i have a 1987 iroc z28 43000 miles it sat for many years it idles good but sputers pops and runs like S$%& when under a load, items i have replaced are fuel pump,fuel filter,tps,iac,plugs and wires,ecm,fuel pump relay,mas air flow sensor,oxygen sensor,ect sensor(guage still dont work) and the icm,im lost and been at it all week and 400 dollars later im broke and cant figure it out. codes reading are 33,34,and 41 is what has me lost< please help, i love my iroc but it aint rocin right now, this is my only mode of transport! and just bought it

 

have you replace the mass burn off relay it is located drivers side by brake booster

 

Hey man. here is a link to a discription of trouble codes and causes.
http://www.gnttype.org/maint/malf.html

 

So here is what you need to do to take care of your code 33 and 34 which are directly related to the MAF Sensor. Forget about the relays for now. Remove the MAF Sensor. Look under the MAF sensor, you'll see some pins inside the bottom of the connector housing. You'll need to clean off the pins with a tiny file or dremel. The goal is to clean off the grime and corrosion that has built up over the years. Make the pins look shiney. Now go to the MAF Sensor wiring harness connector. Inside the connector is the female holes. Here you should get a jewelers screw driver set or a very tiny flathead screwdriver that will fit inside the tiny metal holes. Insert the screw driver and twist the inside of the holes. You want to get the inside of the female connector piece clean as well to expose "bare metal". The results will be a metal to metal connection. Its optional if you want to apply "die-electric grease" to insure connectivity and anti corrosion. When your done, inspect the weather pack rubber boot. Make sure that it is not cracked or worn out. Its purpose is to keep out moisture and contaminates. The boots are circled in the picture below.

Jeweler screw drivers set

 

Disregard the link to the troublecodes.

Continue with the cleaning process that I provided for TC 33 and TC 34.


TC 34 = Which is a MAF sensor error. Causes include (the same goes for TC 33) Poor electrical connection, open and or short in curcuit. Defective MAF sensor or defective ECM.

TC 41 = Cylinder select error = Incorrect or defective MemCal or ECM.

for TC 41, you'll need to get a little dirty and sweaty. Pull out the ECM from under the passenger dashboard. Open up the little access cover. On top of the MemCal's window, you'll see a code. Type in the code here so that we can verify if the MemCal is for the Camaro you got. Here is what you should be looking for in the MemCal below. The code should be something like ABWN, ABWT, or ABWW

 

im gonna try checking all my grounds to the motor and body of the car,and clean out the electric parts you told me and i will get back on here and see what happens,i will also get the #s from the ecm, i know they matched at orileys were i got the new ecm

 

i took it out of the ecm and mine says ABUN

 

ABUN? thats seems odd. I know that GM made a 350 for the 87 IROC. here is what I think is wrong. The PROM ID you gave me is for a 305 engine (1987 305 (5.0L) "F" body Camaro-Firebird-Trans Am). So if you have a 350 in the Camaro, then your gonna run into some compatibility issues. Follow this link to verify for yourself,,, http://chevythunder.com/prom_bcc_1987.htm
I beleive that the injectors are of wrong size. If you do have a 350 and using a 305 MemCal, you'll need to reprogram the MemCal or buy a Moates adapter and have someone burn a EPROM for you to match the 350. Here is what is involved in a 305 to 350 conversion,,,,,, http://tpiparts.net/305_tpi_to_350_tpi_conversion

 

thanx for the help, 33 34 are fixed so far, but 41 is coming back, good news is i think i found the culprit,number 4 plug wire was slightly against the exaust manafold and it just about melted in half lol, that would explain it lol,gettin new wires today.again!!! i will post back with the results, thanx for everyones input, this site roc"s Iroc29 P.S gonna post pics of the car soon

 

That should take care of it (new plug wires). Although I had the very same issue. I had a wire up agianst the header but I never had a troublecode. I just had a bad miss.

 

well no change in anything to the 41 code!! i should also mention im ideleing at 15 to 20 k as well,and cant seem to get it down, i know i should idle at about 7 k. 650 in gear, i wanna change the knock sensor but mine dont want to break free even after wd 40 lol. but the knock sensor isnt making a knock or ping?????? so im lost. any more help? and i checked again it is a 305, some one told me to get a flo chart for code 41 for my vehicle, would this help?

 

The code 41 that I posted is directly from the Haynes repair book. But as for a flowchart, well thats the first time that I heard of such a thing. Now for the idling, this whould help you out big time. Just follow the links and you should get your RPM's at the setting that you want.

1. http://www.highperformancepontiac.co...gta/index.html

2. http://mpikas.blogspot.com/2008/08/t...june-2000.html

Go to the search tool bar on the upper right and type in code 41 and see if there has been other members with the same issue.

 

Also follow this link. Seems like there are other possibilities linking to a code 41


https://www.thirdgen.org/forums/tbi/...ode-right.html

 

ok car is fixed except the 41 code!!! but its finaly running again, but the idle is still up and down and idleing at 1500 rpm, i read the directions to reset my idle but it dosent seem to be getting me anywere!! i cant get the car down to 450 rpm with the idle air control un pluged cause it dies???? any ideas fellow irocs

 

TC 41!!! WOW. That is "cylinder select error." The problem is either the MemCal or the CalPack (the whole PROM) according to the Haynes repair manual. I never heard of this problem before. Give me a day so that I can look around for some possible solutions to that T.C..

 

Disconnect the est bypass when you set your base idle speed so the car won't stall.

Its a tan wire with a black stripe, it breaks out of the wire loom near the ac unit.

