mileage?

Thread view:

Enable EMail Alerts

Start New Thread

Thread rating:

rjh44 - 22 Feb 2005 05:07 GMT

Anyone know what the sticker mpg (city/highway) is on a 1986 CJ7 with
4cylinder 4speed manual trans?

Reply to this Message

Mike Romain - 22 Feb 2005 15:23 GMT

My 86 with a 258 gets a nice 23+ US mph on the highway running around 65
mph.

I would expect the 4 banger to be really close to the same from what I
have read here over the years.

Mike
86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
88 Cherokee 235 BFG AT's

> Anyone know what the sticker mpg (city/highway) is on a 1986 CJ7 with
> 4cylinder 4speed manual trans?

Reply to this Message

griffin - 22 Feb 2005 22:44 GMT

You mean that the 9mpg mine gets is WRONG?!?! Better than the 6mpg my '88 YJ
had when the carb was going.

Can't wait till the snow melts and I can actually fix everything and get
that MPG back over 15. Maybe I can even get it running again properly.
Maybe.

Signature

griffin
'85 Jeep CJ-7
'97 Toyota Corolla SD

> My 86 with a 258 gets a nice 23+ US mph on the highway running around 65
> mph.
[quoted text clipped - 8 lines]
> > Anyone know what the sticker mpg (city/highway) is on a 1986 CJ7 with
> > 4cylinder 4speed manual trans?

Reply to this Message

HarryS - 22 Feb 2005 23:03 GMT

You have got some serious gas issues my 04 TJ with a six gets 17mpg large
tires and all. On the other hand the RAM gets 13 mpg go figure.

HarryS

> You mean that the 9mpg mine gets is WRONG?!?! Better than the 6mpg my '88
> YJ
[quoted text clipped - 16 lines]
>> > Anyone know what the sticker mpg (city/highway) is on a 1986 CJ7 with
>> > 4cylinder 4speed manual trans?

Reply to this Message

Mike Romain - 22 Feb 2005 23:18 GMT

I just did a 4 day bush run and gas station to gas station is 200 miles
so I get an easy check every trip. It was still 10.9L/100km which is
slightly better than 23 US mpg and I still have that beauty of a
Weber-Carter BBD in there... LOL!

Just amazing what a $20.00 carb kit every 2 years does for them...

Mike

> You mean that the 9mpg mine gets is WRONG?!?! Better than the 6mpg my '88 YJ
> had when the carb was going.
[quoted text clipped - 20 lines]
> > > Anyone know what the sticker mpg (city/highway) is on a 1986 CJ7 with
> > > 4cylinder 4speed manual trans?

Reply to this Message

griffin - 23 Feb 2005 01:11 GMT

Ya I'm gonna do that in the spring ...after I replace the timing chain. I'm
not a big fan of trying to drive it home with it backfiring all the time ;p

> I just did a 4 day bush run and gas station to gas station is 200 miles
> so I get an easy check every trip. It was still 10.9L/100km which is
[quoted text clipped - 4 lines]
>
> Mike

Reply to this Message

Mike Romain - 23 Feb 2005 14:13 GMT

You don't likely have timing chain issues. In order for it to jump a
tooth, the gears must be destroyed. Those chains are good for the life
of the engine and then some usually. One of my CJ steel sets is now on
it's 3rd engine incarnation with the exact slop as a new on measured in
degrees.

I would be suspecting something electrical like a cracked distributor
cap or even a burnt valve for backfiring.

Have you checked the amount of play in your chain? Stock new they have
about 15 deg of slop.

