BTS88IROC

Well I'm getting a code 33 by itself. So far I've replaced both relays, I've swapped out the maf AND ducting for ones that I KNOW are in good condition, I've cleaned the IAC, set the TPS to .57, and set the Idle to about 825rpm. I've cleaned all the connections as best as I could, but all this and still no luck. I'm getting the code 33 everytime. And yes the maf is plugged in and I reset the ECM after every little change. Anyone have any ideas? How did everyone clean the connector thats part of the wiring harness? I couldn't get to those things very well. I didn't know what to clean them with. Thats all I can think of is to clean them better, otherwise I'm clueless.

89BlueTA

You could have a FAULTY ecm or ecn connection, check all your wiring. Also if the tps is not working properly, that could give you a code 33. With everything you have replaced I would guess either a wiring short, bad connection or bad ecm.

Nick

BTS88IROC

Its not the TPS, I've checked it on the scanner and its working good, so thats ruled out. I guess I'll try to clean the connections a little more and then start checking all the wires with a voltmeter or something. Will all the wires be getting power with the car on? I guess I could always swap computers with my other 88 IROC and see if that helps it any. Thanks.

Brandon

Vader

BTS,

If you are getting a '33' it means the MAF is reporting excessive intake air flow, not inadequate flow. Therefore it isn't likely that you have a poor elelctrical connection and undervoltage.

When does the code get set? Does it set immediately on startup or after driving? You should know almost right away, since the MAF parameters are watched closely by the ECM and any MAF flow error code will usually set in 600mS.

I'm wondering about the MAF tables in your "Superchip".

BTS88IROC

Vader,

Thanks for the advice. Screw the supercrap chip! I got rid of that thing long ago. But anyways this isn't even the same car, this is a different 88 IROC that I have. This one that is throwing the code is a L98/auto like the one I have. Or at least was an auto, but it is now a L98/T56 combo. Could the fact that I still have the auto chip in be setting the code? I just started burning my own chips. I have diacom/tunercat/pocketprogrammer setup. I think I'm going to start with the corvette AYPY?, I think thats what it is, I don't remember. Anyways its the 88 corvette L98/T56 chip and then I'll work from there. So is that possibly the problem? Thanks for all the help guys. Later.

Brandon

BTS88IROC

Oh yeah, it happens right on start up. I haven't even been driving this car around since I've been trying to get it fixed up to take with me to wyotech in about 2 weeks. Thanks.

Brandon

Vader

B,

The MAF tables should be the same whether it's an auto or manual (I'm fairly certain). Since you're getting the DTC right away, back probe the MAF connector and read the voltage between the 'C' and 'B' terminals ('B' is analog ground). At an 850 RPM idle you should be getting around 800mV, give or take a bit.

BTS88IROC

Well I WAS going to try that yesterday but when I was tightened up the TPS one of the bolts snapped in half! Those friggin things are like plastic or something. It was all white on the inside. Anyways I had to redrill and tap it out and repair a vacuum line i broke and so I didn't get much done yesterday. I'm just getting ready to go hit it again though. Also sorry for being an idiot but what exactly do you mean by back probe the MAF? Does the maf need to be plugged in when I check the mV or not? I guess I'll just try it either way. Thanks for the help.
later

Brandon

Vader

BTS,

The MAF needs to be plugged in, and you need to insert your meter probes or adapters into the electrical connector from the back side (back-probing).

BTS88IROC

Ok well I finally just got around to checking this today and I'm getting a reading from the first wire on the passenger side, (red) and the middle wire (green), but nothing else when the car is running. I'm sorry I don't have my GM manuals around to tell me which wires those are. I left it at the shop. Does this tell you anything?

Swapmaster

https://www.thirdgen.org/techbb2/sho...threadid=92116

Follow this link and go down to the post on Code 33 test.

BTS88IROC

Well from what i read in the post by swapmaster it looked like it was probably my ecm, i just got done swapping ecms in my 88 irocs, and i put the *possibly* bad ecm in the good car and the SES light flashed a whole bunch of times, but didn't stay on and no codes and ran fine. I swapped the known good ecm in the bad car and now I can't even get the scanner to hook up to that car and the SES light is still on. I"m gonna go swap ecms again and see if I can hook up the scanner on the "bad" car. If I can I'll swap them one more time and see what happens.

BTS88IROC

Well I just got done doing th swap again. Both ecm's work fine in the 'good' car (no codes) and both will link up to diacom. Yet in the 'bad' car only the original ecm will hook up with diacom, yet both will run the car. That seems pretty strange to me. I checked the 'bad' cars chip and it does have the original chip. Anybody have any ideas? My idle is being pretty irractic too. When I first start it up it will idle at about 1500 to 2K sometimes until I tap the throttle and then it will settle back down. And my TPS was still at about .54. No matter what my GPS for the MAF is always reading 254 on the bad car.