Engine and Ultimo Troubles

[DTC710]

Hello again Vortex. All last week, my car was down for maintenance. Ended up having an lock cylinder problem where I needed to replace it completely. Long story short, the ignition was stuck in the on position until I could replace the lock cylinder, which completely killed my battery. I didn't think much of it, and just decided after the battery died that I wouldn't waste time trying to charge it up before I fixed the problem. Last Saturday I got the lock cylinder installed and everything put back together. Charged my battery and then all of a sudden, my idle is much lower than it was before. I'm talking around 6kRPM instead of around 8-9kRPM. For a while, I had a hard time preventing my car from stalling on me because the idle was too low. I'd have to immediately hit the gas when I turned it on and switch gears (it's an auto unfortunately so when I say switch gears, I'm talking from reverse to drive) as quick as possible to prevent it from dying. It's slightly leveled out over this past week, but it's still lower than normal and it's a rough idle. Any suggestions on what could be happening here or how to fix it?

On the upside, since my car was down for a week, I got the opportunity to finally install my Ultimos I bought earlier this summer. Love how the car looks, but man for some reason it rides really rough. I can't figure it out. At first, I thought it was because I was so low that I was rubbing on bumps, so I raised the back ones to full height to no avail. Every slight bump in the road I get a loud thud, which gets obnoxious on the roads I travel. I understood that the ride quality wasn't going to be fantastic, and I don't mind a little bouncing around, but I feel like I might have done something wrong because I can't hit even the slightest bump without hearing a solid thud followed by a few bounces. Any suggestions on what is going on here?

TL;DR: Engine is idling too low and Ultimos making odd sounds in the back even though raised to full height now. Help with either would be appreciated.

And of course, pictures for your enjoyment:

[DTC710]

[DTC710]

[2SlowHeart]

As for the thud, did you replace your strut mount bushings? That could cause it.

[DTC710]

As for the thud, did you replace your strut mount bushings? That could cause it.

Interesting! Care to elaborate? I heard that some people recommended buying a refresh kit, but never really looked into it. I assume that is something that comes with it? Thanks for the reply!

[DTC710]

Anyone else have some advice?

[engineman98]

Vaccum leak can cause low idle. Do you have a Check engine light on? If your idle is wrong you should have one. Get your car scanned and let us know what codes it has. I would look at strut bushings also for the noise in the rear.

[DTC710]

Thanks, I do have a check engine light on. I was under the impression that it was because of another known problem, but it makes sense that it would be on for that as well. I suppose I'm going to have to go to the dealer to get it scanned, aren't I?

[engineman98]

Thanks, I do have a check engine light on. I was under the impression that it was because of another known problem, but it makes sense that it would be on for that as well. I suppose I'm going to have to go to the dealer to get it scanned, aren't I?

If you dont have a scan tool either post in your regional forum for someone with vagcom or just take it to local autoparts store they usually do code reading for free Dealership will charge you more than you need to pay.

[theguy831]

still have a sway bar?

[DTC710]

Good call on asking the regional forums!! Thanks for the help.


I do have the rear sway bar in. At least I assume so because I know I didn't remove it. Would removing it improve my ride quality?

[DTC710]

[jmkyler3]

I also recommend a complete front end refresh when do coilovers or springs unless it has been done recently. You have to get a fresh alignment anyway, may as well make it worth it.

for less then $20 and a laptop you can have a VAG COM reader of your own.

[DTC710]

$20?? Man, that's completely worth it. Sounds like its time to wander the Internet and find it. Thanks for the help!

[DTC710]

Also, I am not having any problems with my front end. It's the back that is rough and super bouncy. Just to help with diagnosis. I'll still consider the front refresh kit though.

[DTC710]

Update: Just drove to work this morning with no CEL. Confused the crap out of me because I was convinced that it was a vacuum leak problem as stated above which would cause the CEL to come on, and now it is off. The problem still persists. Terribly low RPM to start (4-5kRPM) and on the verge of dying, but when I got to work I noticed it was back to normal (8-9kRPM).

It will be interesting to see what happens on the way home today. I'll be sure to report back. In the mean time, more discussion on what it might be would be very useful. Are there other things than a vacuum leak that could cause low idle like this?

[dylanneon]

the thud in the back is the rear axle bushings go have them replaced and be happy.

[DTC710]

Perfect! I'll replace those immediately. Thanks for the advice!

[DTC710]

the thud in the back is the rear axle bushings go have them replaced and be happy.

Would these be what you are referring to? Sorry, I'm still a noob at this stuff and learning as I go.

[Dr1ftCody]

a real easy way to check for a vacuum leak is take some soapy water in a spray bottle and look for all the vacuum hoses on the intake and spray them, if you start to see bubbles forming then thats where the leak is, but to me that kinda sounds like a fueling issue more because whenever your on the throttle you keep the car alive but whenyou back off it will die, does the car only do this at start up or even when it reaches operating temp.???

[cruizer34]

Try runing it with the maf unhooked and or try cleaning the maf.

[DTC710]

a real easy way to check for a vacuum leak is take some soapy water in a spray bottle and look for all the vacuum hoses on the intake and spray them, if you start to see bubbles forming then thats where the leak is, but to me that kinda sounds like a fueling issue more because whenever your on the throttle you keep the car alive but whenyou back off it will die, does the car only do this at start up or even when it reaches operating temp.???

It does not do this when it reaches normal temperature.

Try runing it with the maf unhooked and or try cleaning the maf.

Sounds like it's time to research this so I know what the heck you are talking about. Apologies, as I previously stated I still consider myself to be a noob.

[DTC710]

Try runing it with the maf unhooked and or try cleaning the maf.

Okay so I have a general idea of what you are talking about now. Where exactly is the MAF on my 2.0L Jetta? Also, you made it seem like this is a very simple fix. Is unhooking/cleaning it as easy as you make it sound?

As a side note, I saw that most MAFs are electronically controlled by the on board computer. This made me wonder if while my car was dead that something got switched to change how much air is going into the engine. I ask this only because I noticed when I recharged my battery, I had to reset my key fob to be able to unlock and lock my car again because the computer had apparently reset itself from not having power for so long. Could it have also reset something in the MAF since this problem wasn't happening before my car died?

Thanks for the help guys. This is becoming a really useful thread for me.

[DTC710]

Another update: CEL came on on the way home, although I think it has to do with a different problem with my transmission that I'm already aware of. I read something on another website saying that resetting my computer would be useful to maybe resetting the MAF. Vortex opinion? Thanks guys.