open, no problem. Never been able to get it to stop completely, but putting a oil/air seperator on the PCV line helped a little bit. I also don't have an EGR. I'm not sure how much difference the plugs make, but you can try? It doesn't take long to pull them out.

Kurt

If you look at the spark table in that little silver box
it would make perfect sense

Grady

final5-0 · Sep 5, 2009

The_Mustang said:
Or I could throw a Fox puter in there and have some fun for a change. I remember having "FUN" with my fox cars, throwing all kinds of mods at em without much regard to the "tune". Don't get me wrong, I love our SN95's, I can never get used to having a box on wheels again.

Since so many people want Fox (A9x) drivability out of our cars, why can't someone put out a chip that will basically turn our computers into Fox computers? Ours are supposed to be more advanced, correct? So it's not difficult to emulate a slower computer with a faster one.

It is important to remember the almighty Fox A9L

It may allow more mods without acting up
but
If peeps think a serious effort with mods .......
will be in good tune without it being optimized .............

Well ... Their name IS Alice
and
They DO in fact ... Live in Wonder Land

I'm just trying to point out .......
drivability and max efficiency ain't the same thing

Now ... Here is the REAL reason 94-95's ping

Ever wonder why the 94-95 Cobra boys don't sing about ping
but
The GT peeps cry all the way down the road to ... Ping City

Folks ... Its all about how Ford setup the pcm in the GT & Cobra

The GT is just on the verge of ping when it rolled off the line from Ford

The Cobra has a bit more fuel in place
and
A bit less spark

Both will cause the Cobra to not ping as the GT does so often

Another thing I've seen is .....
the combustion chambers in GT's E7's can promote ping

Several years ago I laid back the c walls just a tiny bit in a set of E7's
while I had them off for some down home self porting and ping went
away even though I was runnin 36 for total spark

Grady

99FiveOh · Sep 5, 2009

As far as I know, the E7's in my 94 are exactly the same castings as those found in 93 and prior 5.0's, but miraculously, they don't ping! Why? Cause they have a computer that cares more about performance than emissions.

I've been around these forums long enough to have read the countless debates about tuning vs PIH..etc, etc..

I just don't think it's cost effective to get a dyno tune for trivial things such as pinging, tip in retard, fan controls, etc, when those things should have been ironed out on our beloved 'Stangs before they rolled off the assembly line. They took care of those things with the Fox, why not the SN95?

I know, I know...to properly set up a Fox computer in my car will cost around the same as a dyno tune, however, what happens when I want to add a part? Say a new cam or heads? It's back to the dyno to hand over at least another 200 bucks on top of the 4-500.00 I already spent on the first dyno tune.

I understand an A9L won't be optimal, but it'll be close and more importantly, it will be driveable! That's the key word for most guys, they'd rather leave 10-15hp on the table in the name of great drivability... but here's the kicker... ready? 9 out of 10 people who have swapped claim to have GAINED hp and lowered ET's!! But how can that be when the T4MO is FASTER??? More superior!!!

Do you realize that NASA uses the same ancient technology to launch space shuttles as they did many years ago? That's right. Most of the launch software is still contained on old fashioned real to real tape drives. Why? Because it works. Why mess with success right.

It has always been hit or miss with these cars I'll tell ya. My last one was an awesome ride, yes I got it tuned, but I just spent about 3500 bucks on a supercharger and supporting hardware so the car was worthy of a tune. But not a stock car, it's not worthy of 500$ in tuning. Last I knew, cars were supposed to have good drivability from the factory.

Ford always seemed to have a "Fix" for these types of problems, but I must have missed the technical service bulletin in the mail, or the recall paper.

-end rant

final5-0 · Sep 6, 2009

The_Mustang said:
As far as I know, the E7's in my 94 are exactly the same castings as those found in 93 and prior 5.0's, but miraculously, they don't ping! Why? Cause they have a computer that cares more about performance than emissions.

