Hi everyone. I have a 1991 crx si. over the last few months i had noticed every now and then once the engine was warmed up and i shut it off and re started it before it could completely cool down, (i deliver pizza in it so i shut it off and restart it before it cools often) that it would be very sluggish at starting up warm, idling very rough and with low rpm's. once i got in say second gear it would clear out so to speak and would run fine. now over time this went from being a rare issue to happening every time i start it warm. it drives fine once i get past second gear or rev it up higher than typical idle. i can smell that it has excess gas at the time its idling rough.
I'm a woman, but do have some knowledge of cars and how to change parts and do proper maintenance etc. So....i cleaned the throttle body, checked all of my sensors plug to make sure they were clean and plugged in properly, the fuel filters recently changed also. i took the plugs out and they looked pretty bad soi changed them with new nkg plugs. made sure they were properly gapped etc.
so after the new plugs it ran GREAT! i was like ah-ha! thats all it was.....well it drove great all that day then started doing the same stuttering thing again upon warm start up. my opinion at this point is it is running too rich which is fouling the plugs out slowly. or a little fast since the issue has escalated over the last few months.
my gas mileage is reduced obviously.
so since going through to process of elimination i am down to the oxygen sensor. i DO NOT have any CEL going on at this time nor have i at all.
so my question is would the oxygen sensor going out cause it to do this and get progessively worse over time?
it starts fine, runs fine but once reaching operating temps after i shut it off it starts rough, idles rough until i get the rpm's up and i can smell excess gas, its fouling the plugs out rather quickly now.
so before i buy and install a new oxygen sensor i would like some feedback from a few folks if this sounds like it could just be a worn o2 sensor.
other than this one issue the car runs and operates great.
thanks!
also just in case....its the stock motor with an aftermarket exhaust. nothing else

 

I've thought of 3 things since I finished reading this a couple minutes ago. In order, this is what came to mind:

1) You can test your o2 sensor with instructions on the internet and a $15 digital multimeter. But it would probably be running rich all the time (after warm anyway) through all the gears/rpms.??

2) You can troubleshoot aiming at the low rough idle by finding the several walkthrough's on "Troubleshooting Honda Idle". That's a vague suggestion but the walkthrough will teach you all about the idle system and show you how to clean/test each component. It never hurts to clean/adjust these systems anyway.

3) Shot in the dark, but ....if it's rich on startup, and blows right on out.... it could be a leaking injector. When you turn it off, the primed fuel rail at full pressure would slowly leak fuel into the cylinders. That would result in a slightly hesitant start (because of the lowered fuel rail pressure) and obviously it would be rich until the leaked fuel (in the cylinder) got burned out. Easiest test I know for injectors is to put a fuel pressure gauge on it. Then monitor fuel pressure while running and while turned off but primed. If you prime it (without cranking), it should hold pressure steady pretty well for atleast 5-10 minutes (some argue forever). If you have a leaking/sticky injector, you would see a steady decrease in fuel rail pressure.

I know you probably don't want to "throw parts/money" at this problem, but atleast with the purchase of a fuel pressure gauge, you get to KEEP the fuel pressure gauge. Otherwise, you could have a professional fuel injection cleaning (not the cheap shelf items at the store) and see if it improves.

 

but when you say "sluggish while starting," do you mean "turns over fast but doesn't seem to fire up well" OR "engine turns over weakly"? In my thoughts above, a leaky injector would cause "turns over fast but doesn't seem to fire up well" because the combustion mixture is too rich. However, a "engine turns over weakly" would usually be related to a charging/battery issue, and I don't think that is likely to be related to your other symptoms...

I just wanted to make sure that it ISSS turning over fast, trying to fire, but takes a few turns before it cranks on up.

 

it's turning over just fine and fast enough. so its not a charge battery issue. and generally it does fire right up but when it is "flooded" or whatever is going on after i drive it a little then shut it off...it cranks fine but takes a few good cranks to fire up then idles rough and you can smell its got excess gasoline in there

so yesterday before work after i posted this....i bought a o2 sensor....really cheap brand new for 16.99. well before i could even start to take the old one off i was feeling around checking connections etc.....basically tinkering and the TPS i had never paid much mind to well it was barely being held in by one screw and the gasket had fallen apart.
so of course i thought ah-ha! this must be it! so long story short....got a bran new tps changed it....adjusted it until the idle was where it should be.......and..

it's STILL doing the flooding thing....and now i have a CEL lol never before has it had a cel so i plan to remove the fuse today to reset it.

so still...after it warms up and i shut it off and re start it while its still warm..it idles rough and smells of excess gas UNTIL i either rev it real high for a second or drive a few yards, then it runs fine no flooding until i shut it off again....it never ever does this when its cold.

