RPM not constant at red lights ?
 

Hey guys !

my car is in good shape, it's a '92 SVX with 212K km, transmission was rebuilt at 160K

My question is, since I got the car (6 months), when I'm at a red light or just letting the car go forward by itself without stepping on the gas pedal, sometimes still pretty often, it seems that the rpm isn't constant, it fluctuates between let's say 300rpm and 850rpm, making the car kinda trembling at longer stops or it makes it kinda "hesitate" if I don't give some gas for example when I'm parking.

This seems to be only present when I'm going forward and it's especially annoying when I leave from a red light, that kinda fluctuation makes that the car doesn't jump forward on the road smoothly, just when it starts going over 1000rpm all is pretty much ok. I get overrun by toyota echos because of this :D

Today, for the first time ever, the car's rpm went so low it friggin stopped ! I started back and it's been ok ever since, still doing the problem in the usual variation.

Could it be a clogged up injector ?
I think it may be an overall problem, cause some days the car runs great, and othertimes it seems to not shift smoothly, especially when the car is cold from a start.

thanks !

Have you cleaned the throattle body? I would clean that and change the gas filter. Is your CEL on? If so, check the codes. :)

my first thought is iac but i'm not sure if svx's have one

I would try all of the following:

• Make sure there is nothing obstructing the air flow through the air intake
• If its been a while, replace your air filter while you're in there
• Clean your MAF (if you're not sure how, there have been a number of posts about it)
• Clean out your throttle body (I believe this is a doc in the how-to's about this)
• Toss a bottle of fuel injection cleaner & octane booster into your gas tank
• Make sure all the connections to your battery are firm & free from grime / grease (If the contacts are dirty, a spray can of electrical contact cleaner should do the trick)

All in all, including the air filter, this should cost you < $40, take about half an hour, and could do WONDERS in addressing your problems. I was experiencing weird hesitation and idle in my SVX and the above did the trick.

The 4 gauge alternator mod can also prove helpful in leveling out jumpy idle or other quirky electric behavior.

Good luck!!

thanks guys, I'll try this and let you know !

By the way, my local garage says they can clean up the injectors , I think they connect them to some machine..they told me I had to leave the car for 2 hours there..and that's not only tossing injector cleaner inside the tank but a deeper cleaning..is that the cleaning of the throttle body you're talking about or would it also help ?

An injector cleaning is different than cleaning the throttle body. The injector cleaning will use a pressurized system to de-gunk your fuel injectors; where the throttle body cleaning will degrease the throttle body. The injector cleaning is something I would leave up to your mechanic, but the throttle body cleaning is something you can easily do yourself. You can buy a can of throttle body cleaner at any auto parts store and follow the how to guide posted on this site.

This mod has distinct disadvantages as it bypasses all alternator fuse protection. This is often only a fix for faulty original wiring, which should have been attended to as the first option. Band aides are bad engineering. :(

300 rpms and it keeps going? I thought mine was bad when It dropped to around 600.

didnt you watch the CNN thing about that? they are worthless i know first hand... and i made a buch of money on them..

Where?
 

I would like to clean the throttle body but I can't find this how-to you mentioned. Do you know what it is under or can you provide me a link?:confused:

How-to & Pics :D

http://www.subaru-svx.net/photos/user.php?billb|29447

I had the exact problem... i would check the vacuum lines, make sure the intake snorkel is properly attatched to the throttle body.. What fixed my weird rpm/ stall problem.. is ummm i noticed my intake manifold bolts were all loose :eek: .. just a thought.

I read in the how to that there is a tube you can spray cleaner into to degunk the IAC. Which tube would that be? I'd like to take the whole throttle thing apart and do a better job of it, but I just don't have the time. The shop I usually take it to seems quite uninterested in cleaning anything.

Anybody know what I'm talking about?