33.25mpg road trip on a ALH golf

I'm curious if I set a record for most fuel used to get somewhere per mile in a ALH car lol.
My 03 Golf's Mileage has been declining for a while, 40,39,38, etc. Recent trip to Iowa with a ~400watt inverter going the entire time I hit 33! This is with a 6speed cruising at 2400 lol...

Not sure what is the cause yet. I have a feeling my cat is clogged. Or maybe intake? I'll be cleaning the intake and doing something with the cat soon enough to find out. Car has always let out some black smoke/soot on a hard start, or shift at lower speeds, or even on the highway. I noticed that ever since my mpg has gotten so bad my car no longer smokes at all no matter how hard i drive it.

Did a bunch of vagcom logging and everything seems right, always getting slightly more boost then requested but thats about it, maf reads correct.

Intake is probably clogged.

Air filter, fuel filter, perhaps turbo not functioning correctly? Intake? Egr stuck open??

A 400 watt load is still only about 3/4 hp when the losses from belt drive to alternator to DC and back to AC are all guesstimated. The inverter didn't help, but it didn't hurt anywhere near what driving at 70+ did.
And I seriously doubt that you were using the full 400 watt capacity the entire trip either. Coffee maker left on? Heated blanket for the geckos in their tank?

IP pump leaking? Thats what happened to me and I got 30 mpg on a trip down to Los Angeles so I beat you!

I'm chasing the same problem right now, just cleaned my intake, egr delete, replaced vacuum lines, tomorrow by the end of the day my car will be straight piped. I noticed the same issue with the smoke, and my intake wasn't that dirty so I am hoping this fixes the problem.

First thing that comes to mind is coolant temp sensor or thermostat not working properly. They will make your mpg decline quite a bit.

Intake and egr clogging will limit how high in the rpm range your car can go as well. Try driving your car up to 4 or 5k rpm. If it goes up to this range quickly, it isn't clogged. If it never makes it or takes forever to get up to this rpm range, your intake needs to be cleaned.

Just my .02.

Havn't done anything on it today so no change, but for more details:
Drives somewhat fine and power seems unchanged -not too far down i guess

Filters are new, turbo works fine although slightly delayed and slightly over boosting on vcds. recently just swapped the temp sensor(oem), and looks right on vcds.

IP definitely not leaking, spotted my brothers leaking on his ALH so it was one of the things I looked for.

Still going to clean the intake, mine has never been done and has 212k so we'll see. When I did the timing belt I looked in with a mirror/flash light and it didn't look too clogged. I drive it like I stole it so I'm not sure if that helps or hurts as far as clogging.

The inverter really is 400w continuous draw (600w inverter) and it was for medical use. Not blaming it, been installed for a while and it only cost me maybe 1mpg or so before. Just wanted to be honest. -put another 200miles on without it and got 34mpg carefully filled to same spot.

Turd427 - Curious to see how yours works out! I am still thinking clogged cat myself - I would think clogged intake would cause even more smoke (overfuel) and i literally have 0 smoke out of my tail pipe.

Edit: Here is some log screens from vcds. 3rd gear pull
RPM/Boost/N75
MAF
inj quan/coolant

jprine said:

This is with a 6speed cruising at 2400 lol...

Click to expand...

What speed are you running at? My 5 speed turns about that at 70mph. You 6 speed should drop that greatly. Is it a diesel or gasser trans?

79TA7.6 said:

What speed are you running at? My 5 speed turns about that at 70mph. You 6 speed should drop that greatly. Is it a diesel or gasser trans?

Click to expand...

80/81mph GPS (83-84 speedo) - EFF Code

"fixed" my cat today - Still havn't cleaned my intake (ever). Last few fill ups were in the 33-34mpg range.
Filled it to the very top, drove 45miles combined city+80mph highway+lots of WOT pulls and screwing around, topped it off again and got 41.5mpg. Pretty sure it was the cat. Oh and I got my smoke back lol. Once I put some more miles on and fill up again I'll know for sure.

Edit: Oh if anyone was curious my car has 212k on it.

Did you look in the intake pipe? If you have never cleaned it I will bet it is clogged like a bugger!

I'll get a picture when i do it Just waiting for a good time to make smoke and egr delete stuff.

I'll bet its clogged to, prob why my cat clogged up from the richness :/

Not even the closest to the lowest economy level. I got 12mpg out of my first ALH Jetta for about 800 miles when one of the high pressure lines broke at the connecting nut. That was great - washed off the engine to a bright shine, and when I arrived at my destination, I collected about 2 gallons of diesel as it drained back from the engine blanket under the hood.

Guess it was pretty clogged. About 1" dia left in the inlet.

panthers89fan90, it had been a little slow in the above 3500 range, but not drastic & it was always like that. (owned it for past 115k!)

Swapped in new nozzles right before cleaning the intake and the difference was drastic. ~0 startup smoke now, idles quieter/smoother. The haze of smoke in hard 1st/2nd starts is pretty much gone. This was all pre-intake clean. The drop off in power around 3500 was allot more drastic with new nozzles so thats when I got around to cleaning it.

No new mpg numbers yet

You should be able to hit the high 40's or even low 50's now!

I'm surprised that you could even rev up to 3500 rpm! My car just fell flat at around 2,400 rpm and would then struggle to hit anywhere near that (If I kept my foot into it it would eventually get there).

What were the ports on your head like? Mine were actually pretty decent so I just left them. My wife's car's intake was also clogged, though not quite as bad as mine, but her ports needed cleaning: oddly, her car revved up fairly well, had a LOT better performance than mine even though hers wasn't all that less clogged than mine. I suspect that there's a critical point/percentage of blockage and that hers hadn't yet reached it and mine had: my cruise control also started failing to hold speed when hitting slight inclines (once intake was cleaned That problem no longer existed).

What nozzles did you install?

Here's my Fuelly log for my car ("Tanko" - wife's car is "Tanka"):

http://www.fuelly.com/car/volkswagen/golf/2000/uhoh/333519

I've made a few notes concerning repairs and such that I figured might affect fuel mileage. Initial tank worked out to about 48mpg, but then took a dive. With a fair amount of work done I'm now averaging right at 50mpg (over the last 11 tanks). Waiting to install refreshed injectors with new DLC520s and the Malone 1.5 tune.

Thanks for the link UhOh. Think I'll start using that and get accurate data.