Unknown issue with 318is power flucuations

[Clownshoe]

My old car has had this issue for years now, I sold it with teh problem and the new owners has had more time to find the sourse but no luck so far.

When you are driving there is a very faint drop and increase in power. You bearly feel it but the econometer ossilates by about 1l/100km. The cycle is proberbly about 2 seconds. You only see it when cruizing along.

He has cleaned the MAF (might have improved things slightly) and there are no cracks in fittings. Its been on the diagnostics and no issues found. A number of people have looked at it and no closer to solving the problem. Appart from this the engine runs like a dream.

 

[Major]

List all of the things you've done/checked/replaced. I had this problem on my car and it degraded to the point where the car stalled and was never to start again. Turned out to be a wimpy fuel pump.

 

[DonovanPorter]

TPS ?

 

[S///Mon]

My 318is has been doing the same thing and I have been advised to check my fuel pump. Still the factory installed one from 1998! Could also be a combination of a faulty airflow meter and "wimpy" fuel pump. Mine isnt too bad ATM but will be sorted out in the next 3 weeks (Payday :clap: )

 

[Clownshoe]

I am trying to get hold of teh guy that has it for a list of what he has looked at. I have been through a major service where I changed all the "consumables" like spark plugs, plug leads and the the other stuff. I believe he may have swapped out the computer aswell as cleaning the MAF.

The fuel pump seems like a logical option, I suppose the computer overcompensates when it senses too little fuel? It definitely feels like the computer is compensating for something. Power drops and then it recoveres and so on.

Thanks for ideas i will keep you posted.

 

[blaze94]

Does this happen at idle or driving? Hot or cold?

 

[jog5000]

Howsit Stevie!!

I'm the guy who bought it from him - I've done the general things - plugs, leads, tried a different ecu. There are no cracks in the piping, tried a different MAF.

It happens when any extra revs are given, at slow speed, high speed, and is particularly noticable in the morning for the first 1km of driving... after that its just a feeling in the back of the mind that the car is ever so slightly lurching and you can see the econometer going up and down.... Its not bad in that the car is dying or lurching... but it is noticable if you really concentrate on it...

 

[Major]

I think you should attack the fuel system. Fuel pump, filter, FPR and lines.

 

[Clownshoe]

Is there a way of measuring fuel pressure? Does it not show up as an error code?

Fluctuations... and fluc you westerners too!!!

 

[zaleonardz]

Nope,

You can measure fuel pressure by inserting a pressure meter, which is then plugged inline in the fuel system.

I dont know how much they are, I need to get one.

LZ

 

[Ricky318i]

do not remove the line at the fuel pump to measure the fuel pressure unless you have new hose clamps

 

[jog5000]

Clownshoe, as soon as you get home, we'll have to do a bit of stripping. I mean stripping of the fuel bits... have to get rid of that damn ever so slight surge....

By the way, someone stole my bloody licence plates!

 

[Clownshoe]

By the way, someone stole my bloody licence plates!

Ja, we believe you. Its the cops you have to convince

 

[jog5000]

reported it to the cops when it happened. Was just the front plate. Got a case number and all!