94 GT pinging, help please

Jerry Leaming · Sep 1, 2011

Had a similiar issue years back with my 94...come to find out it was a blown head gasket. The gasket blew out the header side (bottom) causing it to have a pinging sound. If I were you I would do a compression check and/or a leak down test of all you cylinders.

Canary94GT · Sep 1, 2011

Dude, it's killing me... how much would that cost? :\

Jerry Leaming · Sep 1, 2011

The tools arent to much, I believe harbor freight carries what youll need....and you can, with a buddy, do it fairly easily. As long as you have the ability to remove spark plugs you can do it. And come to think of it I believe AutoZone or a local auto parts might even rent the tools.
Taking to a shop is probably going to cost a few hours of labor.

Canary94GT · Sep 1, 2011

Well I've changed the distributor on a '65 stang before, so I don't think I'd have much of a problem doing this one.

I'm just wondering how much a new dizzy costs :\

Edit: Just noticed your head gasket post, didn't see it before.

Wish I had done the compression check when I changed the plugs recently. I hope it's not a blown head gasket.

Also, what exact symptoms were you experiencing with the blown head gasket? I am only experiencing pinging while under load and under 2500-3000 rpms

99FiveOh · Sep 1, 2011

a new distributor is 100 bucks. Ask for a Richporter from Advance Auto. Don't get a reman'd unit, also the new Richporter will have to be ordered.

Canary94GT · Sep 1, 2011

This one?

Richporter Technology FD22 - Distributor 1994 Ford Mustang | O'Reilly Auto Parts

Looks like they can obtain it in a couple days. I'll definitely consider it - I need to take my car to Midas this weekend to have some exhaust tips welded on, so I'll ask them if they have any input on the pinging situation and/or can run tests that I cannot.

99FiveOh · Sep 1, 2011

that's the one

Canary94GT · Sep 2, 2011

I'm kind of starting to wonder if what I'm hearing really is pinging.. so hopefully a guy from Midas can take a drive with me tomorrow and tell me if it is or not.

The noise happens at very low rpm's, when I'm accelerating from idle (~650rpm) to around 1500 rpm. It happens at low rpm, no matter the gear. I really don't hear it in higher rpm's.

Retarding the timing didn't seem to do much, different fuels don't really seem to do anything, and none of these parts have really done much...

It is a "pinging" sounding noise. My passengers seem to have a hard time hearing it, to give a sense of the sound level.

If it is pinging, I'm wondering if it's something like a blown head gasket that isn't really affected by me changing all those parts.

Would it help if I posted picture(s) of my spark plugs that have been in my "pinging" engine for a couple thousand miles?

Canary94GT · Sep 2, 2011

Here are some pics of my spark plugs that were in the engine for a couple thousand miles while I heard the "pinging"

Do they show signs of detonation? All the spark plugs look similar to these.

The oil fouling is probably due to the clogged PCV system that I recently fixed.

Adam95GT · Sep 2, 2011

My first thought was a spun balancer... then I read he checked it. If you can get a video it would be great. I've had a shudder due to 02s going bad.... as well as pinging. As you stated going wot will force open loop and ignore the 02 sensors. You can also force open loop and check how fast your 02s are switching with a tuner.

Your plugs look a Tad bit lean to me.

Adam95GT · Sep 2, 2011

Have you checked your vac lines....?

Canary94GT · Sep 3, 2011

I haven't checked my vacuum lines because I'm not sure exactly how. But also my idle doesn't seem abnormal.

I don't want to use carb cleaner because that can harm plastic/rubber.

Can I use MAF sensor cleaner (safe for plastic) or water (in a spray bottle)?

Also, I did replace the o2 sensors a couple days ago, which may have helped a little bit, but the pinging is still there

If I can get the camera to pick up the sound from inside the car or find a way to temporarily mount it in the engine compartment, I will try to get video of it.

Adam95GT · Sep 3, 2011

Canary94GT said:
I haven't checked my vacuum lines because I'm not sure exactly how. But also my idle doesn't seem abnormal.

I don't want to use carb cleaner because that can harm plastic/rubber.

Can I use MAF sensor cleaner (safe for plastic) or water (in a spray bottle)?

Also, I did replace the o2 sensors a couple days ago, which may have helped a little bit, but the pinging is still there

If I can get the camera to pick up the sound from inside the car or find a way to temporarily mount it in the engine compartment, I will try to get video of it.

Do not use water............

You can get a vac gauge...

Ive always used starting fluid or carb cleaner with no issues. You can also use an unlit propane torch.

Canary94GT · Sep 3, 2011

I have a vacuum gauge but was told they don't really tell you much with these newer cars.

What would I be looking for, just a steady reading of around 18 inches?

Also, what would be the best vacuum line to use?

99FiveOh · Sep 3, 2011

trust me, carb cleaner will not hurt anything. It evaporates so quick that it won't have an impact on anything unless you sit there with a direct stream of fluid right on plastic. It's mostly useful to see if you have any vacuum leaks along the upper to lower intake seal and the lower to cylinder head seal. Hoses can be removed and inspected, however, if they have any kind of miles on them and you pull them off, might as well change them anyway. They are dirt cheap.

Adam95GT · Sep 3, 2011

Canary94GT said:
I have a vacuum gauge but was told they don't really tell you much with these newer cars.

What would I be looking for, just a steady reading of around 18 inches?

Also, what would be the best vacuum line to use?

Doesent matter what line.

Canary94GT · Sep 3, 2011

Vacuum is fairly steady at around 17"

Haynes manual says it should be between 17-22"

So mine is on the lower end.

That could be because my timing is retarded to 6*, right? More retarded means a lower vaccuum iirc?

Also, when I rev the engine, it goes straight to zero then shoots back up about 5" above normal as it should.

Zero Signal · Sep 4, 2011

Your PCV shouldn't have looked like that. How much oil are you consuming? Pull the PCV again and see if it's clean on the vacuum side. If it's dripping with oil, you will want to do a compression test and leakdown test to check for blow-by. The blow by will force way too much oil through the PCV into the intake while driving which would cause pinging and smoking if it's bad enough.

Have you double checked the EGR? I know you said it was fixed, but you should make sure yourself.

89llx · Sep 4, 2011

mine will do that on hot days, unless I run marathon 93

Canary94GT · Sep 4, 2011

Zero Signal said:
Your PCV shouldn't have looked like that. How much oil are you consuming? Pull the PCV again and see if it's clean on the vacuum side. If it's dripping with oil, you will want to do a compression test and leakdown test to check for blow-by. The blow by will force way too much oil through the PCV into the intake while driving which would cause pinging and smoking if it's bad enough.

Have you double checked the EGR? I know you said it was fixed, but you should make sure yourself.

I think before I replaced the PCV valve and filter, I was consuming oil through the air cleaner intake. Since the change, I haven't noticed much if any oil through there, but I just cleaned up the hose to make sure so I need to drive it to see.

I've driven a solid 100 miles or so since I changed the PCV stuff and notice only a couple drops of oil on top of the filter when I look down inside. But the pcv valve itself has a light coating of oil around its base where it slips into the grommet.

I have ordered a new grommet, though, because mine is fairly loose and I'm afraid it may be causing a small vacuum leak.

Oil was changed around 250-350 miles ago and I haven't noticed it drop much if at all on the dipstick. I also never see smoke out the back unless it's a really cold day when it's more like steam. Also, when I pulled my o2 sensors, they were very white, not black. Not sure if that says anything.

A few posts up I posted pictures so you can see my spark plugs that I had in there for a couple thousand miles before the PCV replacement.

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