CB7Tuner Forums

Go Back   CB7Tuner Forums > Beginner forum -- New members post here! > Beginner Technical/Performance

Reply
 
Thread Tools Rate Thread Display Modes
Old 11-16-2014, 02:45 PM   #1
jarodnesss
Newcomer
 
Join Date: Nov 2014
Posts: 11
jarodnesss is cool... so far.
Running rich

Hello I'm am new here, but not new to the Honda game. Can't find a official introduction forum so figured i'd use this while I ask my first question :O I got a 91 accord last week for a daily while I am in the middle of building my RT4WD civic wagon. While I got it for $700 so it need a little work, but the motor is solid as hell and the body is 90% perfect with no rust. So needless to say, this is my first accord and I am in LOVE! hah.

Any ways to my main question. The car seems to smoke, in comparison to maybe like a go-cart or something. I guess you could say it's running rich? Because if you are behind me it smells like a go-cart. I was wondering if anyone else has experienced this issue before? I was thinking maybe its a bad injector or something?

Thanks, anything will be helpful.
jarodnesss is offline   Reply With Quote
Old 11-16-2014, 03:23 PM   #2
wildBill83
CB7tuner Member
 
Join Date: Aug 2012
Location: Back in Texas
Posts: 2,045
wildBill83 seems to have made some friends!
er what!? are you burning oil or coolant? What kind of MPG do you get?
wildBill83 is offline   Reply With Quote
Old 11-16-2014, 03:31 PM   #3
sonikaccord
Contributing Member
 
Join Date: Nov 2005
Location: In Traffic
Posts: 4,124
sonikaccord seems to have made some friends!
What color is the smoke? White, blue or black?
__________________
sonikaccord is offline   Reply With Quote
Old 11-16-2014, 05:25 PM   #4
DAKOTADEMON7
CB7tuner Member
 
Join Date: Nov 2014
Location: Delaware.
Posts: 99
DAKOTADEMON7 is cool... so far.
First thing to do is pull the plugs and look at them. If there real dirty, replace them. If you still have the same problem.you will be able to tell if your running rich on just one cylinder or all of them.
DAKOTADEMON7 is offline   Reply With Quote
Old 11-17-2014, 12:32 AM   #5
jarodnesss
Newcomer
 
Join Date: Nov 2014
Posts: 11
jarodnesss is cool... so far.
Quote:
Originally Posted by wildBill83 View Post
er what!? are you burning oil or coolant? What kind of MPG do you get?
Not sure about the oil or coolant burn yet either. I'm still calculations MPG ATM, like I said only have had the car for a almost a week now.

Quote:
Originally Posted by sonikaccord View Post
What color is the smoke? White, blue or black?
It's black

Quote:
Originally Posted by DAKOTADEMON7 View Post
First thing to do is pull the plugs and look at them. If there real dirty, replace them. If you still have the same problem.you will be able to tell if your running rich on just one cylinder or all of them.
Okie dokie I will do so!


Thanks guys!
jarodnesss is offline   Reply With Quote
Old 11-18-2014, 12:28 PM   #6
deevergote
Don't call me dude.
 
Join Date: Aug 2003
Location: Not New York
Posts: 40,082
deevergote . You'll never be this cool... deevergote . You'll never be this cool... deevergote . You'll never be this cool... deevergote . You'll never be this cool... deevergote . You'll never be this cool... deevergote . You'll never be this cool...
Send a message via AIM to deevergote
Is your check engine light on?
__________________






deevergote is offline   Reply With Quote
Old 11-18-2014, 01:16 PM   #7
oyajicool
CB7tuner Member
 
Join Date: Nov 2010
Location: Smartass city, USA
Posts: 1,679
oyajicool seems to have made some friends!
Possibly, it is due to a faulty O2 sensor.
__________________
A&P-IA
oyajicool is offline   Reply With Quote
Old 11-18-2014, 02:43 PM   #8
F22Chris
CB7tuner Member
 
