zogster

So I'm shaking the car down after a few weeks of disassembly, replacing things, and re-assembly.

Car started first time, and I ran the engine a few times stationary without trouble, for up to 20 minutes. Gentle half-mile test drive completed without incident. Then I took a longer test drive, was heavier on the throttle, and things didn't go so smoothly.

The behaviour the engine is now showing is this:
• Stumbling/choking on hard acceleration - maybe boost related? It seems to run fine from 1k-3.5k revs and then bog down. And it's quite a hard stumble, not a gentle "ooh there's not as much acceleration as there should be"
• Rough idle and often stalling when stopped - have to blip the throttle to keep things going
• Engine starts OK, cold or warm, but dies after a couple of seconds.

What I've checked:
•TPS - as per Clark's Garage procedure, seems to be working fine, though I could only check KLR pin readings at open, closed and one intermediate point.
• Fuel pressure - seems OK, using the crude method of disconnecting one injector and seeing if it makes a difference. It didn't. But maybe that test is too crude to be useful.
• Vacuum - think I may have a slight leak (pulled the vacuum line that connects to the fuel pressure regulator and just blew into it...)

HELP!!

(of course, I'm expecting someone to magically divine exactly what's wrong here, but will in fact spend a week trying to track down an electrical gremlin by eliminating all possible suspects.)

V2Rocket

id double check all the hoses/couplers on TB/IC etc are hooked up fully. wouldnt show up on a vacuum leak but could suck in more air than the AFM expected.

zogster

Sounds like a good next step. The difference between first tests and proper test drive is, I guess, consistent with something popping off under boost... though it could just as easily be something electrical shaking loose I suppose.

Dave951

Another thing to check is that the gap on the speed and reference sensors are within spec.

zogster

You da man V2. The hose that comes off the IC pipe just by the AFM had popped off. Saw it as soon as moved the elephant trunk air duct thingie

V2Rocket

hows it run now?

zogster

Just like a 30-year old German sports car should - running fine!

Starts and idles evenly. Engine smooth under gentle and hard acceleration.

A couple of wrinkles, mostly cooling related, still to look into but nothing major – turbo water pump, cabin heating, both seem to be not working. But the cooling system has been a constant source of hassle... until I've bled and refilled it a couple more times I won't even count the heater thing as an officially recognised Maintenance Issue®