Engine Problem - HPFP, LPFP, Injectors...or something else?

J

Jezzaaa

Member
Hi guys,

I've got a 35is 2012. For a while now it's been exhibiting the cold start hesitance which, if you ask on the forums, is usually one of the pumps or injectors. I've been carrying on using it since it didn't happen every time (particularly not if the fuel tank was full) and, once running, it felt fine.

So I've been telling my wife for months that it's going to fail at some point...and this morning, it did. It started on the button in fact, and only once I was accelerating up the road did it suddenly feel lumpy and gutless, and the engine fault warning light started flashing. In summary:

1. It still starts
2. When you rev it, it sounds lumpy.
3. If you try and drive it, it'll get you up to 20 or 30mph but no more than that (I managed to limp back home again)
4. At no point did the engine cut out or fail to start

So I was just wondering...is this behaviour (still starting but no power/lumpy) still in line with the fuel pump issues? Or does this sound different?

Ta,

J.
 
Hi ZM .... thanks for that. I was also thinking that fuel pump problems don't sound likely...presumably if one or other had failed/degraded, the engine would just not run...or only run for a short time until the burn rate used more fuel than the pumps were supplying.

I guess the coil packs aren't too hard to change, so I might buy one new one and do trial and error. If that doesn't work, then I guess the next one to check will be injectors...which is presumably a trip to the dealers.
 
I agree with Z4M. Most likely coil or injector.

But if you have also been having cold start hesitation then I would side with injectors. They will leak fuel into the cylinder and cause rough starts.

If you have a warranty drop it off at the dealer and let them worry about it. If not then you might want to rule out a bad coil before visiting a garage as they can be very easily replaced.

Eurocarparts had 15% off for black Friday and quidco will give you another 10% cashback. I picked up a new set of coils for a total cost of £120 last weekend.
I have a zero excess warranty so they would replace them as they fail but for £120 it saves the hassle of the car being off the road.

If ordering from ECP be very careful as they have a mistake on their site with part number compatibility. This link contains the correct Bosch part for our cars: http://www.eurocarparts.com/search/413110237/p/home
 
Sounds very much like the issue I had with my 35is - see my thread on it.
BMW ended up changing both pumps without resolution. Then they changed the injectors and problem fixed. All under warranty.
 
Jezzaaa said:
and the engine fault warning light started flashing
Click to expand...


So I was just wondering....
Click to expand...

This is why obd analysis is done.....
It 'could' be anything; a £10 sensor or a £500 fuel pump :roll:

35isDreamer said:
BMW ended up changing both pumps without resolution. Then they changed the injectors and problem fixed. All under warranty.
Click to expand...
So if you wouldn't have had that warranty, that would have been a £2500 repair or so?
 
35isDreamer said:
BMW ended up changing both pumps without resolution. Then they changed the injectors and problem fixed. All under warranty.
Click to expand...
So if you wouldn't have had that warranty, that would have been a £2500 repair or so?[/quote]

They said £3k at the time. I cannot recall if that was injectors only, or if that included the (unecessary) pumps replacements.
 
Thanks for the replies, all. No warranty I'm afraid...so I have given it to my trusted specialist this morning...he promised to check the diagnostics first, but said it doesn't always give them a good lead...so, failing something conclusive, promised to start with the easy stuff...plugs, coils, injectors first and let me know if there's any joy there. He said he's got spare ones of each of those that he can swap out. Once they're ruled out, I guess it must be the pumps. He's a good guy and doesn't take the BMW tech 'money no object' approach! ;)

I'll update you all when I get some news from the specialist.

J.
 
The pumps give different symptoms from what you describe..

I would get the fault code to a cylinder( it will probably just give a misfire fault code), then go into live data and determine whether the injector is working correctly.
Your man can look at injection values whilst undertaking a smooth running test and it may give a good indication if the injector is faulty..

A coil is cheap try once the car is stripped, so would be prudent to change it anyway..

