What's up with this? I've been getting this code for a couple of days now. When I start the engine (cold start), it's fine and then when I drive for just a couple of blocks, I notice the engine losing a lot of power and then the light comes on. Code 33 is the MAF high voltage/low vaccum. What's causing this??
Thanks, Rick

 

Check all your intake ducting for leaks first. Then check all your electrical connections for corrosion/good contact. Swap your MAF burnoff and power relays, (they are the same) and see if you still get that code. Also, don't forget to check your TPS voltage, it should be 0.54vdc +/- .075v. One of those should do the trick, if not, try tapping on the MAF with something like a screwdriver handle while you have the code... if it starts to run better, then it's the sensor itself that needs to be replaced.

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Kevin Irving
85 Trans Am WS-6, 305 TPI, custom burned '86 PROM with '87 "165"ECM, Accel Supercoil & 8.8 Wires, MSD 6AL, Aluminum Driveshaft, TB Coolant Bypass, Ported Plenum, Modified MAF, Syclone Fuel Pump, JET Airfoil

15.556 @ 86.65mph, Nov 10, 2000.... I know it sucks.. but it will get better!

http://www.geocities.com/transam85tpi/

 

Hopefully I come accross a SD system and get rid of the stupid MAF.

 

Hey you should of asked me... Its the wires going to the relays on the firewall behind the booster. They always get ****ed up and touch each other and throw that code. My car was doing the same thing a while back.

 

Vacuum leak or TPS bad or out of whack are the most common causes.

 

This is absolutly a electrical problem not a vacuum one.

 

Not always.

 

Im not arguing. I am just saying that in this situation it is. The car will run fine sitting, if its open loop or closed loop, But as soon as you drive and things start moving the wires rub and the car runs like a 6000lb trailer was just attatched to it. AS soon as it throws a code 33. This is my knowledge with maf cars. If it was speed density I would have no idea, and am admiting to it.
Vacuum leaks are much easier to detect and dont just hit the car and throw a code.
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87z 383,afr 190's, crane hyd roller(224/230-.509/.528,112 sep),Ported and polished mini ram, 30lb inj, 3.42 gears, strange 12 bolt, tremec 5spd, , 1,3/4" slp headers.
"Just remember children, no man can beat you once youv'e found the cliterous." 'chef'

[This message has been edited by 87Z-ya (edited February 14, 2001).]

 

Well, my 86 TA was throwing a code about 2 minutes after I started it up in the morning. The cause was the pipe I was using in place of the stupid factory airbox had gotten too hot at some point and melted, causing a vacuum leak between it and the clamp I was using, upstream of the MAF. Replaced the pipe, no more code 33.
My 85 TA broke a tranny mount at around 30,000 miles. It threw a code 33 as well at the same time. What happened was the alternator was able to move enough to bore a hole in same stupid factory airbox that I replaced on my 86, and caused a major vacuum leak upstream of the MAF. Duct taped the box closed, no more code 33.
Yes, it can be vacuum.

A larger than stock cam and a high TPS setting can also cause this. That is something that can only be remedied by setting the TPS low or changing a table in the PROM.

 

Guys- Check my post TPI not running right. Could this be the same thing???

 

Max Im sure you can have a code 33 and the cause be a vacuum leak. But I doubt thats the case here. When your cars threw the code did they start running like 4cylinders? My car had the vacuum line pop off the canister and threw code 33 but didnt really run any worst. Lately When it throws it it runs like ****, I turn it off jiggle the wires to the maf relay and it goes away. Im not worried about fixing it right because all the factory ecm bs is gone. hahahahah. Im pretty sure raptors case is the same as mine.

 

I think these 33 errors are the hardest ones to track down...


I have 3 relays on my car that are the same part number as the MAF power and burnoff relays. What are the locations for these?
I need to order up some wiring diagrams...

I have a hard code 33 that won't clear on a KOEOff test with a snap-on scanner. I swapped the relays around and there is no change, so I would really like to know which relays are which.
The car runs like crap, and this is with a new Wells MAF, new AFPR and diaphram. The check engine light sometimes goes off after 10 minutes or so, but it still has an erratic idle and noticable lack of power.
With a vacuum gauge hooked up to the brake booster line, I pull 15", so this seems normal. I have aluminum zz4 heads under my stock intake, so the egr is effectively disconnected.

All my air intake is in fine shape - it is a pretty new K&N setup.
I am about ready to bite the bullet and order a new TPS, IAC, MAT and a new set of Accel 24# injectors - everything else has 122K mile on it anyway...

Spring is coming, and I wanna be able to cruise!