Join Date: Apr 2013
Location: Atlanta
Posts: 1,119
F22Chris seems to have made some friends! F22Chris seems to have made some friends!
I'd check your fuel pressure regulator too, these can regulate too much fuel causing this problem. Also the ecu should be reset after if you replace it. The ecu can also be the problem.. It could also be an injector. I'd do a full tune up either way since you just got the car and you don't know what went on, or how long it was running rich before you got it. Check the O2 sensor too, it's probably bad by now.
F22Chris is offline   Reply With Quote
Old 11-18-2014, 02:44 PM   #9
F22Chris
CB7tuner Member
 
Join Date: Apr 2013
Location: Atlanta
Posts: 1,119
F22Chris seems to have made some friends! F22Chris seems to have made some friends!
Sorry for two posts, but I've seen a bad coolant temp sensor make cars run rich too so check that with a voltmeter
F22Chris is offline   Reply With Quote
Old 11-18-2014, 04:57 PM   #10
johnl
CB7tuner Member
 
Join Date: Dec 2007
Posts: 1,630
johnl seems to have made some friends!
As already suggested the O2 sensor is a likely culprit. In closed loop running the ECU relies entirely upon the signal it gets from the O2 sensor. If the sensor is failing (or has failed) then it generates a low voltage (or no voltage) output that the ECU interprets as the AFR being lean, so it enriches the mixture (possibly to the maximum it possibly can), whether or not the AFR is actually lean.

The ECU has no other direct 'window' on actual combustion conditions, so blindly believes what the O2 sensor is telling it. It's not uncommon for the O2 sensor to be very sick before the ECU recognises a sensor fault and throws a CEL, if it ever does.

Depending on how bad the O2 sensor may be, the engine might actually run better if the sensor wires are disconnected, which will put the ECU into 'open loop' and cause a rich AFR (and definitely a CEL if it's a four wire sensor, and maybe a CEL if it's a two wire sensor), but possibly not as rich as the AFR can be with a faulty sensor reporting a non existent lean condition to the ECU. Disconnecting the ECU is not in any way a cure, but can sometimes be used as a 'limp home' measure (say if the AFR becomes so rich due to a faulty sensor that the plugs are fouling with carbon and causing bad misfiring or actually causing the engine to stop running).

Fuel pressure regulators can occasionally fail in such a manner that raw fuel gets dumped into the plenum chamber through the rubber vacuum hose. If you disconnect the hose and see and / or smell fuel then the regulator is probably dead.
__________________
Regards from Oz,
John.

Last edited by johnl; 11-18-2014 at 05:01 PM.
johnl is offline   Reply With Quote
Old 11-21-2014, 03:44 PM   #11
jarodnesss
Newcomer
 
Join Date: Nov 2014
Posts: 11
jarodnesss is cool... so far.
Quote:
Originally Posted by deevergote View Post
Is your check engine light on?
Yes it comes on everytime I start it up after it has sat for awhile.

Quote:
Originally Posted by oyajicool View Post
Possibly, it is due to a faulty O2 sensor.
Possibility

Quote:
Originally Posted by F22Chris View Post
I'd check your fuel pressure regulator too, these can regulate too much fuel causing this problem. Also the ecu should be reset after if you replace it. The ecu can also be the problem.. It could also be an injector. I'd do a full tune up either way since you just got the car and you don't know what went on, or how long it was running rich before you got it. Check the O2 sensor too, it's probably bad by now.
Okie dokie! Thanks!

Quote:
Originally Posted by F22Chris View Post
Sorry for two posts, but I've seen a bad coolant temp sensor make cars run rich too so check that with a voltmeter
It's all good! Post away! And I'll check that out also!

