Failed emissions for NOX, rough idle....?
Thread Starter
Original Founding Member!
Joined: Jul 1999
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From: Granby, MA
Cruise-In 1, 3, 9. 10 & 11 Veteran
Failed emissions for NOX, rough idle....?
My bros car (89 firebird formula 5.0 tpi) runs perfectly smooth when it is in open loop. As soon as she goes into closed loop and drops the idle it begins running like poop. KEEP IN MIND CAR FAILED EMISSIONS CAUSE OF NOX.
Symptoms:
rough idle at 650-700rpms
feels like a skip and stays throughout entire rpm band even as you rev it.
I have disconnected the maf thinking maybe that was it....nope same problem.
New distributor (thole entire thing including cap and rotor etc), wires, plugs, no change.
any ideas on what to do next
sorry for the repeat in post, but getting desperate. Don't really want to pay somebody else to diagnose this but am getting frustrated bigtime.
thanks
Jeff
Symptoms:
rough idle at 650-700rpms
feels like a skip and stays throughout entire rpm band even as you rev it.
I have disconnected the maf thinking maybe that was it....nope same problem.
New distributor (thole entire thing including cap and rotor etc), wires, plugs, no change.
any ideas on what to do next
sorry for the repeat in post, but getting desperate. Don't really want to pay somebody else to diagnose this but am getting frustrated bigtime.
thanks
Jeff
Team Owner
Joined: May 2006
Posts: 21,473
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From: Palmdale, Ca----- 2009 Cyber Gray 4LT A6 F55 452 RWHP 422 RWTQ- RIP 1998 C5 734 RWHP & 585 RWTQ-----
Any codes being pulled from the computer? It might send you in the right direction for the repair. Perhaps TPS need adjusting or new one! What's it's voltage and the O2 senser Voltage?
This will help us to help you out!
Thanks,Matt
This will help us to help you out!
Thanks,Matt
Thread Starter
Original Founding Member!
Joined: Jul 1999
Posts: 9,037
Likes: 88
From: Granby, MA
Cruise-In 1, 3, 9. 10 & 11 Veteran
sorry i left out important information!
Sorry all and Matt.
TPS was changed out, so not that. Plus reset
IAC was thoroughly cleaned and reset.
No codes being set. Scanned numerous times. I disconnected the MAF to make sure and yes it threw a code. I cleared that code. Did this to make sure the ECM was functioning as far a code throwing goes.
O2 sensor is my next test today. I will let you know.
in the meanwhile any other ideas please feel free to chime in.
Jeff
TPS was changed out, so not that. Plus reset
IAC was thoroughly cleaned and reset.
No codes being set. Scanned numerous times. I disconnected the MAF to make sure and yes it threw a code. I cleared that code. Did this to make sure the ECM was functioning as far a code throwing goes.
O2 sensor is my next test today. I will let you know.
in the meanwhile any other ideas please feel free to chime in.
Jeff
Team Owner
Joined: May 2006
Posts: 21,473
Likes: 356
From: Palmdale, Ca----- 2009 Cyber Gray 4LT A6 F55 452 RWHP 422 RWTQ- RIP 1998 C5 734 RWHP & 585 RWTQ-----
Perhaps check the timing to see where it is at. And is it possiblr to retard it a wee(I believe this will help; if not someone CORRECT me!)to help drop the NOX reading. Although that might not allow it to idle much better than your situation now!
Dang SMOG laws!
Thanks,Matt
Dang SMOG laws!
Thanks,Matt
Race Director
Joined: Sep 2000
Posts: 17,298
Likes: 33
From: The Top of Utah
Originally Posted by XtremeVette
TPS was changed out, so not that. Plus reset
IAC was thoroughly cleaned and reset.
O2 sensor is my next test today. I will let you know.
IAC was thoroughly cleaned and reset.
O2 sensor is my next test today. I will let you know.
Originally Posted by XtremeVette
New distributor (thole entire thing including cap and rotor etc), wires, plugs, no change.
RACE ON!!!
Last edited by CFI-EFI; Jun 27, 2006 at 02:52 PM.
Thread Starter
Original Founding Member!
Joined: Jul 1999
Posts: 9,037
Likes: 88
From: Granby, MA
Cruise-In 1, 3, 9. 10 & 11 Veteran
CFI I appreciate the help but.
