AdmAnt13

Ok I had the pacesetter headers installed in my 1990 3.1 by my mechanic. While installing it, he removed the AIR injection system and also the o2 sensor is disconnected for the moment. Apparently the wire isn't long enough, or thats what he tells me. I asked if it could be lengthened but he said it works on resistance and that making it longer would not make it function correctly. I don't know if he is right or just lazy.

Anyway, the car ran fine for about 20 miles. Then as I was driving, it started shaking and losing power. It idles rough and drives rough. The exhaust reverberates a lot, like a low popping noise.
Any ideas? Could this be related to the disconnected o2? How can I fix that? I've heard the car runs bad without an o2 sensor, but didn't realize it could be like this. I also get the check engine light turn on and off intermittently which never happened before.

Any help would be greatly appreciated,
-Adam

firstfirebird

iTrader: (3)

The o2 is in the y-pipe, so why couldn't it be re-used in the same location?

You can extend the wire, but good luck trying to solder it since it made of a heat-resistant metal, lol. Use a crimp connector and make sure you tape it good.

It does not send a resistance signal, but a voltage signal - ANY machanic should have known this or been able to find the info.

Just $0.02, but are you sure this mechanic can be trusted? Are you sure that he didn't break any manifold bolts?

AdmAnt13

Well I'm having my doubts, but hes done my work for years and I've never had an issue before. They y pipe is a new piece with the headers and apparently the new location is about 2 inches longer than the original.

I checked the headers, all the bolts are in place. Even if the bolts were broken, replacing it would have fixed that. Why would that cause my engine trouble?

firstfirebird

iTrader: (3)

It wouldn't cause engine trouble, but would sound like crap and maybe backfure. Breaking the bolt off in the head isn't as easy as "just replacing it", that's why I asked.

If your friend has a welder, just take your o2 sensor to Home Depot and find a bolt that matches the threads and weld it on where you need it (and close up the old hole). If you need to, you can still extend the wire as I had suggested.

AdmAnt13

ok but that still doesnt explain why it runs horribly. Its not just sound, it vibrates throughout the whole rpm range.

anyone know????

firstfirebird

iTrader: (3)

Hook up the o2 and see what happens.

coolrimsatleast

I had a problem with my o2 not reaching too. I tried extending the wire at first, and found out the extra bit of resistance will mess up the signal.

I ended up shifting the whole wiring harness around and pulling it downward to make the o2 wire reach (after picking up a new one with an unmolested wire) and using zip-ties to keep everything in place and off the headers. I had to disconnect the cold start injector though to do this.

Some of us with headers had a problem with the o2 not heating up enough. If you still get codes after getting a new o2 and get the wire to reach, and it turns black after a little while (that's what mine did) then get a heated o2. That made the codes go away and made it run smoother too.

The denso o2 I got also had enough wire that I was able to trim the wire so it had an extra inch or inch 1/2. That gave me just enough slack to reconnect the CSI

Bazookajoe254

Just thought I'd throw this out there because I don't think I saw it mentioned...

Yes, you will get a SES light for your 02 sensor not being plugged in. I forgot to plug mine back in once , and I would get an SES light when going at a steady speed with a steady throttle. But in stop and go traffic, no light.

Once I plugged the sensor back in two days later I didn't get the light anymore.
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Also, I read this in the directions for installing my 02 sensor -- It said splicing into the wire between the 02 connector and ECM won't damage anything, but splicing into the wire between the connector and the 02 sensor will mess up the resistance.

hgffrank

A properly lengthened 02 wire will not increase resistance enough to make a difference as long as you dont get rediculous. Its also a good idea to use the next lower gauge for the extension to help offset what little bit it does impact. However instead of using crimp connectors, opt for the more expensive solder seal connectors. The reason I say this is because they automatically seal the connection and the two wires are soldered together really good when done right. I have done this to lengthen an 02 wire and never had a problem. The biggest problem with crimp connectors are that no matter how well you tape it, moisture still finds a way in, and when it does the connection corrodes and increases the resistance. The key is to get a good connection and prevent exposure to moisture. The solder seal connectors are about $1 each and require a heat gun to properly use, but are far superior to crimp connectors or splice and tape methods. If you dont wanna use solder seal connectors then dont waste you time with crimp connectors, just solder the wires together and wrap with tape or coat with high temp silicone. Make sure you use Rosin core solder. The acid type will cause corrosion and is not recommended for electrical work.

