The Oldsmobile Connection

[88 Coupe]

GM dealer, is always the logical choice.

Norm

[88 Coupe]

myfathersoldsmobile wrote: ........ I bought an O2 sensor,(not from Auto Zone) ........
Why did you buy it? Where, is not important.

Quote: ........ it seems to run a little better ........
Placebo effect?

Quote: ........ the old symptoms still exist .........
Fifty, or so, bucks?

How much beer would that buy?

Quote: ........ I guess I'll check the coil next ........
Good choice.

Norm

[myfathersoldsmobile]

Ok, the latest update. I had my local garage scan the car, (they said it was OBD2??) and they came up with stored codes 131 & 171. The mechanic told me that the MAF sensor was the likely cause of both error codes. I popped the hood to look again at the MAF sensor, planning a replacement. I wiggled it a bit in it's housing, shut the hood and went on my way. The car behaved perfectly immediately after that, and didn't show the symtoms again until much later.
When it stops raining I am going to check that connection and clean it up. If that doesn't permanently cure the problem, I'll get a new MAF sensor. Any other ideas? Thanks!

BTW, 88 Coupe , the O2 sensor was needed anyway, not some placebo flight of fancy, since the head gasket had failed and it was likely very corroded. My suspicions proved correct. The sensor was soon to be junk anyway. :wink:

Jon

[91parkave]

If you have to wiggle the Maf it needs to be replaced, glad to see you found the problem out though,


-marshall

[88 Coupe]

myfathersoldsmobile wrote: ........ since the head gasket had failed and it was likely very corroded ........
Thanks for the clarification.

Norm

[myfathersoldsmobile]

Here is the latest update. I found a MAF sensor at a junkyard and installed it. The problem still persists! Following Norm's advice, I tested the secondary coils and found about 14 ohms in all three tests. Apparently, 8 ohms is the limit. Am I correct that the coils are indeed the problem here? If so, the gold medal goes to Norm. :wink: Please advise.
Also, should I simply grab an ICM from the boneyard rather than buying aftermarket stuff?
Thanks, Jon

[andrewk]

myfathersoldsmobile wrote: Here is the latest update. I found a MAF sensor at a junkyard and installed it. The problem still persists! Following Norm's advice, I tested the secondary coils and found about 14 ohms in all three tests. Apparently, 8 ohms is the limit. Am I correct that the coils are indeed the problem here? If so, the gold medal goes to Norm. :wink: Please advise.
Also, should I simply grab an ICM from the boneyard rather than buying aftermarket stuff?
Thanks, Jon

I have read, not experienced, that some people have problems with the aftermarket ignition offered for the 3800. I also believe most aftermarket ignition stuff is completely overrated, and I would probably buy a good used one. I would take your VOM with you, and when they hand you the part, test it on the spot, before paying for it.

This thread is a good example of what can happen when you think in terms of probability. Luckily for the OP, the only thing he is "out" is an extra MAF sensor.

Andrew

[88 Coupe]

myfathersoldsmobile wrote: ........ the gold medal goes to Norm ........
This is not a competition. To think so, is childish.

On second thought, give it to 91buickman. That is what he is all about.

Quote: ........ should I simply grab an ICM from the boneyard ........
At best you might find one that was replaced just before the car was junked. At worst, it is as old (and has as many miles) as that car, and it is the reason the car was scrapped.

Your choice whether to roll the dice.

Quote: ........ rather than buying aftermarket stuff?
The term "aftermarket" applies to the "names" advertised in car magazines and their "TV Infomercial" equivalents. Accel and MSD are two examples

Refer to my "how much beer" analogy.

OEM (Original Equipment Manufacturers) and OEM replacement quality parts are the most bang for the buck.

Norm

[myfathersoldsmobile]

I'll avoid a lengthy quote to simply say.

the comment about the gold medal and Norm was followed by a wink, normally used to indicate a joke. :wink:
Also there is no risk to looking in the boneyard with a VOM in hand, no dice rolling whatsoever.
I appreciate all the help here. I do wonder about the error codes, though. Are the codes 131 and 171 indeed related to the MAF sensor? Are any of there relevent to coil issues? bear in mind it was the codes that led me to replace the MAF sensor.

[88 Coupe]

myfathersoldsmobile wrote: ........ was followed by a wink, normally used to indicate a joke ........
Wink?

Quote: ........ normally used to indicate a joke ........
I did not see the humor in your statement.

If I was able to see your "wink", would that have made it funny?

Quote: ........ no dice rolling whatsoever ........
Your choice.

Quote: ........ Are the codes 131 and 171 indeed related to the MAF sensor? ........
Possibly. You should see about .5 volts. If it's lower, it's causing a lean mixture.

Vacuum leak is the most likely cause of a lean mixture.

An exhaust leak before the O2 sensor, the O2 itself, EGR, or a restricted fuel filter, can cause a lean mixture.

Malfunctioning coil, wires, plug(s), or lack of compression can cause a misfire. Misfire can cause a lean mixture.

Codes 131 and 171 point to a lean mixture.

Quote: ........ any of them relevant to coil issues? ........
Didn't you test the coil pack?

Did you test the MAF and the O2 sensor before you replaced them? After their installation?

Quote: ........ it was the codes that led me to replace the MAF sensor.
I thought you were following 91buickmans advice,

91parkave wrote: If you have to wiggle the Maf it needs to be replaced, glad to see you found the problem out though ........
and replaced it because it was loose.

Norm

[andrewk]

88Coupe wrote:
Malfunctioning coil, wires, plug(s), or lack of compression can cause a misfire. Misfire can cause a lean mixture.

Wouldn't that cause a rich mixture, as the engine is getting fuel, but not burning it?

[88 Coupe]

andrewk wrote: ........ Wouldn't that cause a rich mixture ........
Not until the next cycle, when the computer compensates for our lean mixture.

Quote: ........ as the engine is getting fuel, but not burning it?
Lack of combustion will not change the mixture, in any way.

Norm

[andrewk]

88 Coupe wrote: andrewk wrote: ........ Wouldn't that cause a rich mixture ........
Not until the next cycle, when the computer compensates for our lean mixture.

Quote: ........ as the engine is getting fuel, but not burning it?
Lack of combustion will not change the mixture, in any way.

I am not sure I follow. If one cylinder is not firing, then there will be unburnt fuel that will make its way down the exhaust, right? And if that happens, won't the mixture perceived by the oxygen sensor be rich, as there is raw fuel there?

At least that is the way I have always understood it, but I could be wrong-

Could you please clarify?

Regards,
Andrew

[88delta88]

There is more oxygen passing through the exhast from a cylinder that does not fire. Oxygen sensors dont measure unburnt fuel, but supply information based on the amount of oxygen passing by it.

[myfathersoldsmobile]

Here is the latest update. I installed a used ICM from the junkyard and the car does fine now, no hesitation either accelerating or at lower RPM's in overdrive. Later yesterday the Check Engine light came on. This morning, there was a rough idle with a Check Engine Light. My first thought was a vacuum leak, so I pulled off the engine cover and found a leak in a lower connection. I replaced that section of vacuum line and the car once again ran fine with no light. I suspect that in the pact few weeks, in addition to the bad coil, this vacuum leak was not enough to light up the Check Engine Light, but probably enough to affect performance.
I will see how she does in the coming week. I appreciate your help in this.

Jon