Secondary air pump problems, possibly?

GroovyBoovy

Junior Member
Messages
61
Anyone got any experience of Secondary air pump problems?
From time to time I will get 2 error messages at the same time, P0491 and P0492 “Secondary Air Injection System Insufficient Flow” both banks, suggesting its the Secondary air pump, or pipe leading to it.

The pipes look ok. I have taken the air pump off the car, the only think I can see is the electrical terminals have some corrosion on them, which I will clean up and put it back on again. Anything else worth checking on it, or in it?

Tar

Rob
 

Gp79

Member
Messages
1,393
Anyone got any experience of Secondary air pump problems?
From time to time I will get 2 error messages at the same time, P0491 and P0492 “Secondary Air Injection System Insufficient Flow” both banks, suggesting its the Secondary air pump, or pipe leading to it.

The pipes look ok. I have taken the air pump off the car, the only think I can see is the electrical terminals have some corrosion on them, which I will clean up and put it back on again. Anything else worth checking on it, or in it?

Tar

Rob

There is also a filter on the pump so worth a clean.
the small metal pipe thats on the underside of the main secondary air pipe has been known to corrode / leak causing issues. Quite hard to see properly when still on the car.
 

conaero

Forum Owner
Messages
34,593
It’s usually the metal pipe that runs round the front of the engine. Water sits in there and it rusts through on the underside.
 

TimR

Member
Messages
2,654
It'd have to be quite a big hole to affect flow..Quite likely a pump or filter failure if the codes are correct..?
The small piping is a vacuum bleed system that checks the valves if Im not mistaken..so not strictly flow in the sense it meant here AFAIK. The valves can also stick from time to time...?
 

Oneball

Member
Messages
11,071
If the valves stick it can allow moisture from the exhaust into the pump and it then siezes.
 

TimR

Member
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2,654
I say that - but having removed paint from mine, there is what looks to be a major repair in the larger diameter delivery pipe...!
 

alfatwo

Member
Messages
5,517
Just disconnect the pump motor, Its an old car now, it wont fail the MOT emission's test on that alone
Its a cold start device to get the cats up to temperature quicker

Dave
 
Last edited:

alfatwo

Member
Messages
5,517
Dont do that - It'll run like a dog 'cos lambdas dont return correct signal values..
It only pumps air into the exhaust system when the engine is starting from cold!
Earlier engines don't have this.
If you have running problems it wont be entirely down to the air pump system!

Dave
 

Oneball

Member
Messages
11,071
I wouldn’t disconnect it but during cold start when the secondary air system is working the lambdas will be running open loop so not giving feedback to the ecu.
 

TimR

Member
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2,654
Interesting..mine ran pretty lumpy after returning these(?) codes ( sticking valve? it hasnt repeated!)

We discussed this when @Lozzer asked..
What does the over rich fueling, unburnt, do to the headers/cats/lambdas..?
 

Oneball

Member
Messages
11,071
Interesting..mine ran pretty lumpy after returning these codes ( sticking valve? it hasnt repeated!)

Wouldn’t surprise me, the ecu increases the fuelling to make it richer when the secondary pump is on, it heats the cats by burning the rich exhaust in the manifolds hence the need to inject air.
 

TimR

Member
Messages
2,654
I forget that closed loop is uncommon enough that I should check myself before I reach for my usual assumptions...! :rolleyes:
 

Lozzer

Member
Messages
2,280
Interesting..mine ran pretty lumpy after returning these(?) codes ( sticking valve? it hasnt repeated!)

We discussed this when @Lozzer asked..
What does the over rich fueling, unburnt, do to the headers/cats/lambdas..?
Yes, I decided to leave well alone for fear of damaging the cats. Maybe the engines that don't have the system fitted have a different cold start map, how would we know.
 

TimR

Member
Messages
2,654
It’s a nuts set up for sure...
Cats to sort emissions but add extra fuel whilst they get up to temperature...which has to produce more exhaust waste....?
Probably wise not to second guess the ECU madness....
 

alfatwo

Member
Messages
5,517
It’s a nuts set up for sure...
Cats to sort emissions but add extra fuel whilst they get up to temperature...which has to produce more exhaust waste....?
Probably wise not to second guess the ECU madness....
Its the same system for all manufacture's of the day, not just Fiat/Ferrari/ Maserati..
Lots of cam bus fault codes on the web, keep you going on lockdown for a few weeks;)

Dave
 

jasst

Member
Messages
2,313
It only pumps air into the exhaust system when the engine is starting from cold!
Earlier engines don't have this.
If you have running problems it wont be entirely down to the air pump system!

Dave
Exactly, Emblem told me it only runs for about 30secs on cold startup.
 

GroovyBoovy

Junior Member
Messages
61
I managed to take the air delivery tube off the car, Maserati are really keen that you don't remove it without taking the whole engine out. The top looks lovely, but underneath the smaller tube, 1 have found 2 tiny rust holes, one for each bank, Looks far to delicate to be welded. I'll clean off the rust and see what I can do to fix it.
 

sparkplug155

Member
Messages
126
Did mine last month. Cut most of the rusted small pipe off - just left about 4 inches of decent stuff at each end and then joined them with some thick walled silicon hose and tie wrapped it to the main pipe. I originally thought I'd use kunifer brake pipe but decided against it in the end.

69325
 

TimR

Member
Messages
2,654
I managed to take the air delivery tube off the car,.... Looks far to delicate to be welded.
It is brazed originally....Presumably because of the delicate dimensions.
Im about to simply connect the two pumps with silicon pipe. Dont forget to include the t-piece junction on the drivers side....


I managed to take the air delivery tube off the car, Maserati are really keen that you don't remove it without taking the whole engine out.

I guess because its such a ball ache to remove ..?! :rolleyes: