Knocking and Pinging

[TC]

I have a 91 Eddie Bauer with the V6 engine. I can't seem to get it to stop knocking and pinging. I used to run Super unleaded gas in it and now I'm running just regular (can't afford the good stuff anymore) Anyway, what can I do to make it stop knocking and pinging and maybe up the miles per gallon I'm getting in town. Thanks

 

[FMExplorer]

TC,
I've noticed in my '93 that when oil levels are done 1/2 qt or the oil is old it will start to knock. As far as the cost for the extra gas... If you check your gas mileage you will find by running premium you actual cost/mile is less than running regular. It may cost 5-10 bucks more per tank, but the mileage is better and the engine will love you for it!

JM

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Jon McLeod
'93 XLT

 

[Explorerdude]

TC,
You may find that if you switch to 89 octane gas and stick to this switch that it'll solve your problem. I'd also say that if you haven't changed your oil lately, go ahead and change it. Make sure you use an Oil that has additives in it and not some cheap off brand. I use Penzoil and I will only get real bad pinging when my oil is old or I use a different brand or grade of gas.

I use to only use premium grade gas. But like you, it got expensive and since the Explorer runs best on 87-89 octane gas I decided to switch back to 89. Before I made my switch I tested several brands and octanes to find the one my truck prefered. I found that Sunoco 89 octane gas runs best in my area, followed by Citgo 89 octane. I found that 90 octane and above actually gets worse gas mileage and makes the engine ping more when you initially switch to it and when you switch back to 89 octane or lower the pining gets worse than better. I asked around about why that was true. I was told that the 4 Liter is designed to run on 87 octane gas that has cleaner additives added into it and that without the proper timing adjustments, 90 Octane and above actually hurts your engine. I have also found out that depending on the climate that which you live in, you may need to switch to 89 octane. If you look at a Chilton Manual or your owners manual it'll explain that.


Your truck doesn't need 90+ Octane. The reason why some engines need that octane level is due to their compression ratio's. If your engine has a ratio higher than 10:1 then the only octane level safe for the engine is 91+. That's why they sell 90+ gas.

However, if you adjusted the timing on your 4 liter you could gain some benifit from 90+ octane gas. But since the Explorer 4 liter doesn't have a true distributer cap and rotor you can't adjust the timing. Dead Link Removed

Of course these are only things that I've found true with my truck. Engines are like women they all have issues. Some are picky and some are not.

Just my $0.02.

Happy Wheeling,

Joe Dead Link Removed
Explorerdude@hotmail.com
94 Explorer XLT
4" Superlift Suspension Lift
33X10.50 BFG AT KO's
Manual Hubs

[This message has been edited by Explorerdude (edited 02-12-2000).]

 

[FC2ED]

My 94 Navajo had a bad pinging problem which was related to a dirty MAF and I think some bad gas. Try claening your MAF and reset the computer.

 

[rockylaurence]

T/C;
I've had pinging for a year now. I avoided fixing the problem by running 93 in it until recently. I decided to try and track down the problem and over the last few weeks I've cleaned the MAS; replaced the o2 sensors , plugs and PCV with no luck (cleaning the MAS did seem to help). My manual states that a possible (the only one I haven't checked yet) cause is "carbon build-up" in the heads, which requires removal of the heads. So. I'm back to the 93. Yes, I have run practically every type of cleaner through it to remove the build-up with no luck. Note: there are several threads out there addressing this issue--check'm out. Let me know if you find a fix.

 

[TC]

Thanks fellas. I'll try the mid-grade and see what happens. As far as the oil goes...I get it changed every 3000 using penzoil 30wt

 

[Explorerdude]

TC,
You should check what your Explorer Manual says about oil viscosity. I believe the Chilton reccomends 5W30. Also make sure the Penzoil you use is the stuff with Purebase. That stuff seems to work real good in my truck. Hope this helps.

Joe Dead Link Removed
94 Explorer XLT
4" Superlift Suspension
33X10.50 BFG AT KO's

 

[raven2]

I remember reading in past posts that pinging can sometimes or is caused by restricted oil flow under load, this can be a result of a poor oil filter, which may be why some have results with an oil change. Try a higher end filter like Mobil-1 , and stay away from Fram.

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91 Sport

 

[ExploreMinnesota]

raven2
I'm curious about your "Stay away from Fram" comment. I've used nothing but Fram filters in my 91 EB since it was new. I use Mobil 1 5W30 and change the oil every 3,000 miles. I have 144,000 miles on it and the engine runs beautifully (except for a bit of an idle problem lately, which I believe I have traced to a vacuum leak) and needs no added oil between changes.

Why should i stay away from Fram filters?


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ExploreMinnesota
91 EB 4x4 Stock

 

[Gofast]

As far as the carbon build-up goes, You can run Transmission Fluid thought the motor. I saw this someplace ( I thought here )where they had tranny fluid hooked up to the PVC valve ( I think ) and let the vacum suck tranny fluid in through the intake. The tranny fluid being much cooler than the carbon built-up on piston tops etc. supposedly broke that stuff free.
( Translated = lot's of smoke ) Not sure if this really works, I've heard this all before. Since I'm pinging at 90 MPH undeload now, maybe I'll gicve it a shot. I always thought it was the O2 sensor giving an inaccurate reading and leaning me out on fuel. Good Luck

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Rob Robertson
94 XLT 4X4 4 door
"It's an Explorer Thing, you wouldn't understand"