Quote:
Originally Posted by johnl View Post
As already suggested the O2 sensor is a likely culprit. In closed loop running the ECU relies entirely upon the signal it gets from the O2 sensor. If the sensor is failing (or has failed) then it generates a low voltage (or no voltage) output that the ECU interprets as the AFR being lean, so it enriches the mixture (possibly to the maximum it possibly can), whether or not the AFR is actually lean.

The ECU has no other direct 'window' on actual combustion conditions, so blindly believes what the O2 sensor is telling it. It's not uncommon for the O2 sensor to be very sick before the ECU recognises a sensor fault and throws a CEL, if it ever does.

Depending on how bad the O2 sensor may be, the engine might actually run better if the sensor wires are disconnected, which will put the ECU into 'open loop' and cause a rich AFR (and definitely a CEL if it's a four wire sensor, and maybe a CEL if it's a two wire sensor), but possibly not as rich as the AFR can be with a faulty sensor reporting a non existent lean condition to the ECU. Disconnecting the ECU is not in any way a cure, but can sometimes be used as a 'limp home' measure (say if the AFR becomes so rich due to a faulty sensor that the plugs are fouling with carbon and causing bad misfiring or actually causing the engine to stop running).

Fuel pressure regulators can occasionally fail in such a manner that raw fuel gets dumped into the plenum chamber through the rubber vacuum hose. If you disconnect the hose and see and / or smell fuel then the regulator is probably dead.
Wow thank you! I love comments like this! Broken down and very helpful'! I will look at the o2 and FPR thanks!
jarodnesss is offline   Reply With Quote
Old 11-21-2014, 03:46 PM   #12
jarodnesss
Newcomer
 
Join Date: Nov 2014
Posts: 11
jarodnesss is cool... so far.
Quote:
Originally Posted by wildBill83 View Post
er what!? are you burning oil or coolant? What kind of MPG do you get?
I'm getting on average 22 mpg
jarodnesss is offline   Reply With Quote
Old 11-21-2014, 07:07 PM   #13
johnl
CB7tuner Member
 
Join Date: Dec 2007
Posts: 1,630
johnl seems to have made some friends!
If the AFR is rich then you should be able to see it as sooty plugs. If all the plugs are equally sooty then it's caused by something that will be affecting all the cylinders (e.g. O2 sensor etc.), but if say just one were sooty then it's more likely to be one injector that's the problem. It is possible that all four injectors could be more or less equally faulty, but not as likely, and even if it were the ECU should be leaning out the AFR until it 'sees' the O2 content in the exhaust gasses that it 'wants' to see (the ECU can compensate for injectors that flow incorrectly, but only if all of them are similarly faulty, and only in closed loop mode).

The ECU can only 'see' the O2 content of the exhaust gasses after the gasses from all four cylinders have mixed together, so the O2 content it 'sees' is an average of the individual concentrations from each cylinder. The ECU can't detect and adjust AFR in each cylinder individually, to do so it would need an O2 sensor at each branch of the exhaust manifold. If all the injectors were injecting too much fuel then the ECU should detect a rich AFR and lean it out at all four injectors.

But, if (say) only one injector were flowing too much fuel then the ECU would still detect a rich AFR and lean it out at all four injectors, which would result in the offending injector still flowing too much (but less so) and a rich AFR in that cylinder, but a leaner AFR in the other three cylinders. Because the ECU 'sees' the average of the rich AFR in the 'bad' cylinder and the correct AFR in the other 'good' cylinders, it will lean out every injector until it gets the sensor voltage output that it wants to see, so instead of having three cylinders with correct AFR and one rich, there will be one still somewhat rich and three somewhat lean, resulting in a misleadingly 'correct' O2 content at the sensor.

Kart engines smell the way they do because they generally run a fairly rich AFR (largely, but not only, because they are usually fairly stressed 'air cooled' engines, that also need the internal cooling affect of a rich AFR to keep the piston cool and prevent seizure), so there tends to be a lot of unburnt fuel in the exhaust gas. But, also because they are (typically) two stroke engines, and also tend to run a lot more oil in the fuel mix than is usual with less stressed engines in things like chain saws and lawn mowers. The smell you describe could be due to a rich AFR, but also it could be burning oil, or both.

