94 FJ80 - No CEL light but runs fine (1 Viewer)

Joined
Dec 25, 2020
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32
Location
san francisco
So recent purchase and the CEL has never worked. Somehow I got it smogged with relatively no issue but after having it looked at for poor gas mileage (10 mpg HWY), the shop who works on lots of 80s, says that he can't pull a code because the CEL doesn't work. The light itself might have been pulled because when I got it, it was not working and the seller was selling for cheap.

It runs fine, albeat with a little loss of power (according to the mechanic) and bad mpg.

The mechanic said it's straight forward to do but time consuming so suggested I do it and then we can look at the codes.

What I'd like to know is -

How do you get to the CEL to replace?

What bulb does a 94 FJ CEL use?

Thanks
 
Joined
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san francisco
Joined
Nov 9, 2012
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10,873
Location
Olathe, KS, USA
10mpg with no roof rack or any lift? Jesus, might as well be a blown ls3. At least something happens when you stomp on the accelerator!
Yes, you probably have issues.

With stock 31" tires, no lift, no winch, I was getting about 15 MPG hwy. Now I average 11.5 MPG (adjusted) on an annual basis (about 15K miles/year) and I have 33" tires, 2.5" lift, winch on the front (no bumper), and carry about 600+ LB of crap with me at all times.

I get a P0401 code every once in a while which is EGR related and I am due for a 100K mile tune-up. I have new-ish exhaust.
I suspect my lack of caster correction and alignment costs me in gas mileage. I usually drive about 75-80 MPH everywhere I go, so I'm above the sweet spot for what these engines like.

Change your CEL bulb (pull the cluster) and replace ALL the bulbs while you're there, so you only have to do it once.
Then check your codes.

May want to consider one of the code reader programs for OBD1 that your can read / watch with your phone while you drive so you can see what everything is doing. I forget the name of the most popular one, but someone will chime in here with it.

Tire pressures, tune up, alignment, vacuum leaks, all contribute to poor mileage. Go through a complete PM cycle on it and see if it makes a difference.
Gas cap
Oil fill cap
PS Cap
Intake hose
Plugs
Wires
Cap
Rotor
Valve Cover Gasket
Spark Plug Tube Seals
Distributor O-Ring
PCV Valve
PCV Grommet
Fluid changes in all gear cases
Wheel bearing adjustment
Grease your driveshaft slip joints and U-joints
Have your exhaust checked for back-pressure and temps before / after the cats.

Then pull your EFI fuse for 5 minutes to clear your existing codes and let it start to relearn your driving parameters.

Use OEM parts, because yes, they make a difference.


Not all dealerships are created equal.
 

MyWhiteSheep

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Dec 3, 2019
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605
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Cameron, NC
Isn't it normal-ish for 10mpg? Lots of people I hear from are like this. The ones that's aren't damn near rebuilt their whole engine. I fluctuate in the 11s-13s. . just depends on how aggressive Im driving.
 
Joined
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Messages
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Location
Olathe, KS, USA
Isn't it normal-ish for 10mpg? Lots of people I hear from are like this. The ones that's aren't damn near rebuilt their whole engine. I fluctuate in the 11s-13s. . just depends on how aggressive Im driving.
10 MPG is low, even for a stock truck. If it was heavily built, I would say no.

Also, since my truck is a DD and the majority of my stops and starts are in the city, before I take a trip of 2 hours +, I will pull the EFI fuse to clear my codes and improve my mileage because the truck sets it's parameters on the average of most stops / starts. If I just jump in it and go, it will keep my fueling at a higher level based on engine temps, RPM, O2 sensors, and where it normally runs.

I have tried it multiple times and it has proven to be effective by about 0.5 MPG on 2 hour+ trips. From a % standpoint, that's a 4.3% increase in mileage for 5 minutes of jacking around.
 

MyWhiteSheep

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Joined
Dec 3, 2019
Messages
605
Location
Cameron, NC
10 MPG is low, even for a stock truck. If it was heavily built, I would say no.

Also, since my truck is a DD and the majority of my stops and starts are in the city, before I take a trip of 2 hours +, I will pull the EFI fuse to clear my codes and improve my mileage because the truck sets it's parameters on the average of most stops / starts. If I just jump in it and go, it will keep my fueling at a higher level based on engine temps, RPM, O2 sensors, and where it normally runs.

I have tried it multiple times and it has proven to be effective by about 0.5 MPG on 2 hour+ trips. From a % standpoint, that's a 4.3% increase in mileage for 5 minutes of jacking around.
OK I think im tracking. Im pretty heavy. Raptor lined, front and rear bumper, winch, drawer system, and 37s.
 
Joined
Dec 8, 2006
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9,897
Location
New Jersey
How do you get to the CEL to replace?
One bulb out I could deal with, but when the second one went out, it made me crazy. You need to pull the dash cluster. It is not difficult, just time consuming as many parts have to come off to get to it. Everything on the interior of these trucks come apart pretty easily, but old plastic can be brittle so try not to force things. Great time to really clean things up. The most difficult part was reconnecting the connectors on the back.

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retrofive

retrò
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meridionale oregon
Years ago I took my ODB1 '94 down to the local auto store. We goofed around with the various plug-in they had for their scanner. We found one and was able to pull the codes from the port on the firewall.
 

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