Header Problem

[Purple RS]

I just put a set of headers on my 89 Camaro which has a TBI 305 motor. Headers are the ONLY mod to the motor. Everything was fine beforehand. I took care of a leak and replaced the gasket on the passenger side, but the problem persists. At idle, the motor runs extremely rich and the exhaust pops randomly but frequent (not very loud but annoying). My guess is that unburned fuel is being ignited by the cat. My O2 sensor is new, but that doesn't mean it's not bad, it's also located about a foot further downstream than stock at the end of the driver's side collector. I'm half tempted to try the O2 sensor from my V6 Camaro because it operates in the Y-pipe in front of the cat (about 3 more feet downstream). Any insight???

EDIT: Sitting here, I just thought of something I should check. I had to lengthen the harness end of the O2 connector so that it could reach the new location. The new location is on the back side of the collector where the original was on the front side and a little closer to the head. Being rotated around like that, I needed wire to cover about twice the length of the sensor. Maybe my splice isn't secure??? Would be like running with no O2.

[aaron_sk]

How old is "new"? I had a Bosch unheated sensor go on me at around 3K miles. They're crap, but they're also the only ones carried around here.

[Purple RS]

How old is "new"? I had a Bosch unheated sensor go on me at around 3K miles. They're crap, but they're also the only ones carried around here.

Less than 500 miles I think

[aaron_sk]

http://www.thirdgen.org/techboard/exhaust/236775-what-do-about-o2.html

Apparently the harness end of the line wont affect it, but I haven't ever tried it.

[Purple RS]

I also read earlier today on TGO that new headers can kill an O2 sensor. Can't say as I believe it or not. Mine aren't new, but they are newly coated.

[cargodz]

You also have to keep in mind to be extremely careful with the O2 sensors when installing... Any dust, particles, or oils (including from skin) can make the O2 sensor go bad instantly... But checking your wiring would also be a good start.

[Purple RS]

I unplugged the O2 sensor to keep the car in open loop just to see what it would do. Still have random pops through the exhaust, so I apparently have a leak or 2 I need to track down. My guess is a leak at the collector to y-pipe connection, or one of the 3 A.I.R tubes.

[smoker]

i hate fuel injection and computers.....id say carb it, cam it, new ignition system

[aaron_sk]

i hate fuel injection and computers.....id say carb it, cam it, new ignition system

:confused0

Not only would that not solve the exhaust problem, but you'd still have to tune it and you'd be tuning it blind since you have no feedback from an O2 sensor.

BTW, Al, is it running unusually rich? Any time the ECM gets a low or nonexistant signal from the O2 it goes to full rich, which can cause the exhaust to snap. I've had problems with that before.

[Purple RS]

:confused0
Not only would that not solve the exhaust problem, but you'd still have to tune it and you'd be tuning it blind since you have no feedback from an O2 sensor.
BTW, Al, is it running unusually rich? Any time the ECM gets a low or nonexistant signal from the O2 it goes to full rich, which can cause the exhaust to snap. I've had problems with that before.


It is VERY rich. Maybe then the O2 is bad, I have no way to check it though. I have a new one to put in, but first I'm going to see if I can seal up a leak or two.

[smoker]

:confused0
Not only would that not solve the exhaust problem, but you'd still have to tune it and you'd be tuning it blind since you have no feedback from an O2 sensor.
BTW, Al, is it running unusually rich? Any time the ECM gets a low or nonexistant signal from the O2 it goes to full rich, which can cause the exhaust to snap. I've had problems with that before.

first of all this isnt an exhaust problem, it sounds like part of the fuel delivery system. which in this case may include the 02 sensorand you wouldnt be tuning it blind. by bypassing all the computer shit you would be right back to having a carb'd v8....imagine, tuning a car with a timing light and degree wheel or by ear and seat of the pants driving.....plus this being a tbi motor, the new carb and ignition system would allow for far greater performance mods to be done.

[aaron_sk]

I agree, the rich issue is probably causing the noise. I can artificially create the problem right now by screwing the AFPR all the way in and punching the throttle on my TPI Camaro.

However I fail to see how swapping to a carb makes anything easier. If I needed to tune the A/F ratio I would have to purchase an O2 sensor, take readings, and adjust from there. You would also posibly have to rejet if you're dumping to much gas. With TBI you can make all your adjustements with a laptop, and be done with it.

As for performance mods, there is nothing that can be done with a carb that cannot be done easier but costlier with EFI.

[Purple RS]

I don't think this is a fuel delivery problem. The car ran just fine in bone stock form prior to putting the headers on. I believe I have all my leaks sealed up, and I have continuity from the O2 sensor to the ECM. The O2 sensor now instead of being about 3 or four inches from the head, now sits about a foot downstream and in a larger diameter tube, maybe that has something to do with it. Maybe I'll opt for a heated O2 sensor and see if that helps any.

[aaron_sk]

Can you tap one of the headers for an O2 bung Al? Mine is right above the drivers side flange, and it works pretty well.

