hey i have a 1987 camaro iroc-z TPI i have been having the service engine light on since i bought the car i put the GM code reader on and it showed the code for the knock sensor so i replaced it then it showed code 33,34, and 42 i replaced the maf sensor and it got rid of code 33, and 34 but 42 is still coming up and it is having lots of problems i replaced the ecm, ecu, and ignition control mod. but still no luck it seems to be misfiring or backfiring or something like that it feels like its been shaking alot but doesn't want to run nice i got a few macanics confused they can't even find the problem thats why i'm on this site i'm looking for some help please

 

Code 42
This code will be set when the engine is running at 600 rpm or greater, and there is no pulse on the white wire from the ecm to the ignition module for more than 200ms (milliseconds).
Common causes for this code include bad connections, frayed wiring, or broken wires such as the tan/black (ecm pin D5) purple/white( ecm pin B5) or white wire (ecm pin D4).
Check your wiring carefully along with the connections back to the ecm.

 

thanks alot i'll try that

 

i checked all the wires and nothing seemed wrong all connections were clean nothing seemed broken on wires were broken, frayed or bad coonection are there any other wires to check or other problems that might be the reason for the car acting up

 

just want to no if you fixed it and what it was im having same prob

 

I'd check to see if there's any power to the wire. I don't really remember how these work but I think there's a wire that plugs into the sensor right?

 

ya all the wires that we were talking about all lead into the icm inside the distributor cap i found a problem with the coil being bad but it still never fixed the hesitation problem

 

Make sure EVERY spark plug wire is on the dist. cap tight. Push on each one to make sure. Also make sure the wire on the ign. coil is good. Also, where did you get the knock sensor? I put a new one in my car once only to have the light come on a few seconds after starting the car. I ended up just putting the old sensor back on.

 

ok put all new wires from the computer to the icm and changed the icm and got the knock sensor from GM tried to start the car and still the same thing stalling and shaking and if i even put my foot on the gas it becomes major backfiring but the code 42 went away and chaged to code 33 so i put all new wires from the computer to the maf sensor and put a brand new maf sensor in but still can't seem to find the problem i checked all the relays but i can't seem to find the problem

 

Have you checked the throttle position sensor? Adjusted? How about the Idle Air Control motor? Adjusted?

Just to be clear; Your "check engine" light is off now?

 

the check engine light goes on and off it flashes then it stays on then it goes off it seems like it can't make up its mind so i hooked the code reader in and it flashed a code 33

 

You may find some useful info in the code/diagnostic to follow:

http://www.freeautomechanic.com/diag...blecodes5.html

JamesC

 

One possibility, a code 42 will set when the est bypass is disconnected to set the timing.

Did you clear the codes and it came back, or have you not tried to clear the codes?

 

i've cleared the codes but nothing changed still runs horrible

 

as you can tell by the title it won't run smooth just constant backfireing through the exhaust put on new spark plug wires, distributor cap, roter, wires from the ecm to distributor (ICM), wires from the ecm to the MAF sensor, MAF sensor, EGR valve, PVC valve, IAC sensor, ICM, ECM, ESC. The car was running good when i first bought it but had a code for the knock sensor and never worried about. Blew out the clutch and needed the car asap so i took it to canadian tire was the worst decision ever. i told them to check out the car about the code and put a new clutch in it once i got it back running like garbage took it to another shop and they got it running better they used a MAC scan tool and pulled up the code 33,34,42 but the code for the knock sensor was code 43 anyways they got it running better with a new MAF sensor cause the old one came out in 3 pieces and a new ESC brought it home and parked it for the season now runs like crap shakeing and backfiring through exhaust won't stay running i start it and it backfires like 3 times and stalls itself. another person i knew said that he set the timing and it turns itself back to standard timing once he got it running. I'm hitting my head against the wall for taking it to canadian tire and i'm looking for someone that can help please.

 

I have seen some code 33 and 34 come with vacuum line and leak problems. Also, have you checked your throttle position sensor (TPS), for voltage. Book says .054v, but I like .65v. But check all your vacuum lines and fittings, and all the gaskets for the runners and plenum and throttle body butterfly shaft for leaks.

 

alright i found a quick fix when i take apart the connection on the tan/black wire ECM D5 the car comes up with a code 33, and 42 but it runs nice slight misfire but when i put it back together it runs like garbage i've replaced all the wires from the computer to the distributor and from the computer to the MAF sensor i also replaced the coolant temp. sensor and check the MAP sensor so if there are any other solution please

 

ok i think i found a major problem i took apart the distributor and seen that the pick up coil was in 3 pieces so i replaced it and now i don't get spark to any spark plugs i've check to make sure all the connections are hooked up and everything is cleaned on the coil and distributor but still no spark can anyone help?

 

THANK YOU JamesC went to that site and checked to see if my prom chip was seated and it was not. Have been working on this for years and was about ready to give up. The code 42 never brought up a check engine light and car would just stall. Have been to a few shops and they were not able to figure it out including GM. Thanks!!!!