Floods on start/running rich

[anonymous1]

Hi,

For a month or so now, I have been have had an issue with starting the car. This is intermittent and as such I haven't paid it as much attention as I probably should've.

When I start the car it is normally fine and turns over quickly. However, every so often the revs will stay at around 12-1400 and the car will judder and in some cases cut back out. I've found this is due to the engine having flooded. Once running, it seems to continue to run rich with white smoke and a heavy smell of petrol from the exhaust.

I'm unsure of what would cause over fueling on start up and was wondering if anyone could point me in the right direction.

In the past I have changed the intake/exhaust gaskets, the throttle body gasket, the down pipe to mainfold gaskets. Replaced the elbow behind the MAF as this had a split. Others parts have been changed to, but these seem like the ones that could poss be linked to me? I did also change out the sparks last time it happened and disconnected the battery to allow the ECU to reset.

I have searched the forum, but only seem to note people having a problem with the car running rich in general and not so bad that the engine floods on start up.

Cheers in advance for any advice. :D

[Morgenster]

FPR or injectors unless you're flooring it when cranking.

[anonymous1]

FPR or injectors unless you're flooring it when cranking.

Hi,

Thanks for the reply, I forgot to mention I had changed the FPR and the hose that goes from it to under the intake.

I haven't replaced the injectors as yet, but have been considering doing so.

Also, I managed to get the codes read earlier today and it showed as being a faulty MAF, just looking into getting a replacement one. Stealer only wants £380.00ish, so may order 2 just in case one goes whilst I'm out and about! :D

Cheers again on the reply.

[whiskychaser]

White smoke is usually steam, not fuel - thats black. Are your plugs sooted up? Fast idle makes me think idle control valve. Sure that can be checked with a meter but my Bentleys is in a box somewhere :-( You can clean the MAF but most important is that the wire is intact. The wire glows when you switch off so just remove the airbox and have a look? You know what the code was?

[bubba966]

Vac leak throws a MAF code as well. Had an M50 that was having a no start issue that threw a MAF code. Replaced the MAF and still didn't run. Found out after that that a MAF code can mean a vac leak as well. Turned out a $6 vac hose connector was the problem after throwing a good amount of $ at new parts.

[anonymous1]

Hi Whiskey/Bubba,

The fast idle only happens on the initial start-up, whilst the engine seems to be struggling to keep going. Once the car is warm and in general my idle is only about 550? I've had the MAF out and the wire is intact, haven't checked for it glowing as yet thugh.

It didn't bring up a code at the garage, it just came up stating MAF issue - not present (last occurred 8 starts ago). I've found I can get a second hand one for £95 including delivery and was looking to order it today as I need the car to be reliable for the weekend. So here's hoping it is the MAF - otherwise I'll prob end up at the side of a country road with sheep for company. :(

Last time I changed plugs they were sooted and comparing to the pictures for diff conditions, they showed as the engine having been running too rich. I was thinking steam on the exhaust, but the recovery guy who came out last time reckoned that, along with the smell of petrol (which is strong at the exhaust until it's been running a good while) indicated running rich.

I've replaced quite a few of the vacuum hoses as I've been able to get to them, but no doubt there are a couple I haven't done as yet. Looking at them as best I can, there aren't any obvious cracks or tears in the ones I can see. When I changed the intake gaskets, I did change the hoses under there at the same time.

COlin - any joy on rebuilding that gearbox?

:D

[Morgenster]

Given that your idle can vary from 550 to 1400 I'd guess the idle control valve is just fine.
- how long does it take the car to go from open loop running (rich on startup is not very abnormal) to closed loop running (idle to 550 and no fuel smell)?
If your engine really pissed itself with fuel you would be able to crank just once or twice and then the engine would likely be a goner. So the problem's not so bad, yet.
-Does your idle keep at a steady RPM or does it start to hunt, fluctuate or shoot up and down anytime during warmup or driving? If no then I'd hazard there's not really a vacuum leak or a really minor one.
Motronic is a bit of a bitch sometimes and it's 'diagnostic codes' can be very misleading so they are pretty useless. It's best to look at a number of parameters that are measurable like engine temp, rpm, exhaust gas composition, fuel pressure, vacuum measurements, resistance and voltage testing on sensors, etc. etc. It's little nagging running issues that are more work to diagnose correctly because the root cause is often a component that hasn't completely failed and may appear to be working correctly.

[anonymous1]

Given that your idle can vary from 550 to 1400 I'd guess the idle control valve is just fine.
- how long does it take the car to go from open loop running (rich on startup is not very abnormal) to closed loop running (idle to 550 and no fuel smell)?
If your engine really pissed itself with fuel you would be able to crank just once or twice and then the engine would likely be a goner. So the problem's not so bad, yet.
-Does your idle keep at a steady RPM or does it start to hunt, fluctuate or shoot up and down anytime during warmup or driving? If no then I'd hazard there's not really a vacuum leak or a really minor one.
Motronic is a bit of a bitch sometimes and it's 'diagnostic codes' can be very misleading so they are pretty useless. It's best to look at a number of parameters that are measurable like engine temp, rpm, exhaust gas composition, fuel pressure, vacuum measurements, resistance and voltage testing on sensors, etc. etc. It's little nagging running issues that are more work to diagnose correctly because the root cause is often a component that hasn't completely failed and may appear to be working correctly.

