Jump to content
Ultimate Subaru Message Board
RXJ

Morning bog down.. rpm issues

Recommended Posts

Everyday the 93 Loyale, warm weather, cool matter, doesn't seem to matter, starts but I can't proceed. If I try to move too soon it'll bog down.

 

I have to turn the key once and stay off the gas.

It works itself to idling at 3000rpms...I can tap the gas to try to bring it back down to 2000 rpms but too much tapping causes more bogging down.

 

I sit and wait.

 

Suddenly,like a switch was activated it'll drop to 1000 rpms and I'm good to go.

 

I lubricated my idle air control module, manually pushed the plunger, shot it with compressed air...

 

The sudden drop of rpms, as a routine, still leads me to believe that module is the issue..

 

Anyone have other ideas?

I did search and my head is spinning..

 

many thanks

Share this post


Link to post
Share on other sites

sounds similar to what I was experiencing at one time , but not so extreme with the high rpm's..I exchanged my idle control unit and it fixed the problem..cleaning the unit may help, but I doubt it...with car Not running..the way I checked my unit...was to remove the large rubber hose attached to it and proceed to blow as hard as you can..( I removed the unit from the throttle body)..if you detect any air escaping..this would explain your problem or at least in part..also this part is expensive to replace as a new item..

Share this post


Link to post
Share on other sites

Thanks..yeah..prob the idle air control unit.

 

It used to only happen during cold weather months, now it's everyday no matter what.

 

Is the plunger stuck in the open position or closed when this happens??

 

Is there anything else that could be associated with the sudden drop in rpms?

Share this post


Link to post
Share on other sites
Thanks..yeah..prob the idle air control unit.

 

It used to only happen during cold weather months, now it's everyday no matter what.

 

Is the plunger stuck in the open position or closed when this happens??

 

Is there anything else that could be associated with the sudden drop in rpms?

..my experience was also as you described...only in the cold and then progressively over time getting worse ...no matter how warm it is..maybe the plunger in the main body part is dirty or the 12volt plunger needs to be cleaned..remove both parts..clean and see what happens..its kinda of hit and miss..lucky for me I had a spare part..not perfect but at 90% I am happy...

Share this post


Link to post
Share on other sites

Whether it's normal or not, I don't know, but we have a 93 Loyale and it does the same thing. It doesn't really bother us though because the Loyale gets babied and is never driven until it has warmed up. I know it's warmed up when the computer kicks the idle back down to normal after starting it; usually takes about 5 minutes.

Share this post


Link to post
Share on other sites
I'm having a similar problem. does you're car stumble occasionaly when cold on the road?
...unrelated to the idle problem...perhaps your 02 sensor needs changing...

Share this post


Link to post
Share on other sites
I'm having a similar problem. does you're car stumble occasionaly when cold on the road?

 

no, sorry xoomer...is it just when cold or when any moisture is in the air?

 

 

Whether it's normal or not, I don't know, but we have a 93 Loyale and it does the same thing. It doesn't really bother us though because the Loyale gets babied and is never driven until it has warmed up. I know it's warmed up when the computer kicks the idle back down to normal after starting it; usually takes about 5 minutes.

 

I have a hard time walking away from the car letting it rev at really high rpms but that 5 minutes is about right.

So the computer tells the control module to move the plunger ?..or it's been trying to move the plunger but it gets stuck?

 

Is the plunger supposed to allow more air in at first start or less (i know this is a dumb question which I should know..this is really just a choke right...but anyway, which is it??)

Share this post


Link to post
Share on other sites

You actually have a really good question, I mean the spfi is just a throttle body...I'm pretty sure there is no type of choke mechanism on a TBI..

 

I'm not exactly sure what it is that makes the engine maintain the higher revs, maybe somebody else can chime in?

 

It even mimics a choke a little bit too because when it is up to it's highest revs (ours will get up to about 2700 RPM all on it's own) you can even "kick it down" so to speak. It will still be idling higher than usual, but just a little higher.

 

The weird thing is how ...out of nowhere it drops if you actually just let it sit and do it's thing on it's own. It'll be steady at 25-2700 rpms and then when it decides to it'll just out of nowhere *plummet* to about 800 rpms.

