OIFVET

I recently discovered the smog pump on my '91 5.0 is bad. the motor was idling crazy which lead me to replacing the IAC valve and adjusting the TPS. after these replacements/adjustments the idle was still acting up so i pulled off the hose leading from the smog pump to the EGR valve hook up and it idled just fine-@1000 RPM. I was driving home on the highway today in 5th gear driving close to the posted speed limit and the car surged like it wanted to shut off. about ten minutes later the car actually did shut off, so i pulled to the shoulder let the car sit for a min and it fired right up. driving thru the streets i could hear what sounded like an exhaust leak(louder then usual since the smog pump line at that time was unhooked).

once i parked it i got under the hood and found that the sound was coming from the EGR valve opening, i plugged it with my finger, the sound went away but still heard the exhaust leak.....My question is would leaving the smog pump hose unhooked and both ends not plugged cause the air/fuel ratio to be off thus shutting the car off?

I dont have the $$ to replace the pump so i'm considering blocking both ends off until I can do so...

bluebeastsrt

I recomend throwing the entire smog pump system in the trash. You probably have a vacuum leak with all the stuff unhooked.

mjr46

smog delete ftw!!!

65Raven65

+1

One of the first things I did when I first got my Fox.

OIFVET

I read on a review for the smog pump delete kit from americanmuscle.com it is only recommended for vehicles w/o catalytic converters, i recently put two cat's on for emissions, wont this mess up my emissions if i delete the smog pump?

ALMOST STOCK

Yes it will.

65Raven65

You shouldn't need a kit. Take the pump off, chunk it in the garbage can, and run a shorter belt.

There's lines you'll remove and things you'll need to plug and a pipe you have to cap off, maybe that's the stuff in the kit? You can get what you need for less than $5 probably. Wish I had more detailed info for you, its been a decade since I did it.

Deleting the pump shouldn't affect your emissions enough that you wouldn't pass a sniff test, but I'm not positive. Maybe someone else will know for sure. I didn't have cats on mine so it wasn't a concern.

OIFVET

re-connected the smog lines, adjusted TPS til idle was at 1500 RPM then backed it down to 900 idled great for about ten minutes then started acting up again...i just ordered the new pump and TPS(just to be safe) i'll let y'all know how it goes after the replacement tomorrow.

OIFVET

quick update, i replaced the TPS first to double check and see if it wasn't the pump. I let the motor warm up to operating temp, idled it to mimic the car driving down the street and the idle was still irregular so it is confirmed that the smog pump indeed needs to be replaced. when i replace the pump and reapply the belt do i need to re-tension the belt or will it be good?

dawson1112

The smog pump shouldnt have anything to do with your idle at all. I have a 94 gt and I eliminated it all together. I also could be wrong about the 91 but the hoses from the smog pump should not go to the egr . One should go to the back of the heads and one should go to the cats. The egr and smog systems are completly seperate entitys. The egr should have a tube connected to the exhaust manifold or header, and also a vacuum line to operate it.
Now if your egr is sticking open it will cause an erradic or stumbling idle. I may be wrong on the 91 But im pretty sure they all work the same up to 95.