Good luck
 
Jezzaaa said:
Thanks for the replies, all. No warranty I'm afraid...so I have given it to my trusted specialist this morning...he promised to check the diagnostics first, but said it doesn't always give them a good lead...so, failing something conclusive, promised to start with the easy stuff...plugs, coils, injectors first and let me know if there's any joy there. He said he's got spare ones of each of those that he can swap out. Once they're ruled out, I guess it must be the pumps. He's a good guy and doesn't take the BMW tech 'money no object' approach! ;)

I'll update you all when I get some news from the specialist.

J.
Click to expand...

Sounds like it's in good hands.

He's right about the diagnostics being crap for misfires. The only way I can tell is by when the misfire occurs. High RPM/high load misfires tend to be from plugs, Low/Mid RPM/High load from coils and injectors (when the car hits peak boost) and High load below the boost threshold has always turned out to be injectors for me. It's not completely accurate but gives a good point to begin troubleshooting from.

It's not unheard of for the cars diagnostics to mis-report cylinder misfires which really seems to confuse the BMW techs. I had that happening with a faulty injector and BMW spent 2 weeks replacing parts only to find it was another cylinder causing the problem.
 
Update from the specialist...needs a new set of spark plugs and two coil packs!

So you guys were on the money....getting it back tomorrow...and only a few hundred pounds worse off :)

Thanks again for the advise.

J.
 
Good man....


I might just throw some plugs in mine next week.. It has full BMW history,but thats no guarantee of anything...lol..
 
Hi, I'm new to posting here, nice to meet you all!

I'm interested in this thread as I've got a 2009 / 55k miles E89 35i which has recently started missfiring on cold starts. Luckily there was a week of warranty left so I got the car looked at and they couldnt find any fault codes, and suggested new plugs, which aren't covered under warranty :x

I'm happy with a the more simple tasks, I owned and maintained a Caterham for a number of years, but does anyone have any tips on the procedure to replace the plugs? I've seen you need a special socket to fit the plugs, and I think these are the right plugs - http://www.ebay.co.uk/itm/331410467031?_trksid=p2060353.m1438.l2649&ssPageName=STRK:MEBIDX:IT - otherwise am I missing something?

M.
 
If you are out of warranty and want to throw money at it try replacing the coils, Eurocarparts do them for £20 each.
Certainly on my 23i the plugs have a fine wire centre electrode, so would double check those.
Looking at the wear on my old plugs they look good for about 60k miles.
Quick look ebay, looks like there's a lot of quad electrode plugs.
 
martins said:
Hi, I'm new to posting here, nice to meet you all!

I'm interested in this thread as I've got a 2009 / 55k miles E89 35i which has recently started missfiring on cold starts. Luckily there was a week of warranty left so I got the car looked at and they couldnt find any fault codes, and suggested new plugs, which aren't covered under warranty :x

I'm happy with a the more simple tasks, I owned and maintained a Caterham for a number of years, but does anyone have any tips on the procedure to replace the plugs? I've seen you need a special socket to fit the plugs, and I think these are the right plugs - http://www.ebay.co.uk/itm/331410467031?_trksid=p2060353.m1438.l2649&ssPageName=STRK:MEBIDX:IT - otherwise am I missing something?

M.
Click to expand...

Those plugs have the right part number but the picture doesn't match up with what I have in my car. Mine have three ground electrodes and that picture only shows 1.

I doubt that plugs are the issue though. Best advice would be to extend that warranty.
 
Hi, thanks both of you, I've extended the warranty but it has a £100 excess so was keen to avoid that. If one or more of the injectors are leaky, would you just see/smell unleaded on the plugs?

Best

Martin
 
R.E92 said:
Those plugs have the right part number but the picture doesn't match up with what I have in my car. Mine have three ground electrodes and that picture only shows 1.
Click to expand...

I think the pic is wrong, the description further down describes them as:

Number of Poles: 3;
Click to expand...

Best

M.
 
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