low octane knock
Thread Starter
|
Junior User
Joined: Apr 2003
Posts: 72
Likes: 0
low octane knock
I'm running the cheap gas in my 3.0 99 ranger(46000 miles) and I have engine knock. I read on some previous posts to try running a few tanks of the higher octane gas. If I return to the cheap gas( at todays gas prices, how can I afford not to!!) and the knock continues can any harm be caused or is it just an irritating knock?
thanks,
Mick
thanks,
Mick
Senior User
Joined: Mar 2003
Posts: 366
Likes: 0
From: Aloha (Portland), OR USA
low octane knock
You can also try switching brands of gas, as this can help, too.
If the knock is still not resolved by switching brands, there's likely something wrong, but until you can figure it out, you might as well put the good stuff in, as any sort of knocking is bad.
$.20-.30 more per gallon is a lot cheaper than an engine!
If the knock is still not resolved by switching brands, there's likely something wrong, but until you can figure it out, you might as well put the good stuff in, as any sort of knocking is bad.
$.20-.30 more per gallon is a lot cheaper than an engine!
Junior User
Joined: Mar 2002
Posts: 58
Likes: 0
From: North Beach United States
low octane knock
I have a knock in my engine as a result of running low octane gas. The knock goes away when you run 93 octane. I got tired of the knock did some research here on this site. I took it to the dealer and they had the same info (TSB) from FORD on low octane engine knock. Let them do the work recommended and I did a tuneup all for the total price of $700.00. Needless to say the problem still persists and at the same time the valves also tap. I have the same Ranger 99 3.0L V-6, 4x4, OffRoad package. The work they did was replace the ignition coil, clean the throttle body, EGR valve, oxygen sensors, flush the fuel injectors. I did a tune up new plugs, wires, PCV and fuel filter and the knock is still there. OH yeah they also reprogrammed the PCM with new octane setting and reset the timing. Then the service manager has the nerve to tell me this is the nature of the 3.0L engine. Correct me if I am wrong, but an engine with 70,000 miles on it should not knock.
Freshman User
Joined: Oct 2002
Posts: 46
Likes: 0
From: San Antonio Texas
low octane knock
I have a 98 3.0 and it has never knocked (at least as of this morning 
.) I use 87 octane and a few times in New Mexico I had to run 86 and it did not knock. But I do run some Marvel Mystery Oil thru it now and then, installed quality plugs and wires. So I do not think this is a problem with the 3.0. Or I just might for once in my life be the lucky one!!! Good Luck on finding the problem or a good service shop.
GNORMOR
.) I use 87 octane and a few times in New Mexico I had to run 86 and it did not knock. But I do run some Marvel Mystery Oil thru it now and then, installed quality plugs and wires. So I do not think this is a problem with the 3.0. Or I just might for once in my life be the lucky one!!! Good Luck on finding the problem or a good service shop.GNORMOR
Senior User
Joined: Mar 2003
Posts: 366
Likes: 0
From: Aloha (Portland), OR USA
low octane knock
My Ranger has had knock problems a couple times, but it is always after one of my family members uses it (and probably buys gas at some questionable stations). If I run a tank of a good quality premium, it'll clear up and be just fine for quite until the next time someone borrows it!
Only one time has it been bad enough where I went and bought some of that "SHOGUN" octane booster. It completely cured the detonation in that terrible tank of gas.
Ever since I replaced the plugs, wires, cap, and rotor, I haven't had any knock problems, even when someone else borrows it.
Either way, knocking isn't the nature of ANY engine - sometimes the dealers say the stupidest things.
Only one time has it been bad enough where I went and bought some of that "SHOGUN" octane booster. It completely cured the detonation in that terrible tank of gas.
Ever since I replaced the plugs, wires, cap, and rotor, I haven't had any knock problems, even when someone else borrows it.
Either way, knocking isn't the nature of ANY engine - sometimes the dealers say the stupidest things.
Thread Starter
|
Junior User
Joined: Apr 2003
Posts: 72
Likes: 0
low octane knock
I have also noticed that I do not hear the knock when idling or if I give it some gas. It is only when I am actaully driving. Is this the same with others who have experienced the knocking?
99 Ranger 3.0
5 speed
46000 miles
99 Ranger 3.0
5 speed
46000 miles
Senior User
Joined: Mar 2003
Posts: 366
Likes: 0
From: Aloha (Portland), OR USA
low octane knock
You'll generally only hear low octane knock (detonation) when under load, such as going up hills or passing.
Detonation is generally caused by bad (or too low octane) gas in my experience, but I've also seen clogged or malfunctioning EGR valves, worn ignition components, misadjusted timing, or excessive carbon deposits on the pistons cause detonation.
You should never hear a constant knock when cruising, and if you do, I'd bet you either have been getting some REALLY bad gas or have a clogged EGR valve or some worn plugs and/or wires.
Keep us posted on what you find out!
Detonation is generally caused by bad (or too low octane) gas in my experience, but I've also seen clogged or malfunctioning EGR valves, worn ignition components, misadjusted timing, or excessive carbon deposits on the pistons cause detonation.
