No CEL's! So far so good.

I have had a 5-8 CEL for a long time. I have tried many things with no luck. I was thinking it was a bad MAF sensor because the CEL would switch to 1-4 if I swapped the MAF's. I cleaned it, checked the resistance value and made sure it was sealed well. Still no luck. I had the other MAF rebuilt about 20 months ago. I found the other day that the resistance value on the rebuilt MAF was at 387 instead of 383 like recommended. So I tried adjusting it down to 383 to match the other one. Not only did I still have the 5-8 CEL, but then I was getting some popping and spitting from bank 1-4 when cold. I was just about to send off the MAF sensor for rebuild when I tried one last thing. Today I decided to adjust both MAF's to 387. BINGO!! No CEL's, No spitting/popping when cold. Idles smooth as silk. I have put 3 hours on her in two test drives today and so far, not even a blip of a CEL. I did do the reset of the ECU's after setting the values to 387. So for now, I am one happy camper! I have dealt with a CEL issue of one kind or another since I got the car so this a big deal for me.

 

That's great news Todd, glad you finally settled that issue.

 

Thanks Mike! I am hoping it is settled. At least I know I am in the ball park for the correct settings on my MAF's.

 

Ok, day two and still no CEL's. But, there is one strange thing happening. After I run the car for about 5 minutes or so, I get a Slowdown 1-4 light for about 15 to 45 seconds. Then it is gone not to return during that trip. Keep in mind that when this happens, I am only running around 30 to 40 mph. No high revs or anything. It only happens the one time. Any ideas? The car runs great and if this does not change, it is not really an issue but if I could stop it I would be even happier.

 

I'm just curious, how did you adjust the resistance? Thanks, Bob.

 

Todd, I hope the fix works out for you. Have you considered Dave Helms' gold connector kit? Instead of chasing ghosts...banish them forever.

PS Dave is on the left in the photo.
Image Unavailable, Please Login

 

Well, I remembered that I did not disconnect the battery long enough to clear the ECU's. I checked them tonight and found a bunch of codes that I have had for some time now. I was expecting to not see anything. But after I did a good reset on the ECU's, they all went away except for a 4121 on my 5-8 bank. I did not get any CEL's or Slowdown lights this time. I am going to check the 5-8 thermo sensor next. If that is alright, I think I will leave it until I replace my stock cats with hyperflow units and see what I get then. I will install Daves connector kit at some point. But I really do not think that is the cause right now.

 

Hello Bob, I drilled small holes in the plugs on the two MAF's. I then screwed in a small screw into the hole and pulled the plugs out with pliers. The adjustment screws are under the plugs. You can then turn the screws to raise or lower the resistance values as needed. This is covered in the 348 primer.

 

Thanks, I've got a 355 so have not read too widely on the 348.