Mike
86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
88 Cherokee 235 BFG AT's

> Ya I'm gonna do that in the spring ...after I replace the timing chain. I'm
> not a big fan of trying to drive it home with it backfiring all the time ;p
[quoted text clipped - 7 lines]
> >
> > Mike

Reply to this Message

griffin - 23 Feb 2005 15:18 GMT

Been through the following:

The entire electrical system. Then I had the local Jeep mechanic go through
it all and replace almost all the under-the-hood wiring. He managed to get
it running again after trying to retime it over and over but it only ran
when the engine was fully warmed up and it would backfire quite a bit if not
driven at the perfect RPM. Replaced about 15 wires, a couple of connectors,
the distributor cap/rotor/plugs/plug wires. Did diagnostics on all the
coils/sensors/etc.

The ignition system has been checked.
The fuel system has been checked.

The only thing left that hasn't been opened up is the TChain cover. When my
Jeep stalled during offroading, I'm thinking the dist cap was wet
(unbeknownst to me at the time). When I was getting pulled home, we tried to
pull-start it and it backfired something fierce. That *could* slip the
timing chain a tooth from the force, could it not? Oh well, when it's warm
out it's only like a 3-4 hour job to check that and it's the only thing I
can think of. If it is the TChain that has to be replaced, is there any way
to do it without taking the Rad out? Not sure it would survive.

Signature

griffin
'85 Jeep CJ-7
'97 Toyota Corolla SD

> You don't likely have timing chain issues. In order for it to jump a
> tooth, the gears must be destroyed. Those chains are good for the life
[quoted text clipped - 23 lines]
> > >
> > > Mike

Reply to this Message

Mike Romain - 23 Feb 2005 23:28 GMT

I think the 85 has a steel gear and chain set like my 86 has so jumping
is unlikely but possible.

One sneaky timing thing I don't see mentioned. Under the rotor is a
felt pad that needs to be soaked with oil. This lubs up the timing
advance plate and it's sleeve that sits on top of the distributor
shaft. If this goes dry, the timing will seem to change every time you
check it or it will stick with no timing advance allowed.

To test grab the rotor and see if you can turn it a bunch with a spring
loaded snap back. If not, that could be the trouble. It should be
really smooth and free in the movement.

To check the timing chain, you hand turn the engine with the distributor
cap off until you reach TDC on the timing mark. The rotor should be
pointing just before #1 or #6 if the chain is on the right tooth, way
off if jumped. You then turn it back the other way while watching the
rotor. The second the rotor moves, you look at the timing mark and that
gives you the 'slop' in the chain. 15 to 17 degrees is normal for new
to still good. Get higher and you could suspect a jumped chain.

Mike

> Been through the following:
>
[quoted text clipped - 53 lines]
> > > >
> > > > Mike

Reply to this Message

griffin - 24 Feb 2005 03:57 GMT

Ya, we did the timing chain/rotor test and were about 22 deg off. We never
checked the actual TDC by pulling a plug, though and we HAD moved the
distributor slightly beforehand on a previous suggestion by someone so we
might have messed up the alignment. However, it's timed enough to start, so
we will double-check that in the spring again. Will also look into the rotor
pad ...thanks for that tip!

I'll let ya know what happens ...

> I think the 85 has a steel gear and chain set like my 86 has so jumping
> is unlikely but possible.
[quoted text clipped - 76 lines]
> > > > >
> > > > > Mike

Reply to this Message

Michael White - 23 Feb 2005 04:33 GMT

rjh44 (rjh44@adelphia.com) wrote on Monday 21 February 2005 11:07 pm:

> Anyone know what the sticker mpg (city/highway) is on a 1986 CJ7 with
> 4cylinder 4speed manual trans?

I had an '81 CJ7 with that same setup a few years back. If I kept it at 55,
I got about 24 or 25 MPG. If I pushed it up to 65, I got about 13 MPG. If
I recall, city mileage was in the high teens.

The real adventure begins when you hop on the Chicago freeway system doing
55 MPH in -any- lane. The only thing saving you is that you're in a 20
year old Jeep and they're in an expensive new car.

Signature

Michael White "To protect people from the effects of folly is to
fill the world with fools." -Herbert Spencer, 1891

Reply to this Message