Premium Gas, how do I get my 360 off of it!

[Wagoneer622]

Here is one for you guys to figure out. I was having problems with a miss and stuff at idle a while ago. After doing a compression test I found out that my #1 cylinder only had 55 psi. The reason behind this was really bad carbon build up due to a bad carb running really rich all of the time and this also affected to the intake valve on the cylinder. So I went out and bought a bottle of octane boost/carbon cleaner and filled the tank twice with premium gas. Wala, it did the trick, even got rid of the spark plug knock/ping. Here is the problem, when I tried putting regular and mid-grade in the truck throws a fit! It runs like crap and the knock is back. Any ideas on how to wain this thing off of the high test, my pockets are only so deep! Thanks for your replies.

Chris
83 Wagoneer Ltd.(360/727/229)

[Michael]

When you find out let me know.

[Wagoneer622]

LOL! I sure hope that there is a way, I think I spoiled my motor by treating it to the good stuff and it is being like a spoiled kid when they don't get what they want!

Chris
83 Wagoneer Ltd.(360/727/229)

[looch]

I always use as high test as I can. I love my jeep to much to feed him anything else. Not only is my gas mileage better when using the higher octane, but I am sure it keeps the engine insides a touch cleaner. In one of my tech books about my jeep it says to run no less than 89 octane because of emission control devices. In Montana we have a choice of 87, 88, and 91, but I have noticed that other states seem to offer much higher grades. The difference in cost from the 87 to the 91 is about 8 cents a gallon, and I never really seem to notice the extra change. I suppose the best way to be able to run the lower octane fuels would be to clean the carbon out of the engine periodically with something like seafoam. Just don't let your neighbors see you doing it (serious smoke). I don't really know how good this is for your engine though.

[Cecil14]

You shouldn't have to run premium unless you've got a higher compression ratio, upwards of 9.5:1 I think. Stock shouldn't be anything more that 8.5:1 or so. Not anything requiring premium for sure. Check your timing, I know that can contribute to pinging and various other things. Not sure what else to tell you...

Anthony

[ February 26, 2002: Message edited by: Cecil14 ]</p>

[Don S]

Hi Wagoneer.....Some times Carbon can't find it's way out like TIP the cat. Small pieces can wedge into the spark plug gaps creating a rough running mill. In the old days us Gassers would get a friend and park our truck against a pole. The buddie would work the loud petal and the other would twist on the dist. 'till the ping went away. You were chicken if you wore a glove.. :eek: :eek: ......or ear plugs :rolleyes: .....this was when we put 8v batts..so we could start our trucks......... :rolleyes: ..........ds

[Jeepzilla]

I'm with the group that thinks that the gas is not the problem. Low compression in only one means trouble somewhere. I say change your plugs to be rid of carbon on them, change your oil to be rid of the carbon sludge you made with the carbon cleaner, and check and adjust your timing. Find out why that cylinder is low--could be a collapsed lifter or a bent pushrod making for poor valve function, either of which is potential disaster for eating a valve or spalling your cam lobe. Could be a fatigued valve spring, broken keeper or loose rail. Also, did you fix that rich carb??

[steve t]

I just went through this with my 87 gw - would knock slightly even on pure 93 octane! While I was having the loose steering column repaired, I hand the timing checked. I was told it was advanced 18, instead of the 12 that is suggested. I haven't heard a knock since. I may even try some regular gas! Performance seems to be about the same, but I have to check the milage.

By the way, the loose steering column did turn out to be stripped bolts holding the thing together on the inside. Now it's solid. Thank you to all who gave advise on this.

[SpruceMoose]

its not a low-buck method, but i put in a jacobs ignition system, and after a few months i was able to run regular. i assume it burned out the carbon and lowered the compression ratio back to where it belonged, and/or got rid of glowing pieces of carbon causing pre-ignition. runs great now, and 20 cents per gallon cheaper!

sm

[Wagoneer622]

I was thinking that it could be the timing, the only thing that I am afraid of is that it is time for a new timing chain, after all the Wagoneer is an 83 with 135,000 miles on the original chain. I will adjust it either tomorrow, Friday or Sat. It all depends on when I get the time to do the job so I can do it right and spend the time messing around trying to get things perfect.
I also had the idea of changing the ignition system even if there is nothing wrong with it. I don't like it. Between my father and myself this is the 6th FSJ that has been owned in our family and never have liked the ignition, at one time or another they seem to give a problem.
Thanks everybody for the suggestions, everyone here is so helpfull when called upon for help or advice. Thanks again!


Chris
83 Wagoneer Ltd.(360/727/229)

[joe]

I'm throwing my $0.02 in the "you don't need premium fuel" pile.
If you need premium fuel on an 8.25:1 compression motor to keep it from pinging you're just masking another problem. Bad tune-up, timing off, tired motor in general, timing chain, bad EGR valve-system etc. IMHO all your doing is dirtying the motor with a bunch of un-needed additives you get in premium fuel.

[bigwillys]

Premium? Whats that? :rolleyes: Jus kiddin, but seriously, i never give my wag anything but good ol' 87, and i've never had a problem. Try dialing you timing in, and you should be fine, unless u are running a compression ratio higher than 9.5:1. Even the 10:1 429 in my 64 caddy WOULD run on 87 without pinging, so the 8.25:1 stock 360 shouldn't have a problem.

[Michael]

Here, check this out. Okay I know it is timing. And I am sure it is timing advance. I disconected my vacuum advance, plugged it, plugged the end of the distributor. Voila...no ping. I drove 50 miles this after noon...no ping once. Drove really good to be honest. So on that note. I am adjusting my advance timing this weekend. We will see how that does.

[Wagoneer622]

Michael,
Thanks for the heads up! I will give it a shot an saturday when I get home from fishing.(Opening day for winter flounder). I will let you know how I make out with it. Thanks again!

Chris
83 Wagoneer Ltd.(360727/229)

[Don S]

WOW!!....A season for Flounder? Did a grin-aid go off in my helmet? :confused: ..I hvn't fished for a while....I caught my last flounder at low tide by hand in California...Guess they got a stingray season also by now... :D :D ......ds..

[Budde]

I have to use Premium gas or my '79 will diesel when I shut it off, which will cause a vacuum line to blow off, which will cause me to get dirty, which will cause me to cuss!!!!!!!!!

It also seems as though gas from certain companies burns great, while gas from other companies causes me to loose power. ???????

[Don S]

Hi Budde.........Locally...........I was told that,like say 87 octane,is all the same at THE fuel distributer. The indvidual service stations order it with the ADDITIVES of their choice. Most additives cost more than the gasoline. So, due to cheating.....ooops cost saving., :eek: ...The same BRAND of fuel/gruel..may burn/explode differently from station to station :mad: :mad: ....ie...tex-hic0 in Calif. afew years back...........mabeeee de-regulation is not :cool: ......ds..