 

count those blinks on the ecu to read that code (before you clear it), and please post it here.

 

ok, sorry i have been working and hadnt had the time to look up how to read ecu codes until now...which is surprisingly easy. I have 7 blinks. which i looked up and says it has to do with the TPS. so i checked it......i just replaced it the other day(not sure if i had mentioned that yet) and it is properly plugged in etc.
So to be quite honest i'm not sure what to do now. I did try to reset the cel 2 times and both times within a few seconds of starting the car it came back on.
So it has a brand new TPS i have checked the plug and it is properly plugged in and the wiring looks fine to me not worn or melted or anything like that.
So what could be going on here?
Also since thats the only code i am getting does that mean it IS why my car keeps flooding itself when warm?

 

the ironic thing is i never had a cel before. and i found the tps wasnt even fully installed....it was missing a bolt and the gasket was mostly gone and broken.
But when i put a brand new one on the car and it is bolted down right with a new gasket now...i get a cel. fml

 

I can't remember, but did you calibrate the TPS install with a multimeter? a halfway hanging tps might not throw a code because it isn't moving. An uncalibrated tps might cause the code bc it is sending a signal that is not acceptable to the ECU.

 

I understand that not calibrating it will cause the code thing to happen. But my issue still remains. I was hopeful that it was the TPS since it was missing a bolt and the gasket wasn't in the best shape.
But it wasn't whats causing the flooding issue. So I'm really at a loss here.
It seems to do it more often on a warmer day, yesterday it was quite cool here and all day at work it never once acted flooded when I started it back up.
The temperature outside did go up considerably towards the end of my work day and at that point it started doing it again.
I have ran seafoam through it weeks ago hoping it was dirty fuel injectors or something, it didn't help.
It only does this after I have drove it some then shut it off and re start it before it has the chance to cool down completely. And it does seem to do this more often in warmer weather.
and just in case I didnt mention it previously there are no other ecu codes that have been thrown other than the tps one it had after i changed it and didn't use a volt meter thing when adjusting it.
So do you have any other ideas what could cause it to do this? maybe worn plug wires? an issue with maybe fuel pressure getting too strong in warm weather like a gas cap not releasing excess pressure? I'm just shooting in the dark here trying to figure out what it could be.
Something I found interesting also is the screw on the Tb thats suppose to adjust the idle or air/fuel mix has always been all the way down yet the car has a normal idle. It was that way when I bought it. I'm not sure where it's suppose to be but its all the way tight and loosening it really doesnt do much if anything so it's staying all the way tight.

 

I just scrolled up and re read some of your replies from earlier, I think I am going to take it to a shop and have them test my injectors. You mentioned a fuel pressure guage and a leaky injector could be the culprit, So I am going to have that checked.

 

Depending on the cost of testing your injectors, I'd really consider buying my own fuel pressure gauge. Theoretically, colder weather means that you are pulling in colder air, and colder air is more dense (it contains more oxygen). So theoretically, on a colder day, you are pulling in more oxygen and that natually balances the excess fuel.

Please don't spend any money unless you have more than my advice?

 

Today at work it got so bad my husband had to bring me a backup car and bring my crx home. He cleaned the PCV valve and said it was totally gunked up again....I just recently replaced it with a brand new one and cleaned the hoses its connected to. after driving it a bit he said it gunked up again and started the crappy idle thing. So i s it possible to bypass this damned thing? I read a ton online and its about 50/50 as to what people are saying about bypassing it by plugging one side off and running the other end with a filter. If so which end should I plug and which should I filter?
It seems this is whats causing the horrid idle issues at warm startup....when its clean its perfect but becomes filthy quick!

 

you need to look into the reason for it getting fouled up. how many miles on the engine? is it consuming oil? is there excessive smoke?
i would REALLY consider fixing the TPS issue, a wrong signal will cause rich condition.

 

I have the impression that she has calibrated the tps just before posting this message....seems as though the problem still remained??

