smog pump??? how would I find out if my truck had one?

[charlesg]

anyway to find out?? 91 r3500 454

 

[84 M1008]

Why, do you plan on replacing it?

 

[charlesg]

no, if it was removed do I have to reprogram the ecu for it not being there?

 

[84 M1008]

How does it run without it?

 

[charlesg]

kinda runs like ****, that is what got me thinking about a chip was talking to a guy that burns them and he asked about that. Said there is a part of the program that runs the air valve for the pump. The truck falls on its face when getting on it.

 

[Craig 85]

Napa lists this smog pump for a 1991 R3500 with a 454. NAP 51278. I then found some info on motorhome P30 chassis with a 454. On label it says 1990-1994 the smog pump was eliminated. In 1993, I ordered a C2500 Suburban with a 454 and I don't recall a pump on that one, even in California. The cat was just IFO the rear axle though.

You must be registered for see images attach

 

[84 M1008]

I think you need to get a reflashed ECM.

 

[skysurfer]

Is the underhood sticker still there? Was most likely found on the air cleaner housing.

 

[charlesg]

I think you need to get a reflashed ECM.

any suggestions on who to buy from?

 

[84 M1008]

Stand by

 

[84 M1008]

steve.maneu eBay seller.

 

[bucket]

No tuning needed to run without the smog pump. I've got plenty of experience removing them and all still ran well.

 

[84 M1008]

Is there a distributor on that motor?

 

[1987 GMC Jimmy]

Yeah, nothing should need to be done to it. At least regarding the smog pump. How did you plug the holes, and does it have any exhaust leaks right there at the manifolds that could be confusing the O2 sensor? I think it’s something else. Any check engine lights?

 

[charlesg]

Is there a distributor on that motor?

yes it has one