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Getting atrocious mileage?


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Since buying the 7 last year I'm still slowly figuring and sorting out misc problems as I've put maybe 500 miles on the car, likely under that.

 

The recent is that I feel like I'm filling up far too often. I don't have a working odometer as the speedometer has been swapped for a SPA unit since original build and the speed output hasn't worked right for at least 10 years from what I've gathered. I don't even know if it's tranny pickup or hall sensor on rear axle (didn't see anything on axles)

 

Now while fixing that is on the list, I've decided to test the MPG the old fashioned way. Filled up in one area, drove 8 miles highway and filled up again. Used right around 1.1 gallons.

 

Today I drove about 50 miles and am at half tank already.

 

 

Lets say empirically, with variables I average 10mpg. Thats quite low isn't it?

 

 

 

2001 Zetec, Jenvey ITB's, injectors have been swapped to high impedance. Pectel ECU.

 

I haven't done a compression test but thats probably going to happen soon.

 

Car feels quite peppy but I can't tell if I'm down on power as I have nothing to compare it to.

 

Oil doesn't smell like gas.

 

No obvious leaks anywhere, I fixed a previous return like leak.

 

Any ideas of what else to check for? I should be getting about 20mpg or more, no?

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Certainly pull your plugs to see if they indicate that you've been running rich. Does the Pectel ECU tuning software give you the opportunity to check your AFRs through the rev range?

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Certainly pull your plugs to see if they indicate that you've been running rich. Does the Pectel ECU tuning software give you the opportunity to check your AFRs through the rev range?

 

Checked the plugs and I'll upload pictures but in meantime I created a new problem.

 

Some of the crud around spark plug has fallen onto the cylinder and now I'm trying to master mind a way to get it out.

 

 

I know nothing about data logging the Pectel unfortunately. I'll have to look into it.

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Some of the crud around spark plug has fallen onto the cylinder and now I'm trying to master mind a way to get it out.

 

 

Vacuum cleaner - adapt something as a nozzle to fit into the spark plug hole.

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Some of the crud around spark plug has fallen onto the cylinder and now I'm trying to master mind a way to get it out.

 

Portable air tank. Blow it out with compressed air.

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Portable air tank. Blow it out with compressed air.

 

That would probably blow more chunks into the crevice above the top ring than back out the spark plug hole. I like the idea of taping clear plastic tubing to a vacuum cleaner hose better.

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Here are some pictures.

 

#1 tunnel - only really dirty one

 

fxQg4Rihttp://www.usa7s.net/vb/attachment.php?attachmentid=15338&stc=1

 

#1 plug

http://www.usa7s.net/vb/attachment.php?attachmentid=15339&stc=1

 

http://www.usa7s.net/vb/attachment.php?attachmentid=15340&stc=1

fxQg4Ri.jpg

hUrHfck.jpg

GMSPQ4P.jpg

jEnQDPI.jpg

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Cylinder and rest of plugs

 

http://www.usa7s.net/vb/attachment.php?attachmentid=15342&stc=1

 

http://www.usa7s.net/vb/attachment.php?attachmentid=15343&stc=1

 

http://www.usa7s.net/vb/attachment.php?attachmentid=15344&stc=1

 

http://www.usa7s.net/vb/attachment.php?attachmentid=15345&stc=1

HdJSdCi.jpg

D9dUusx.jpg

JgWueZz.jpg

KCCFbNH.jpg

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What is that stuff on the plugs? Mud?

 

I think so. Same stuff that's in the channel. I wiped it off

 

Some of the tips looks much smaller than the others (a little hard to tell in pictures)

 

Might just replace all while I'm at it. Any recommendations? Same ones? They are motorcraft platinum now.

 

Doubt it's the issue but can't hurt.

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Did you have water sitting on top of the head over the winter?

I’ve had water on top of my engine after getting caught out in the rain

 

This car has never seen rain during my ownership and hasn't been used much in the last 10 + years in California. I doubt it saw rain back then too.

 

 

What mileage should I expect with highway driving, 6spd, Jenveys on Zetec? Even a ballpark. 20?

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I find mileage depends on how you drive it. I have a 2 liter Zetec, ITBs, Emerald ECU, stage 3 cam,and I can go through half the tank in 20 minutes at a track day, or about 5 gallons. If I drive it in a less spirited manner, I might get 20 MPG, but what is the point of driving it if I just putt around? So, the 20 mpg is more theoretical than something I've verified.

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I find mileage depends on how you drive it. I have a 2 liter Zetec, ITBs, Emerald ECU, stage 3 cam,and I can go through half the tank in 20 minutes at a track day, or about 5 gallons. If I drive it in a less spirited manner, I might get 20 MPG, but what is the point of driving it if I just putt around? So, the 20 mpg is more theoretical than something I've verified.

 

Alfonse, thank you for the reply.

 

I understand that it will vary depending on how you drive it, but if I'm getting ~8/10 mpg on just highway and putting around means I'll be getting 2/3 mpg on a track day I'll be running out of gas very quickly and there is a serious issue that I need to address.

 

Trust me, I'm not bringing this up from the economic perspective/concern.

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I don't like the look of all that gunk in the threads of the #1 plug. Even if there's all manor of crap in the "tunnel" for the plug the threads themselves should be pretty clean having spent their life engaged in the head. Sure, some gunk may brush into them on the way out, but they look pretty uniformly covered. Did that plug feel right when you loosened it and threaded it out?

 

Dave

 

Edit: sorry, no wisdom on what mileage you should expect, but 10 does sound low for street driving.

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I was thinking overnight (don't look shocked!;)) - I wonder if that gunk in the threads is coppaslip/copper grease as the prior owner was dealing with a sticky thread? Looks like it was applied at time of inserting the plugs and has a similar consistency after high heat application. I would feel a lot better if thats what it was - since it should not hurt the engine inner in miniscule trace amounts although you probably dropped more than that into the cylinder? If it were mud gunk then it should have dried up by now (and be easy to vacuum out). If it is still wet consistency then that will confirm it is a grease of some type.

 

I think all would agree the street driving mileage is lower than you would reasonably expect. So your question is a very valid one to solve.

 

So it is probably time for a retune on the dyno but before then - thinking my way through the air, fuel, spark equation:

 

 

  • I would change those plugs to a heat spec suitable for your engine. Don't assume what spark plugs you have in there are correct - start from scratch and check as you may have the wrong plugs currently and that is part of your problem.
  • Any evidence of piston scorching or carbon build up in each cylinder? Usually the signs of lean or rich running appear visible from a cylinder inspection through the spark plug hole.
  • Does your exhaust tip look black with carbon deposits? If it is clean then did you clean it and was it black before?
  • Any evidence of water or other contamination of the ECU?

 

 

Edited to add: Still not convinced that crud on the plugs is not dirt/mud. Will be interested to hear if it dried out by now

Edited by Croc
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If you are using that much gas, you should see exhaust smoke and smell raw gas. You could get better mileage with a BBC. I get 22 MPG on the back roads and 30 MPG at 75 on the expressway. Dave W

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Never Seize on the plug threads on a aluminum head is what your supposed to do. It also collects dirt.. a few things to think about. New plugs , fresh gas, and maybe the O2 sender is crapped up or not working. It’s this how it ran when you got it??

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