E30 325i SE 1991, Running problems. Info required.

[Rich_e30325i]

Hi there, new first post.

I was wondering if anybody could be of any help with my bmw 325i.

Starting...
Car sometimes fires up first time, sometimes it will not but it will turn over and over and over and over, then i stop, go to start again and it fires up right away.

this happens hot or cold.

Running....
1st gear pulling off ok, get to around 2-3k and it starts to bog down, i put my foot down some more and it will bog some more then just take off like a bullet, then it does it in 2nd and so on.

Its like if i drive ok it does not like it, but full throttle its absolutley fine ???

At 70mph on the motorway, foot to the floor, runs fine, the moment i let off the throttle to cruise at 70mph it judders like a misfire or (pinking) as a friend described.

I have changed the following already to no avail....
Coil
Plugs
Distributor
Rotor Arm

also sealed up an intake areas with jubilees, like round the idle control valve etc as there is nothing to stop leaks on this area.

Please give me any info that might be the culpret of these highly annoying problems.

Many thanks and if i think of anything else to add, ill post again.

Thanks in advance again.

Richard

p,s.

Parts are easy to obtain for this car as i have a 2nd as a doner car so i can mix and match if needed.

[Nelly]

It might be the throttle position senser (under the trottle body) or try another ECU in it.

Sorry i can't help out much more Richard but, brain has gone to sleep atm.

Neil.

[Rich_e30325i]

Great, will look into it, anybody else have any ideas ?

[abelai]

failing crank postions sensor. If it doesn't get a CPS signal then it won't start.

[Rich_e30325i]

great, thanks again will also change this today. many thanks.

im guessing this will also cause problems on the running of the engine too.

im a bmw newbie, i do motorcycle mechanics mainly but have a friend that knows bmw 325i inside out but hes working solid for 2 weeks at brands hatch at the mo so im going solo.

lol

thanks for your help and any other info that might help me out in this annoying situation would be greatly recieved.

[abelai]

intermitant CPS signal can cause all sorts of problems. Try cleaning the connections and the sensor its self. You can see it at the front on the drivers side probably covered in oil and crud.

[Rich_e30325i]

ok great,
Do you know if there is any way to check if this part (CPS) is faulty ?

I have changed the famous blue thermostat today, and have noticed not much difference (if any) in engine smoothness.

Also, I have discovered my exhaust is blowing from the front pipe, could this also be a cause for lumpy running on these engines (2.5l m20)?

Many thanks.

[georgen]

Have you tried removing the ICV and AFM and giving them a really good clean with carb cleaner ? I tried this today, along with replacing a leaky air hose, and the difference is unbelievable. It's got to be worth a go right ?

[Brianmoooore]

For the starting problem, try connecting a small 12 volt lamp between the + terminal of the coil and the car body.
The lamp should light when the ignition is on, and stay lit while cranking. It's possible that your ignition switch is intermittently faulty.
Another possible cause is that this is the first sign of a failing fuel pump. The supply voltage to the pump drops by a few volts when the starter motor is operating, and this might cause it to stall.
For the part throttle juddering, check out the fuel pressure regulator. At low throttle openings, the vacuum in the plenum chamber is transmitted to the FPR by a small rubber tube. If the diaphragm in it is defective, fuel can leak through, and get sucked through the rubber tube, where the port into the plenum acts like a seventh injector, causing a rich mixture and consequent juddering. The easiest way to check, is to temporarily replace the pipe, or part of it, by a clear plastic pipe, so that you can see if any fuel is passing through.

[Rich_e30325i]

Wowzers, many thanks, you all seem to know your stuff.

I will carry these tasks out tomorrow after much research on the areas of which georgen and brianmoooor have spoken of. i will let you know the outcome.

Thanks again for your time.

Rich


PS
could somebody point me in the direction of the FPR on these models?

many thanks.

[E30BeemerLad]

See where the arrow is pointing to the thermostat? The round thing with the hose coming from it is the FPR

[Rich_e30325i]

ok great, cheers beemerlad, i got it now.

[Rich_e30325i]

Have you tried removing the ICV and AFM and giving them a really good clean with carb cleaner ? I tried this today, along with replacing a leaky air hose, and the difference is unbelievable. It's got to be worth a go right ?

Yeah done this today, seems to have made a small difference but the juddering is just really annoying me now....

So far i have changed the following to no avail.....

COIL
LEADS
DISTRIBUTOR
ROTOR ARM

Also i have cleaned ....
AFM (Air flow meter)
FPR (Fuel pressure regulator)
ICV (idle control valve)
CPS (crank position sensor)

and also sealed up and made sure there are no vacumm leaks.

The juddering is there all the time and the car also boggs down to no power around the 2500- 3200 rpm range. I think this is a conclusive problem which effecting both the motorway juddering and this annoying bogging down around 2500-3200rpm.

Any info is greatly recieved...
Im now thinking weather or not to swap the ECU from the old car to my currently annoying one.

What do you think ?
Are there any downsides to swapping an ecu, i Heared that they require the full rev range to be obtained for them to work correctly again ?

Thanks

Rich

[Stan0870]

hello mate,i swapped my ECU in another one of my vain attempts to cure my starting problems, as long as you match the codes off the unit and the precise fuel injection system ie- motronic - early motronic etc.. its probably worth a stab if you can pick one up cheap enough?, it seemed to have no adverse affect on my engine or electrics. but i could stand corrected of course!! when you say you changed parts of your high tention system ie:- dizzy cap etc.. was that recently?

[Rich_e30325i]

yeah past few days though i think the problem has been cured but i got bored and went in. it is a suspected fuel pressure regulator....

I took mine off my car had a look...was like hmm ok yer great (how do i know what its functions are lol) gave it a tap kick wollop and a clean...then thought to myself no this might not work...so i went over to the bmw that has sat there dormant for a few weeks to notice that when i removed this part there was fuel in there along the injector rail yet a car that i had only just used was dry of it.....

Anyway, its swapped over, car is not running like a bag of crap in the 2500-3200 rpm ranges, though im going out in it this morning and if it does it again i shant be too happy.....grrrr

i just hope this has fixed the judder too becuase the only thing i have left to try...(becuase ive done most of it already) is the ecu.....HMMM

Its a good day today because.....IM getting an LSD too i really hope i dont fucking crash it lol.

[fivepint]

I had similar symptoms and with brians advice the TPS below the TB was cleaned and calibrated and also the loom connection below the inlet manifold which carries signal from Coolant temp sensor and injectors was cleaned this made a massive difference... worth doing as it costs nothing