My 87 Iroc is still throwing a code 33. People have told me change relays,MAF. I changed everything they told me but nothing works. Someone told me that if you have an intake leak then it will throw a code 33. Is this true?

 

Yes that is true, any leak on the induction system could throw a MAF code. The ECM calculates that the voltage output from the sensor does not correspond to the signal from the TPS, IAC position, and engine RPM due to the low airflow through the sensor.
Check all duct connections as well as the ducts themself for cracks, and also the plenum and TB bolts.

 

simple question.......but did you reset the computer by disconnecting battery?

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87 z28 bowtie aluminum 420small block dry sump crower lt. wt. knife edged crank oliver lt wt rods brodix track 1's super ram intake slp 1 3/4 headers accel dfi art carr 700 r4 3.42 gears ssm sub frame/ladder bars.....other parts on the way ,soon to be finished!! couple more weeks!!!

 

code 33 is the Maf sensor reading to high, so it would most likely not be seen if you have an intake leak. I have heard many people saying that it was caused by a bad burn off relay so thats something to check out. When does it come on? All the time or only at light throttle?

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355 10:1 , AFR 190 heads, LT4 HOT cam w/ 1.6 roller rockers, complete Superram intake, 58mm BBK TB, 24# injectors, screens out of MAF, MAT relocated, March underdrive pulleys, Streetdampner, Crane HI-6 ignition, 160 thermostat, K&Ns, TES headers(Jet hot coated), Mufflex 4' cat back, B&M shift Kit, 2500 converter, and 3.27s. Chip is custom(doing it myself) Just got a 2 1/2 Harwood and soon to be painted.

 

d@mn 33! is this a summer thing?? as soon as summer came around the TPI board here had twice as many posts.. im having the same problem but one of the wires is coming apart from the relay. ses light comes on when i start probably 50% of the time. it's weird.

 

I had this problem before and the cure was a new MAF. Here is the catch I replaced it with two different ones from Napa auto parts and still got the code 33. I went to the dealership and bought a replacement from them and it fixed the problem. I paid more but no more 33. By the way my light always came on when I would hold a steady throttle. It never came on during acceleration or decrease in.

 

An intake leak significant enough to effect the MAF would probably show up as a code 44 first. Again I would recheck the MAF connections, switch the relays and see if it throws a 36 instead.

Check the intake manifold bolts (especially the center 4) for about 40# torque. Recheck all air connections from the air cleaner to the TB.



...pay particular attention to the air box (#4).. they are bad about cracking right on the seam where you can't see it. Yes, and be sure to unhook your battery for a few before you recheck codes.

 

Yeah, check for vacuum leaks. Anything leaking on the motor side of the mass air meter can cause a false air reading. My code 33 was set from a leaking intake gasket. Changed gasket, everything went back to normal.

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L98, 3.27 9-bolt, Hooker shorty headers, custom 2.5inch Y-pipe, no cat, 3inch 2chamber flowmaster, JET AFPR, Ported MAF, Best ET: 13.86 @100mph. 1.99 60'
17 inch ROH "ZS" wheels. 17x8.5(front) and 17x9.5 (rear). Firestone Firehawk SZ50s. 245/45/zr17s and 275/40/zr17s. T56

On the way... Radar Blue 89 Formula, T56, Ram Jet 430, Ram Air, 17inch ROHs.

 

you guys forgot to mention the TPS sensor.. if its out of specs you can get a code 33.

 

would you maybe have a larger than stock throttle
body bore? 48mm stock, 52 or 58mm aftermarket.
have been seeing a rash of 33's because of larger
bores and cfm ratings....
a custom chip burner can burn that out if
after following all the service procedures
are follwed.
airdeano

 

I've been getting a code 33 lately but its only when I punch the gas. The check engine light flashes and the car bucks a little, and then the light goes off and everything goes back to normal. I dump the codes and 33 is what it gives me. If anyone knows whats going on here it would be appreciated.

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"Though I cruise through the valley of Rice I shall fear no turbo, for torque art with me."
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1985 IROC-Z w/T-tops, 305 out and 350 L98 TPI engine in, Hooker Super Comp Headers, 3" Hooker Super Comp Cat-Back, 3" CatCo Cat, Rebuilt TH700R4 with Shift kit, 3.73 Richmond gears, Auburn differential, Accell SuperCoil, Accell 8.8 racing wires, BBK AFPR, Homemade Ram-Air (thanks to Andris Skulte), MAF screens removed, Dropped A/C, TB coolant bypass, Hurst Dual-Gate Shifter, Air Foil, K&N filters, Holley performance fuel pump, Spohn Subframe Connectors, Re-located Spohn Lower Control arms, and more to come.

 

I agree w/ Ron, check that TPS. The ECM uses MAF vs. TPS% and if they do not equal predetermined values set in the ECM, it condems the MAF. I have fixed a couple of MAF codes after seeing the TPS was out of spec.

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