Also, you should try to re-route the 02 wire and see if you can get another couple inch's. Usually the wire goes into the harness. If you have to its ok if you open the harness and pull it back to give some extra slack, then tape the wire up really good where it comes out of harness to prevent chafing.

Stevo

iTrader: (45)

Lengthened o2 sensor wires can cause problems? Thats new to me...

Sure its just not the fact that you guys need heated o2 sensors to work correctly with headers.

Like so, when i installed my headers, i extended the wire because my o2 bung was way down in the y pipe. Car didnt idle worth a damn it fluctuated up and down, no code just it couldnt idle and itd stall out every few stop lights, anyway yesterday i installed a heated o2 sensor and now the car idles as smooth as can be...

Its a good time if your car has miles on it to replace the o2 sensor anyway. New single wires o2s are under $20, heated 3 wire o2s can be had under $65.

hgffrank

your right, typically lengthened 02 wires dont cause any problems, but when people do crappy connections or get carried away with length then it "can" effect the circuit impedance thereby reducing the signal strength. I agree also that a heated 02 sensor is sometimes needed with headers. but many can get away with single wire 02's. Depends a lot on the placement of the 02 sensor. Also another method to get around the need for a heated 02 is to get some heat wrap and wrap your headers really good. That will keep the heat in the headers and allow single wire 02 sensors to work properly. An inherent problem with headers is that they loose ALOT of heat due to thin wall designs. Wrapping the tubes will almost always cure the problem of 02 sensors not heating up. Also by wrapping the headers you will increase the velocity thereby increasing scavenging and unlocking a bit more power. Properly coated headers can acheive the same result. If you headers are coated make sure its safe to wrap them before doing so. Some coatings cant handle the retained heat when wrapped.

AdmAnt13

Well, I'll try shfting the harness first since thats the easiest thing to do. If i can't do it for some reason, I'll try extending the harness wire first befoire extending the o2 sensor wire.

I'm hoping this is the cause of my problems. The car ran fine for awhile. Its not like I started up one day and it ran horrible, I was drivng for awhile already and then as I mergred onto the highway and accelerated, it bogged down and started sounding strange. I'll fix the wire today or tomorrow and let you guys know what happens.
Thanks for all your help.

Six_Shooter

iTrader: (2)

I've extended or shortened just about every wire in an engine harness and NEVER once experianced any problems with doing so. Solid connections and careful routing away from heat sources is what's needed.

Coonect your O2 and your car will thank you.

firstfirebird

iTrader: (3)

THANK YOU!!!

hgffrank, have you actually tried to solder to the nickle wire that comes out of the o2 sensor? Go get a JY sensor, and tell me how you did it. I have a lot of experience soldering, but the heat-resistant alloy the stock o2 sensor uses would not solder for me. I did not try soldering on the o2 to ECM side howerver.

DaSkinnyGuy

If your hearing a popping sound that shouldnt be a problem. Its not backfiring. Its the exhaust rumbling. You should be hearing this when you are letting off the gas and will notice this more when you have a manual.

Where abouts are you in north jersey. Im in Hopatcong

thomas1976

Admant13,
my oxigen sensor wire came out of plastic protection tube that went to the front, so I just opened the protection tube and made it come out 4" earlier. But mine is a 91 v8 lo3 with oxigen sensor on the driversside so not sure if its the same on a v6.

The simptoms you described could also come from a slightly burned sparkplug wire tuching a header or something. No wire schould come in contact with the headers or exhaust.