 

Tc 41 turns out to be a PROM error. Check the I.D. number of the memcal. Verify if the memcal belongs to the car. Make sure the memcal is inserted properly.

 

ok i called chevy and my ecm wich is brand new and prom are a match, im 99%sure the prom is in there right! it only goes in one way right? i have also checked the harnes conections to the ecm and all is well! how do i go about getting a new eprom, chevy said they nolonger have them due to the year of my car its to old.. im gonna try and fix the high idle today as well!! i also noticed a rattle from the top end of the motor, i used to have a slight tap wich has turned to a rattle when rpms going up or down when hitting the trottle, only happend after i put seafoam in the intake,i did it by the directions, i didnt put any in the oil only gas and intake via vacum line any ideas???? it has been one thing after another with this car

 

Did you visually see the codes on the MemCal? Do you know anyone with the same year and vehicle? Is the ECM a 7165? Find your MemCal here and post which one it is..... http://chevythunder.com/prom_bcc_1987.htm
You could save yourself some money if you spend $50 dollars in parts. All I gotta do is if your up for it, then I would have to talk to one of my buddies to program a blank EPROM.

 

As for the ticking. I dont know what the issue is. You could check the valve lash on the rockers. Check to see if there is any oil coming out of the push rods. To verify if a valve has lash, get a hose or tube and put one end to your ear and the other next to the rocker/push rod while the IROC is on. Inspect each rocker. If you hear an obviously loud tick, then youll have to adjust your lash. This method must be done with the engine running which is messy because there will be oil spalshing everywhere. Or you can just try spinning each push rod with your thumb and index. If there is relatively easy spinning with little or no resistance, then there is lash.

 

yup the ecm is a 7165, i know that the prom says abun and that the the # on cthe prom gooes to that ecm, but the thing is i didnt have a code 41 with the old ecm that this prom came out of, that ecm got replaced cause i was out of stuff to replace to get the car running right,and it still dont lol but does run better, still havent got to the idle yet but i will today, thanks for all your input and help CHEVY86 IROC Z, next week i will need to be finding a prom!!! if you have a hook up on one that would be great cause i know no one with another iroc

 

If the car sat that long and you want to send me the injectors to test for you, I'll run them and see what you got. If they're good I'll just send them back. If it's been sitting that long with that few miles, would be good to know.

 

well if this new route dosent work i just might but bad part of that is this is my daily driver!!!! it would have to be quick, thank you every one for the help and input to help me get my iroc rocin again!!!! a real big thank you to this site!!!!!!!!!!!! THIRDGEN ROCS!!!!!!!!!!

 

A code 41 is not relevant to F.I's. Im trying to help out this guy while your trying to find a reason to make him buy F.I's. If he needs injectors, Im sure he'll contact you. But if he asks me for any suggestions on buying F.I.'s, Ill let him decide on SouthBay or Fuel Injector Connection strictly because they both supply the famous Bosch III injectors for under $150 for a set of 8. Might I add that they supply the 19 lb for iroc29's 305 and have excellent Customer Support.

 

iroc29, did you do the TPI tune as I posted 2 links on post #12?

 

On the ECM that you just replaced, did you get it from a parts store? I ask because about 1 year ago I replaced mine with a Reman from Autozone. They had sold one to me that was completely bad. While I would crank, there would be white smoke pouring out of the tailpipes. Out of curiousity, I reinstalled my old ECM (which was the core), and cranked it. The result was a LOUD A$$ backfire. The vapor was fuel being compressed into vapor form from the cylinders. But the IROC started. So I went back and got another Reman ECM. This time the IROC turned on. My point is that not all replacement ECM's are gonna work. There are some odd ***** out there. Unfortunately it is us the consumer who finds out that what they just bought is bad. So If you still got the reciept, I would go back and ask for another ECM. You still do got the receipt dont you.

 

As do we....Thanks!

 

Okay. Sorry if I came out strong but I felt that the thread was being Hi-Jacked so I appologize for my post.

 

HA! No problem. No need to apologize. Just trying to develop a reputation here which is hard enough, (well not the right kind) but it's like I was invisible in the post above!!



I thought it was funny which is the only reason I responded... Kinda like "HEY!! I'M IN THE ROOM YA KNOW!"""

 

Its all good .. Try this approach....

 

yea i have the recepit, i got it from orilyes auto parts. but there is a no return policy on all electric parts, ive been reading on the articles you sent and im doing the tuning this weekend the first chance i get, the car is gonna sit this week till i get paid so i can change the oil, the oil is why my top end is having a rattle,the oil is preety thin cause of the gum out oil cleaner i put in, so im not gonna drive it till this weekend when i change it and dump a big thing of lucas in it but i believe all the help and nfo you have provided will fix my issues!!!!!!! one more question tho!!! How come my brandnew fuel pump hums just like the old one , its quiet at first but after a while of driving it gets loud again

 

Mine does the samething too. According to GM, the hum is the bearings or something in that nature are causing the noise but with that said, GM still claims that the noise is not a defect and will not render the pump as failing. There is a threat that focuses on that topic. From what I have read, there is no straight or direct solution to the noise.

 

and also why does my 305 tpi have the centerbolt valve covers and a auto trans, from what i read some one has done some engine or trans swaping or head swaping or its realy a 350 and or could have a roller cam wich the 305s with the heads i have only came with a 350 or 305 with a manual trans, the more i dig in this car the more things are not factory any sugestions on why my 305 has those heads and a auto trans, any easy way to see if its a 350 from the top of the motor