Good morning, since this is my first post I feel the need to compliment this forum. I've mostly been a spectator for the past few months but I'm jumping in as a poster at this point.

Changed the timing belt, water pump, coolant outlet flange, and thermostat on my 2002 Audi A4 1.8T yesterday. Belt, water pump, and tensioners were relatively simple compared to some of the vehicles I've done. Found top dead center, removed the crank pulley/balancer, removed tensioners and belt, changed water pump, installed new tensioners, gapped tensioner arm to hydraulic tensioner body to 8mm, held tensioner position while the tensioner nut was torqued, verified 6mm-10mm gap between tensioner arm and hydraulic unit body, then pulled the retaining clip to engage hydraulic.

Once this was done, I rotated the engine one full revolution and timing marks were dead on with TDC. The only time the pulley were moved once the belt was removed was a one-tooth counter-clockwise turn to the camshaft in order to install the new belt. No issues with the timing belt.

I also removed the alternator and throttle body to replace the thermostat housing and sensor. Again, everything went smoothly, alternator re-installed and throttle bodt reinstalled.

Fired up the motor, initially started but immediately died. I instantly remebered that I didn't plug the TPS harness back in. Plugged in harness and it fired right up but very rough idle with CEL. I slowly brought up the RPM's and it smoothed out at 2000+ RPM. However as soon as I let off the gas it was back to hesitating and misfiring. I popped the top cover back off the timing belt and brought the crank pulley to the timing mark and the camshaft to timing mark and it was spot on.

I haven't scanned the PCM for DTC's although I know they're present with CEL ON. Question is once I started the motor with the TPS unplugged, will the condition exist until DTC's are cleared? Or will it clear after a certain number of key cycles? I have a feeling it's TB/TPS related but I will need to confirm with a scanner.

Any advice would be greatly appreciated... thanks fellas.

 

Really just need to check the code if youre sure that timing is set correctly.

 

Thanks for the reply. I am 100% sure that the timing is set correctly.

Also, I am not new to automotive forums although my thread has all the makings of a rookie Fishing for answers when I already know the answer... retrieve DTC's. I'm just sitting at work and it's driving me crazy.

I was more curious if anyone has experienced this issue after removing the throttle body. I read the Sticky regarding common issues and the throttle body write-up is linked to a page highlighting a throttle position sensor re-learn/reset following removal. But I didn't remove the sensor, rather the entire throttle body itself.

Thanks again... I'll follow up when I scan the DTC's.

 

5 DTC's:

Random/Multiple Cylinder Misfire
Cylinder 1 Misfire
Cylinder 2 Misfire
Cylinder 3 Misfire
Cylinder 4 Misfire

Would this be indicative of incorrect ignition timing? I triple checked the timing again tonight. If it were off even 1 tooth on the cam sprocket the timing marks would be off. They are both dead on... crank pulley mark is dead inline with the mark on the lower timing cover and the cam sprocket mark is exactly inline with the mark on the head.

I'm stumped

 

Verified timing for a 4th time... no problems there.

Well it stopped idling rough, now it won't start at all

New code, P0321, both CEL and EPC light on. All signs are pointing towards the crankshaft position sensor. I though it may have been a result of the brake cleaner used on the crank timing gear until I found the location of the sensor on the side of the block near the oil filter manifold.

I also found the test procedure so I'll take some resistance measurements to determine if it needs replaced. The code indicates there is a signal coming from the sensor, it is just an intermittent one. Similar to any mag style pickup that tries to read a reluctor ring (I'm assuming this works that way) I'll pull it, clean it and give it another shot.

More to follow!

 

Had to have the car towed to the dealer (thankfully free with my insurance) because the ECU was immobilized and neither key was recognized. I had no idea that was the probblem the entire 2 days I chased the "no start" issue.

Car was idling rough because of the P0321 code, Crank position sensor... so with reprogramming ECU to recognize the keys, new battery, and new crank position sensor $440. I don't feel too violated... only place in town that would touch it.

I was definitely stuck though... they said that it won't start unless they replace the sensor... and if I don't do the battery then the immobilizer could kick on again. Ultimately it was the bad battery and it sitting for 3 days that caused the ECU to lose memory.

Anyhow, the car will be running tonight.