 

Thanks to everyone who has taken time to read this long thread and reply.
I really don't want to start a new post so to clarify things a bit YES the TPS is fine and has been taken care of.
I had replaced the PCV maybe a month ago maybe less when after reading what could be causing my issue found info on a clogged or worn pcv. So I didn't think to re check it at all since it was a new part that supposedly lasts in excess of 30k miles.
But yesterday when i t was starting so rough after warming up that I called my husband to bring me a different car and park mine at home until we could figure out wtf is going on he checked the pcv it was once again clogged, he cleaned it and the hoses and said it idled and ran perfect.
He then took it for a short drive after which it was already doing the crap idle thing AGAIN.
So he checked and sure enough it was already getting gunked up.
SO....when the pcv is clean its runs and idles perfectly, however the pcv for whatever reason is getting clogged at an alarming rate.
The engine has over 280k miles on it, someone asked about my mileage.
Soooo. i've searched online and have found some vague references to that higher mileage engines with perhaps worn piston rings could cause excessive blowby? in effect causing the pcv to clog fast.
I also have read several threads where people have bypassed the pcv entirely just allowing it to vent freely, but none of those were honda crx's so i'm not exactly sure if this is something I should do and if so what's the easiest way and like I was asking lastnight....which part do i vent from ???
Would it vent out from the valve cover gasket hose connection or would it vent from where the bigger hose is connected down further on the engine?
Sorry this is so long it just seems like maybe I'm not explaining this well or some people aren't understanding?
thankyou!

 

Oops almost forgot to mention, someone asked about if it was having smoking issues....NO Smoking whatsoever upon normal operation, I do have some small amount of oil consumption...nothing serious.
the only time I have EVER seen any smoke from my tailpipe is when it is doing the rough idle at warm startup if i give it some gas to blow out what i assume to be excess fuel? it will blast out a greyish??? poof of smoke that smells strongly of gas and then it runs fine and no more smoke ever.

 

I'm impatient and needed to drive my car.

So I bought a pack of vacuum plugs/caps and plugged off where the pcv hose connected to the intake and left the bottom section of the hose that connected further down on the engine attached but with a small filter I purchased at autozone for 5 bucks.

Idles good, starts right up and ran all day at work with no issues whatsoever.

So I am left to assume it is possible and perhaps of benefit in some cases to not use the pcv.

I sincerely hope this doesn't create a new problem, but for now it has solved the only issue I was having with my car.

input and or criticism is welcome

 

Sounds like it's time for an engine rebuild.

 

Probably so 4drEF....280k miles is a lot for sure.

I plan to research swapping engines over the next few months and towards the first of next year buy a new engine and have it installed. I just don't know much about that yet and need time to save for it. So esentially I need to make this old beast last as long as possible.

It's running great right now with the setup of eliminating the pcv. I've even found some awesome suggestions on home made catchcans for any potential sludge/oil that may come from the blowby tube I have the filter on right now.

 

Keep an eye on how much oil it is consuming.

 

Will do! I plan on making the catch can tomorrow before work and installing it so I can see exactly how much oil/sludge crap is actually coming from there.

 

Update: I had a mechanic look at the car yesterday....this is the same mechanic who before replacing my timing belt said I would need more than just the belt...which i argued and said just put it on and put it in time properly. in the end I was right and it didn't need anymore work just a new belt and it was good to go.

His summary of my problems is that I have worn rings and seals and to just drive it til it blows up which could be soon or could last awhile.
Now keep in mind I have no oil in the water or vise versa and it isn't smoking.

I'm no pro mechanic just a girl with some mechanical knowledge and the internet!
So to me his diagnosis seemed a bit grim and maybe incorrect.
Correct me if I am mistaken here but if I had worn and failing rings and seals wouldn't I see some smoking like a considerable amount?

My primary issue this entire time has been the car seems to want to have a "rich start" after it has achieved operating temps or on warm days.
Recently I read about a potential souldering issue with the main relay? idk maybe maybe not.

So in summary....TLDR I know.
If I am not seeing a signifigant amount of smoking and there is not water in the oil or oil in the water does this really support the mechanics conclusion of bad rings/seals drive it til it dies? it runs great no cutting out etc....it just has a rough warm start and appears somewhat flooded when that happens. I have tried many solutions up to and including bypassing the pcv which I would like to not do honestly.

Also want to note that with the pcv bypassed and a catch can in place it does accumulate a small amount of oil/sludge in the catch area but nothing alarming by any means.

 

So did the pcv bypass only temporarily fix it? Curious because my 305k mile d15 is having similar issues.

 

Yes. After bypassing it the car ran perfect for a week maybe then started acting up again. So I'm reconnecting it today.