sputtering and jerky idle - Page 6

#76 02-26-2004, 02:07 PM

Quote:

Originally posted by mranderson
we have got to figure this out people, it feels like my car is gonna die from the rough idle

Mine to Mr. Anderson.. Have you tried turning ON your air (climate control) ? When i turn mine on, my idle RPM sgoes up and it idles fine ... Jim

maximvsv · #77 04-13-2004, 02:36 AM

I have the 'warm engine' sputter. Sitting still or at speed, when the rev's are around 1500. The plugs and coils were replaced some time ago. I have the oil dipstick sticking up from the tube, so I'll check on the PCV.

One thing that's been bugging me is slow throttle response, so I'll check on the TPS, too.

#78 04-17-2004, 09:57 PM

I have had this problem ever since I got mine. Did any one come to a conclusion as to what the problem is????

immortal_suby · #79 04-18-2004, 06:07 AM

This problem mysteriously disappeared in my wifes svx for a couple months, then came back again recently.

I just pulled the whole intake, cleaned the intake out thoroughly, put in all new vacuum hoses, put in a new PCV, put on a new crank pulley(unrelated, I know)

We'll see if any of that helps.
So far it hasn't done it again, and the idle has smoothed out - I am guessing she had alot of vacuum leakage - the hoses were very brittle under the intake and some snapped right off very easily.

pylon500 · #80 04-20-2004, 09:33 AM

It's hard to believe that we've been chasing this rough idle problem for 6 months now!!

I've just re-read the entire post (I didn't realize I'd posted here so many times myself)

Just as an up-date, here are my symptoms to date;
1/ Out of the blue the engine will just lose one cylider which is mainly noticable at idle. (found by pulling injector leads)
2/ Sometimes it will lose two cylinders which gives a very jerky idle. (seems to go away, or not be noticable, above 2000rpm.)
3/ Neutral to Drive, or Reverse, gives a good 'CLUNK'.
4/ 'Rich' or unburnt fuel smell at idle.
5/ There seems to be dead zone in the rpm range from 600rpm till about 1500rpm. (makes it very hard to drive away gracefully, more like 'slowly pushing gas pedal, then suddenly, LIFT-OFF!)
6/ Have found that if I pull up somewhere and just leave the car running, you can listen to it missing and trying to change it's idle and alternating between running on 6, then 5, then 4 cylinders, then back to 6 again. It will do this for about (on average) 10 minutes, then it just up and dies,

followed by some assorted electrical clicks and whirs, then silence. If I then go out and re-start it, it runs properly!

7/ Sometimes after this start-up, the engine will hunt in rpm between 1200 down to almost stopped. (has actually stopped a couple of times.)
OK, now for the things I've done to it;
1/ Cleaned injectors.
2/ Cleaned plugs (they looked alright anyway!)
3/ Replaced a coil!
4/ Cleaned, then replaced the TPS.
5/ Lost count of the number of bottles of injector cleaner used.

6/ Replaced an O2 sensor.
7/ Replaced the fuel filter.
8/ Bought a replacement fuel pump.
9/ Delved into the fuel pump, (WAY too scary for me!)
10/ Finaly got mad and ripped off the entire inlet system and did the following;
a/ Cleaned the inside of the whole inlet manifold,
b/ Pulled out the PCV valve and cleaned it, (my dipstick still pops up)

c/ Replaced all the vacuum lines with fresh rubber,
d/ Replaced the EGR solenoid (which I broke my bad, Thanks Paddles!)
e/ Cleaned all the crud out of the EGR return tube,
f/ I also pulled both rocker covers off and replaced the seals to stop some of the leaking! (THAT was fun, NOT)
Finally I rang a SUBI dealer for some more ideas, and he said, "Oh yeah, I've heard of this, all you have to do is clean the connector contacts to the ECU just behind the battery"
Armed with a can of electrical contact cleaner, I attacked EVERY plug and pin and wire I could get at and...
PRESTO it ran like a charm!

(I was so happy!)...
For about a MONTH!

