Losing Power Uphill

[CortlandCH]

I was driving in the mountains the other day (Colorado Rockies), when something caught my attention. Up some of the steeper roads, keeping the car in “Drive” doesn’t cut it and the car can’t keep up speed. I have to manually shift down to 3rd gear or so to make it up the hills and not lose substantial speed. Average mountain road speeds are about 45mph (72kph). Are these usually pretty rough uphill? I know they’re heavy suckers with small engines, but it definitely concerned me.

My fuel pump is a little whiny, but is within spec at idle. I haven’t measured fuel pressure in a scenario like a hill climb, since I use the tap at the rail in the engine bay, but does anyone figure this could factor in? I’ve heard that aged fuel pumps can sometimes create low power during hill climbs.

2005 A4 B6 1.8T Quattro 5-Speed Automatic.
Altitude correction is applied.

Just trying to stay ahead of the next thing that might need replaced, if anything. This is less of a “diagnose my issue” post and more the fact that I’m still learning what to expect from this car.

[TobiqueSlang]

I don't know how much of a climb the mountains in Colorado are but assuming it's similar to what its like going through the rockies on the Coquihalla in BC you shouldn't be seeing too much power loss on hill climb. if it's significant though you might be on to something.

if the pump is whining bad though I'd change the filter first, might be clogged up some and the pump is working overtime to compensate for it.

[Gin+]

Normal. Drop it down into S or shift manually. You'd be throwing a CEL for lean fuel mix and/or feeling misfires if your fuel pump was that weak.

[B5carl]

The turbo might be on its way out or low compression? My Honda 1.7 NA is very slow uphills

[CortlandCH]

if the pump is whining bad though I'd change the filter first, might be clogged up some and the pump is working overtime to compensate for it.

I changed the fuel filter about a year and a half ago, but the fuel pump whine has been noticeable for the past couple years. I’ve always figured it’s on its way out, given how loud it is on a hot day. Very noticeable, especially outside of the car, though I have no CEL or misfires. The engine just doesn’t handle any heavy loads (which, from what I gather based on what I’ve heard from others, is normal). The car doesn’t react to full depression of the accelerator pedal, especially with the AC on, as “normal” acceleration with my car is about 12-14 seconds (0-60mph). I figure that’s pretty normal with the quattro and tiptronic, but I wouldn’t know better.

[CortlandCH]

Normal. Drop it down into S or shift manually. You'd be throwing a CEL for lean fuel mix and/or feeling misfires if your fuel pump was that weak.

I completely forget S mode exists half the time. With current gas prices, I never dare touch it! I’ll give S a go next time, and see how it changes things. I know it runs the gears longer before shifting to maximize the power curve… whatever that is for a stock 1.8 anyway haha

[CortlandCH]

The turbo might be on its way out or low compression? My Honda 1.7 NA is very slow uphills

Not sure. I’ve been banging my head for a couple years now since I keep neglecting to get a darn boost gauge. I just need to save up and pull the trigger so I can finally get some peace on my boost pressure numbers.

No misfires or CEL, runs nice and smooth aside from low power (or normal power, I don’t even know anymore). I’ll borrow a compression tester this week and see what numbers I come up with. I tested compression a couple years ago and everything was peachy, even for an AMB, but the engine performance has never really changed since I bought it (maybe slightly better as I’ve cared for it).

[BumblebVR6]

I changed the fuel filter about a year and a half ago, but the fuel pump whine has been noticeable for the past couple years. I’ve always figured it’s on its way out, given how loud it is on a hot day. Very noticeable, especially outside of the car, though I have no CEL or misfires. The engine just doesn’t handle any heavy loads (which, from what I gather based on what I’ve heard from others, is normal). The car doesn’t react to full depression of the accelerator pedal, especially with the AC on, as “normal” acceleration with my car is about 12-14 seconds (0-60mph). I figure that’s pretty normal with the quattro and tiptronic, but I wouldn’t know better.

How many miles on the pump? Mine died out of the blue at around 140K miles. No warnings and no lean codes of any sort before.

[CortlandCH]

How many miles on the pump? Mine died out of the blue at around 140K miles. No warnings and no lean codes of any sort before.

Assuming it’s still the factory pump (wouldn’t be surprised, I still have factory ignition coils somehow), it’s got 197509 miles on it! I’d have to open the cover and see to be sure, but nothing in the Carfax for this car suggests it was changed at any point.

[TobiqueSlang]

How many miles on the pump? Mine died out of the blue at around 140K miles. No warnings and no lean codes of any sort before.

Mine did the same at 184k, went to the grocery store, was perfectly fine, got into the car, got halfway through the parking lot and then died out of no where.

[CortlandCH]

Let me know if this doesn’t work, but here’s a video of my fuel pump whine. You can hear it pretty well even several feet away from the car.

https://drive.google.com/file/d/195UFSOE4Q_crPTf5xANNn3jjsD4li_Hv/view?usp=drivesdk

[CortlandCH]

I may have figured it out, or at least part of it. Given the noise coming from the pump, I’m sure it’s either not helping, or it’s set to die soon.

I removed my Upstream O2 sensor, and found the head to be very white, like one would see with a clogged cat. I stuck a scope inside the O2 sensor hole and poked around to see my turbo and wastegate flap (thankfully, they look fine, other than being powdery white).

The catalytic mesh is pretty clogged-up. Not sure what all of this is that would be clogging it, but there are sufficient “clusters” of mesh that appear to be blocked.

I have posted all of my findings (videos/photos) here for anyone to refer to:
https://drive.google.com/drive/folders/1--yNItC8cNqedVsK9-j0aFKQPsa3dctv

[Nimbus]

My fuel pump went out at 92K. Also no CEL or warning. I was driving up hill, elevation ~3900'. Had just got off highway and was climbing a winding road in California. And then a slo-o-o-w stop, all power went.

[CortlandCH]

My fuel pump went out at 92K. Also no CEL or warning. I was driving up hill, elevation ~3900'. Had just got off highway and was climbing a winding road in California. And then a slo-o-o-w stop, all power went.

Well, aside from my obvious catalytic converter clogging, this is worth considering. My fear is the same happening to me during a mountain drive or something. I plan to follow the Bentley manual instructions for testing fuel pump volume, as that’s another indication that the pump is going out. Apparently you can have sufficient pressure, but lack volume.