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89 Firebird Formula
WS6 package,ZZ4 Crate engine
SLP 58MM TB, Edelbrock TES Headers
Random Tech 3" cat, SLP 3" stainless exhaust
9 bolt rear, Hotchiss swing arms, Lakewood panhard rod
Corvette 2/4 servo, kevlar band, full poly rear.
Centerline 16x8 rims, B.F Goodrich drag radials

 

I have heard and read about non-Bosch MAFs having problems and using a Bosch MAF solved it. Whether or not that is your problem, I dont know. I kinda doubt it, but theres always the possibility.
What cam is in the car? And wheres the TPS at?

 

It's a zz4 crate, so the cam is a 474 lift on the intake, 510 on the exhaust - 208/221 duration. I have the tps set at .56, set using the snap-on (I think it's the 3500) scanner.

I hate to throw away $130 on the Wells, but OTOH, partszoneonline or gmparts has a real Bosch one for $200...
I still need to really spend some time on this before I go blowing money on parts, but the weather sucks.
I also ordered Tunercat and I have an eprom programmer, so I am also going to play around with the MAF tables and stuff - I am still running a stock chip, and that zz4 is pretty heavily modded, so I really need to tune the chip.


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89 Firebird Formula
WS6 package,ZZ4 Crate engine
SLP 58MM TB, Edelbrock TES Headers
Random Tech 3" cat, SLP 3" stainless exhaust
9 bolt rear, Hotchiss swing arms, Lakewood panhard rod
Corvette 2/4 servo, kevlar band, full poly rear.
Centerline 16x8 rims, B.F Goodrich drag radials

 

lee heres some basic bs from a good book. Turn ignition on and check voltage on the dark green wire at the maf. If its 5 volts, check the purple wire and see if there is 12 volts. If there is 12 volts check the ground. If the ground is bad its probably the maf. If you dont get the 5v at green check b12 on the ecm and see if it has 5v volts. If it does then the wire has a short. If there isnt 12v at the purple wire, put 12v to g on the aldl. If there is now 12v at the purple wire @ the maf then the 3 prong oil sending unit is bad. If there isnt 12v at the purple wire then the maf power relay or wires are bad. The burnoff relay is the middle one from the factory, The 2 outers are fp and maf power, dont know which is which.

 

Who makes non-bosche MAFs for our cars. Delco MAFs read by frequency and Bosches use voltage.


I had the same prob. It was a PIA to find because everything (moving through the flowcharts) checked out. Here it was the wiring harness to the MAF. The pins were spread out too much causing an open in the CKT.

[This message has been edited by JoelOl75 (edited February 16, 2001).]

 

That's for a Z right? All the ones on my birds are the two outer ones on the firewall on the driver's side.


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"Perfection is a trifle dull. It is not the least of life’s ironies that this, which we all aim at, is better not quite achieved."

-W. Somerset Maugham

 

87Z-ya wrote:
lee heres some basic bs from a good book. Turn ignition on and check voltage on the dark green wire at the maf. If its 5 volts, check the purple wire and see if there is 12 volts. If there is 12 volts check the ground. If the ground is bad its probably the maf. If you dont get the 5v at green check b12 on the ecm and see if it has 5v volts. If it does then the wire has a short. If there isnt 12v at the purple wire, put 12v to g on the aldl. If there is now 12v at the purple wire @ the maf then the 3 prong oil sending unit is bad. If there isnt 12v at the purple wire then the maf power relay or wires are bad. The burnoff relay is the middle one from the factory, The 2 outers are fp and maf power, dont know which is which.

Thanks 87z. I had already done most of this using a snap on scan tool and graphing waveform meter. That's why I was so frustrated. I was over at my local auto recycler today looking for some stuff for my New Yorker (I need an Infinity CD player head if anybody has one ), and just for the hell of it, I also picked up a new ECM for the bird just for a spare. I swapped memcals, hooked it up and started it, with predictably no change in the way it runs. I had already probed the wires at the MAF using an insulation piercing probe so I knew the voltages were correct and present. I gave it the wigle test and there was no change, but when I pushed the connector into the socket to make sure it was firmly seated, the car stalled. Pulled the connector, blew all the dielectric grease out, and one of the female displacement connectors was bent out of position, giving a high resistance connection - if there was any connection at all. I used a tiny dentist pick to bend it back in the original position, fired her up and... it ran! Just goes to show that it's the stupid things that get ya!



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89 Firebird Formula
WS6 package,ZZ4 Crate engine
SLP 58MM TB, Edelbrock TES Headers
Random Tech 3" cat, SLP 3" stainless exhaust
9 bolt rear, Hotchiss swing arms, Lakewood panhard rod
Corvette 2/4 servo, kevlar band, full poly rear.
Centerline 16x8 rims, B.F Goodrich drag radials

 

If your MAF went to lunch make me a resonable offer for a used but fully functional ported MAF (E-mail)

 

Had a feeling it was probably electrical.