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Unplug the the O2 sensor and car runs smoothly?

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No . . . it just started happening the last couple of times I drove it to work. The first time I thought my TPS maybe was actually out of adjustment. This time I know it wasn't though.
 
Well I replaced the TPS . . . and so far, no code 22, so thats good. My idle is still really rough and almost seems to be getting worse.

Since I replaced the TPS, I haven't been able to get the IAC to hold a setting. Even when I think it is set and I watch the computer, it will fluctuate between say 21-27.

Then when I turn the car off and turn it back on the number will be WAY out there say around 80 or sometimes worse. Or sometimes way down, almost to zero. I have tried cleaning the IAC, but it makes no difference.

Things I have tried so far:
--Took the EGR off and cleaned that (though it really wasn't dirty) and replaced the vacuum line going to it.
--I tried unplugging that MAF because I read in an old post that if you unplug the MAF and the rough idle goes away, you have a bad MAF. Well, I tried it, and my idle just got much worse.
--Checked the resistance between coilpack towers. They were 13.98, 13.85, and 13.81.
--Checked all the grounds I could find
--Replaced TPS (see above)
--Replaced cap on vaccuum block
--Verified the PCV valve is working properly and that there are no obstructions in the line
--Verified the battery is fully charged

MAF readings are still 7-8 at idle.

I haven't checked the plugs or wires yet . . . that is next on the list, once the car cools down. What should the resistance of the plug wires be?

My headlights and interior lights will sometimes pulse, but I don't detect any fluctuation in voltage coming from the alternator. Could this be related to my current problem?

Thanks for the patience.
 
84GNTTYPE said:
Since I replaced the TPS, I haven't been able to get the IAC to hold a setting. Even when I think it is set and I watch the computer, it will fluctuate between say 21-27.
IAC numbers should fluctuate. Numbers look good.

84GNTTYPE said:
Then when I turn the car off and turn it back on the number will be WAY out there say around 80 or sometimes worse. Or sometimes way down, almost to zero. I have tried cleaning the IAC, but it makes no difference.
Numbers will start high on the IAC and settle down as you start the car and let it idle. Be sure to drive the car a bit after you reset the ECM and IAC/TPS. Then reheck it.

84GNTTYPE said:
Things I have tried so far:
--Checked the resistance between coilpack towers. They were 13.98, 13.85, and 13.81. MAF readings are still 7-8 at idle.

Coil resistance seems too high. It will go up when the coil gets warm though. What is the resistance cold? Should be around 11.5K
MAF readings are high as well. Could be a function of the TPS/IAC adjustment. You are looking for around 4-5 @ idle. What is the idle RPM?

84GNTTYPE said:
I haven't checked the plugs or wires yet . . . that is next on the list, once the car cools down. What should the resistance of the plug wires be?

My headlights and interior lights will sometimes pulse, but I don't detect any fluctuation in voltage coming from the alternator. Could this be related to my current problem?

You can have the wires check out good but that does not mean they are ok when they get hot. Easier to replace them and the plugs as well. Coilpack still may be the issue with the spark.

Pulsing headlight is not a good thing. Something is possibly cutting off. Split second cut off. Did you verify the ECM voltage?

Did you verify the grounds on the inner fender?
Did you verify the alternator output on the car?
 
Voltage to ECM:

Key off: 12.38
Key on (but not running): 12.25
Running: 14.92-15.10 (continuously fluctuating)


Voltage out of alternator: 15.15-15.31 (continuously fluctuating)

After I checked the ECM and alternator I took it for a drive. I noticed that when I idle in "drive" the pulsing of the lights seems to match the stumbling of th engine pretty closely. Is it normal for the voltage coming from the alternator to fluctuate continuously like my numbers? I know its not a large range, but is that enough to cause a problem?

I did check the fender grounds, they were fine.

Forgot to check the coilpack cold . . . will have to do that tomorrow.

