Is there any hope?..

[PCT Hiker]

On Thu, 31 Jan 2002 23:07:11 -0600  BlackSE-R <nissanser92@yahoo.com> wrote:

>I think I'm beginning to lose my head. I have tried everything people have
>suggested to me. I checked the famous archives. I talked to mechanics. I
>keep on getting low miles per gallon. Last time I tanked: 137 miles; 8.402
>gallons. That's roughly about 16.3mpg. I drive a 92 se-r, no mods, 115k
>miles on it, I bought it from this one guy who had to sell it, because he
>was forced to leave the country. Other se-rs get more than 20mpg. Guys, if
>this happens to me, I'm popping the Champaign bottles and having a huge
>party. Any suggestions on how I can fix this problem? I'm hopeless now...
>Thank you up front, for any suggestions...

Yep, your mileage sucks.  Something is wrong. It's not hopeless.  Don't
lose your head, use your head.  You can fix this.
For good mpg, your car needs sufficient well-mixed, accurately metered
air/fuel, good compression and a properly-timed good spark in all 4
cylinders, efficient transfer of power to the wheels, and an minimally
restrictive exhaust system.  That's all.
-ECU show any codes?  If your ECU never gets out of open-loop mode (or is
stuck in fail-safe) you will waste a LOT of fuel...16mpg sounds about
right.  All critical sensors (O2, TPS, crank angle, MAF, coolant temp,
knock sens.) must operate in approved range to reach closed-loop (feedback).
-Spark plugs show any clues? Lean, rich, oil?  Are they the right plugs,
properly gapped?  Don't mess with anything but spec NGK plats...you can use
5's if 6's foul.
Have you:
-checked the O2 sensor function via the ECU diagnostic?
-verified idle speed 850/ignition timing at 15-17 deg. BTDC (and not, say,
10 deg)?
-regrounded the MAF and checked for proper function?
-looked for vacuum or intake air leak(s)? (idle manifold pressure should be
steady 18-19 inHg @sea-level)  Check the AAC/FICD, (cold-)air regulator,
EGR, PAIR, and PCV valves for proper function.
-thoroughly cleaned the TB/intake manifold?  Lots of gunk builds up here.
-replaced/cleaned the air filter?
-checked battery, alternator, coil, corroded connections etc. as potential
cause of weak spark under load?
-checked clutch for gross slippage (you'd probably have noticed
this...popping clutch in 5th @idle should stall engine)
-checked wheels for proper tire pressure and alignment?
-checked brakes (incl parking brake) to be sure they aren't dragging?
-checked fuel system for leaks, proper fuel pressure, dirty filters? (there
was a recall on pre-93(?) fuel pumps...check w/ dealer to see if yours was
done.)
-checked your cat. converter and muffler for fouling/blockage?
-looked for a dead cylinder? Check for healthy spark and compression
(misfire: fouled plug, bad HT wires, bad distributor cap/rotor; OR fuel:
dirty/plugged fuel injector; OR mechanical: worn/bad piston
rings/valves)?  A dead cylinder would waste about 25% of your fuel, so
again 16mpg sounds about right.

Good luck!