Share this post


Link to post
Share on other sites

The tbi systems I am familiar with (Chevy) there is no choke. With the system I am familiar with when the ecu temp sensor is cold it ups the amount of fuel. The two things I check when having a hi idle problem is map sensor and coolant temp sensor. That is just my experience with the throttle body's I have messed with I have to say I haven't messed with any tbi subarus but I would think they are similar.

Edited by mikaleda

Share this post


Link to post
Share on other sites

 

The weird thing is how ...out of nowhere it drops if you actually just let it sit and do it's thing on it's own. It'll be steady at 25-2700 rpms and then when it decides to it'll just out of nowhere *plummet* to about 800 rpms.

 

this is exactly what happens to mine

 

 

and thanks for that input mikaleda and others

Share this post


Link to post
Share on other sites

I am not saying with any certainty, but I suspect the little electrical plunger attached to the idle control receives a varied amount of voltage form the ecu to determine the plunger opening thus the idle speed..but if your plunger is worn out / dirty or both you will have problems..I say the above because I have applied my volt meter to the idle control and observed under 12v at the control and at other times full battery voltage..it's been a while, and can't remember..the ecu could be providing the ground rather then supplying power..I also drive a vanagon with same style idle control, but information is fed to the idle control thru a separate module/computer...this is my best guess

Share this post


Link to post
Share on other sites

I don't know if that's how our sub's warm up, but that is how

fuel injected sportbikes warm up.. the idle starts off high until

it's warmed up.. call it "fast idle".

 

My subbie has been doing i lately too. sucks pulling out of the driveway only to have it bog down. i guess i need to watch the rpms' before i move.

 

usually when it's chilly a bit.

Share this post


Link to post
Share on other sites

As a general rule of thumb I try not to go anywhere in my vehicles until the temp gauge starts to move. That's not to say I haven't jumped in the Loyale after it's been sitting, started it, thrown it in drive and went on my way, but I try to keep that to minimum. I can tell it doesn't like it.

 

My GL (carb) however, I couldn't do that if I wanted to. I wouldn't get more than 3 feet before it stalls and it would buck like a horse for the first 2.

Share this post


Link to post
Share on other sites

well i swapped out my air control module with a used one found on ebay...cost $48 bucks, came in looking very new....nothing's changed....still have to sit in the car during the morn to tap the gas so it doesn't idle at 3000 rpms...

 

My original module, which I saved, I tested it by applying direct 12 vots, the plunger moved at least...tested the new on the same way, plunger moved...i guess this doesn't test for any wear and I've yet to try the blow into the tube test...

 

I don't wanna sit in my car during winter for 5 minutes till it kicks down to lower rpms....wouldn't mind if I could walk away to get a coffee....just venting a bit here.....

let's say the modules are fine, both "new" and old....what next?

Share this post


Link to post
Share on other sites

my ea82t starts up within the first rotation and climbs up to about 2500 and slowly idles down to 800. it takes about 5-10 minutes depending on how cold it is. i can start it and drive it instantly no matter how cold it is, i never do, but i could.

 

this to me sounds like a fuel issue on your part. too much or not enough.

 

any tbi subaru i have owned will start and drive just fine no matter the temp

 

check the FPR if its leaking into the vacuum line(which i have seen on mostly loyales)it will cause a bog until its up to OT eventually it will cause hard starts and other problems..

 

same goes for the fuel filter, during a cold start it uses more fuel to keep it running, so if the filter is clogged then you get boggy cold starts.

 

on the mpfi system there's a high idle screw. its in a recess on the back of the TB. im not sure TBI has one but it might be worth a look.

 

i dont see the problem in you car running 3k rpm for a few minutes that just makes its warmer faster.:Flame:

 

hope you get it figured out :popcorn:

Share this post


Link to post
Share on other sites
I don't wanna sit in my car during winter for 5 minutes till it kicks down to lower rpms....wouldn't mind if I could walk away to get a coffee....just venting a bit here.....

let's say the modules are fine, both "new" and old....what next?

 

I have a spare key for that. When it's real cold out and the car is parked nearby, I'll trudge out there, start her up, turn the heat on high, lock the doors and head back inside.