The exshaust tuching the car frame or heat shields can cause some annoyng vibrations too.

I keept all emissions accessories and had no problems at all.

hgffrank

I guess I should have clarified. I would always solder in the extra wire just before the connector where the 02 sensor plugs in. If you extend the actual wire coming out of the 02 sensor then you are wasting time, not only because it will be a royal PITA, but because the next time you have to change the 02 sensor, your gonna have to do it all over again. its much easier and smarter to extend the "harness wire side" before the 02 sensor connector. that way you will always have the extra length when you replace the sensor.

sorry for the miscommunication

AdmAnt13

I know what sound you are talking about, but this is completely different unfortunately.

We're not to far at all actually. I'm in Montville, bout 5 minutes from Parsippany area. I would say 40 minutes?

Its more how the engine vibrates than the exhaust rumbling or hitting something. Its not a rattling at all, the engine is just rough...really rough. Its hard to explain, but its internal, thats for sure.

The spark plug theory is worth checking out. I'm dropping it off in a few hours, my mechanic will take a look at what the hell he did and fix it or free (i won't pay him otherwise). I'll let you all know tomorrow what the problem actually was. I told him to lengthen the harness side of the o2 wire as well as all the other things you all have mentioned.

Thanks for all your input. It helped me quite a bit.
-Adam

hgffrank

Dont get too cocky about it. If your mechanic does work and you dont pay him, he can put a lein on your car and refuse to give it back. So you better ask for an estimate or have it in writing that the work is on the house. Not sure about your state, but here in Michigan we arent even allowed to touch a car until an estimate has been wrote up and signed by customer. Otherwise they have to sign a waiver which approves any repairs necesarry without cost limitations. Those are a really bad thing for customers.

Dale

iTrader: (12)

I've cut and shortened/lengthen wires like six-shooter said, soldered the wire and never had an issue. How else are you to fix burn wires n such?

In my tech write up about installing the headers(since I was the first to buy a set)... I mentioned that you had to get an extender or cut and splice your factory harness. Guess nobody reads what gets wrote.

And yes, if your o2 is not hooked up, or any sensor that causes a check engine light, your car is gonna run like crap. The pop your hearing is probably the raw gas your engine is dumping in/not burning, catching fire off your hot headers/exhaust. Once you get the o2 fixed, clean your plugs or replace them.

pairtoe

iTrader: (4)

well im almost in the exact same boat as you are. i put on the pacesetters and the y-pipe and just bolted a bullet up for now. but anyways my 02 wire was to short, so i stretched it as far as i could and finnaly got it to connect. but then after about 5 minutes of running the headers got hot and melted the plug connectors, so now i got to lengthen the wire. but if your hearing alot of popping thats prob just an exhuast leak.

Dale

iTrader: (12)

another thing, popping sound could be where the headers touch the heads, and not tight or flush creating a small gap.

AdmAnt13

Its not that strict here at all. I already talked to him. He agreed well before I brought the car. I've demanded this before as well and it was honored so no worries. Thanks for the heads up though.

Ok Dale, sorry but i guess I'm a little lazy when it comes to reading all those tech articles. Actually didn't know there was a v6 header article written up.

Everyone is putting too much emphasis on the pop nose. I really just described in wrong. Its just the rough idling and such thats making the exhaust sound a bit different.

Anyway, he didn't get to the car today, so tomorrow I should know. Thanks guys.

AdmAnt13

Ok, well it was the o2 sensor all along. He just pulled the harness closer and put in a new heated o2 sensor since the old one went bad in the few days it wasn't hooked up. I don't know how so quickly, but whatever. He didn't charge me anything so I'm happy.
Thanks for all your help guys.
-Adam

firstfirebird

iTrader: (3)

Cool!

Read post #6 .

AdmAnt13

lol yeah I know.

82-T/A [Work]

What you've just learned is the sad truth that the vast majority of mechanics (even ASE certified ones) really have no clue what they are doing and are complete morons.

