My dd FC just started running rough for no reason. Like, it's always been reliable as ****, and just NOW decided to be a bitchass.

It sounds, looks, and feels like a vacuum leak, but I(/we/Jesse/microdrifter001) can't find ****.

Here's a video:


http://vimeo.com/10239348


It's running rough as ****, and won't idle.

It's just a stock S4 NA with emissions removed and an intake. All the vacuum nipple caps are accounted for, and there aren't any rips or tears in any vacuum lines.

So far, I've checked:

- AFM, cleaned it and tried another one
- cleaned and replaced plugs
- switched spark plug wires, they're fine
- coilpacks, both are working
- switched fuel pump, ****'s fine
- Put fresh gas in it


Right now, I'm regasketing the upper and lower intake manifolds to see if that helps...I'm ******* running out of ideas though...


Broken TPS?

Stuck seal?





halp.

 

Based what I saw, is the person starting it giving it throttle to start the car? (I'm assuming that it doesn't start at all, based on what I saw, unless you give it throttle)

(Edit) Watched it a few more times, can't be the same problem I had with my S4.

 

Still running like ****, but I managed to get it up to normal operating temp.

Then, it started smoking a little bit.

Then, I noticed my fuel line to my secondary fuel rail is bulging like a ************.




WTF?

 

...aaand there's very little/no pressure in the return line.

What does this mean?

Dead primary injector(s)?

 

i havent had a lot of experience with cars but i have had problems in the past with running rough and have gone through striping the intire intake several times, diagnosing and replacing most everything you've mentioned. until i got to replacing my primaries and MAF which really made things much better for me, but i never had bulging fuel lines.

i noticed you said you replaced your fuel pump, but did u do the filter too?

 

Wow. Get that fuel line/pressure thing sorted out before you have a failure and fire. It sounds like you may have a blockage in the return line (hence no pressure there). If that is true you may have excessively high pressure in the rails. This may be causing the engine to run rich. I don't see anywhere in your list that you checked fuel pressure. You can get a fuel pressure guage setup from Harbor Freight for $16. Download the online FSM and check the fuel pressure per the factory procedure. You also need to open the return line and clear the (potential) blockage (blow out with air pressure). And you are going to have to replace that fuel line.

 

i know that this post is probably really old but i was wondering if you ever figured this out? im having a no idle/ running rough problem with my 88 n/a. its popping and backfiring bad while i try and keep it running. if i rev it slow its perfect but if i stomp on it it backfires and pops pretty bad. any help would be nice

 

Check compression, then fuel pump and fuel filter.