 

Have a cup of coffee, head back out, nice and toasty low idling car.

 

I always thought it was strange how you can "kick down" the SPFI car.

 

When it's idling real high when you first start the car up, if you kick the pedal it will actually kick down to a lower rpm. It's odd.

Share this post


Link to post
Share on other sites

my brain is foggy right now...AK splain fpr please

and yeah, I can't just hop in and go so maybe yur onto something

 

175, it has nothing to do with anyone stealing the car, it's just the 3000 rpms..I cringe at the thought of it running so high first thing in the morn, and it sounds brutal, so I sit and tap and like you say I can kick it down to 2000rpms but still not be able to drive away until it takes it upon itself to drop to 1000 and below.

 

I have to turn the key once to start and stay off the gas, let her putter and then she climbs and keeps climbing.....if she by some chance doesn't start on the first turn of the key, then staying off the gas doesn't work for the next turn. On the next turn I have to floor it...she sounds as if it won't happen but then it starts....90% of the time first turn of key, stay off gas is good to start, 10% I have to floor it hoping she starts...and so far she always does...but the idle issue and the inability ti drive away immediately still remains...

Share this post


Link to post
Share on other sites

You know..i changed my air flow sensor and it seems to have stopped bogging as much. Don't bother me tho, just a quirk of the car. I bog down to before i'm warmed up:D

 

Does it clear up? Cause i noticed if i'd let it warm up a little b4 moving it wouldn't do it.

Share this post


Link to post
Share on other sites

oh yeah it clears up once she drops to 1000 rpms and below..the car runs beautifully..

 

carry on, lots of good advice here...just venting a bit

Ak, fuel pressure regulator...thanks..my brain is still like sludge

Share this post


Link to post
Share on other sites
175, it has nothing to do with anyone stealing the car, it's just the 3000 rpms..I cringe at the thought of it running so high first thing in the morn, and it sounds brutal, so I sit and tap and like you say I can kick it down to 2000rpms but still not be able to drive away until it takes it upon itself to drop to 1000 and below.

 

Yeah, I know what you mean. Usually when it's bad enough for me to lock the doors and wait inside for her to warm up, I'll start the car, let it creep up to 3k on it's own and then do what you said; kick the accelerator and she drops down to a more manageable 2-2300 rpms and then go inside.

 

I really do think it's normal, we need more SPFI owners to post up their cold start experiences.

 

The only difference I'm finding between your and my cars is that our never struggles to start.

 

Whereas you were saying 90% of the time your car will start usually on the first turn, ours does 100% of the time...aside from that, sounds identical.

Share this post


Link to post
Share on other sites

Have had to let the '88 Wagon SPFI FT4WD 5-speed warm up the past few days due to frost on the windows.

Up to this time, I have just started it and headed on down the road, no drivability issues doing so.

 

Fast idle is around 2200-2300, seems to be a steady run at that engine speed.

When it gets warm enough to drop to normal idle speed, it'll bounce a few times between high/low idle. I find that to be quite odd in itself. May do it 3 times, may do it 6-7 times.

 

Engine and all the associated SPFI components is out of a '92 Loyale Wagon. Recall it doing a nice fast idle and dropping to a steady low idle.

 

I have yet to pull the IAC off and clean it, but I'm putting it on the to-do list for this weekend.

Share this post


Link to post
Share on other sites

When it gets warm enough to drop to normal idle speed, it'll bounce a few times between high/low idle. I find that to be quite odd in itself. May do it 3 times, may do it 6-7 times.

 

Does it sound like it's "panting" ?

I forgot my car used to do this.. in warm weather too...sitting at a stop light it would, at random moments, be panting like the family dog..

 

fwiw, i cleaned my mass air flow sensor (not the IAC) with the official spray (forget what it is at the moment..crv or somehing like that) a while ago and it hasn't helped morning bog down...I think i read here in a search that that particular sensor comes into play more so on the highway..

 

my latest trick, as of two days ago is to turn the key 3 times, without turning the engine over,to get the pump putting gas where it should be for an initial start.....I don't think this has done a damn bit of could but figure it couldn't hurt :-))

Edited by RXJ

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now

×