You should never hear a constant knock when cruising, and if you do, I'd bet you either have been getting some REALLY bad gas or have a clogged EGR valve or some worn plugs and/or wires.
Keep us posted on what you find out!
Trending Topics
Posting Guru
Joined: Jul 2002
Posts: 2,205
Likes: 1
From: Vancouver WA
low octane knock
Where I used to work there was a '98 Ranger 3.0 that the tech's got to drive around. It would knock/ping no matter what brand/octane of gas was used. It was horrible on the 87 octane stuff, a little better on 89, and a little better yet on 92, but still there. If someone put 87 in it, the truck would ping constantly driving down a smooth, flat road at a constant speed. With 92, it would usually only do it under load. That truck was one of the biggest POS's I have ever driven. The '01 and '02 4.0's were 100% better.
FTE Stories
Ford Trucks for Ford Truck Enthusiasts
3 Best / 3 Worst Parts of Modern Ford Ownership
Brett Foote
10 Amazing Upgrades That Solve Common Ford Truck Owner Headaches
Pouria Savadkouei
Every 2026 Ford Engine Explained
Brett Foote
10 Ugly Ford Trucks That We Still Kinda Love
Joe Kucinski
10 Things Every Truck Owner NEEDS (2026 Edition)
Michael S. Palmer
Rezvani's Latest Post-Apocalyptic Monster Is a Ford F-150 Raptor Underneath
Verdad Gallardo
Top 10 Most Expensive Ford Trucks Ever Sold on Bring a Trailer
Joe Kucinski
2027 Ford Super Duty Buyer's Guide (Every Model, Engine, & Package)
Brett Foote
Top 10 Ford Truck Tragedies
Joe Kucinski
Senior User
Joined: Feb 2003
Posts: 148
Likes: 0
low octane knock
I had a 84 ranger that would knock with the cheap stuff(87 octane) but wouldn't with the 89 octane. I had it for ten years. Now I have a 94 ranger. I still get a knock on occasion with the cheap gas. I haven't experienced any major problems due to this knock. It has many many miles on it and is still going like new with almost 200K miles on it. I have just learned to accept it and run a tank of Premium throgh it when it starts to knock. otherwise I run the cheap stuff.
Senior User
Joined: Apr 2003
Posts: 485
Likes: 0
From: DIXIE
low octane knock
I have a 1999 3.0 myself. It just hit 60k and was knocking (really more like pinging) for the last 3 or 4 K. I cleaned the MAF sensor with some break cleaner and it went away. I guess the little wires were dirty and messing up the mixture. Anyway, might want to try this first. I did the same thing to my wife's Expy and it cleared up the 4.6 as well. Hope this helps.
P.S. AFTER YOU CLEAN THE LITTLE BUGGER, LET THE TRUCK SIT FOR ABOUT 15 MINUTES BEFORE YOU TRY TO START IT.
>>>>Life is tough, Life is tougher when you're stupid..... John Wayne
Thread Starter
|
Junior User
Joined: Apr 2003
Posts: 72
Likes: 0
low octane knock
I guess I need to go get myself a shop manual, because I don't even know where to find the egr valve or the maf sensor.
This is my first new(er) vehicle, I've always had old classics. My daily driver prior to the ranger was a 66 VW doublecab pickup. I still have her, she just needs some tlc. Anyway, no fancy hi tech valves and sensors on that old baby. Just fewer moving parts to break more often!!
This is my first new(er) vehicle, I've always had old classics. My daily driver prior to the ranger was a 66 VW doublecab pickup. I still have her, she just needs some tlc. Anyway, no fancy hi tech valves and sensors on that old baby. Just fewer moving parts to break more often!!
Senior User
Joined: Feb 2003
Posts: 148
Likes: 0
low octane knock
That is something I will have to look into myself. Maybe it will help the eronious tach reading I was getting.
I don't know if I agree with go AV's though but It appears as if my team is now the Motor City Deadwings. Enjoy the playoffs.
I don't know if I agree with go AV's though but It appears as if my team is now the Motor City Deadwings. Enjoy the playoffs.
Elder User
Joined: Oct 2001
Posts: 724
Likes: 0
From: Cypress, CA
low octane knock
I have experienced the same knocking and pinging problems with my '90 4-cyl. Following up on another thread in this forum the problem has been solved. It was EGR-related. The control for the EGR was failing. I found this out with a vacuum guage. Using "tee" fittings to tap the vacuum line to the EGR, I ran a length into the cab with a vacuum guage. Driving down the road the vacuum would raise to 5" - opening the EGR and after a few seconds - maybe a minute - the vacuum would slowly return to 0 - thus closing the EGR and let the pinging begin. After replacing the control and cleaning out the EGR truck runs fine - no pinging or knocking on 87 octane fuel.
Hope this helps
Russ
Hope this helps
Russ
Thread
Thread Starter
Forum
Replies
Last Post
Binkowski
1967 - 1972 F-100 & Larger F-Series Trucks
49
Dec 2, 2014 07:06 PM