[smoker]

I agree, the rich issue is probably causing the noise. I can artificially create the problem right now by screwing the AFPR all the way in and punching the throttle on my TPI Camaro.
However I fail to see how swapping to a carb makes anything easier. If I needed to tune the A/F ratio I would have to purchase an O2 sensor, take readings, and adjust from there. You would also posibly have to rejet if you're dumping to much gas. With TBI you can make all your adjustements with a laptop, and be done with it.
As for performance mods, there is nothing that can be done with a carb that cannot be done easier but costlier with EFI.

well were gonna have to agree to disagree here then. efi can be modified to work as well as carb'd engines but not the tbi system, you can get far more power with a carb than with the tbi setup. the biggest problem people have with carbs is they think their stock small block needs a 750 double pumper just because they switched manifolds when a 600 is probably the best option for most streetable small blocks. i personally hate efi of any kind, i hate power adders too for that matter, do it on motor and motor alone or put on a skirt and admit you cant build a motor.


oh and the o2 sensor affects the fuel delivery purplers, thats what i meant

[aaron_sk]

I can appreciate the old-school idea of a huge engine and a huge carb, but those days are long gone. I personally don't want to own a car I cant drive on a regular basis, or one that can't start below 45 degrees, or one with such a choppy cam you can't idle.

BTW, stock TBI is crap, but I've seen guys getting good results with the Holley Commander 950TBI, or bottling it.

[Purple RS]

Can you tap one of the headers for an O2 bung Al? Mine is right above the drivers side flange, and it works pretty well.

Which flange? Just after the head, or just before the Y-pipe? If by the head, which tube do you have it in? I'm not crazy about removing it from the car, although it's easier than the passenger side.


oh and the o2 sensor affects the fuel delivery purplers, thats what i meant

Thanks, I realized thats what you meant after I posted

[aaron_sk]

Mine is just before the Y-pipe flange, yeah. If you don't mind throwing money at it, you can buy a new non-heated O2 for $25 at Schucks, or a heated one from TPIParts for $75.

[Purple RS]

That's where mine is too, and the non-heated ones don't seem to be doing anything for me.

[cargodz]

I can appreciate the old-school idea of a huge engine and a huge carb, but those days are long gone. I personally don't want to own a car I cant drive on a regular basis, or one that can't start below 45 degrees, or one with such a choppy cam you can't idle.
Now that's funny :rolleyes:
I guess as the ultimate old schooler here I gotta jump in on this one since I was building up carburated cars/ trucks before most of you were out of diapers and some even born :p LOL
So what you think we didn't drive anywhere during winter back in the old'n days when it got really cold... Heck my 78 Blazer I had (last carburated owned vehicle) was the only one that would start one year when it dropped to 30 below 0 with wind chills of -50-60... Don't get me wrong... there is pros and cons to both, but ya gotta love a vehicle that has a motor anybody can tear down and rebuild in a weekend.

Oh by the way... one more thing that may lead to your problem that I recently thought of... (and yes it has to do with the O2 sensor too)... If your new headers are thicker and larger diameter then you may not have the proper depth for the O2 to get a proper reading... I thought of this cause we encountered this problem on a truck a couple years ago... guess that's one of the downfalls of getting older, it takes me longer to remember stuff :p LOL

[smoker]

no one mentioned huge engines, im a ford guy at heart and any windsor based block will do, 302 or 351.....both small blocks, both capable of real power without any nos or blowers or anything, both streetable when built, the last 302 i built went 11.4 on motor alone, not a real radical build but still very quick for a street car. i know you can make just about anything run mid 11 second times but not on the money i did it with, it was a junkyard motor to start with and a 85 mustang 4 cyl car with not motor or trans to start with. i had 2 or 3k in the entire car including body work by the time it was done.

[aaron_sk]

I was building up carburated cars/ trucks before most of you were out of diapers and some even born :p LOL

Now that one I'll give you guys. Hell, most of the cars I've worked on were older than I was. :lgh

I can honestly understand why guys stick with carbs, since that's what they now. But most of my experience has been on older EFI cars, and I preffer it. Easier to work on IMO.

[cargodz]

Now that one I'll give you guys. Hell, most of the cars I've worked on were older than I was. :lgh
I can honestly understand why guys stick with carbs, since that's what they now. But most of my experience has been on older EFI cars, and I preffer it. Easier to work on IMO.
More ease of not working on them if you leave them stock if you ask me :p
I've always been a GM fan myself... with the good ole 350 being my canvas more times than I can count with fingers and socks off :p LOL
It's not to say that I have anything against EFI systems as that's the majority of what I see now... And there is something to be said for a 4cyl. putting out over 300 ponies... New or old a muscle car is a muscle car when it comes to running at the track, but man does it make it easier when you can get by with a standard 49 piece tool kit, vice grips, and a hammer ;)

[Purple RS]

Well, decided this isn't an exhaust problem anymore. I have a feeling something else went out as soon as the headers were added. I've been looking at fuel delivery or ignition. Started with ignition because the cap and rotor were shot, so I replaced those. Also replaced the coil with one I had in the garage. Symptoms still persist but now I can get a decent idle, as soon as a load is put on the car (especially on a hill), the motor hesitates and wants to rattle the valves out. I also still get the random pops in the exhaust. Also, it doesn't like any base timing advance, so it's still at the stock 0* for now, and the computer likes to add about 15* at idle.

[William from NOLA]

I would make sure you don't have a DEI system...



(lol joke from a thread I made :))

[MobileAudio219]

Check your spark plug wires, make sure none of them are burnt and that they are snapped on all the way... Also might want to make sure you didnt get a couple crossed...

Pull your egr valve and make sure its clean and functions properly...

Its probably something easy that your over looking....

[Purple RS]

Check your spark plug wires, make sure none of them are burnt and that they are snapped on all the way... Also might want to make sure you didnt get a couple crossed...
Pull your egr valve and make sure its clean and functions properly...
Its probably something easy that your over looking....

That's exactly what it was. After all the checks and double checks I did, a second set of eyes was all I needed to see my mistake. #2 and #4 wires were crossed, put them on the right plugs and made a world of difference.