86IROC305

I've been having problems with Code 33 for about 3 months now...It all started when I damaged my old Maf sensor when removing the screens(costly error ), When I was doing that I accidentally broke the element and had to replace it with a Cardone unit. Then next day the check engine gave a code 33...I thought it was defective so I took it back and replaced it, same problem. I cleaned out the connectors and replaced all replays(MAF Power and Burnoff)and had no problems for about 2 weeks. I was driving it then and the check engine light came on and started running like sh*t. I traced down for vacume leaks and found the intake was leaking so I replaced the gasket(and did a cam swap also).... I though this had fixed the prob, but after 3 weeks of perfect driving the light came on I was baffeled (and pissed off). I then checked the TPS no problem there and replaced the MAF connector with a better one I found at the junk yark (cleaned it with some electrical cleaner spray) still, same problem. What really gets me is that it can run fine for days and then all of a sudden the light comes on and starts running sh*tty. Could this be a bad PROM or ECM I'm about out of ideas and this has become a everday problem now. Any ideas?

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86 TPI 305 Iroc-Z
Accel HEI Super Coil
Flowmaster
K&N Filters
Comp Cams High Energy 12-210-2

Christos

Odd! I also own a 1986 IROC TPI 305, and i am having the same problem. my car won't even idle! it backfires when i accelerate, etc.

replaced the MAF with a new borg-warner, but it ran worse. i took it out and put the old MAF back in. still runs poorly, but it runs a bit better.

code 33. arrrgh. after i replaced the MAF, i got a code 44! when i reset the ECU and put back in the old MAF, it hasn't given me a code 33 again.

it did give me a code 42 tho, after i disconnected the ECU (or what i thought was the ecu) to check the timing.

who knows. i have heard there is a ECU replacement for our model/year IROC. im waiting for next paycheck to pick up a new ECU and see if it fixes the problem.

good luck on yours!

Grumpy

It's time consuming and a pain to do, but the best answer is switching over to a 90-92 ECM. The MAP system takes the quess work, and hassle out of the MAF systems. Then if you really want a car that runs right get into doing some of your own prom work.
Grumpy http://www.gnttype.org/carofthemonth...omdetails.html

86IROC305

There are a few more things I forgot to mention..... My TPS voltage is set at .56v and will steadily increase until 3.20v, It will not go past 3.2v though even by manually opening it to wide open throttle. The code 33 will only come on when the car is moving and not at idle or when I rev up my motor. I can also hear what sounds like my fuel pump cutting out sometimes...Could this have anything to do with it? As far as the connection to the MAF and wiring is concerned, I tryed messing with the MAF plug with the engine running and no code. The wiring to the ECM looks good and is not next to any plug wires (they are also good). My MAF unit is a reman Cardone (from AutoZone) and I'm not completly sure that that isn't the reason why I'm getting a code 33. Well the next thing I'm gonna try is getting a new TPS, because if I've read correctly from other post, it should be around 4.5 or so at WOT. Any suggestions ?

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86 TPI 305 Iroc-Z
Accel HEI Super Coil
Flowmaster
K&N Filters
Comp Cams High Energy 12-210-2

gta324

If your TPS isnt working correct check/change it. The ECM uses data from the TPS and MAF if they doesent "mach" it probably throws a code......

Make sure you have the right input to the TPS.....

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GTA -89:Free flow muffler,dual 3" HF cats, Edelbrock headers, Vette heads, 1.52 RR 7/16, ZZ-9 cam, Big Mouth, AS&M LTB, ported plenum, 52 TB, MSD 6AL, TPIS level V prom, Mod .MAF, Superior shift-kit and some minor mods. and more to come!
http://www.itv.se/tacs/members_cars/m279/m279.html (Swedish Trans Am Club)

travsirocz

did you check the maf relay on the driverside firewall. that will throw it too.

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1987 Camaro Iroc-Z Z-28 with a TPI 5.7
-Ram Air,K&N Filterchargers, Gutted Mass
Airflow Sensor, Throttle Body Airfoil,
Edelbrock TES Headers and Y pipe, Gutted
Cat, 3 inch exhaust, Flowmaster
-Hypertech Thermomaster Chip, 160 deg Stat,
Adjustable Fuel Pressure Regulator
set at 50 psi, MSD Cap, MSD 8.5mm wires,
Accel Coil, MSD 6AL Ignition Box, Accel
Plugs
-Richmond 3.73 Gears, B&M Transpak,
B&M Rachet Shifter, Energy Suspension
Products
-Fiberglass Cowl Induction Hood,
Purple Neon License Plate Frame,
16X8 Rims with BFG 245 50's,
Pioneer Deck, 2 JL 12's in a Q-Logic
Box with a 300 Watt amp

What you can put between your ears,
no one can take away.

86IROC305

Well I took an old spare original MAF sensor that one of my friends gave me(not sure if it was good or not) and hooked it up... exact same problem, so I'm thinking of getting a new TPS sensor and checking the relay at the firewall (I replaced it about 2 months ago and it could have gone out again). Since I don't have access to a Diacom, I'd rather spend the money on the TPS($40) and relay($10) then paying someone at least that much to tell me that was my problem. I just need to get it fixed soon because it's really getting annoying

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86 TPI 305 Iroc-Z
700R4 (rebuilt)
Accel HEI Super Coil
Flowmaster
K&N Filters
Comp Cams High Energy H268

87Z-ya

iTrader: (1)

Check the connectors going into the 3 relays at the firewall. The wires going into the connectors tend to loose the sheathing and touch each other.

