Exactly what needs unplugged/ disconnected to do compression test on RS4

[tootall91]

Hey guys,
Im going to be doing a compression test on my RS4 and wanted to make sure I covered my bases.

I know to disconnect the wires going to all coil packs
I read something somewhere about pulling a fuse for a fuel pump but I cant find the post now?

Anything else I need to do?
I should do this with a warm engine, correct?

[vacsimile]

Why?

All coils and spark plugs out. Fuel pump fuse should be #28 on the fuse panel on the left side of the dash. It's labelled on the inside of the cover. This only kills the low side pump though, so you'll have to use VCDS to reduce the high side fuel pressure or just run the engine until it stalls after pulling the fuse. It will run for several minutes on residual pressure in the rail. Throttle should be held open, so just hold down the gas pedal while cranking. And yes the engine should be warm unless you are diagnosing misfiring on cold starts or something to that effect.

[audinutt]

Or unplug the crank sensor that would stop ignition and the injectors

Sent from my SCH-I605 using Tapatalk

[vacsimile]

Or unplug the crank sensor that would stop ignition and the injectors

Sent from my SCH-I605 using Tapatalk

Yeah very true. Still pull all the spark plugs though.

[jnorwooddds2004]

Are you still around? Did you ever solve your oil consumption issue?


2006 B7 S4; currently running Liquid Moly Race Tech 10W-60 in Texas; OE Tuning Stage 1 ECU; 6 speed manual transmission

[RHawk]

I'm also having a high oil consumption issue. Changed the oil and 2 weeks later I'm 5 qts low. No noticeable puddles, light smoke on startup can't tell if I have any major smoke on decel, either way I'm losing oil as fast as I can pour it in. Need to do a compression test and leak down test to see where to start. Anyone know of a good place to get parts, I'm on a strict budget, however I have plenty of time.

Sent from my HTC6535LVW using Audizine mobile app (http://r.tapatalk.com/byo?rid=87676)

[vacsimile]

I'm also having a high oil consumption issue. Changed the oil and 2 weeks later I'm 5 qts low. No noticeable puddles, light smoke on startup can't tell if I have any major smoke on decel, either way I'm losing oil as fast as I can pour it in. Need to do a compression test and leak down test to see where to start. Anyone know of a good place to get parts, I'm on a strict budget, however I have plenty of time.

Sent from my HTC6535LVW using Audizine mobile app (http://r.tapatalk.com/byo?rid=87676)

Strict budget + Audi, especially an S or RS model, do not mix.

If you are truly consuming that much oil and didn’t just underfill the engine in the first place, I would skip the compression and leakdown check and just borescope the cylinder walls.

Also, how did you get 5 quarts low?? The oil level warning should pop on at one quart low.

[RHawk]

Low oil light IS on. Also verified by the dipstick. Add a quart, check the stick, repeat until stick is correct, count empty oil bottles. In a week, repeat all steps.
I refuse to believe that I cannot perform a rebuild at a reasonable cost.
The reason parts are expensive is because 1) the rarity of this engine and 2) the parts have the Audi (or vag) name.
Anyone interested in my budget build tune in, I'm about to make history. I'll update with a list of parts and where I sourced them. I will win, I always win.

Sent from my HTC6535LVW using Audizine mobile app (http://r.tapatalk.com/byo?rid=87676)

[vacsimile]

Low oil light IS on. Also verified by the dipstick. Add a quart, check the stick, repeat until stick is correct, count empty oil bottles. In a week, repeat all steps.
I refuse to believe that I cannot perform a rebuild at a reasonable cost.
The reason parts are expensive is because 1) the rarity of this engine and 2) the parts have the Audi (or vag) name.
Anyone interested in my budget build tune in, I'm about to make history. I'll update with a list of parts and where I sourced them. I will win, I always win.

Sent from my HTC6535LVW using Audizine mobile app (http://r.tapatalk.com/byo?rid=87676)

lol, good luck with all that buddy. Are we talking about an RS4?

If the cylinder walls are scored, you won’t have many options. Replace the engine or take it to a shop that can machine alusil blocks. It will probably be cheaper to buy a used engine.

[RHawk]

It's an S4, if the walls are too badly damaged I will be looking for a block, if not this will be a parts only job. I have sent cylinders with nikasil coating to a place in Wisconsin for years, they will accept nikasil multicylinder engines, but the cost is usually around $150 per hole. Not bad for a new replate. But again looking to get this done on a budget.

Sent from my HTC6535LVW using Audizine mobile app (http://r.tapatalk.com/byo?rid=87676)