You say you're getting 22mpg (10.7 L/100km, assuming US gallons). As a comparison my car gets about 8.5 L/100km (27.7mpg). I drive my car fairly hard, with habitual 'rev matching' and heel / toe shifting on pretty much every downshift, so it would seem likely that your AFR is quite rich, or at least so down on power that your having to flog it to some degree...
__________________
Regards from Oz,
John.

Last edited by johnl; 11-21-2014 at 07:41 PM.
johnl is offline   Reply With Quote
Old 11-21-2014, 07:18 PM   #14
deevergote
Don't call me dude.
 
Join Date: Aug 2003
Location: Not New York
Posts: 40,082
deevergote . You'll never be this cool... deevergote . You'll never be this cool... deevergote . You'll never be this cool... deevergote . You'll never be this cool... deevergote . You'll never be this cool... deevergote . You'll never be this cool...
Send a message via AIM to deevergote
Before we make any assumptions, pull the error code. That will give you (and us) a much better idea of what we're looking at.

All the guesses so far are good ones, but without more information they are just that... guesses. Pull the error code. Chances are it will be either code 41 or code 43, or possibly both. Again, though... just a guess until you actually do it!
__________________






deevergote is offline   Reply With Quote
Old 11-22-2014, 11:25 AM   #15
jarodnesss
Newcomer
 
Join Date: Nov 2014
Posts: 11
jarodnesss is cool... so far.
Engine codes:

12 EGR - exhaust gas recirculation lift valve
17 VSS - speed
41 Primary oxygen sensor heater
jarodnesss is offline   Reply With Quote
Old 11-22-2014, 12:37 PM   #16
deevergote
Don't call me dude.
 
Join Date: Aug 2003
Location: Not New York
Posts: 40,082
deevergote . You'll never be this cool... deevergote . You'll never be this cool... deevergote . You'll never be this cool... deevergote . You'll never be this cool... deevergote . You'll never be this cool... deevergote . You'll never be this cool...
Send a message via AIM to deevergote
There we go. Now we can do some proper diagnosing!

First, make sure the wiring to those senors is in good condition.

The o2 sensor is most likely the primary culprit, though the other two certainly don't help. Replace that o2 sensor with a Denso or NTK unit (no Bosch. They don't work.) You can find them cheap on RockAuto.com. Be sure to get the correct sensor for your year and trim level, as the different engines (F22A1, F22A4, and F22A6) have different o2 sensor configurations.

Clean your EGR system, and replace the valve if necessary. Cleaning out the EGR ports can be fairly involved, so save that for last. You might not HAVE to do it... but it wouldn't hurt. You can find instructions in the DIY section of this site.

Replace your VSS. It'll be nice to have a working speedometer again, I'm sure!


The VSS and o2 sensor codes are most certainly putting your ECU in limp mode. In limp mode, the ECU is running on pre-set fuel tables, overfueling for safety (as it is safer to add more fuel, rather than risk running with too little fuel... which can cause serious engine damage very quickly.)


Fix those problems. Inspect your spark plugs, as they may be fouled from running rich. Replace if they're noticeably discolored. Disconnect your battery for a few minutes to clear the codes from the ECU. Drive around for a while at a variety of speeds to complete a full drive cycle. Barring any additional problems, all should be good. You'll notice an increase in fuel economy AND power.
__________________






deevergote is offline   Reply With Quote
Reply

Thread Tools
Display Modes Rate This Thread
Rate This Thread:

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Forum Jump


All times are GMT -5. The time now is 08:05 AM.


Powered by vBulletin® Version 3.7.1
Copyright ©2000 - 2018, Jelsoft Enterprises Ltd.