S4 turbo issues
 

Hey all,

A week ago I purchased a completely stock 88 T2 (with 103k miles on the original engine) from Denver and drove it 500 miles back home. It did great. I have had a few issues since getting home, though, and I would appreciate advice.

First, it has been idling funny. It stays around 1k rpm but bounces around between 500 and 1100, regardless of whether A/C is on or off. Only once so far has the car actually died while idling, so I'm not sure if its a major issue or sign of things to come.
Second, today was super hot (90+ F) and it seemed to me that the car lacked a little power. I went to get food and of course I stalled at the window of the drive thru. Then it wouldn't start. It's the first time I'd had a hot start issue. I let it sit for about 5 minutes and it started back up, but barely. So I took it home and I noticed that the engine was hotter than usual. Engine temp was halfway between C and H, but it normally sits around a third the way up from C. Oil pressure was good. Coolant level is good.

Any suggestions for preventative action? Compression test? It may have been a fluke thing with today's heat and not hot starting, but I also know thats a sign of low compression.

Thanks
Tab

being a s4 your temp gauge should NEVER go past the 1/4 mark, if it hits the halfway mark, its usually overheating

your running sounds like a vacuum leak, but hopefully you didn't overheat it due to the OEM gauge not being very accurate

Thanks for the reply - good to know. Is the no-hot-start the beginning of the end? Also, any ideas of what would cause it to overheat? I'll check the coolant level again now that its cooled off a bit.

A compression test is always a good idea. I would check the TPS and make adjustments if needed per the FSM or per the instructions in the 2nd gen section. Make sure the basics are replaced, filters, plugs, wires and check for any brittle vacuum lines. There have been times that my TII gave me starting fits and compression was great and it always an great. They seem to heat soak and act up. I sent my injectors to WitchHunter Performance - Injector Cleaning & Flow Testing Services for a cleaning and flow test and that seemed to help with mileage and ease of starting. Something to consider.

Thanks for the advice. I bought a compression tester last night, will probably get to that tonight. Vacuum/leak down test seems so overwhelming for these cars but I'll check youtube and the forums. I think I have most the parts I'll need from testing other turbo cars I've had. :icon_tup:

Front and rear rotor read a little over 70psi on the overall compression test, now to take out the schrader valve and see what has failed... :(:(:(