What i've been messing with for a while...

[GTMaster]

Hi,

I thought i'd fill in other 400 series owners about my problem as it may help in future torubleshooting. It caught me by surprise as the car has been running perfectly for the past 8-9 years.

Started off with the car not being able to accelerate properly and when you floored it it just didn't go above 2000-3000 rpm. Read fault codes, had the "usual" fault that's been there for a long time 412 and a code for the Lambda Sond. Checked the dist. cap and found corrosion on the centre ht lead. Cleaned it, took cap off and cleaned the segments too (had some deposit on them). Checked air filter and air passage which isn't blocked. Tested it, still the same. Plugs and all the leads were changed recently, the plugs were nearly white. Checked for spark, had spark from coil and at plugs. Removed fuel line off injector rail and worked the fuel pump from the relay and found the fuel to be insufficient (didn't look like 3.5 bar to me). Changed the cap and rotor in the hope that maybe at higher rpm the spark maybe weak. After replacing it the car didn't start at all, plugs had petrol on them. Checked for spark at plug:no spark and no spark coming from ht coil. Cleaned the flywheel sensor which was clean and nothing. Had a LED light tester put onto the sensor and no signal. Changed the flywheel sensor and still no spark from ht coil. Ignition module was working so had to change coil. After changing coil the car started and worked fine for a day. Removed fuel line again off rail and still the flow of the fuel seemed to be weak.

[GTMaster]

Since then i've been trying to fing out why there isn't enough fuel going to the rail. The pump is working and managed to test the fuel pressure at the pump using an oil pressure meter. It reached 3.5 bars but would've been better to measure at the rail. Removed line off fuel pressure regulator and according to the service manual 0.5l of fuel has to come out after 30 seconds. This was good too (?). During this time i was checking for fault codes as the car was used sometimes and it once put in a code for the MAP sensor. I measured the sensor with a multimeter and it seems ok so erased codes and it hasn't come back since. Checked all vacuum hoses in the engine bay and they are all fine. Had the fuel filter changed yesterday. It had a Bosch one which seemed to be fairly dirty even though it was changed not long ago. Afterwards car ran perfect then started to have the same problem again. I've even driven without the petrol cap on but it didn't change anything. The exhaust pipe doesn't seem to be blocked either as the gases are leaving as it normally did. I have noticed though that after running the engine and opening the fuel cap there's a slight hiss or gas sound sometimes followed by a quiet gurgle. Any good way of checking whether the breather pipe is clean?
So any help/comments welcomed maybe i've missed something. It would've been good to check MAP sensor with the engine running, as well as the Lambda sond and also the throttle plate sensor with an oscilloscope. Also a proper fuel pressure meter would've been good too...
Hope i have been able to give hints to other owners who are having similar problems with their car.

[B20F]

I have noticed though that after running the engine and opening the fuel cap there's a slight hiss or gas sound sometimes followed by a quiet gurgle. Any good way of checking whether the breather pipe is clean?

This is normal to hear. There should be a slight overpressure in the tank to guide the petrol fumes to the evap charcoal cannister. The cannister is located at the lhd side of the radiator if you stand in front of the car. So no breather pipe, the cannister has a valve which opens when engine is warm and leads the petrol fumes to the intake manifold to be burned off. The tank itself has 2 valves, one overpressure and one underpressure.
I would first check the lambda, here's a great howto test it.
The non starting can also be caused by a bad ignition lock.
ps;
which engine?

[GTMaster]

Hi,
Thanks for the reply.
It has the 1.7i cat engine (B18FP). I know that it's normal to hear that sound from the petrol filler cap in summer but i didn't think that i'd hear it in winter as well since it's colder and it doesn't expand as much as in summer, though in cold weather it has to let air in....( i always mix up these systems with the ones in older cars without evap canisters) Could the tank over and under pressure valves get blocked in any way, and then what is the second pipe running above the filler pipe going to the tank? (it's molded in one piece with the filler pipe).
I wouldn't think it to be the ignition lock as even now it starts fine and runs great on idle.
I've wanted to check the lambda sond but i just can't get under the car.
I've even tried what you once mentioned in another thread by taking off the evap canister vacuum hose off the manifold and blocking it off. It didn't seem to make any difference...
This week i'll be taking it in to someone who'll hopefully be able to look under the car properly.

[B20F]

The lambda can be tested in situ. The measurements are done on the connector from the lambda. Just follow the wire coming from the lambda to the connector.
The second pipe in the filler you mentioned is the one for the expansion tank.

[GTMaster]

Well a breakthrough might have happened. Seems it was the fuel pump that was causing the problem. I had thought of it but wasn't sure since i never could measure the fuel pressure properly . Went out for a spin with an auto electrician friend of mine without the rear seat bank in place. He found the pump to be loud and upon reaching 3000-4000 rpm it went silent so we thought it must be the pump. Found one for a Fiat Brava since it had the same brand of fuel pump (will write up it's model no.) a Walbro, which fit perfectly. We hoped that it would be able to attain the same pressure and upon fitting it and starting the engine it was much quieter and the car ran well.
Hope that it'll keep running well since it is such a reliable car.