Anybody familar with Mk4 Golfs?

[mcandmar]

Need some help with a 1.6 Golf i am working on at the moment, car runs like crap, way down on power when you floor it and surges and hesitates on part throttle.

So far fitted a new O2 sensor, managed to free up the EGR valve which had stuck closed, removed and cleaned the throttle body, and using vagcom confirmed there are no codes and the throttle body/EGR valve are now calibrated properly.

It feels to me like it would run fine if it didnt have that stupid drive by wire fuzzyness between my right foot and engine. Its like every throttle input has a half second delay, and when you change gear it hangs onto revs for half a second too. Anybody have any experience with these, any suggestions other than setting fire to it?

[irishs2]

Dont the butterfly throttles get gummed up and require cleaning.. learned this with my own runabout mk4 gti.

[murat]

Is it 8v or 16v?

If its 8v it has a variable intake manifold, you can check if it functions correctly

[diesel des]

Stuck throttle or blocked cat can cause these. Seen it on a mrk4 golf myself.

Sent from my GT-N7105 using Tapatalk 2

[Rusty]

Definitely a boost leak

Have you verified throttle angle in VAG com vs. actual?

[Rusty]

Definitely a boost leak

Have you verified throttle angle in VAG com vs. actual?

[spink]

pretty sure thats the same engine that is in an a3, check the spark plugs,they are a bit awkward to get out.Mate had his car about 6 years and complained it was running *****,took the spark plugs out(easier said than done) and 2 or 3 of them were completly missing their ends,car ran mint after,worth a look

[jaychen]

recently pulled the motor out of one of these and the gbox about 3 times.. about to do the 4th this weekend.

what codes did it show?

[mcandmar]

Its the DOHC 16v motor, AZD engine code. It was moaning about O2 sensor pre-heater, replaced that. Then EGR insufficient flow, which then turned into EGR calibration not completed after trying to calibrate it unsuccessfully. On removal i found it was stuck closed but got it freed up and passed the calibration procedure so no error codes at the moment.

The underside of the throttle body was caked with filth which took plenty of carb cleaner and scrubbing to clean up. It now passes calibration and seems happy.

Also found a torn vacume line to the fuel pressure regulator which i replaced, boost test completed

Must confess i haven't pulled the spark plugs yet, dont know why i didnt think of that so will check them later tonight.

I was discussing the performance issue with a friend and he said "just how fast do you think a 110hp golf is supposed to be"

Either way its still not right, it should pull smoothly 2-3000rpm on part throttle, and wont be happy until i get that right.

P.S. Did i mention the driveshaft worked loose, snapped the bolts and made a hole in the side of the gearbox casing

[spink]

Ok not sure this a3 is a 16v or not but well worth checking the basics

[Sleeper_Avant]

check resistance of coilpacks,

should be circa 9k ohms.

air leaks, there a ****er for air leaks!

and air flow meters

but if you havent had the plugs out yet, why you changing o2 sensors??!!

[mcandmar]

O2 error was pre-heater circuit, it was fubar plain and simple.

Pulled the plugs and there not very old, judging by the oil and filter its been serviced recently. All the plugs looked the same, if anything a little white and lean looking. They were NGK platinum, gaps all reasured 1.1mm as per part number, but haven't confirmed if they are actually the correct ones, never assume anything and all that.

Noticed two of the coil packs were different implying they had been changed at some point. Pity i didn't see your above post before i had them out but the issues don't imply coil packs to me. Its weird in that idle and tiny throttle bellow 2000rpms is as smooth as anything, and WOT above 4000rpms pulls clean and consistantly (just wouldnt pull the skin off a rice pudding). Its the bit in the middle driving normally when it hunts about with the power coming and going.

Figured i'd try a redneck tune up and chucked a crap ton of injector cleaner into it with a plan to drive it with a led welly for the next few days. That should sort it out

[Monkeymagic]

I'd check compression the 1.6 16v have alloy blocks and suffer with ring/bore wear. It more common then not to find the egr fault on these engines although technically if it's seized shut it shouldn't hamper performance.
Have you tried clearing faults then seeing what comes back.?

[mcandmar]

Not getting any codes now, freeing up the EGR valve did make a big difference to the idle, was very lumpy and sounded like it was laboring under load before hand.

Compression test isnt a bad idea, but it dosent smoke or use any oil so cant be that bad. Does have 96k miles on it though..

[Sleeper_Avant]

check the coil packs.

if there is paperwork to prove its had plugs, fine but dont think it has because other bits look new

i get given cars like this every day, usually the basics are overlooked.

if ignition system is fine, check for air leaks