bretamo

Hello,

I am writing for guidance on correcting a check engine light error after installation of new headers and H pipe exhaust.

After researching this forum, I do not find a clear cut answer to this problem for the 87-93 Mustangs.

Do the 5.0 have a post converter sensor, and do I need to install a MIL (Multifunction Indicator Light) Eliminator? Or is it simply the O2 sensors need cleaning and/or replacement?

Thank you in advance for any clarity that can be provided on this topic.

Bretamo

vfast

no they have just 1 sensor on each side.....check to make sure you don't have an exhaust leak..then clear the computer by removing the neg cable for about 10 mins..let me know if this doesn;t work

Demon_Mustang

Actually, this is a common problem for people with aftermarket exhausts. For about $20 you can get a EGR simulator (similar to the MIL Eliminator, but directly to the EGR valve) from ebay: EGR Simulator

And if you don't have any cats anymore, meaning you bought off-road H-Pipes, then you can get a shorter belt and eliminate the smog pump.

Dbeck002

there really shouldnt be a check engine light after changing the headers. the only sensor that has to do with the exhaust are the O2 sensors. make sure they are nice and tight on there and not rattling when you shake em. if they are old, replace those.

only thing i can think of is when you were installing the headers you yanked on a cord or something and its causing the check engine light.

88GT40

if they are off road h pipe you will need the mil eliminator if engine light stays on it's easy fix.

bretamo

Thank you for your reply!

There is a slight gasket leak between the head and new headers, which I have located between the two cylinders nearest the firewall on the passenger side.

I'll attempt to fix that and disco the battery as you advised and see if that works.

Thanks again!

Bret