Under the hood of a 1993 Corvette

[norwegianvette]

Hi.
I have somthing look like a vacuum clock located in the left front well where the headlights will be stored when not in use. This thing make a noise when the car is restarted when warm, sounds like a fan which is not having a good time. Can anyone give me any info regarding this part and what it do? It is black and made of plastic by the look of it.

Thanks.

 

[sweabe]

Hej,

I belive you are talking about the air pump of the "Secondary air injection (air) system"

From the -94 FSM,

"The PCM turns "ON" the air pump during start up any time engine coolant temperature is above 15 C (59 F). The air pump will operate for a maximum of 240 seconds, or until the system enters Closed Loop operation"

//sweabe

 

[Hib Halverson]

Adding to what "sweabe" posted, the Secondary AIR pump is an exhaust emissions control device. It only runs for a short period after start-up when air injection into the exhaust is required to reduce emissions when the engine is running rich after start-up but before the system goes closed loop.

Generally those AIR pumps are pretty reliable and durable except for the little sponge filter "sock" that goes over the pump's air intake. On C4s they are often rotted away and should be replaced if the pump is to last a long time.

 

[sweabe]

Generally those AIR pumps are pretty reliable and durable except for the little sponge filter "sock" that goes over the pump's air intake. On C4s they are often rotted away and should be replaced if the pump is to last a long time.

Good advice as always, but I just checked my -94, and the intake is through the air cleaner housing. Does it differ between years?

//sweabe

 

[norwegianvette]

Thanks guys, i am a bit worried as it makes some noise when running. Is that normal?

 

[sweabe]

Mine made some noise once, but I haven't heard it since. I belive it was right after I replaced the air filter last winter, and when doing that I disconnected the air pump hose from the air cleaner housing. Maybe there was some sort of dust that fell into the hose

//sweabe

 

[norwegianvette]

Thanks. I might done something stupid here :W I replaced the original airfilter with a 3 filter intake from SLP last winter. I never saw any hose connected between the filterhouse and the air pump :ugh It might be that the pump suck air from outside the filter now and that´s why i can hear it (no damping of sound). Where is the hockup between the air pump and the intake?

Hur er leget i Stockholm

Steve

 

[sweabe]

Where is the hockup between the air pump and the intake?

Hur er leget i Stockholm

Steve

On the upper left side of the air filter housing.

Stockholm has been very dry and hot these last few weeks, as most of Sweden. How about Norge?

 

[norwegianvette]

It looks to be a vacuum tank of some sort, sounds as a fan when starting up te car of some reaseon. Have vacuum as cruise controll works fine so cant be a leak. Also, only happens when the car is warmed up. I think my car have no smog pump but being away i cant check this out closer. Had a picture from "Sweabe" and if things are not different between 1993 and 1994 this must be a vacuum tank:W

 

[John Robinson]

Noise

In my FSM GM makes the following statement about the Air Pump. Note the section marked IMPORTANT

 

[OldCorvetteFan]

Here's the AIR pump on my '95. You can see the output hose on top, which goes to the exhaust system. If you look closely, you can just make out the input hose underneath it.

This second photo shows the input hose connection to the air intake. It then runs down to the pump.

Hope this helps!

Steven

 

[norwegianvette]

In my FSM GM makes the following statement about the Air Pump. Note the section marked IMPORTANT

View attachment 594

Thank you.

It might be ok, my second worry here is where the air comes from. I have no hose connected to the airfilter unit going to the pump:W

 

[norwegianvette]

Here's the AIR pump on my '95. You can see the output hose on top, which goes to the exhaust system. If you look closely, you can just make out the input hose underneath it.

This second photo shows the input hose connection to the air intake. It then runs down to the pump.

Hope this helps!

Steven

Thanks,

Mine dont look like that. It is the vacuum sphere and a conical looking thing that i think is the pump. They might re-designed it in 1993? Still, i dont have that hoseconnection from the airfilterhouse as you do.

 

[OldCorvetteFan]

Thanks,

Mine dont look like that. It is the vacuum sphere and a conical looking thing that i think is the pump. They might re-designed it in 1993? Still, i dont have that hoseconnection from the airfilterhouse as you do.

Are you talking about the vacuum accumulator shown in the bottom left hand corner of this picture?

I don't see a conical part. Can you take a picture and post it?

Steven

 

[norwegianvette]

Are you talking about the vacuum accumulator shown in the bottom left hand corner of this picture?

I don't see a conical part. Can you take a picture and post it?

Steven

That´s my problem, i work "off shore" and won´t be home again before august 18. If you look at the drawing John Robinson sendt me som posts up, and the second drawing. Thats similar.

 

[John Robinson]

93 Air Pump Picture

Here is what the air pump looks like on a 93. It is different than the later years.

http://i285.photobucket.com/albums/ll72/John-68/AirPump005.jpg

 

[norwegianvette]

Here is what the air pump looks like on a 93. It is different than the later years.

http://i285.photobucket.com/albums/ll72/John-68/AirPump005.jpg

Thanks John, thats the baby. Where do it get air from and where is the filter. Is it a good idea to buy one from a later model? must be a reason GM made a new pump for the 94 up.

Regards,
Steve

 

[John Robinson]

Air Pump FSM



These are the sheets from my 93 fsm for the Air Pump Hope you can read them. Sorry they are not in order
John

 

[norwegianvette]

Thank you John. You are very helpfull.

All the best,
Steve