M52 start up issues

[ecorrea21]

Ok here's the deal, on a cold start up usually in the morning; the car starts up and the idle goes up and down between 500 and 900 RPM. I can here the air pump making poping sounds like a dragster at the starting line. Once the pump cuts off the symtom goes away and she runs great. The code reads a lean condition. I'm suspecting a leaking diaphram in the air pump. has anyone experienced this? or have any ideas what might be the problem?:help

I posted on E-39 site but I guess no ones had this issue on there five's

[maritusE36]

any check engine light? should pull a code for secondary-air malfunction. personally i would just replace the pump and valve for it if its never been done before.

[ecorrea21]

Yea I got a check engine light, I forgot the exact code but it was a lean condition on both bank one and bank two. Once she's at temp. it runs great. I'm going to put a vaccume gauge on it when its cold, see what it reads cold vs. at temp.
Thanks for your reply

[ecorrea21]

Ok here are the codes
P0505 = Idle control malfunction
P0170 = Bank one fuel trim
P0173 = Bank two fuel trim
P1188 = Fuel control bank one
P1189 = Fuel control bank two
the last code was P1250 but I couldn't find out what that code was:help

The pressure hose from the check valve to the aux. air pump feels like a Gummie bear and also looks to have some cracking so today I'll get a new one. my problems only exist when the air pump is running during the first few minutes of start-up hopfully this will cure it. If any one can help with the code P1250 and let me know what it is I would appreciate it greatly

[keeptheuroalive]

I would replace the air pump and reset the codes to see if they come back. I suspect the air pump is your problem.

[Julian]

Why would the air pump be your problem? All that does is inject air into the exhaust manifold at start up to get the cats up to temperature. I had the secondary air pump go bad on my car and it ran perfect other than throwing a code for the air pump. I think you should be looking elsewhere for your problem.

I think it's that P0505 code.

[redflame]

i'd start with cleaning the ICV and injectors

-Sam

[ecorrea21]

I suspected the air pump because I hear loud popping sounds from where its located (like a dragster with a huge cam idling at the starting line) while it's injecting air, when it turns off everythings back to normal; no idle fluxuations, poping sounds stop and I've got smooth power thruogh the whole RPM range.
I was thinking that maybe, either because of the bad pressure hose between the check valve and the air pump, or possibly a hole in the diaphram in the air pump I have a massive vaccume leak causing the fluxuation during cold start-ups.
I already had the injectors cleaned, I'll check the ICV and clean it too anyway. I also bought the pressure hose for the air pump today

Anyone know what the code P1250 is?????

Anyway I just moved to Texas and my tools & Bentley manuals are still packed so I'll have to try and find them. I've got everything in storage and its gonna suck pulling everything out

[SergeK]

I have this same problem.. My airpump is dead.. as is an o2 sensor and a cam sensor.. i think 1250 is cam shaft angle sensor, but dont quote me...
The cam sensor WILL make your car idle like junk