Like Thomas1976 said, the problem to me sounds JUST like a bad spark plug wire. If the guy was too dumb to properly hook up a 1 wire O2 sensor, then he's probably too dumb to properly route spark plug wires also. It sounds like the spark plug wire is grounding out on an exhuast manifold or something and is shorting out.

Find a mechanical engineer somewhere in your neighborhood and beg him to look at it. Chances are, he's probably a million times smarter than most mechanics you'll be able to find.

It is for this reason that I decided to teach myself everything I could about cars. I do everything myself now, I refuse to take my car to a dealership or a garage unless something is under warranty.

9 times out of 10, you bring a car in to have something fixed and they break something else.


Todd, @ http://www.PontiacPerformance.Net
2006 Pontiac Solstice
2004 VW Beetle Convertible (Wife's Car)
2002 Ford Crown Victoria LX-P74
1987 Pontiac Fiero SE / V6
1984 Porsche 944
1981 Pontiac Trans Am WS6
1973 Volkswagen Type-2 Transporter

AdmAnt13

Yeah your absolutely right. He is a moron and keeps breaking more stuff that he fixes. I know a guy who is the best mechanic I've ever seen. He's from austria, has every certification imaginable..even built his own airplanein his shop, but he refuses to do engine work because he is in such high demand. He will only do suspension related problems..and or electrical. Hell he even fixed my Polaris Sprotsman 500 ATV.

I mean, my main problem is fixed...but the engine bogs down now. I replaced the air filter..that helped...a little. Then replaced the fuel filter...that helped alot. But still is happening. Thinking its the spark plug wire like you say. That or faulty EGR but thats a long shot. Hopefully he'll take a look at my problem anyhow.

firstfirebird

iTrader: (3)

I thought it was cool of me to figure out the problem over the internet, though .

It's not rocket science, but since I don't think my wife will let me ride in a rocket....














At least she lets me drag race!!!

82-T/A [Work]

Well, there are a few things you can check. I guess the first step I would recommend is to of course do a general inspection in the engine compartment. Nothing should be disconnected, burnt or missing. GM was pretty cheap back in the day, and they typically did not use any more wiring harnesses than they needed to. Typically the only unused plug you'll see is for a cruise control servo (if yours isn't equipped). There should not be any wires touching the exhaust anywhere.

If it passes a visual inspection, then the next thing I would do would be to check your car's computer. Do you have a check engine light? Your car is equipped with an OBD-1 computer. All you need is a paper clip and something to write with.

Do you know how to check the codes in your ECM?


Let us know first if you see the CHECK ENGINE LIGHT on in your dash.

AdmAnt13

Firstfirebird...I was crying when I read that....so funny.


I'm not to sure how to check the computer. That would be nice to know. I do know the the engine light hasn't turned on since the o2 sensor was plugged back in. I looked over the engine compartment yesterday and didnt find anything out of the ordinary. One plug is not plugged in, but it must be the AIR injection system because the plug is in the exact spot where it used to be. My mechanic did route the wires away from the headers..but they are still pretty close and are stock replacements, not the aftermarket heat shielded ones.

The bog happens not at WOT but maybe half throttle when you take off or are cruising at 30 or 40 and push for a little more speed. Maybe that will help your diagnosis.

BTW you guys rock. Thank you so much.

82-T/A [Work]

Ok, lets see... sometimes the ECM will record error codes and store them, but not display a SES light if it's nothing major. The way to check the ECM codes is to stick a paper clip in the ALDL (computer diagnostic terminal) "A" and "B". (I believe). Your best bet is to get yourself a Haynes repair manual. They are about $15-25 bucks at most auto parts stores. It will tell you the exact location of the ALDL (forgot where it is) port, and the specific orientation of it so you know what leads are A and B.

Basically, you stick the paper clip in, and then turn the car to the ON position (but don't start it). The SES light will flash code "12" three times to let you know the ECM is "OK". It will then start to cycle through the codes. It will display each code THREE times. Once all of the error codes have been displayed, it will again display the "OK" 12 code three times.

