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cheapguy
08-23-2009, 07:52 PM
Please Help!!![[=(]
I have a 2000 A4 1.8T (126KMiles). I bought it exactly one year ago knowing it had a low compression on Cyl 3 (85-90psi). It also had the following codes:

Random misfire
Cyl 1, 2, 3, 4 misfire
17536, 17647, 17521

The reason I bought it because it ran fine with lots of power (even with the low comp).

Since last month I noticed that the turbo doesn't spool up, it stumbles when I am driving, the check engine light flashes more often, and just runs horrible.

In the service manual, I see a fuse for turbo. Does anyone know how to get to it, and could it be the problem of the turbo?

I replaced all the coil packs, spark plugs, and air filter. I took it to one mechanic and he did a wet/dry test, and said I needed to re-build my engine. The compression in cyl 3 is still the same as last year. It doesn’t smoke, and didn’t have to add a drop of oil for the year. I told him it was running fine for a year with that low compression; he gave me some BS…..

NEED HELP!!!
Thanks

EuRo_KiD
08-23-2009, 08:07 PM
I stumbled upon this link which is very helpful in identifying codes

http://www.bentleypublishers.com/tech/audi/audi.dtc.table.htm

17536 (P1128)-Long Term Fuel Trim mult.,Bank1 System too Lean (Check vacuum hoses and MAF)

17647 (P1239)-Cyl.3-Fuel Inj.Circ. Open Circ. (injectors could be bad)

17521 (P1113)-Bank1-Sensor1 Internal Resistance too High (o2 sensor is bad)

Hope that helps a bit [up]

walky_talky20
08-23-2009, 08:12 PM
17536 - Long Term Fuel Trim (multiplicative) - Bank1 System too Lean
17647 - Cylinder 3 - Fuel Injector Circuit - Open Circuit
17521 - O2 Sensor - Bank1-Sensor1 Internal Resistance too High

The first code is usually attributed to a very dirty or faulty Mass Airflow Sensor. But I would look into the second code first. If the fuel injector is indeed faulty for cylinder 3, then it could be causing both of the other codes.

If you have vag-com (full version), you can do an "Output Test" and advance through the tests until you get to the Fuel Injector tests. You should be able to hear each of the injectors click individually and repeatedly during the tests. If injector #3 doesn't click, you'll have to determine whether it is the injector itself or a wiring issue. If you don't have vag-com you can use a meter to check for power to the injector connector and check the resistance of the injector itself and compare to one of the others.

Hopefully it just as simple as a bad injector. Good Luck.

cheapguy
08-23-2009, 08:21 PM
Thanks for the code reference.

cheapguy
08-23-2009, 08:26 PM
Thanks for quick response. What I really want to first is figure out why the turbo is not spooling. I used to hear it for few seconds (loud) once I start the car. I think my latest problems have to do with the turbo. When I run the car with the cyl 3 coil pack disconnected, I can definitly feel the miss. I think the injectors and the electrical are working fine. I suspect the MAF and turbo. The turbo is unknown to me.

EuRo_KiD
08-23-2009, 08:32 PM
Your best bet would be to see if you have any vacuum leaks or boost leaks first. Start with the simple things and work your way down. Check all your hoses and stuff.

walky_talky20
08-23-2009, 08:35 PM
^Good Advice.

I believe the ECU will go into soft limp mode when it has a lean code like what you have. In soft limp mode it will limit the boost by half or so. I wouldn't suspect turbo problems until you take care of the other codes. I'd definetly check out injector #3, unless you know why that code was set (perhaps you unplugged it at some point?).

The turbo does not spool at idle. If you are hearing (or not hearing) a loud whirring, vacuum cleaner-like noise upon a cold start, it is probably the secondary air injection pump. Unless it sets a code or causes you to fail inspection or emissions, I really wouldn't worry about it. It doesn't have anything to do with how the car runs.

For a quick check, try unplugging your MAF and see if the car runs any better.

EuRo_KiD
08-23-2009, 08:39 PM
^^ Better Advice lol

Ya, if your car runs better without the MAF then your MAF is bad. But if it does run better without the MAF don't get happy and drive the car without the MAF for a long time as it will give you more problems.

If the MAF is bad and you get a new one you have to reset the ECU once you have installed it.

cheapguy
08-23-2009, 08:51 PM
Is MAF the one on the top of air cleaner looking like a niple with wire coming out of it? How do I access it? Can I clean the MAF or it dosen't matter if I cleaned it?

Thanks!

myb5quattro
08-23-2009, 08:51 PM
The turbo does not spool at idle. If you are hearing (or not hearing) a loud whirring, vacuum cleaner-like noise upon a cold start, it is probably the secondary air injection pump. Unless it sets a code or causes you to fail inspection or emissions, I really wouldn't worry about it. It doesn't have anything to do with how the car runs.

For a quick check, try unplugging your MAF and see if the car runs any better.

I was just about to post a video of my car at a cold start and ask why it makes a weird buzzing sound. This is quite a coincidence that I ran across this thread haha you just helped two people! Thanks [up]

cheapguy
08-23-2009, 08:54 PM
If it was the MAF I'll do a victory dance first and change it ASAP!
Thanks for your help. As soon as I knw where the MAF is I'll check it out.

EuRo_KiD
08-23-2009, 08:58 PM
If im not mistaken its on the intake after the filter and yes it has a wire coming out of it.

Yes you can try and clean the MAF to see if that helps. But if you are, make sure you use isopropyl alcohol. Make sure you're careful with the wire on it and make sure you let it dry really good.

walky_talky20
08-23-2009, 09:55 PM
Yes, it is inside the airbox. There is a wire going into the top of the airbox with a rubber grommet on it. Pull out the rubber grommet and you will see the plug for the MAF. The button is a bit hard to push to release the clip. I usually use a small screwdriver, but be careful. The last thing you want is a broken clip and an unreliable connection at the MAF. The connector is quite similar to the coil pack connectors if you are familair with those.

lifwanian
08-24-2009, 01:43 AM
85 - 90 psi isnt too low... I guess its low for these cars, since mine is at like 165 psi or something like that, but I do know evo's are at like 90...

mike-2ptzero
08-24-2009, 06:58 AM
85 - 90 psi isnt too low... I guess its low for these cars, since mine is at like 165 psi or something like that, but I do know evo's are at like 90...

90 is very low for a motor period and the 1.8t is 185-190 psi stock.


Not sure how you think an EVO is 90psi when it is a 9.0:1 compression, unless you thought 9.0:1 meant 90psi.




The 3rd code is most likely the cause for the 1st code. The 3rd code is the first 02 sensor which thinks the car is running way to lean. This could also be causing the rest of the misfires since the ecu is going to be spraying way too much fuel in all 4 cylinders and this would cause all 4 to misfire.

If you have a vagcom check block 032 readings, I bet they are very high on the + side.

cheapguy
08-24-2009, 09:05 AM
Thanks guys---we are getting somewhere. I diconnected the MAF connector, and it runs better..no more stumbling/hesitation...it only dies when I do a complete stop which is no prblem. I plan to remove the MAF, clean it and put it back. If it didn't work, I'll order one online. I'll post my findings.

cheapguy
08-24-2009, 07:41 PM
I took the MAF out and cleaned it. I noticed that two tiny wires (hair like) were hanging from one of the flat sides of the sensor (I should have taken the picture). They were connected to the sensor body on one side and just hanging...That worried me. So, I installed the MAF back, and test drove it. It ran much much better so I know I didn't damage the MAF. However, I am still getting the flashing engine light. A friend is going to help me reset the codes and get the new codes. I am happier, but not there yet. Thanks for all your help.