5.3 runs very rough under load

[Craig C]

after terrorizing the neighbors by unhooking the exhaust it proved to be both cats plugged big time. After a a morning in the exhaust shop its back to running like a champ.

Thanks to all those with their advise.

 

[VikingTrad3r]

after terrorizing the neighbors by unhooking the exhaust it proved to be both cats plugged big time. After a a morning in the exhaust shop its back to running like a champ.

Thanks to all those with their advise.

nice work craig. did u ever try the temp before and after the cats? ive read that is the way to test for a plugged cat but never done it myself.

 

[treehan77]

How much were new cats? You had the shop do all work?

 

[Craig C]

400 parts and labor. since they were welded in I didnt attempt it. Didnt want to try to cut out and piece it back together.

 

[treehan77]

400 parts and labor. since they were welded in I didnt attempt it. Didnt want to try to cut out and piece it back together.

Good to know, doesn't sound too awful bad to get it back in shape

 

[electro]

Why did you have plugged cats?

 

[VikingTrad3r]

Why did you have plugged cats?

fuel trims will tell...

 

[SLCHOE]

Why did you have plugged cats?

fuel trims will tell...

Yep. Now that you've spent the money on the cats it's time to find out what caused them to deteriorate. Sounds like you have a vacuum leak and the PCM is compensating by adding fuel (high fuel trims) to get the a/f ratio to stoichiometric ratio (14.7 parts air to 1 part fuel). Excessively high fuel trims will kill your new cats in no time flat especially with them being weld-in universals. Find the root of the problem and fix that too. You're not done yet.

 

[VikingTrad3r]

Yep. Now that you've spent the money on the cats it's time to find out what caused them to deteriorate. Sounds like you have a vacuum leak and the PCM is compensating by adding fuel (high fuel trims) to get the a/f ratio to stoichiometric ratio (14.7 parts air to 1 part fuel). Excessively high fuel trims will kill your new cats in no time flat especially with them being weld-in universals. Find the root of the problem and fix that too. You're not done yet.

^^^. he is right.

if you have a laptop, all u need is an elm327 and u can scan your fuel ttims.

OR. what type of phone do you use and I can maybe make a recommendation that's even easier then a laptop

 

[VikingTrad3r]

well, i was under my denlfali xl today after i had been running it for 20 minutes. my driver side cat appears to be on its way out because the exhaust was completely cold behind the cat. the other side was nice and warm.

ill hook up a scanner and see what the numbersbehind the cat.