A code of "12" is displayed by a series of flashes on the SES light. It would look something like this:

"FLASH", PAUSE, "FLASH", "FLASH"

(followed by a 5 second pause in between each instance of each code).




Off the top of my head, a hesitation like that in the mid RPMs can be caused by a failing MAP sensor. I believe the MPFI 3.1 in the later year Camaros used a MAF system (Mass Air Flow) sensor... (someone correct me if I'm wrong). A failing MAF sensor could result in symptoms like this.


You might want to try disconnecting the battery for a few minutes to reset everything. With the additional flow from the headers, it's possible that the ECM is used to using far different fuel mapping in those rpms. It typically takes a little while before it correctly adjusts itself. I would try resetting the computer by disconnecting the battery for 5 minutes. This will also flush out any old ECM codes from issues that you no longer have. I would then work from that point.

The Camaro / Firebird is a GREAT car to learn to work on... I would highly recommend getting that manual. That's how most of us gear heads start off anyway.

daves12secV6

iTrader: (3)

the 3.1 is a sd car it does not have a maf
it uses a map sensor instead.
the aldl port is on the driverside below the sterring wheel on the right side nexto the center console
the paper clip goes here
xxxxoo
xxxxxx

between the to o's once the paper clip is in turn the key on the ses light will flash the code 12 three times then any stored codes and 12 three more times

all the codes are listed on this site so u dont need to buy a manual to see what they are

rx7speed

think the mechanic was refering to the added resitance of the wire being made longer would add more resistance interfering with the voltage signal. either way though this is a low current signal and a little extra resistance wouldn't change things that much. atleast with how little the resistance change would be.

firstfirebird

iTrader: (3)

with Dave. I buy a manual just to have easy access to torque specs .

https://www.thirdgen.org/service-eng...ht-error-codes

^^Click on FAQ's at the top of the page, then go to miscellanious to get to the SES light low down.

Dizturbed One

To be straightforward and logical, O2 sensors work by the reaction of heat and oxygen altering the resistance of the element. The wire to the connector must be "tuned" to give the proper resistance to the ECM and be part of that. Knowing that changing the length of a wire changes a wires resistance automatically tells you that and suggests you should not alter it in any way. The resistance is altered if you change anything from the tip of the connector to the tip of the O2.

But I still don't see how your mechanic would think that's a problem knowing that the ECM wire going to it could be safely lengthened since it reads the O2 by calculating the low-voltage signal that is being altered by the resistance of the O2 at the connector; not trying to transmit a specific resistance across 10 feet of wire.

Lengthen the wire on the vehicle side and hook up that O2, it is definitely throwing a code. Whether or not that is the only code, who knows. Did your headers have an EGR stovepipe? EGR's can do some pretty bad stuff, I even had one blow in half once on a car with a clogged cat. They often have symptoms just like you're describing and the fact that the headers were just done makes me wonder about the condition of that EGR. Those digital suckers can get pricey when they're brand new too. I'd junkyard one off a slightly newer FWD 2.8, 3.1, 3.4, or 3.8 (FWD Buicks have them) if it turned out to be an EGR problem.

Good luck.

firstfirebird

iTrader: (3)

Why does everybody keep saying it will change the resistance?!?!?!

The o2 is measured by voltage, NOT resistance. The biggest issue with lengthening an o2 wire is because of the material the wire is made of that goes from the sensor to the connector. It is nearly impossible to get a solid connection to the heat-resistant nickel alloy used to protect the wire from melting . I have tried to solder and crimp to no avail when I wanted to "steal" the harness connector to use on my wideband. I eventually had to dissasemble the connector and use the WB wire in place of the nickel wire to get a solid connection to the ECM.
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EDIT: it takes a lot of resistance to change voltage...

The voltage might drop.0000001v for every foot of wire added.