Checked the resistance of the plug wires just for the heck of it. About two year old Magnecores. Resistances were 3200, 3600, 4200, 4600, and 5900.

Thanks.
 
Voltage looks ok. Fluctuation is fine. You will always get that.

Sounds like an electrical miss. You may want to change the plugs. When you remove them, make sure they are all the same color and dry. How many miles are on the plugs? If that does not help, change the wires on the passenger side.

Did you verify the O2 ground wire to the ECM also?
Connectors at ECM clean?
Are you using an exhaust gasket?
Ground connector on firewall ok?
Is the inside of the ignition module hard or soft?
What is the O2 reading when you disconnect it?
 
I just resolved my rough idle problem and you will never believe it. I blew out one of the screws holding the turbo onto the intake which caused a vacuum leak. Take a can of carb cleaner and spray around the base of the turbo to the intake. Any change in idle will point you to the leak. This method works on all vacuum lines. Brad
 
Had the alternator rebuilt, the voltage regulator was bad. No more pulsing headlights, but it still runs the same.

Coilpack resistance, when cold, is 13.12, 12.99, 12.92.

Ground on firewall is good. Do you mean header gaskets? If so, yes I have copper gaskets.

When disconnected, the O2 readings stay within about 100 of 446.

I plan to take a look at the plugs tomorrow.

What do you mean by the inside of the ignition module? Sorry for the easy question.

Can most shops check my coil pack and ignition module, or do they need a special tool?

Thanks.
 
84GNTTYPE said:
Coilpack resistance, when cold, is 13.12, 12.99, 12.92.

When disconnected, the O2 readings stay within about 100 of 446.
I plan to take a look at the plugs tomorrow.

What do you mean by the inside of the ignition module? Sorry for the easy question.

Can most shops check my coil pack and ignition module, or do they need a special tool?

Your Coil pack resistance seems to be on the high side.
You should be looking for around the 11-13K. You may have a "weak coil".
Do you know anyone yo can swap it with to verify?

If you remove the coilpack, you' will notice it consists of 2 parts. The bottom section is the ignition module. When you seperate the two, you'll see that the electronics of the ignition section is "sealed". If the seal material is soft or mushy, it is bad.

Many opinions on coil pack testing. There is a coil pack tester and some swear by it, other won't. IMHO, the real test is on the track/road, but the tester gets you close.

Do you still have the code 22?
Can't remember sorry. Any other codes?

Now that you tried everything else, you may want to review the ECM and the O2 sensor wires from the ECM. It may be defective.
Hey, at least you know everything else is good or fixed thus far right? :D
You are close!
 
Checked the ignition module, the seal material feels kind of like a harder rubber. It's not mushy really, but it's not rock hard either. Hard to quantify I guess.

No I don't know anyone else with a TR in my area.

No code 22 anymore that I can tell. I haven't had it out lately for more than a 10 minute ride. Nope, no other codes.

Will look into the ECM and O2 sensor a little more closely.

Couldn't find my 3/8 swivel, so I will check the plugs as soon as I find it, or get a new one.

Thanks.
 
I don't detect any stumble other than idling or the first couple times I take off after starting it . . . like leaving my parking stall and then leaving the stop sign at the parking lot.

Checked the plugs tonight. They all seem to be burning fine (they're white). There is some carbon build-up around the inner edge of the barrel of the plug.

Checked the O2 sensor wires at the ECM. I checked the voltage of the O2 ground. It was 0 with the key off. When I turned the key on it showed -0.00. Not sure what the negative means? With it running it showed -0.02.

Where does the O2 ground go to?

Unplugged the O2 sensor tonight when I was done to make sure it was still doing the same thing . . . and sure enough. I unplugged the sensor and it smoothened right out.

I read something in the GM Chassis manual that the a/c clutch and power steering switch effect idle quality too? There wasn't much info on the topic, was wondering if anyone else has ever heard of that?

