Roads88

I got done replacing my Catco Cat because it became clogged after 6 months.

I took it for a test drive and it started normally and idled maybe a little rough. When it warmed up (ecm closed loop) The idle swings back and forth 500 rpm while idleing and car will surge at low speeds.

I ran the codes and i got a code 42, but was unable to get a repeat of the code.

I drove the car today and filled it with gas. Right after leaving the gas station the warning light came on and stayed on. checked codes again and got code 44 oxygen sensor circuit (lean exhaust indicated). Cleared the codes and drove it again. Not long after warmup same thing again. The car runs strong, However not as smooth as before and the idle still swings up and down

On a car with stanard exhaust I assume the O2 senser is in the exhaust manifold. Where would it be on mine with Hooker headers (2055).

Anyone delt with this problem. I have been having one problem after another lately and my frustration level is about topped out.

Thanks

Trickster

Not exactly sure about where it would be with the hooker headers. But when you find it, check the wire to make sure it has not melted from touching the headers or is not close enough to them for the heat to affect it's operation.

Roads88

Ok, thanks I will. Do you think thats what is causing my problem?

I know it would just be a guess.

Trickster

It is one of the first items covered in the code 44 troubleshooting chart.

Roads88

heheh. I should have said the" idle" problem. the code popped up the day after the idle and rough running.


Hell... maybe the clogged cat caused some damage to the sensor.

either way, the code 44 needs to be addressed. Thanks


At least, I got to play with my rebuilt tranny. The shift kit is sure nice.

Roads88

well, there has been a change.

How the car will only start with the gas pedal depressed and held. It won't idle at all.

I haven't had a chance to get under the car and look for the O2 sensor. However, when the car is cold, It should run under open loop. That being the case, the O2 sensor, Maf, ect. should not have any effect on the ECM. Correct?

Following that logic...It sounds like its in the ECM.

Or am I missing something.

Trickster

This might help some.

Trickster

Here is the second half of that.

Roads88

Ok...Got under the car, found the O2 sensor. Wires and pig tail all ok. Decide what the hell, replaced it anyway. No change and throwing 44 code

cleared codes, unpluged maf. added code 33 to code 44. Figured 33 was ecm saying "hey cant find maf".


Think I have just about gone as far as I can without a scanner.


My neighbor has a 85 vet and I think he told me he has a scanner.

I will keep you posted

suggestion are welcome, Of course.

Trickster

Well, as the last thing under "NO" on that chart suggests. It could be a shorted wire from the ECM to the O2 sensor or it could be a bad ECM.

1bad91Z

iTrader: (1)

Trickster - are those charts etc... from the F-body CD (fbodycd.com)???

Trickster

No, they're from a cd I'm making for myself from the service manual I have and several other sources I've collected info from.

Roads88

Trickster.... Thanks for the replie on the PM. Made the change on the first post of this thread.


When I get the scanner and make sure the ecm isn't the cause. I think I will change the fuel filter.


The hunt continues....

The upside is i'm learning something....

Roads88

Ok...after two days of checking and rechecking here is were i am.

Checked and replace O2 senor. Based on O2 sensor voltage, both sensor and ecm are not causeing problem.

Replaced fuel filter. Run several pressure tests and everthing seems to be within specs.

Check MAF, its doing ok.

Suspect leak in front area of driver side header, tighed bolts. Ran better for a short time but still throwing codes 33 and 44.

Replaced IAC valves codes 44 and 33 are gone and car idles the way it should. However now getting code 42 and car runs like one or two cylanders are not fireing when your driveing.

Replace ignition module and no change

Check timing and it is right on.

Next I'm going to recheck plug wires and check plugs for fouling or soaked in fuel by possible bad injectors. May pull injectors by the rails and see whats going on there.

May have to wait awhile have other jobs to take care of. SH%T

any ideas feel free to jump in.

Roads88

Well...went ahead and changed the ECM after trying several ignition modules and still get code 42

Checked plugs and wires. No fouling on plugs(checked drivers side). I DID find a bad plug wire. It was arcking right through the protective cover. Went ahead a changed all of them and better covering to protect the wires from the headers.

The car is now firing on all cylinder. Took it out and ran it, IT ROARS

However, at cruse speed, below 2000 rpm, the car surges a little and still code 42.

The light does not come on while driveing, Its just there when I pull the codes and I'm running out of ideas


At least now the car is driveable if I need it.


I can't help but wonder if the bad plug wire( #1 cylinder) was pushing gas into the exhaust and thats what killed my cat.

MikeInAZ

I can't tell which code is giving you crap. I think it started with 44 and last post said 42?

Code 44 is a very elusive code. Before you nickel and dime yourself to death try tightening the intake manifold bolts that you can get to. Probably reach 4 of them fairly easily.

Took me 10 months to find my 44.

I am code free........

Also sometimes 33 pings off of a 44 whereas you solve 44 you may solve an intermittent 33.

The previous post is correct alway check the 02 and wire first BUT I don't think it's the culprit. It's just doing it's job telling you hey your exhaust is lean.

The reason it's lean is you have two air intake sources. Your MAF (measured) and your leak (unmeasured) ergo your car is calibrating to what your MAF measures.

Roads88

I did put a wrench to my header bolts but they were nice and tight. code 44 and 33 are long gone. Now its just code 42.

Except for the surging at cruse and a little bit of rough idle, the car runs great

With the tranny work, the car ran up to 140mph in no time. at WOT it drops into OD at about 4000 rpms. Could not be happier

After swapping several iginition modules and the ecm, I going to put in another distrubtor I've got. Found a couple of distrubtor wrenchs on E-Bay that look like they will do the trick. The ones for sale at NAPA and Kragens won't work at all. No room in there to move them.

One thing is for sure, I've learned a hell of a lot.

Roads88

Ok, got the wrench but my ^$^$(** back is screwed up. Hoping to swap out the distributor this week end. Keeping fingers crossed.


Getting old blows.

Roads88

well...Swapped out the distributor and no change.


Time to give the car to a pro and see what the issue is

Its going in the 8th of next month. I'l keep you posted.