Error code 42 (EST circuit)

[Eskareon]

Greetings.

The car is a 1992 Buick Park Avenue, base model. It has a lovely 173,000 miles on it and I am not the first owner. About a month and half ago, I was driving along the road and the engine died. No hesistation or stalling, it simply cut off and a few of the dash lights flipped on (red LED for battery, check engine, maybe another). I got the car off the road, turned everything off, and restarted the engine. It ran fine after that.

About a week or so later, it did it again, but this time it stuttered a bit first when I was applying gas and then cut off. A month goes by, nothing. Then, yesterday evening, the engine started to stutter as soon as I turned the car on. I left it alone and figured I'd check it out today. It ran fine this morning, but this afternoon did the old insta-die and shut down on me. Power is still present and there are no real surprising sounds - the engine simply dies and I coast down the road, praying I still have some pressure in my brake lines.

I ran a paper clip from A and B on the... switch thing... and got the code 42. Browsed through my Haynes, and it described the ECM as taking information from both the crankshaft sensor and the camshaft sensor and then sends instructions to the EST to set the proper spark timing.

So, how do I go about fixing this problem? It sounds like it still could be a variety of things - camshaft/crankshaft sensors, or the ECM, or the EST? If it's any help, the tachometer became "unreliable" a few months ago - it'll randomly jump up to 6000 or so RPM when I'm driving, and sometimes will show me an idle speed of 3000. The engine is, of course, not jumping around like that, but the tach seems to think so. The oil pressure gauge has just recently started to do the same thing.

Suggestions?

[rotaran]

This is what i found about code 42:

"Electronic Spark Timing -
Check for faulty connections, or a faulty ignition module"

That was also my thought.

Good luck.

Mike

[Eskareon]

Figured I'd update. Actually, I fixed the problem about 3 weeks ago. It turned out to be the ignition module after all, bought a new one for 80 bucks, installed it, good to go.

Of course, now problems are arising again. The car is shuddering whenever I accelerate. Seems almost like its choking and acceleration is nil. If I just drive slowly and accelerate slowly, I'm fine. But even if I try to "get on" the accelerator a little, it'll accelerate like it's missing a couple cylinders and begin to shake.

Sooo. Time to check the spark plugs, wires, etc. Troubleshooting is ever-so-fun. 174,000 miles out of the car so far, so I guess I can't complain too much.

-E

[volkerc]

[quote=Eskareon]Figured I'd update. Actually, I fixed the problem about 3 weeks ago. It turned out to be the ignition module after all, bought a new one for 80 bucks, installed it, good to go.

Of course, now problems are arising again. The car is shuddering whenever I accelerate. Seems almost like its choking and acceleration is nil. If I just drive slowly and accelerate slowly, I'm fine. But even if I try to "get on" the accelerator a little, it'll accelerate like it's missing a couple cylinders and begin to shake.

Sooo. Time to check the spark plugs, wires, etc. Troubleshooting is ever-so-fun. 174,000 miles out of the car so far, so I guess I can't complain too much.

-E[/QUO
i'd go with the crankshaft sensor.

[Eskareon]

Already replaced that, and the camshaft sensor, before I replaced the ignition module with the first problem set. However, I couldn't for the life of me align the crankshaft sensor just right so it was still rubbing a little bit. Now, it just operates with magnets so I'm assuming a little plastic being rubbed shouldn't change much... tachometer seems to be stable, etc, so I'm hoping it isn't the crank sensor getting blown. Sigh.

[aarcuda]

replace your air cleaner

[96parkaveman]

Hello,
did you ever figure out what the problem was? I don't exactly know when you posted this but I seem to be having the exact same symptoms with my 95 buick park ave Please let me know what the problem turned out to be. I also replace Ignition Module and even coil packs. Car won't even start. But the problem started out like yours. Would run like crap shifting terrible and even being jerky. Then sometimes it would run normal. Now doesn't start. thanks

[Eskareon]

Originally Posted by 96parkaveman

Hello,
did you ever figure out what the problem was? I don't exactly know when you posted this but I seem to be having the exact same symptoms with my 95 buick park ave Please let me know what the problem turned out to be. I also replace Ignition Module and even coil packs. Car won't even start. But the problem started out like yours. Would run like crap shifting terrible and even being jerky. Then sometimes it would run normal. Now doesn't start. thanks

It's been awhile, but if I remember, the ignition module went bad - again. I had replaced it with a new one from AutoZone and less than a year later it tested bad again. So I had gone through a lot of other parts thinking it couldn't be the brand-new ignition module, and I wasted a lot of time and money

If you just replaced the ignition module and coil pack, I'd say definitely check the spark plugs and wires if you haven't already. Other than that... hm... could be a starter. It's really just a shot in the dark, though.