The problem, as I see it, is that there are so many things in the computer system that interact, that it's hard to pin point it's cause.
I'm sure that most of the things we see here on this post are actually resultant symptons, not actual problems.
I put many things down to my car being well used/worn out! (347000klms)
I'm still tending to lean towards the fuel pump, my reasoning being that at idle, with the TPS at the idle position, the fuel pump drops back to a low flow that is actually below the requirment for idle.
An injector fails, the rpm drops, the ECU spots this and adds fuel flow to the injectors, the engine kicks, the knock sensors retard the ignition, the engine drops to idle, the fuel flow drops, and the whole cycle starts over!
Depending on ambient temperature, engine temperature, electrical load on alternator, A/C on or off, this will dictate whether the engine will hunt up and down or drop to what appears to be a stable rough idle, but is really the ECU correcting the engine at almost every revolution!! (computers can do that sort of thing!)
An interesting sign of this going on, and the possible weak fuel pump, is that just lately under normal driving my fuel guage goes to empty after only about 100k's (I think that one of my float senders does not work)
However, if the car is left idling roughly, the pump is in high mode so the tank 'jet-pump' works, and the guage will climb up to quantity!
So, trying to change the fuel pump was not for me, and to pay a dealer to replace it would cost almost what the car is worth!!
I'm for trying to fit a second pump inline up front somewhere
Any ideas?
Arthur.

James Scott · #81 04-21-2004, 03:02 AM

Wish I could give a magical answer to your dilemma! I had this for 6 to 8 months, doing the same basic stuff you have, when it just sorta went away (?). It comes back (intermittent rough idle) very infrequently now (once every month or two) to remind me how humble I should be. I also did alternator mod + recently added the ground wire "octopus" with 6 grounds (photo "soon"). I also removed (and cleaned and checked for ground continuity or voltage) many harnesses under dash (esp ECU) and rear of passenger side of engine (+ignitor).

Yes Bro, it's still a mystery to me too, unfortunately.

May the Spirit of smooth idles visit you and yours!

Landshark · #82 04-21-2004, 06:50 AM

i read on Nasioc that a similar problem on an Impreza was solved when the guy put in some aftermarket fog lights. he felt that what actually fixed the rough idle and hesitation was the additional grounding on the ECU.

maybe add an additional ground wire to the ECU - it would be cheap and easy to try.

mbtoloczko · #83 04-26-2004, 07:25 PM

Quote:

Originally posted by Landshark
i read on Nasioc that a similar problem on an Impreza was solved when the guy put in some aftermarket fog lights. he felt that what actually fixed the rough idle and hesitation was the additional grounding on the ECU. maybe add an additional ground wire to the ECU - it would be cheap and easy to try.

Now that would be an interesting solution.

#84 04-26-2004, 07:36 PM

Has anyone cleaned their air control valve? I read through this thread once but forgot if that was mentioned. May be worth a shot.

mranderson · #85 04-26-2004, 08:38 PM

Quote:

