Hi guys,

I just had MAC's installed and drove the car home (5 min drive) and it ran perfect. Today I took it out for a longer drive, and the first few mins drove fine again and after about 6 or 7 minutes it would studder/misfire at any RPM.

My wires are new AC/DELCO and I noticed #5 wire is touching the header primary. Looks slightly whitish at the spot where its's touching. Certainly not burnt through very deeply (as far as I can tell) just the very outer layer is discolored.

Is this whats causing the poor performance?

I also added new AC/DELCO O2s, so I doubt it's those.

If it is the burnt wire, will re-routing it solve the problem or will I need to buy a whole new set of Delco wires?

Just confused as it drove great for the first few mins then once it got hot it started running like crap.

Thanks.

 

Sounds like the problem starts when it goes into closed loop. I would double check the o2 connections.

 

It does sound like whatever it is, it's coming on after 5-6 mins driving. What should I be looking for on the O2 connections?

 

I've had the same problem. I had a few burned plug wires. I took them out and taped the up with 3m 88 Electrical tape and put them back on. Made sure they wernt touching the hedders or heads again and it ran fine.

 

Thanks for the suggestion. Were your wires 'slightly' burned like mine with the whitish discoloration? Where did you get the 3M 88 Electrical tape?

 

Yes they were slitely discolored like ur discribing. I got the tape at Lowes or home depot. u can also use the 3M 33+. The only diffrence between them is the thickness. the 88 is thicker and a lot tougher. When u put them back on make sure they dont touch the hedders again though. I'd also suggest getting some Plug wire boot protectors. You can get them for like 40 bux for 2 at oreilly. I got all 8 of mine for 20 bux but i had a friend that worked there so we did a lil under the counter trade.

 

Ok thanks. I'll look into getting those plus the boot protectors.

 

Your wire is burned, best to replace the wire. Make sure that none of the wires ever touch the headers. Run the car in the dark with the hood open when the engine is up to temp, look for sparks. You can use a inspection mirror to see all angles. Very common problem w/header install.

 

Ok...I understand. Problem is I just put new Delco wires on there and I don't want to have to buy a whole new set again because they don't sell them individually. Any suggestions?

 

Burnt wire. Lots of Zip ties keep away from the headers. Guaranteed to be your problem

 

The problem is that stock wires for not wire wound, they are a carbon type compound. When over heated I.E. white colored you have dried out core causing the spark to have to jump inside the wire. Not in all cases, but most. Get a set of MSD or Accell wires the have wire wound cores and thicker jackets to withstand more heat from the headers.

 

I just got back in town so I haven't had a chance to fix this issue yet. I will be looking at it tomorrow. Thanks for the suggestions.

 

I bet either you or whoever installed the headers had to extend the O2 sensor on the driver side and spliced wires into the O2 sensor side instead of on the engine harness side. The O2 sensor wires have a gap in between the insulation and the wire and uses that as the control to determine whether the exhaust is rich or lean. The splicing ruins the gap and makes the sensor go bezerk and the car goes extremely rich or lean on that side. the result is a poor running car when it goes into closed loop, just as you described.

The fix: new oxygen sensor on that side and a 12 inch extension which can be bought from summit. Look at my sig and ask how I know all of this.....

 

Thanks for the tip. I didn't do the install, but I looked at the O2 wires and they were uncut/spliced. I did pull the plug wire that was touching the #5 primary and it was pretty well burnt through the insulation. I have used Laredo's suggestion and 3M taped up the injury and zip tied. Drove the car afterward and it was fine - no more issues. I will eventually replace this wire entirely, but for now the electrical tape fix worked.

Thanks to all for your help.