Code 33 -- What's the most common cause?
#1
Burning Brakes
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St. Jude Donor '05
Code 33 -- What's the most common cause?
My 87 started radically hunting for idle RPM the other day. I had just washed it, no engine cleaning, and when I went to put it away; big trouble!
The engine RPM cycled up and down and the car stalled very easily when I tried to take off gently. I had to goose it a couple of times just to get it in the garage.
Last night I started it again and the same thing happened. Hello Mr. paperclip. Code 33 -- one of the MAF sensor codes.
I've got the Manual, the V-O-M and the test light and all, but I am kinda slow with this kind of work. Is there a very common cause for this code? (There are no mods on the car to speak of, and the wiring seems to be in good shape.)
Also, if I have to start probing the harness; what's the right way to do that if the weather-pak connectors have to stay connected?
The engine RPM cycled up and down and the car stalled very easily when I tried to take off gently. I had to goose it a couple of times just to get it in the garage.
Last night I started it again and the same thing happened. Hello Mr. paperclip. Code 33 -- one of the MAF sensor codes.
I've got the Manual, the V-O-M and the test light and all, but I am kinda slow with this kind of work. Is there a very common cause for this code? (There are no mods on the car to speak of, and the wiring seems to be in good shape.)
Also, if I have to start probing the harness; what's the right way to do that if the weather-pak connectors have to stay connected?
Last edited by Rich Silvestris; 08-25-2005 at 08:39 AM.
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Burning Brakes
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St. Jude Donor '05
Thanks, guys. I waited to see if there would be a tie breaker here, but no luck. The relays are dirt cheap, so I will probably replace them for starters. If the problem persists, I'll do the real work. I sure hope it's not the MAF $en$or!
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Always always always replace relays and check connections first, they are the usual cause.
Then its the MAF.
Then its the MAF.
#6
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Code 33 = High gms of air/Sec, or >45 gms/sec. Either MAF is bad or the MAF power relay and/or MAF burn off relays are bad. A burn off signal while the car is running can also result in a code 33, but that is intermittant, meaning the SES light will go out after 20 seconds. Good luck, and time to spend $$$ if indeed your MAF sensor is bad.
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Originally Posted by Rich Silvestris
The relays are dirt cheap, so I will probably replace them for starters. If the problem persists, I'll do the real work. I sure hope it's not the MAF $en$or!
RACE ON!!!
#8
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St. Jude Donor '05
Originally Posted by CFI-EFI
Cheap or not, why throw miney at the problem, blindly. CHECK the relays before youpay to replace possibly good parts. Things would go more smoothly if you followed the trouble shooting charts in your factory service manual. The manual isn't cheap, but once it is among your other "TOOLS" it will continue to advise on subsequent projects. The money spent to replace a good relay is gone.
RACE ON!!!
RACE ON!!!
I wanna minimize my down time, so I can ........RACE ON!
#9
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Originally Posted by Rich Silvestris
$30 down the drain and 15 minutes wasted if it doesn't work;
Originally Posted by Rich Silvestris
Then there's the fact that if the diagnosis points to a relay, I'd have to get it the next day anyway; so it would be longer before I could get to drive the car again.
I wanna minimize my down time, so I can ........RACE ON!
I wanna minimize my down time, so I can ........RACE ON!
RACE ON!!!
#10
Team Owner
My biggest concern with the mid-80s C4s is that the wiring SUCKS.
You see, in 1990/1, SAE mandated a change in the composition of the wire. This improved the insulation a ton. If you look closely and many of the weatherpacks on a higher mileage C4, the wire will start to pull back, the insulation gets hard and brittle, it can and will crack, and is prone to abrasive failures - it chaffes.
Check the harness ends, check where the relays mount. You name it.
Something else I have observed... if the relays fail, they can damage the MAF. It's not likely, but it can happen.
Also, if that is the original MAF, it is a "early design". They were not as durable as the later design MAFs. When you replace, all GM MAFs are built to the new standard, and I am pretty sure that all the aftermarket are, too.
However, when these things reach this kinda price point, it's best to make sure everything around them is ok.
You see, in 1990/1, SAE mandated a change in the composition of the wire. This improved the insulation a ton. If you look closely and many of the weatherpacks on a higher mileage C4, the wire will start to pull back, the insulation gets hard and brittle, it can and will crack, and is prone to abrasive failures - it chaffes.
Check the harness ends, check where the relays mount. You name it.
Something else I have observed... if the relays fail, they can damage the MAF. It's not likely, but it can happen.
Also, if that is the original MAF, it is a "early design". They were not as durable as the later design MAFs. When you replace, all GM MAFs are built to the new standard, and I am pretty sure that all the aftermarket are, too.
However, when these things reach this kinda price point, it's best to make sure everything around them is ok.
#11
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St. Jude Donor '05
Results!!
Update: I took today off 'cause the bride and I are headed for a weekend away. I did my weekend chores last night and this AM, and I took the time to throw in the relays. Then I drove the car on a couple of errands. No SES and no hiccups!
Thanks for all the input guys. The manual is great, but it was written in 87. The guys on the forum are today's manual to me.
Thanks for all the input guys. The manual is great, but it was written in 87. The guys on the forum are today's manual to me.
Last edited by Rich Silvestris; 08-26-2005 at 12:56 PM.