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Slow acceleration, stuttering, what to check next?

4416 Views 8 Replies 5 Participants Last post by  CaptainTrap
99' 318i e46 1.9

Car has recently failed an inspection, but thats just the beginning of my problems.

It is stuttering when you first get going in the morning...while the secondary air pump is on...needs about 5 minutes to warm up. Even after a warm up, when you hit the gas pedal hard to the floor, not much happens...you have to kind of push it down half way before it has steady acceleration. also, it won't go over 5krpm. like its blowing air or something.

The secondary air pump, here:

http://www.ebay.co.uk/itm/Secondary-Air-Pump-Emissions-316i-318i-16v-N42-BMW-E46-3-series-/380398492804?pt=UK_CarsParts_Vehicles_CarParts_SM&hash=item5891845c84

seems to be leaking around the edges when the car starts initiallly. but seems ok when its warmed up. a lot of hills around here...seems to struggle with them.

also, i found a vacum leak (see
http://realoem.com/bmw/showparts.do?model=AL32&mospid=47631&btnr=11_2071&hg=11&fg=45 and replaced the hoses 1,3, 5, 12

Have noticed air filter box is not sealed either, so I've ordered the replacement clips as it seems to have gone missing

Checked the ignition control module (with a used one, but might put old one back on as it seems worse)

Car needs a new muffler, so could that be blocked?...should arrive soon

Replaced the fuel filter, spark plugs and oil change

Any ideas what else I could check?

let me know what you think cheers
1 - 9 of 9 Posts
Are you throwing an SES light? If so, get it scanned and give us the codes. This will help immensely.
yes..light is on...will have to go get it scanned cheers

btw, any recommended diagnostic tools?
Most of them will tell you the codes you need to know. We'll go from there.
yes..light is on...will have to go get it scanned cheers

btw, any recommended diagnostic tools?
My car was doing the same thing, results my Air Intake Hose had a small hole in the back allowing air to escape which made my car stutter and I would force the car so much it would simply keep turning off until it was warm. Check that out, if so I removed the hose and covered the hole with special black tape that does not melt when hot until I could replace the entire hose and it worked just fine.
ok thanks.

got two error codes. 141 & 171
See attached.

I've also noticed the secondary air pump leaks slightly from the edges when it warms up, but it seems like normal operation?

Posted a video. When you hit the accelerator hard, the revs don't go up, its sounds like its sucking air. Notice in video, you hear a pop as well.

Attachments

OK, seems like its the MAF is bad. Disconnecting it and car comes to life as normal. Going to order a new one. Does anyone know if its ok to drive the car temporarily, while its disconnected?
Atleast mine got crazy when i was dumb and didn't put plug properly, not sure what it does when unplugging it completely.
OK, seems like its the MAF is bad. Disconnecting it and car comes to life as normal. Going to order a new one. Does anyone know if its ok to drive the car temporarily, while its disconnected?
i have a used MAF which i replaced with a new one back when I was chasing a vacuum leak. I am 80% sure the used one is fine. Turned out my valve cover gasket had a crease and was taking in un-metered air

let me know if you want to buy it off me. I will give a great price for it and you can install it and confirm it works before you pay me.
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