99 Integra GSR with 90K miles. All started with a blown head gasket…rings were bad too. Changed the head gasket, rings, and rock bearings. Polished the head, sealed the valves. Most of its done at my buddies shop.

Only problem seems to be with the rough Idle …Other than that the car feels fantastic. In the morning at a cold start with AC on, the rpm drops to 500 or so ..the needle goes back and forth from 900 to 500. After a while it settles down at 900 rpm.

Other than that, at cold starts, there is unburnt fuel ( my guess) spraying from the exhaust. That seems to happen only at cold start.

Any ideas?

 

By rough, do you mean the engine has a hard time idling to the point to where it feels like it will die, or do you mean that the idle fluctuates a little until it the engine warms up to operating temp?

As for the fuel from the exhaust your probably running a little rich. Do you plan to get it tuned? Or was the motor rebuilt completely to stock specs with its original ECU?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by DC_Legacy &raquo;</TD></TR><TR><TD CLASS="quote">By rough, do you mean the engine has a hard time idling to the point to where it feels like it will die, or do you mean that the idle fluctuates a little until it the engine warms up to operating temp?

As for the fuel from the exhaust your probably running a little rich. Do you plan to get it tuned? Or was the motor rebuilt completely to stock specs with its original ECU?</TD></TR></TABLE>

I would say, its more like it has hard time idling and drops to a point where its going to die.
I also think its running rixh..does it have anything to do with 2 sensor is bad / 2.5 flange welded CAT I have?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by schumi &raquo;</TD></TR><TR><TD CLASS="quote">

I would say, its more like it has hard time idling and drops to a point where its going to die. </TD></TR></TABLE>

Is your cam timing correct, is it stock? How do your plugs look? They could be fowling. I ran some GUMOUT after my rebuild to clean the injectors and its caused my plugs to fowl which caused my motor to idle like S*it. I took the plugs out and cleaned them and it idled fine afterwards.

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by schumi &raquo;</TD></TR><TR><TD CLASS="quote">I also think its running rixh..does it have anything to do with 2 sensor is bad / 2.5 flange welded CAT I have?</TD></TR></TABLE>

I dont think your flange would effect the fuel issue, but is your check engine light on regarding the 02 sensor?

Its hard to say with out knowing what your setup is. What engine? Which ECU? Is the motor modded? Did you increase the displacement? How old is the 02 sensor?
Give some details.

 

It's set up for stock set up. Haven't checked the plugs yet.

Chkck engine light come on sometimes ( just ran 800 miles or so after rebuild. CEL came thrice and it went off after some time)
Engine is stock 99 GSR. Stock ECU. No other mods on the engine. 2.5 " flange was welded to an old stock CAT. Its has a JDM 4-1 header, CAT back, Intake etc etc..

thanks a lot

 

I would check the CEL codes when it does. If its the 02, then I would replace it before it causes some serious A/F problems that could possibly cook your internals if it were to run too lean.


I'd check the plugs, perhaps there fowling from running too rich. If they look OK then check the ignition timing with a timing light. Maybe it needs to be advanced a hair or two from the dizzy. Also verfiey that your throttle cabling is snug and not bogging the motor from being too lose. Goodluck!!

 

Talking about the O2 sensor, I just realized that my stock CAT had 2 O2 sensors ( all 96 -99 GSR's has 2 in the CAT). When I had to put the 2.5' header, I welded a 2.5 " flange to a "CAT" ( not sure which one) which has only one O2 sensor at the header side of the CAT....

 

Well, Is the ECU an OBD2a originally from that car/motor? If so I would suppose a stock ECU would throw a CEL in the absents of that 2nd 02 sensor. I got a 96 LS (2 02 sensors), however when I built my LS/V I swapped the CAT for a test pipe that didnt allow the 2nd 02 sensor to fit in its original location, so I left it off. I havent had any problems with it either because the ECU was a chipped OBD1 & CROME programmed, or because OBD1 cars didn't feature that secondary 02 sensor hence the ECU doesn't have any compatibility issues with the way I have it setup, I don't know.

Your probably on the right track though.

 

ECU is an OBD2 originally from the original 99 GSR motor. Surprisingly, there is no constant CEL without the 2nd O2 sensor.

Aprat from CAT and O2 sensor stuff, what else should I focus to address the rough idle and fuel spary from exhaust? thanks

 

Well I dont claim to be an expert on fuel system management, but if your only running one of the two 02 sensors than I would try to find a way to fit that secondary sensor in your new CAT with the 2.5" flange adapter.

From what I can recall as to how it was explained to me by my tuner is that you can run one of two sensors, but the secondary sensor is suppose to give the ECU a more accurate reflection of how much fuel is being burned so I would assume that having the secondary 02 would help in trimming back excessive fuel consumption. My advice is contact a reputable tuner and ask about it.

I haven't had my motor officially dyno tuned yet, so every day when I crank my motor up I have this problem too. Hopefully after the tune it will help but I think since Im using a test pipe vs. a CAT I'll always have some fuel saturation through the exhaust.

 

did you set the timing correctly? and did you verify as the above asked that the cams are setup right?

 

My buddy/frins who has a shop has looked at it couple of times already ( correct the timing etc). May be that is not good enough

Rough idle and spray from exhaust is only in the morning ie. at cold start...
after a minute or so it setlles down and everything seems to be OK

 

are the plug wires on correctly?

as you can tell something is up with the combustion cycle. fuel out the back means you aren't burning all of the gas that the injector squirts in. be careful with this stuff since the last thing you want is uncontroled fire.

 

Can it be some condensation in the muffler?

I am not sure whether the spray, that comeout is fuel...I took a white blank paper and had the spary on it...Its more like water. As I said, it happens only at cold start in the morning

 

May be its the Idle Air Control Valve? I have never cleaned it....If I get time, will give it a try

 

Just a curiosity, but since you mentioned that you welded the 2.5" flange to this other CAT, did you do any other kind of mods to the CAT? More to the point, did you hollow the CAT out to make a poor-mans test pipe?

 

Actually I got the set up s\from some one. As far as I remember, its just a stock looking CAT which had only one bung in it.

Why do you ask?

 

Because if the CAT was hollowed it would probably allow fuel saturation to pass out the tail pipe. Its always been my understanding that a catalytic converter heats up from exhaust gases then once hot enough burns any un-burn fuel while superheating exhaust emissions causing a conversion to less harmful emissions.

 

I was mistaken about the set up...infact I still have two O2 sensors.
First O2 sensor is on the end of JDM header. Second O2 sensor goes at the back of the CAT. I think, I am getting old and forgetting things!!!!

In that case, the code that is throwing 'Too rich on bank 1' is due to something else...nothing to do with the CAT and O2 sensors

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by schumi &raquo;</TD></TR><TR><TD CLASS="quote">

In that case, the code that is throwing 'Too rich on bank 1' is due to something else...nothing to do with the CAT and O2 sensors

</TD></TR></TABLE>
So you verified your CEL code?