Another poor mpg thread.

[bloc]

Is it along the frame rail or something? You don't happen to have the part numbers for both do you? Or would they be different on my 93 than your 97?

Pre-filter is in the tank attached to the fuel pump. Just a plastic frame with mesh all over it. In-line is under the intake manifold.

 

[jonheld]

Is it along the frame rail or something? You don't happen to have the part numbers for both do you? Or would they be different on my 93 than your 97?

No. It's up under the intake on the left side. It looks like the front left tire needs to come off and the skirts need to be removed for access. Not as easy as the 91 on the frame rail, but still doable.
I buy all my stuff from Onur @beno because I have a man crush on him and he sleeps, eats, and breathes part numbers and I always get the right stuff.

 

[LS1FJ40]

Many of us have our speedo calibrated various ways.. Mine is done via GPS and SGI-5, and "dead on" is between two settings, so I went with the one that reports mileage a little short. With our stock speedos indicating a little fast, mine now reports closer to actual speed.

Trust me, I couldn't believe I hit high 15s with AC at 70 on one tank.. but the next one was all-freeway, GPS running the entire time to verify distance, and even topped up to the cap to avoid spout-stop error. 15.4. Outside of the actual off-roading, my worst tank that whole trip was 14.2. Headwind. I even have a second trip a few months apart to the same area with very similar results.

I attribute it to the high tire pressure, part-time kit (more on this in a bit), all new plugs/wires/filter, it being a 94 (seem to run leaner), maybe even the 0w-40 oil (100c viscosity is closer to a 30wt)... actually maybe not. Second trip was with 5w-40 diesel oil.

On the part-time.. same truck, same plugs/wires/fuel/etc, same run, same lift, same tires (though less pressure.. closer to 32), stock bumpers, no second battery, no winch, no sliders (so truck significantly lighter).. 12.5 on the identical freeway trip when full-time AWD.
So apparently a bit more pressure and part-time kit added 2mpg freeway, despite the few hundred # of steel/battery/winch and new front bumper being significantly worse from an aerodynamics standpoint. Though on that, I'm only running a low 2" lift, which probably helps.

Basically, my experience is that part-time DEFINITELY makes a difference, despite what (many) people on this board have posted. Which just makes sense, to me.



All of that said.. I think @LS1FJ40 needs to check condition of the catalysts. Would a bore-scope fit into an O2 sensor hole and turn backward to have a look?

I've run 15w-40 since I bought it. Mainly because it would leak out a lot slower. Now that I don't have any leaks I will go to 10w-40. Plus it is almost winter.

I'm having my muffler shop take a look at the cats on Monday. They do some sort of pressure test or something. They did it on my 92 last year when I replaced the O2 sensors.

 

[LS1FJ40]

No. It's up under the intake on the left side. It looks like the front left tire needs to come off and the skirts need to be removed for access. Not as easy as the 91 on the frame rail, but still doable.
I buy all my stuff from Onur @beno because I have a man crush on him and he sleeps, eats, and breathes part numbers and I always get the right stuff.

Don't we all have a man crush on @beno?

Emailing Onur now...

 

[LS1FJ40]

Crap. Onur is out of the office until the end of the month... Off to the dealership I go...

 

[jonheld]

Crap. Onur is out of the office until the end of the month... Off to the dealership I go...

I think he just forgot about his autoresponder. He'll answer the email.

 

[LS1FJ40]

I think he just forgot about his autoresponder. He'll answer the email.

Had him send me the air filter too. Anything else you can think of.

Have done the following:
New plugs
New wires
New distributor cap
New rotor

Not related but have also done:
Valve cover seal
Plug seals
Oil pump cover seal
Crankshaft seal

 

[LS1FJ40]

Only other thing I can think of is that I'm getting a little bit of oil (couple of drops) in to the distributor cap. Could that be affecting the quality of Spark?

It's very little oil. Not enough to pool. Just have a slight film in the bottom of the distributor. Not so much even the cap.

 

[Fosters]

Something is not calibrated right. No way you are averaging 18.5 mpg on a consistent basis.

Oh yeah,
All calibrated and confirmed by GPS and gas fill up...granted I drove at 55-65 mph to get this result and is not my normal behavior...
That said my regular driving and mileage is typically 13.9-15.4mpg

 

[LS1FJ40]

Oh yeah,
All calibrated and confirmed by GPS and gas fill up...granted I drove at 55-65 mph to get this result and is not my normal behavior...
That said my regular driving and mileage is typically 13.9-15.4mpg

MPG only counts if the vehicle is moving under its own power and not being pulled or transported!

 

[MODist]

Driving up hill both ways on your way to school/work will impact your mileage.

 

[woodsman 44]

Only other thing I can think of is that I'm getting a little bit of oil (couple of drops) in to the distributor cap. Could that be affecting the quality of Spark?

It's very little oil. Not enough to pool. Just have a slight film in the bottom of the distributor. Not so much even the cap.

Yes.....There should be NO oil getting into your D-cap at all

 

[LS1FJ40]

Stopped by my muffler shop. I scheduled my appt for Tues. To check the cats they drill a hole in front of the cat and run a pressure test.

He said he can also check the O2 sensors while he's doing things. Im going to plan on replacing them anyway but curious what his finding are.

 

[suadero]

Only other thing I can think of is that I'm getting a little bit of oil (couple of drops) in to the distributor cap. Could that be affecting the quality of Spark?

It's very little oil. Not enough to pool. Just have a slight film in the bottom of the distributor. Not so much even the cap.

Don't change to thinner oil yet! You might want to think about a new distributor before that.

Don't think that amount would gum up the works for MPG though.

Think you are doing good getting the cats checked (gives great piece of mind if nothing else). Curious to hear about the o2s - how they test. Still think injectors or possibly filter. I ran with my canister unplugged and dangling and got better mileage than you.

 

[suadero]

I was reading about something else just now (5VZ-FE) and saw something about cleaning the MAF sensor in case of poor running, so that's also a thing you could try at a relatively low cost.

 

[LS1FJ40]

I believe this is the fuel pressure regulator... the hose at the bottom of it comes from the charcoal canister. As soon as I cut a new hose and hooked it back up the smell went away. I wonder if this was affecting my mpg?

And I wonder how long it was like this. It's new hose so I know I touched it in April. I wonder if I forgot to hook it back up?!?!

 

[suadero]

When I said earlier in thread that my canister was hanging off, it was nearly in the same location.

I think you are missing a clamp, actually, on the valve side. I just replaced that hose on Luigi a few weeks ago.

 

[LS1FJ40]

When I said earlier in thread that my canister was hanging off, it was nearly in the same location.

I think you are missing a clamp, actually, on the valve side. I just replaced that hose on Luigi a few weeks ago.

Yep. I added a clamp. Should be good to go now.

 

[ppc]

I believe this is the fuel pressure regulator...

The fuel pressure regulator attaches to the front of fuel rail. What your picture shows is part of the evaporative emisions control circuit possibly some type of check valve. The hose not connected would be a small vacuum leak but I don't think that would impact MPG very much.

 

[LS1FJ40]

The fuel pressure regulator attaches to the front of fuel rail. What your picture shows is part of the evaporative emisions control circuit possibly some type of check valve. The hose not connected would be a small vacuum leak but I don't think that would impact MPG very much.

Damit!