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87 TX import
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Discussion Starter · #1 ·
Hi all,

My 87 has just had a remanufactured E4ME carb. It runs great but I'm only seeing 14mpg (Imperial) with steady highway driving. Smells a little rich, but isn't smoking at all.

Engine light comes on sporadically at highway speeds.

Starts and idles nice. Maybe a little hesitant to pull away but I'm not familiar with power delivery on these engines so can't be sure.

What should be my first port of call?
 

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If you can get a ‘sniffer’ in the tailpipe (or a stand alone oxygen sensor) it’ll likely confirm what I suspect-the off the shelf ‘rebuilt’ carb is jetted rich, because rich hides a lot of driveability problems. (Edelbrocks are fat out of the box for that reason, too). My 305/200C/2.41 combo will return mid 20s mpg on the highway and doesn’t smell like unburnt fuel. It will set the check engine light after an extended idle but never when cruising. The factory O2 sensor is pretty basic; its main function is to detect a variation from stochiometric balance. That variation will be either rich or lean. Lean will run poorly and possibly overheat, rich too long and your catalytic converter is dying.
Patrick
 

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87 TX import
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Discussion Starter · #4 ·
If you can get a ‘sniffer’ in the tailpipe (or a stand alone oxygen sensor) it’ll likely confirm what I suspect-the off the shelf ‘rebuilt’ carb is jetted rich, because rich hides a lot of driveability problems. (Edelbrocks are fat out of the box for that reason, too). My 305/200C/2.41 combo will return mid 20s mpg on the highway and doesn’t smell like unburnt fuel. It will set the check engine light after an extended idle but never when cruising. The factory O2 sensor is pretty basic; its main function is to detect a variation from stochiometric balance. That variation will be either rich or lean. Lean will run poorly and possibly overheat, rich too long and your catalytic converter is dying.
Patrick
Thank you for that. I'll treat this as an expensive lesson and go with my original guy for a proper tune up when I can get it to him.
 

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"14mpg (Imperial)"

That works out to be about 16.8 mpg in US gallons. Doesn't sound as bad to us yanks.
 

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Yes. Less US gallons per mile and more miles per gallon.

Exact same mileage, just easier for the americans to understand.
 

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Deputy Regional Director, Region 13
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Sorry. I had it backwards 😂
it's that crazy British system. at least he's not using Whitworth bolts!

The first thing any fledgling British car restorer learns is that his (or her) car has "Whitworth bolts."

They think this is interesting, buy a set of "Whitworth spanners," discover these spanners fit their bolts, and believe they now know everything they need to know about British fasteners. Unfortunately, at this point they know only enough to make themselves dangerous. Instead, what they should have said to themselves is "Oh my God, what other weird and incomprehensible things have they done to the fasteners on my machine?"
 

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Hi all,

My 87 has just had a remanufactured E4ME carb. It runs great but I'm only seeing 14mpg (Imperial) with steady highway driving. Smells a little rich, but isn't smoking at all.

Engine light comes on sporadically at highway speeds.

Starts and idles nice. Maybe a little hesitant to pull away but I'm not familiar with power delivery on these engines so can't be sure.

What should be my first port of call?
good luck getting that thing tuned properly! I've just had mine replaced and engine rebuilt at 114k, and did u know that a 305, 5L, 4bbl, has a "cold start" RMP of 2200!?! That 87 Chevy, 1 Off, is Electronic, and my "former" mechanic says, "that's the best he can do" ....it take 10 mins of cold start idle BEFORE I can leave the driveway, EVERY DAY! If I dont warm it up COMPLETELY, it will "stall and die" as soon as I put it in GEAR! EVERYTIME!
So, I say again, "good luck" tuning that thing! (I'm still looking for a "qualified" mechanic in SoCal/San Diego area to "Tune It Properly)
Btw, I get 18mpg Hwy @ 65mph, cruise control
 
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