1999 VAG Golf GTI 1.8T AGU Cyclinder 2 Misfire

calvintibia001

So I housemate's Golf GTI is giving me a headache,
It have a Cylinder 2 Misfire, it happens from time to time, sometimes when you floor it, it will fix itself.

I changed the Spark Plugs, set of LS Injectors (known to be good), there is oil in the engine.
Tried swapping the Coil around, makes no difference.
Did a Dry and Wet Cold Compression test, all cylinders around 90-100 psi.

Not sure what to do next, check the wiring for the injector and coils ?

Codes from VAG-COM

00561 - Mixture Adaptation

Possible Causes
Mass Air Flow Sensor (G70) faulty
Fuel Pressure too Low
Leaks in Intake Air System and/or Exhaust System
Injector(s) faulty (i.e. coked)

01165 - Throttle Body Control Module (J338): Adaptation Not Successful

Possible Causes
Throttle Body Adaptation Conditions not met
Throttle Body Control Module (J338) faulty

16500/P0116/000278 - Engine Coolant Temp. Sensor (G62): Implausible Signal

Possible Causes
Wiring and/or connections faulty
Engine Coolant Sensor (G62) faulty

jonbot

even cold, 90-100 psi is very low

even a B21FT makes like 130 or so

have you looked at the plugs?

given the fault hasnt moved with injectors or coil, youre looking at a worn/ fouled plug or no compression

if the plugs are fouled, as id expect with such low compression, youre probably looking at needing a set of rings

when you say 90-100psi, was this 90 dry, 100 wet? or did the compression not change between dry and wet?

if the plugs are good and clean, perhaps leaky valves

calvintibia001

The compression does not change between dry and wet, its both within the 90-100psi
Does opening the throttle change the compression reading, i forgot to open the throttle in all test, would that decrease the compression reading ?
Plugs u meaning Spark plugs ? I changed the plugs like a week ago

Ex850R

How were the old plugs or pull these and check.

calvintibia001

These are the old plugs, Left is Cylinder 1 and right is Cylinder 4
Cyclinder 2 plugs was white ish colour, so I guess it's eating oil ?

jonbot

throttle needs to be open during a compression test

plugs look alittle crap

white is usully too hot/ running lean, all that black crap is oil

Philia_Bear

Needs proper compression test and leakdown test to see about hg

jonbot

and burning cause 90's VAG product

calvintibia001

jonbot;23725 wrotethrottle needs to be open during a compression test

plugs look alittle crap

white is usully too hot/ running lean, all that black crap is oil

Philia_Bear;23730 wroteNeeds proper compression test and leakdown test to see about hg

I'll do another compression test soon, the car was running perfectly after the compression test, maybe coz after the wet compression test, there is oil on the rings ?

jonbot;23740 wroteand burning cause 90's VAG product

This is the first VAG car I work, and it's a bitch

calvintibia001

Is it possible that the Injector Pulse is shorted and grounded somewhere else ? How can I check it

jonbot

Noid light

Oscilliscope

calvintibia001

jonbot;23785 wroteNoid light

Oscilliscope

Can I actually use a Multimeter, or will it change so quick that it won't register ?

jonbot

It probably wont react quickly enough

It might change and tell you something, it probably wont tell you if 12v or not

egads (she/her)

Mercilessly googled, http://forums.parallax.com/attachment.php?s=58b830a29b91806b8cebb866abdbf6bf&attachmentid=76167&d=1291824601
Should be buildable from easily gettable bits.

calvintibia001

jonbot;23787 wroteIt probably wont react quickly enough

It might change and tell you something, it probably wont tell you if 12v or not

I might check it with a multimeter, I think it at least would show some numbers when it fires, I am just checking if Cyclinder 2 is out of ordinary from other cylinder

egads;23788 wroteMercilessly googled, http://forums.parallax.com/attachment.php?s=58b830a29b91806b8cebb866abdbf6bf&attachmentid=76167&d=1291824601
Should be buildable from easily gettable bits.

Don't really understand all that lol

egads (she/her)

LED wired to resistor pretty much gives you a polar noid light.

calvintibia001

egads;23821 wroteLED wired to resistor pretty much gives you a polar noid light.

I'll go with a Multimeter for the time being, if it comes back inconclusive, i'll try to make that thing

calvintibia001

The Multimeter basically show the same between all the Injectors, and I did a proper compression test again, it's still 90 psi across all the cyclinder

Ex850R

Isn't that too low? You need leakdown test for sure as somebody mentioned earlier.

brock

Assuming this is the same engine (I know nothing about VAG engines) http://forums.vwvortex.com/showthread.php?3521125-DIY-How-to-do-a-Compression-Test I think that engine has bigger issues than injectors or coils.