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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.

86IROC305

Thanks for the advice...I haven't had a chance to check, but I bet that's what's happening... The connections to the relays looked a little "melted" when I replaced them about 2 months ago. They really wern't all that bad then, but that is something I've overlooked recently.

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86 TPI 305 Iroc-Z
700R4 (rebuilt)
3.42 Posi
Accel HEI SuperCoil
Flowmaster
K&N Filters
Comp Cams High Energy H268

formuladave

I've had on and off problems with Code 33 for the last year. If you have a BBK aftermarket throttle body, check to make sure the phillips head TB throttle shaft screw is not contacting the TP Sensor arm. That is what was going on with mine (discovered it while zero-ing TP sensor -would never return to .54V I set it at). Removed the sensor, ground down the screw a few mms (dremel w/sanding roll)and freed up the sensor arm. No more code 33s. Frustrating, but hope it helps someone else avoid the same. Good luck.

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Dave
87 Formula 350/auto
Flowmaster Cat Back
SLP Performance Y-Pipe
52 mm BBK Throttle Body w/airfoil
SLP Cold Air Induction
Ported Plenum
Accel 300+ Ignition
Adj. FPR (44 psi)
Hypertech PROM
Hotchkiss STB
Global West SFCs
Global West Steering Brace
Jamex Springs

irocz

if you're only getting 3.20v from the tps, the computer is going to throw a maf code. it looks at the tps and thinks you're at about 3/4 throttle then it looks at what the maf is saying (full throttle) and gets confused.

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87 IROC-Z, 5.7, auto, 3.27, leather, !cat, Holley fpr, K&N'S, SLP 1-3/4" Jet-Hot coated headers, SLP .218/.224 .495/.502 cam, Comp 1.5 roller tip rockers, $uperPITAram, Edelbrock lower intake, Holley 52mm tb, Dynomax\Flowmaster catback. Coming Soon(?)- Fasttrack/Accell DFI

1989 Pontiac 20th Anniversary Turbo Trans Am - 161,000 miles, !cat, 9" K&N

deadbird

Assuming you originaly had a Bosch MAF

Clear the codes and run the engine until the engine until the check engine light comes on or are satisfied that it will not.
Since this code indicates that a high voltage signal has been seen on the MAF signal wire, the possibilities are an open in the MAF signal wire between the ECM and the MAF, a bad connection at the ECM, a bad MAF or a problem with the power supply to the MAF.
If the check engine light comes back on, connect a digital voltmeter to the MAF output wire, dark green(CKT 998) at the MAF. Turn the ignition switch on. If the voltage is close to zero, then check the voltage at terminal B12 of the ECM. If the voltage at the terminal B12 is 5volts, repair the open circuit in the dark green wire(CKT998) which runs from the ECM to the MAF.

If the voltage at terminal B12 is 0, inspect the connections the ECM. If they are good replace the ECM.

When checking the voltage at the dark green signal wire of the MAF, if the voltage is 5v, check the connection to the MAF. If the connection if good, check for a 12v power supply to the MAF on the purple wire with the engine running. If there is 12v, check the ground at terminals A and B of the MAF. If the ground is ok, replace the MAF.

If there was zero volts on the purple wire at the MAF, apply 12v to terminal G of the ALCL connector. If 12v now appears on the purple wire, check the fuel pump fuse. If the fuse is ok, replace the oil-pressure sending unit. If the purple wire still does not have 12v on it when power is applied to terminal G of the ALCL, check the wiring to the MAF power relay. If the wiring is good, replace the power relay.

- Quoteth the repair and modify chevrolet fuel injection book

hope that helps


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Da Boid

- 4 out of 5 people think the 5th is an idiot


[This message has been edited by deadbird (edited December 05, 2000).]

86IROC305

I just went over all the connections for the MAF and they all checked out perfect (except for the purple wire ready 14v instead of 12v), so next I double checked my TPS to a spare one I got with another TB and it read 5v at WOT and mine only got up to 3.5v at max. I replaced the spare TPS with mine and drove it for a good 30 minutes and NO PROBLEMS Also my car pulls more at WOT than it did before so I'm 99.9% sure the problem is solved. I just wanted to say thanks to all for the suggestions and BTW who sells the "How to repair and modify chevrolet fuel injection book" I sure I'll need something else from it later down the line.....

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86 TPI 305 Iroc-Z
700R4 (rebuilt)
3.42 Posi
Accel HEI SuperCoil
Flowmaster
K&N Filters
Comp Cams High Energy H268

deadbird

http://shop.barnesandnoble.com/books...P3BWU0&sourcei d =00013809151992613097&bfdate=12%2D07%2D2000+02%3A06%3A00

Barnes & Noble

It's a good book to have

[This message has been edited by deadbird (edited December 07, 2000).]