2_point8_boy

Lengthening the wire will not give you a problem as long as you solder it. I NEVER use any kind of crimp connector in any of the cars that I work on and do wiring in. Even for the radio. If you have a bosch or acdelco O2 sensor, you can solder the wire as they do not use a stainless wire. Denso and a couple of others do though, so I tend to stay away from them since they use a screw-style crimp connection.

It does not take that much resistance to change voltage.

rx7speed

to reply to your tantrum there on the first part. Because it will change the resistance. now listen even though the o2 is read off the voltage signal resistance will change the measured output voltage. if you don't understand that then read up a little more on electronics if you do understand that then learn to read as I have said it and others have as well just as we have said taht the voltage change won't really be enough to change anything.

Street Lethal

iTrader: (16)

^ Aren't you in the wrong forum.....

AdmAnt13

Ok well, the o2 sensor has been hooked up already just by pulling down the harness a little more.. No extending wires or anything had to be done. So that problem is fixed.

I have a Haynes manual and know where the port is. Thanks to Dave i know where to put the paper clip without digging out the manual in my garage. Now should I find out what codes are being created..or just disconnect the battery, reset everything and see what happens?

Anyway quick way to check if the EGR is the problem? How do I check if its my MAP sensor also?

Thanks guys.

rx7speed

sorry I thought this was teh big block section on the typeRgen forums




as far as the MAF first run codes see if you get any. if you want to veryify the MAF though d/c it. if your problem stays the same or doesn't get much worse then could be. if your problem goes from bad to horrible then chances are your maf isn't the problem.

AdmAnt13

ok so just checked if there were any codes. All it did was continously flash a 12 over and over. Thats a good thing I assume right? I watched in for about a minute and thats all it did so I'm guessing there are no trouble codes.

Next step...EGR..MAP?

82-T/A [Work]

It can't hurt to pull the codes before AND after. Although some of your codes (if you read them first) may have to do with things you've already fixed.
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Hahah... I hate to make a crack, but... what exactly is a Honda big block? The 3.2-3.5 V6? Heheh, or the 2.2 L4?

I thought I was bad-*** because I have a 1969 Oldsmobile 455 (bored to a 468) Big Block, but now it's very common to see people with 572s and other ginormahoochie sized motors...

82-T/A [Work]

My guess would be the MAP sensor then. The MAP seldomly sets a code unless it's completely failed.

It could be any number of things though.

When a MAP goes bad, you typically get bogging and jerking.

By the same token, if you're ignition pickup (the little coil inside the distributor that goes around the shaft, not to be confused with the ICM) can also start to go bad and that could ALSO cause similar symptoms.

AND... improperly gapped spark plugs, or timing set too retarded could also cause these symptoms.


It's tough, but most of these issues are all fairly cheap to fix.

Try driving the car around for a bit and see if it gets worse or if it gets better. (Do this after resetting the computer by disconnecting the battery for 5 minutes).

AdmAnt13

ok will do and let you know.

daves12secV6

iTrader: (3)

be aware if u reset the ecm by unplugging the battery,the car can and will idle like crap for a few days.
it takes a while for the ecm to relearn the idle
also it will reset the blms,which will also take a day or so to reset

firstfirebird

iTrader: (3)

Tantrum? I fully understand electronics and I don't care how many people say that the sensor won't read correctly. Extending a voltage based wire should not change the ouput if correctly connected as 2.8boy said.

My statement was directed at your thoughts about the mechanic...
Not this...

daves12secV6

iTrader: (3)

umm just saw ur cai thread,and now i have to ask were to u have ur air temp sensor hooked upto ?????
cause i cant see it screwed into the cai anywere

AdmAnt13

Thats not the prob. The IAT sensor is brand new and its screwed in..the CAI had an opening for it right behind the filter. Cannot see it in the pics from that angle.

MAP sensors are expensive. Hope it not that... Summit has it for $80.00

Can it be unplugged to test if it is the problem or is that ill advised? What about the EGR? Unplug it? yes..no?