Originally posted by pylon500
It's hard to believe that we've been chasing this rough idle problem for 6 months now!!
I've just re-read the entire post (I didn't realize I'd posted here so many times myself)
Just as an up-date, here are my symptoms to date;
1/ Out of the blue the engine will just lose one cylider which is mainly noticable at idle. (found by pulling injector leads)
2/ Sometimes it will lose two cylinders which gives a very jerky idle. (seems to go away, or not be noticable, above 2000rpm.)
3/ Neutral to Drive, or Reverse, gives a good 'CLUNK'.
4/ 'Rich' or unburnt fuel smell at idle.
5/ There seems to be dead zone in the rpm range from 600rpm till about 1500rpm. (makes it very hard to drive away gracefully, more like 'slowly pushing gas pedal, then suddenly, LIFT-OFF!)
6/ Have found that if I pull up somewhere and just leave the car running, you can listen to it missing and trying to change it's idle and alternating between running on 6, then 5, then 4 cylinders, then back to 6 again. It will do this for about (on average) 10 minutes, then it just up and dies, followed by some assorted electrical clicks and whirs, then silence. If I then go out and re-start it, it runs properly!
7/ Sometimes after this start-up, the engine will hunt in rpm between 1200 down to almost stopped. (has actually stopped a couple of times.)
OK, now for the things I've done to it;
1/ Cleaned injectors.
2/ Cleaned plugs (they looked alright anyway!)
3/ Replaced a coil!
4/ Cleaned, then replaced the TPS.
5/ Lost count of the number of bottles of injector cleaner used.
6/ Replaced an O2 sensor.
7/ Replaced the fuel filter.
8/ Bought a replacement fuel pump.
9/ Delved into the fuel pump, (WAY too scary for me!)
10/ Finaly got mad and ripped off the entire inlet system and did the following;
a/ Cleaned the inside of the whole inlet manifold,
b/ Pulled out the PCV valve and cleaned it, (my dipstick still pops up)
c/ Replaced all the vacuum lines with fresh rubber,
d/ Replaced the EGR solenoid (which I broke my bad, Thanks Paddles!)
e/ Cleaned all the crud out of the EGR return tube,
f/ I also pulled both rocker covers off and replaced the seals to stop some of the leaking! (THAT was fun, NOT)
Finally I rang a SUBI dealer for some more ideas, and he said, "Oh yeah, I've heard of this, all you have to do is clean the connector contacts to the ECU just behind the battery"
Armed with a can of electrical contact cleaner, I attacked EVERY plug and pin and wire I could get at and...
PRESTO it ran like a charm! (I was so happy!)...
For about a MONTH!
The problem, as I see it, is that there are so many things in the computer system that interact, that it's hard to pin point it's cause.
I'm sure that most of the things we see here on this post are actually resultant symptons, not actual problems.
I put many things down to my car being well used/worn out! (347000klms)
I'm still tending to lean towards the fuel pump, my reasoning being that at idle, with the TPS at the idle position, the fuel pump drops back to a low flow that is actually below the requirment for idle.
An injector fails, the rpm drops, the ECU spots this and adds fuel flow to the injectors, the engine kicks, the knock sensors retard the ignition, the engine drops to idle, the fuel flow drops, and the whole cycle starts over!
Depending on ambient temperature, engine temperature, electrical load on alternator, A/C on or off, this will dictate whether the engine will hunt up and down or drop to what appears to be a stable rough idle, but is really the ECU correcting the engine at almost every revolution!! (computers can do that sort of thing!)
An interesting sign of this going on, and the possible weak fuel pump, is that just lately under normal driving my fuel guage goes to empty after only about 100k's (I think that one of my float senders does not work)
However, if the car is left idling roughly, the pump is in high mode so the tank 'jet-pump' works, and the guage will climb up to quantity!
So, trying to change the fuel pump was not for me, and to pay a dealer to replace it would cost almost what the car is worth!!
I'm for trying to fit a second pump inline up front somewhere
Any ideas?
Arthur.

so wait....did cleaning the ecu harness work or not?

Landshark · #86 04-26-2004, 08:40 PM

Quote:

Originally posted by Tim-H
Has anyone cleaned their air control valve? I read through this thread once but forgot if that was mentioned. May be worth a shot.

i would like to do this, but haven't had the time yet. i'm pretty sure this is the problem in my case, because of the cold start/weird idle (unless it is warmed up for a few minutes on cold days after sitting all day) when i get into it after work. i may try the additional ECU grounding, too. can't hurt i suppose.

mbtoloczko · #87 04-27-2004, 08:24 AM

Quote:

Originally posted by Tim-H
Has anyone cleaned their air control valve? I read through this thread once but forgot if that was mentioned. May be worth a shot.

Where is the air control valve?

Landshark · #88 04-27-2004, 08:28 AM

Quote:

Originally posted by mbtoloczko

Where is the air control valve?

buried in the throttle body somewhere. that's all i know....

i read that someone removed it for cleaning and borked their car up pretty good. i would try to gently clean it without removing it, if that's even possible.

#89 04-27-2004, 02:32 PM

I removed mine without a problem, all there is holding it on is 4 screws. I even went as far with mine as taking the motor off the end to clean the valve better. The problem the other person had may have been that they put the motor back on in the wrong position, it is adjustable. Mark the positions before removing the motor if you do. I'm not sure how it can be messed up too badly unless you unknowingly drop something in it, or break one of the electrical plugs off. I would be careful though and if you arent comfortable with it don't do it. It's not a cheap item. All there is to it is a valve that moves back and forth controlled by an electrical motor which is completely sealed up, so theres no chance of the internals getting messed up.

I was told my post sounded a little cocky, so I'm sorry if it does, its not meant to be.

Item number 2 here.

#90 04-27-2004, 02:46 PM

Also, do not change the position of the motor, mine appeared to be a little less than half way open, but i found out that's how its supposed to be. and only clean it with throttlebody cleaner and q-tips. Other chemicals may be ok but I wouldn't chance it. Spray the TB cleaner into it until it starts flowing clear out of the other end. then fill it up cover both holes and shake it a little. Removing the motor didn't appear necessary but did make cleaning the valve easier, instead of having to hold it shut with one q-tip while cleaning it with another.