I just don't think it's cost effective to get a dyno tune for trivial things such as pinging, tip in retard, fan controls, etc, when those things should have been ironed out on our beloved 'Stangs before they rolled off the assembly line. They took care of those things with the Fox, why not the SN95?

I'm right with ya Mark

Yes ... Its not cost effective to pay a Pro or Purchase self tuning
equipment to deal with the things you speak about

Agree or disagree with what Ford did ... makes no difference

I just wanted to help GT peeps see what they are up against

I will stand firm about my findings with those old iron E7's

Before I ever got involved in self tuning I was able to run 18 with
my old combo which would have put total advance at about 34
and I did not have to deal with ping. Only difference was a different
set of E7's and the work I did on them.

Again ... I see and can relate to your thinking

Grady

turbogt · Sep 6, 2009

final5-0 said:
It is important to remember the almighty Fox A9L

It may allow more mods without acting up
but
If peeps think a serious effort with mods .......
will be in good tune without it being optimized .............

Well ... Their name IS Alice
and
They DO in fact ... Live in Wonder Land

I'm just trying to point out .......
drivability and max efficiency ain't the same thing

Now ... Here is the REAL reason 94-95's ping

Ever wonder why the 94-95 Cobra boys don't sing about ping
but
The GT peeps cry all the way down the road to ... Ping City

Folks ... Its all about how Ford setup the pcm in the GT & Cobra

The GT is just on the verge of ping when it rolled off the line from Ford

The Cobra has a bit more fuel in place
and
A bit less spark

Both will cause the Cobra to not ping as the GT does so often

Another thing I've seen is .....
the combustion chambers in GT's E7's can promote ping

Several years ago I laid back the c walls just a tiny bit in a set of E7's
while I had them off for some down home self porting and ping went
away even though I was runnin 36 for total spark

Grady

My cobra has NEVER pinged, even when lugged on a hot ass day

99FiveOh · Sep 6, 2009

uh, ok?? I think Grady was just confirming that fact when he said "Ever wonder why the 94-95 Cobra boys don't sing about ping"

I believe it's a combination between the head design and tune. I wonder what a J4J1 computer would do with E7's?

earleys94gt · Sep 6, 2009

If memory serves me correctly, aren't the E7 heads off the trucks; like 302 F150's?

So, do they have the ping problem too?

Do the trucks have the 24 lbs. injectors like the Cobra's do?

Is it just a simple matter of more fuel?

99FiveOh · Sep 7, 2009

Yes, E7's were originally a truck head. I doubt the trucks have the pinging problem because they are built to be under heavy loads and rough running conditions all the time. And since they are the top seller for Ford (have been for many years) they always had to be spot on as far as drivability and reliability.

Our cars were built to bridge the short gap between Fox's and the 4.6 powered Mustangs. So the cars are really a hack to begin with. While they are a refined vehicle compared to Foxes, it doesn't look like enough attention was paid to the tuning they gave us. Again, like the F150's, they knew the Cobra's would get "Used" for their purpose, so they took a little more time in making sure they'd be reliable.

Anyway you slice it, the GT's got the short end of the stick! Even V6's seem to take punishment better than GT's do!!

GTA_V6_Mustang · Sep 7, 2009

Well I had a horrid pinging problem too on one of my 94's with e7's. What I ended up doing was seafoaming it, cleaning MAF and IAT and using 1 range colder plugs and it was good. Then when I changed to a 70mm t/b and P&P cobra upper and lower was able to run more timing with less problems, I remember reading something about the better fuel/air distribution of the GT40/Cobra intakes. And to help it even further a phenolic intake spacer allowed even more timing without pinging. And as far as my 2 sn's go ive never had issues with driveability and mods. Especially the red one and believe me if one was going to have driveability issues with an aggressive cam my red one would. I guess it all has to do with the way you keep it too. The smallest vacuum leaks you dont even realize you have all add up and cause issues. I keep my cars running tip top so driveability never seems to be an issue with my sn's

Oh and to answer the original post I personally think lowering plug gap helps a little. Like I said It was one of the things I did that helped.

Does a large plug gap really cause pinging?

99FiveOh

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