Premium gas?

[wagoneer88]

I'm 16 and just recently got an 87 G. Wagoneer for x-mas. I was told it spark knocks very bad if you don't put premium in it. Doees this happen on all Grand Wagoneers or just mine? and it there anything you can do to so it will run on regular gas?

[Fornesto]

I wouldn't worry about the premium gas. Everything I've read is that most cars don't need it and don't know the difference. I've got a 2004 that doesn't even require it. The little jump in octane will probably go unnoticed. But, if the premium takes away the knock...20 cents more per gallon X 15 gallons in a tank X 10 miles to the gallon X # of miles left in it...it might be worth it..I wouldn't think so. If you saved 20 cents for every gallon you put in it, you could probably rebuild the engine.

[carrotman]

When I was 16, I made life hell for my father because he would'nt buy me a car or a motorcycle. I finally bought my own at 20 and then I had to drive him around. So you are pretty lucky.

There is knocking and there is pinging. If premium gas cures the pinging you should check the timing first. Pinging sounds like marbles shaking in a can. Knocking is worse.

[uberhahn]

if the knock is really bad, something else is wrong. you can upgrade the ignition cheaply with Ford components, or go aftermarket.

for engines with electronic gizmos, turbochargers, and superchargers, hi-oct is a must. for FSJ, it's a luxury. I wouldn't really bother with the expense. do some research and find out why it really knocks badly.

[Don S]

..
wagoneer87;

Welcome to our FSJ group. I hope we can help..

When your engine starts pinging back off the throttle because the pinging damages the pistons and bearings.
. Over the years I have seen many engines pinging due to carbon build up.
... The carbon build-up gets hot and it will glow igniting the fuel mixture causing pre ignition.
I’ve been using upper-lubes for over 50 years and will continue until they pry the bottle out of my cold dead hand…!!!
... It takes a little driving time for the OB oil to work.

The idea described in the link below has worked wonders for me and others over the years. If you have short runs with a cold engine it may take a little longer for it to work. It doesn’t cost much…
FUEL TANK ADDITIVES
http://groups.msn.com/ATexasOklahomaJeepClub/ouraycotopic.msnw
http://www.ifsja.org/ubb/ultimatebb.php?ubb=get_topic;f=2;t=010756

... Harsh treatments for removing carbon could create a problem with the rings. I have used the ‘sudden’ water and the sudden ATF treatments with no harm but never again. Once I learned all the benefits of using 2 cycle Out Board oil as an upper-lub I just don’t let the carbon form.

Have a good one, http://www.michiganjeepers.com/forums/images/graemlins/wave.gif and … CUL.. Don S..

[andy d]

a messed up distributor will cause pinging. if everything is working right, a stock 360 should run fine on 87 octane.at the rate a 360 uses gas it would be worth your while to fix it

[mdill]

Like others have said, spark timing is critical,
if checks out, then there could also be an issue
with the EGR system, then finally you maybe running
lean on fuel.
any of the above or in combination could cause
pinging.

Mike D.

[Outback Jeep]

Just some info in high octane fuel. As stated above the high octane fuel will reduce piston knocking. To make a very long story short. High octane fuel actually slows (now we are taling milliseconds) the burning process of the fuel so as to allow the fuel to burn evenly across the top of the piston. In doing so the force of the burning fuel is even across the top of the piston, and the force is all directed down ward. If the fuel burns to fast, most of the force from the burning fuel will be to one side of the piston (what ever side to spark plug is on). This causes most of the force to be down ward but, some of the force to almost be side ways, causing the piston to 'hit' the side of the cylinder wall (for lack of a better term) causing the pinging noise (rember we are takling thousandths of an inch). This is why high compression motors require high octane fuel because the forces of 'built' motor are greater the combustion process must be more controlled.

Brian Matthiesen
Outback Jeep---The Leader in Full Size Jeeps

[grand_wag_85]

This knocking isn't after you shut it off right? Mine will sometimes knock, backfire and restart for a bit if I rev it high and shut it off before it goes back to an idle. How many miles are on it? I feel for you, my 85 GW is my 1st car(truck). People at school might say it's ugly or gay, but deep down they're really jealous and want one. Trust me!

[Nobby]

Do a search on ping in the tech section, you'll find alot of info on it for the 360.

Supposed to be OK on regular, however it seems that the jets in the carb were leaned out to help get the somewhat dinosaur like V8 through the emmisions. A cure from a supposedly experienced Jeep tech is to enlarge the jets slightly(its in the tech section somewhere). You may notice that one cure for the knock is to hit the gas a bit more I.e send in more fuel and this will in turn stop the knock.

As already mentioned on our somewhat well used engines carbon build up etc serves encourage the knock, on an already leaned out system.

Interesting note that Jeep recognised this knock as being an issue and hence put out an anti-knock kit to help stop this. This involved a change in the EGR valve and retarding the ignition. This still can be obtained and I have posted previously to this effect. Just run a search using my member #

Other points of note, Hotter the engine the more the Ping is encouraged. Cooler running spark plugs will aid this. I experence less ping during the winter. Many of us have moved down to the next cooler plug from the supposedly recommended one.

IMO they sort of squeezed the issue by running 2.73 gears in the axles on standard set-ups for the later models, this eventually with a tired carboned engine serves to encourage the issue.

As already said timing and general fuel system condition i.e vacuum, CTO's, EGR etc if not operating correctly will not help. For example the EGR circuit as well as helping NOX emmisions will serve to cool the combustion chamber and help prevent ping.

[ January 15, 2004, 11:12 AM: Message edited by: Nobby ]

[Don S]

Originally posted by grand_wag_85:
Mine will sometimes knock, backfire and restart for a bit if I rev it high and shut it off before it goes back to an idle...
grand_wag_85:

... WHY?.. :confused:

Have a good one http://www.michiganjeepers.com/forums/images/graemlins/popcorn.gif and CUL.. Don S..

[gpd]

Do the TFI upgrade, will improve your mileage to.

[grand_wag_85]

When it stalls it does that, and what is the TFI upgrade?

[viscacha]

I run premium year round. I played around for a couple years on stuff like timing, (12 deg.) I keep it at 12. In the summer at 105f, 6% grades and going really fast, the only thing that works for me All the time is premium gas. Puts my mind to rest. :cool:

[Nobby]

Originally posted by grand_wag_85:
When it stalls it does that, and what is the TFI upgrade?Do a search there is alot of info on this. here's a start for ya.

http://www.ifsja.org/ubb/ultimatebb.php?ubb=get_topic;f=2;t=024380

[WHAT?]

the way I see it, premium gas is not much of an advantage when you are pouring it into the manifold with the accuracy of a bucket!(carbeurator) smile.gif

[89grand]

I have to run 91 octane in the summer or I get mild pinging too no matter what I try to do to stop it. In the winter though, I can run regular, it all seems to be related to the temp of the engine. 91 octane doesn't cost that much more, about $4 a week and I would really hate to see the $$$ from engine damage caused by pinging. So anyway, I use premium in the summer and mid grade in the winter.

[grand_wag_85]

Ok I see what it is, I've already done most of that stuff already.

[jeepguzzi]

I used to get by with the mid-grades until I changed the carb and intake to an Edelbrock. Now, I have better throttle response, no pinging, and I can run regular unleaded. Check for vacume leaks, also. They might lean out an already too lean engine.

[grand_wag_85]

Try using octane booster. It should be a little bit cheaper than super.