Hi,

That's the pain, it seems only to be really bad until it warms up (which tends to take about 10 mins driving) and then the petrol smell goes. But until then you can smell it from by the drivers door sometimes. I have had it flood the engine a couple of times on start up, but very rare.

Other than this, the RPM is steady at between 550-600 at idle once warmed up. On a good day it's at about 7-800 on warm up. No real driving issues, occasionally feel like I have slight power loss, but then it'll kick in again. ;)

I used to have a fuel leak and this was dripping onto the sensor under the intake at the front. (Think it's the engine temp sensor, but not definate?)

Was looking to order the MAF before 14:00 today for delivery tomorrow/Fri, but not sure it'll be worth it now. Suppose I can always resell it if it turns out mine isn't bad though. (sure I'd lose some value on it, but hopefully not too much)

Thanks for all the advice. :D

[Morgenster]

Try the MAF first then and see what happens. Could still be the culprit.

[anonymous1]

I ordered the MAF earlier today and should be here for Friday at the latest, so in time for drive at the weekend. I'll let you know if I notice any difference.

Thanks for the help.

On another note, I also ended up ordering a new rear trailing arm assembly as well, as I've been told the offside one is bent to a degree that makes it impossible to do the rear tracking... think that one might be slightly trickier and time consuming than changing the MAF though. Here's to fun times! :D

[whiskychaser]

Last time I changed plugs they were sooted and comparing to the pictures for diff conditions, they showed as the engine having been running too rich. COlin - any joy on rebuilding that gearbox?
:D
Mixture is controlled by the ECU and that take signals from the various sensors. So as Morgenster says you need to look at them. I dont see ALL the injectors leaking unless you are extremely unlucky. Did you take them out or am I mistaken?

On the gearbox front, time seems to be taken up being gardening assistant. But the husband of one of Alison's workmates is getting a new shed to put his train-set in. Which means I get to go play trains AND I get a nearly new shed too! So finding the fault isnt that far away:D

[anonymous1]

Howdy,

MAF came today and fitted it before, car starts fine and doesn't seem to be running rich so far as the super strong smell of petrol has gone. Took it out on a small test drive before and it seems (probably in my head) to feel a bit smoother on accel and running. Got a 170 miles trip over the weekend, so that should hopefully give a better idea.

I'll still be checking the other sensors when I get a chance just in case.

Cheers for the help. :D

[e34.535i.sport]

Howdy,

MAF came today and fitted it before, car starts fine and doesn't seem to be running rich so far as the super strong smell of petrol has gone. Took it out on a small test drive before and it seems (probably in my head) to feel a bit smoother on accel and running. Got a 170 miles trip over the weekend, so that should hopefully give a better idea.

I'll still be checking the other sensors when I get a chance just in case.

Cheers for the help. :D

Glad it sorted it!!! Fingers crossed for the long temr fix... Now just for the trailing arm ;)

[anonymous1]

Glad it sorted it!!! Fingers crossed for the long temr fix... Now just for the trailing arm ;)

LOL! The trailing arm is looking like it'll be fun. Going to order new bolts and nuts tomorrow. Got to take off the collar nut from the wheel hub, which from Bentley is tighten to a worryingly low torque of 250Nm. Can't remember if the torque wrench even goes up to that? If not, then may have to consider a new one. Think you may see another thread popping up shortly about this one! :p

[e34.535i.sport]

LOL! The trailing arm is looking like it'll be fun. Going to order new bolts and nuts tomorrow. Got to take off the collar nut from the wheel hub, which from Bentley is tighten to a worryingly low torque of 250Nm. Can't remember if the torque wrench even goes up to that? If not, then may have to consider a new one. Think you may see another thread popping up shortly about this one! :p

Hmmm IIRC the torquey we got only does up to 200nm... If it were me I'd use that then swap to 'big breaky' and put a bit more on it! :D

On the bright side you only have that big one to remove in place of my six annoying little hex bolts! *Should* be a piece of p*ss mate. :D

[anonymous1]

Hmmm IIRC the torquey we got only does up to 200nm... If it were me I'd use that then swap to 'big breaky' and put a bit more on it! :D

On the bright side you only have that big one to remove in place of my six annoying little hex bolts! *Should* be a piece of p*ss mate. :D

LOL! I wish, I've got to disconnect it at the diff again... so time for me to try and get past that annoying cable tie again!!! :(

[e34.535i.sport]

LOL! I wish, I've got to disconnect it at the diff again... so time for me to try and get past that annoying cable tie again!!! :(

Wo strange - U gotta take the axle off altogether? I thought it woulda been a 'leave it hanging' job! :D

(Hey this is well quicker than text! LOL!)