I have a working ECM on the way. I just have to pull my chip and Calpack from my ECM and put them in this one. I also have a MAF coming.
 
84GNTTYPE said:
Checked the O2 sensor wires at the ECM. I checked the voltage of the O2 ground. It was 0 with the key off. When I turned the key on it showed -0.00. Not sure what the negative means? With it running it showed -0.02. ........... Where does the O2 ground go to?
The meter goes neg because it is in the 3 decimal negative area and will show -0.00. For the sake of this experiment to “Zero”.
I belief the ground goes to the front of the engine.


84GNTTYPE said:
Unplugged the O2 sensor tonight when I was done to make sure it was still doing the same thing . . . and sure enough. I unplugged the sensor and it smoothened right out. ………… I have a working ECM on the way. …… I also have a MAF coming.
Read somewhere it could be the MAF.

84GNTTYPE said:
I read something in the GM Chassis manual that the a/c clutch and power steering switch effect idle quality too? There wasn't much info on the topic, was wondering if anyone else has ever heard of that?
The added load on the engine of the AC and power steering will effect the idle but the ECM should adjust through the IAC. The issue here is still your O2 CC. Hopefully the ground check, MAF and ECM swap will fix this.
 
Looked at the ignition module again tonight and got a second opinion (from my Dad) about whether it's soft or hard. He said definitely soft. I have trouble with subjective things like that.

We're both curious about the reasoning behind a "soft" seal on the ignition module meaning that the module is bad? I know you can't get hot-air ignition modules or coilpacks anymore . . . so what is my best option for converting it? I've seen that they can be easily converted to the 87 TR type and I also saw an article on gnttype.org about converting them to a modern Type II ignition module and coilpack. Thoughts?

I'm pretty much at a stand still now until either the ECM and MAF get here (hopefully less than a week) or a decide to do the ignition module and coilpack.

Thanks for your time.
 
have you checked for a short in the wiring to the o2 sensor somewere under the split loom? my old GN had a coroded wire inside the insulation of one of the o2 wires that caused a simular problem that was intermitent.
 
highboost said:
have you checked for a short in the wiring to the o2 sensor somewere under the split loom? my old GN had a coroded wire inside the insulation of one of the o2 wires that caused a simular problem that was intermitent.

Not sure what you mean by the "split loom". Thanks.
 
Also . . . I did a search on here and found more pics and a description of what a "soft" ignition module looked like. The one I saw and the description I read was that it gets very gooey and sticky. Mine is not like that. It is definitely not hard, but it is still a solid and does not stick to things. Hope that makes sense.

Thanks.
 
Mine ended up being the ecm. You about have to have two of everything to be able to swap things out. (I just happened to have an 87 that I was rebuilding, so I converted to the 87 ecm and ended up using quite a few parts off of it) You can get the conversion stuff for the 87 coil from caspers, I don't think it cost too much. They have an adapter plate and little wiring harness adapter to be able to plug in. (Easy swap)
Good luck.
 
Put in the different ECM tonight . . . still runs the same. I didn't have a chance to drive it, so I just idled it for awhile . . . is this sufficient? The MAF I got doesn't fit right, I'm not sure if is for an 87 or what.

I'm not sure what I'm going to do next. Prob try and get ahold of a MAF. I hate to just keep buying things hoping it will fix it, but I'm not sure if there is another option with this car.

I was thinking I should try and find what the ECM's response is to a Code 13 (open O2 circuit). If I know what the ECM is doing, maybe I can figure out why it runs better when I do it. Gonna start a new thread for that.

Thanks.
 
Stopped and talked to my mechanic tonight. He said it definitely sounds like a fuel problem.

I replaced the fuel filter and swapped in a different fpr I had. Still no change.

I'm going to take it down tomorrow after work and let him check it out a little.
 
The mechanic says the problem is the MAF sensor. I ordered one today. Hopefully that will fix it.
 
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