Half Jap Boost Junky

Ok, I did the search thing, but I can't seem to find anything with the same conditions so here goes.

S5 TII rebuild w/ approx. 360 miles on it.

When I picked the car up from the shop, the engine flooded, but it has been fine since. I've been following the break in proceedure from fc3spro.com so no boost and no reving past 4K (I normally keep it around 3K to be on the safe side). The its been running fine until tonight.

I started the car up with no problem and drove to a friends house. When it was time to leave, the car didn't start on the first try as normal. Second time was fine and it drove normally.

Stopped off for a coffee for about 15 minutes and this time the car just wouldn't start. I pulled the EGI fuse and cranked, but it didn't work. I pulled the plugs, cranked it for 10 seconds, put the plugs back in and the car started fine.

NOTE: I didn't have any oil or anything to inject oil into the rotor housings before I started the car again.

So the car starts fine now, but when I accelerate at low rpm (between 2K and 3K) the car starts to jerk, but once I'm above 3K it seems fine. This happens in all gears.

I replaced all four plugs with a set of used ones that I had lying around since the others were fouled. It seemed to help slightly, but the problem persists. Did I screw up my rebuild by not injecting the oil after I unflodded the engine?

The general theme seems to be that hesitation is usually caused by bad plugs, wires, compression or injectors. I won't be able to take the car for a compression test until at least Wednesday so I was hoping someone could give me some insight. I can't imagine that the wires or injectors would just go so suddenly without any previous symptoms.

Thanks for any help.

eriksseven

iTrader: (6)

How bad is the 'jerking'?

This might not be it, but if you are accelerating slowly (meaning slow enough so that you're not making any boost), the car will buck slightly (and lightly) repeatedly as the ECU trys to decide how much fuel to spray...

When I'd accelerate on my fresh rebuild, I noticed that as I was creeping up in the RPM's at about 1/4 throttle and out of boost, my narrowband A/F gauge would start flopping around from rich to lean, rich to lean until probably a little after 3k RPM's. Then when I'd hit around 3.8K RPM's it would go fully lean for a second (causing a hesitation) before coming back on smoothly (rich) til I'd shift at 4k RPM's.

As soon as I was broken in and driving at WOT, both of these problems dissapeared.

Perhaps you're experiencing a similar problem?

Bukwild

how many thousand miles on the leaky *** fuel injectors?

Half Jap Boost Junky

God only knows how many miles are on the injectors. The car itself has about 160,000 Km so I would assume that the injectors have at least that much milage on them if not much more.

My question is why would the injectors start to crap out so suddenly?

As for my throttle response, the jerking was not there until after I unflooded the engine. It was accelerating fine before with little throttle and no boost.

I called the shop today and of course he is too busy to take a look this week. He suggested that I run some injector cleaner through the fuel system and see what happens. I don't really think this is gonna do anything, but heres hoping. I guess I'll find out if it helps in the next few days. As for possibly replacing the injectors, I'll be ordering a pair of Bosch 1600cc as soon as my paypal transfer clears as well as a pai of the Greddy 720cc. However I'm pretty sure I shouldn't install them until I get my Haltech in, and that won't be until after the initial break in.

Keep the suggestions coming and thanks again.

SonicRaT

iTrader: (6)

Have you checked the common culprits? Faulty grounds/TPS out of spec/etc?

Half Jap Boost Junky

I havn't really had a chance to look at anything yet. Its been raining here for the last 3 days and I don't have much room in my garage to move around.

I can't imagine that it would be a faulty ground or the TPS. If there was a faulty ground somewhere, there would be sparatic symptoms leading up to the failure and I would assume that the same would go for the TPS.

I've been driving the car for the last couple weeks with abosolutly no problems. The flooding was the first indication of any problem and the hesitation presented itself once I got the car running again, and it is consistant.

I have a few days off so I'll try and take some time and look into this problem in more depth.

Keep 'em commin'

Half Jap Boost Junky

Well, I took the car for a spin today and it hasn't flooded again yet.

I also noticed that if I keep my boost gauge in the vacuum side at about 10, the car doesn't hesitate. It only does it when I start to build boost.

Does this sound familure to anyone? Again, everything was fine until the engine flooded the other night.

Wankel7

Check the timing ?