No need to give yourself a heartattack. First off I did not buy any parts. Had them. Second, the distributor needed to be changed anyways, it was original and needed it badly. The pickup coil was horrid. The other parts I had on hand (the tps and IAC) so no money there. Only place I can see I messed up was the EST wire and not disconnecting it. As far as timing goes, ok yeh I should have used the timing light. But the problem existed before the distributor was changed anyways. I have the manual already for my car but my bro doesn't own a good one on his firebird...hence the reason for all the questions. He is in the process of getting one....
sorry if I upset you the wrong way. But the comments about go ahead throw more money at it wasn't the type of help I was lookin for. Iam just trying to figure the problem out and only can do it by getting different opinions and options on what I might have overlooked....thats all.
sorry if I upset you the wrong way. But the comments about go ahead throw more money at it wasn't the type of help I was lookin for. Iam just trying to figure the problem out and only can do it by getting different opinions and options on what I might have overlooked....thats all.
Thread Starter
Original Founding Member!
Joined: Jul 1999
Posts: 9,037
Likes: 88
From: Granby, MA
Cruise-In 1, 3, 9. 10 & 11 Veteran
timing.
Originally Posted by CFI-EFI
With the new distributor, you've already exceeded the cost of the FSM. Too late now, just keep throwing money (parts) at it.
Who set the timing...and how?
RACE ON!!!
Who set the timing...and how?
RACE ON!!!
Dad did it....put it back to where it was very carefully marking the original distributor position.
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Racer
Joined: Jun 2006
Posts: 408
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From: Elkton MD
Closed loop rough
High NOx often results from leaking or sticking EGR valve - and a flakey EGR will really roughen up the idle and degrade power performance.. If it's ok in closed loop, the EGR is probably not leaking. But something may be telling the EGR to open prematurely or too much. Will be a tough nut to find the root cause if that's it.
BUT, it is easy to disconnect the EGR to see if it cures the rough running (even if it throws a code). At least if it cures the rough running, you'll have a better idea where to look.
Good luck.
BUT, it is easy to disconnect the EGR to see if it cures the rough running (even if it throws a code). At least if it cures the rough running, you'll have a better idea where to look.
Good luck.
Thread Starter
Original Founding Member!
Joined: Jul 1999
Posts: 9,037
Likes: 88
From: Granby, MA
Cruise-In 1, 3, 9. 10 & 11 Veteran
how do you disconnect EGR functions?
That is exactly his problem, once hot or closed loop it starts behaving badly. We were swaying towards EGR but had no way of proving it. Well without buying parts and were staying away from that for now.
Thread Starter
Original Founding Member!
Joined: Jul 1999
Posts: 9,037
Likes: 88
From: Granby, MA
Cruise-In 1, 3, 9. 10 & 11 Veteran
sorry rick....for any confusion
Originally Posted by rick lambert
just responded to your other post?????Dealing with two separate cars and two separate posts.
My car which is the vette and runs fine, I was just curious about timing seeing that my dad set mine and my bros' and did it without a timing light. I was curious if I should mess with mine as far as resetting the timing goes....and thats why that post.
My bros car ....the 89 firebird is what this post is all about. His is a closed loop problem and I had mentioned what things had been done to his car so far in attempts to solve his problem. Distributor replacing just happenened to be one and was purely coincidental. Sorry to confuse.
Jeff
Race Director
Joined: Sep 2000
Posts: 17,298
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From: The Top of Utah
Originally Posted by XtremeVette
No need to give yourself a heartattack. First off I did not buy any parts. Had them. Second, the distributor needed to be changed anyways, it was original and needed it badly. The pickup coil was horrid. The other parts I had on hand (the tps and IAC) so no money there.
sorry if I upset you the wrong way. But the comments about go ahead throw more money at it wasn't the type of help I was lookin for. Iam just trying to figure the problem out and only can do it by getting different opinions and options on what I might have overlooked....thats all.
sorry if I upset you the wrong way. But the comments about go ahead throw more money at it wasn't the type of help I was lookin for. Iam just trying to figure the problem out and only can do it by getting different opinions and options on what I might have overlooked....thats all.
RACE ON!!!
Instructor
Joined: Mar 2004
Posts: 212
Likes: 0
From: Fairfax VT
Rough Idle
Hi All,
I had a similar problem on my 87. It turned out to be the EGR valve, tube and switch. I replaced them all (needed it done anyway) and the problems were gone.
Just a thought
Regards.
Don in RAINY VT
I had a similar problem on my 87. It turned out to be the EGR valve, tube and switch. I replaced them all (needed it done anyway) and the problems were gone.
Just a thought
Regards.
Don in RAINY VT
