Code 42 Experience

M

MNwe4

Member
Joined
Sep 29, 2008
Just thought I'd share a hard start popping experience I had the other night. Luckily I was with some members of the MGNTA and we figured it out. I had the car out and was trying to get the new tune dialed in. We decided to call it a night and headed back and parked the cars. When I went to start mine again it would fire up very rough, pop and miss, then violently die. Had to rev it hard to get it running. The scanmaster and powerlogger would throw a code 42, which is EST (electronic spark timing). After going over a few things we decided to try a coil pack/ignition module that was laying around. The car wouldn't even crank so it was bad. So we hooked mine back up and put the plug wires back on and wallah! It was either a poor connection with the plug wires or a poor connection with the pack/module. Don't know which but it drove home just fine. I have changed the wires just to be safe. No more code 42.
 
Problem not Solved!!!!!

Alright guys, the problem showed back up, so new plug wires were not the answer. Sorry, I thought it was good since I drove it home 40 miles the other night and got into it a few times. This time the car broke down while driving, just pop pop dead. Couldn't get it refired either like last time by holding down the gas. It would start, pop repeatedly, and then die. Once again, threw a code 42. The EST(?) on the passenger fender is not bad as we tried a known good one the other night. I got lucky and was able to start it after a while and drove it home the 1/2 mile missing all the way, no pops though. Got it in the garage and it idled fine. Any thoughts??? :frown:
 
When I had a code 42 I needed a new module. Try a known good module/coil pack and see if that eliminates the problem.
 
Ignition module on mine, Just make sure and use AC parts or you might be doing it again shortly
 
I was going to give the coil pack a shot tonight after work, or do you think it's going to be the ignition module and not the pack?
 
Will do. I'm picking up a coil pack and module on the way home tonight. Echlin is the manufacturer and it's from Napa. I was told Echlin is their OEM, non-economy model so they're a little more spendy. About $130 more spendy :eek: I'll post results once when I can.
 
MNwe4 said:
Will do. I'm picking up a coil pack and module on the way home tonight. Echlin is the manufacturer and it's from Napa. I was told Echlin is their OEM, non-economy model so they're a little more spendy. About $130 more spendy :eek: I'll post results once when I can.
Click to expand...

repaired a 87 GN today....103.00 for the module(under the coil pack) at autozone......also had code 42.......runs like new now....also had to replace the coil pack cause the connectors broke instead of unplugging:mad:...coil pack at the zoo was 42.00......
 
Ok, here's tonight's progress. Old coil pack had resistance of 950kOhms instead of being around 12kOhms, so I went out and got a new one. Made the swap and it fired right up and idled great. Revved it and everything was fantastic, so I shut it off. Tried to fire it up a few minutes later and the exact problem is back. When I picked up the coil pack I also bought the ignition module, but it ended up being the wrong one, go figure. Another trip for parts is in store for tomorrow. I'm also going to try another computer. Different chips didn't matter, but maybe the newly refurbed computer went bad, but I doubt it.

What puzzles me is that it will start good sometimes but is not repeatable at all. Still sound like an ignition module???
 
MNwe4 said:
Still sound like an ignition module???
Click to expand...

Sounds EXACTLY like an ignition module.... they heat up a little and go freaky and unpredictable..... hopefully you'll get a 'good' non-oem (AC Delco) module from napa or AZ or wherever... it may take a few trips.... as many of us have experienced..... if you can swing it and have the time, you'd be well advised to just go ahead and spring for the oem module from nos4gn or equivalent.... 'course, you're luck is probably alot better than mine... :wink: feel lucky??? :biggrin:
 
MNwe4 said:
I'm also going to try another computer. Different chips didn't matter, but maybe the newly refurbed computer went bad, but I doubt it.
Click to expand...

Me too... highly doubt it... ign. module failures outnumber ecm failures about 100 to 1.... I wouldn't bother with the ecm for now..... it's the module.... :wink:
 
Yes, also my guess is module. But, when my GN gave code 42, it was caused by broken EST cable joint between ECM and ign module near to ECM. It was broken in the solder joint, which I made when making Maftpro wiring and the joint area was not supported properly with tape.
 
Well, put a new ignition module on last night and the car fired multiple times and idled great. I'll drive it today and we'll see what happens. :rolleyes:
 
Problem Solved!

Well, the car is back up and running. It turned out to be a bad connection from the negative to the head and/or the loose connector on the positive terminal. So, before you go spending 500 bucks on parts like I did, check your battery terminals and grounds!!! Big thanks to northerngn as he helped me track down and fix the problem. Also, thanks gnwanted for letting us use your place and drink some brews. Hopefully I'll avoid any more problems for the rest of the season.
 
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