Technical Major running problem

[m20b25]

Car is a 2000 1.2 16v cable throttle

This started yesterday, I drove down the road and the fuel just cut out in 6th gear, I coasted to a halt. Started up, driving perfect then it cuts off the fuel again. Staggered home and tried a test drive. I found out that if I pressed the accelerator all the way to the floor, the car would go, badly, but it would drive at least.

Since then I have replaced:

• Crank sensor
• Throttle body and stepper motor
• Coolant temp sensor
• Air mass meter

In that order.

The crank sensor is brand new, it improved the car alot but it was still cutting the fuel while driving. After changing the temp sensor and tb with motor the car was going well until about 2 miles of driving, then back to cutting the fuel unless I floored it. All other parts are known good working parts. All the connectors for those parts were cleaned and electrical contact spray applied, all to no noticeable effect. I've gone through the fuel system, the pump is new, fuel injector pipe is new, the o2 sensor is a working part and the injectors are new. Connectors cleaned to match.

Its as if when I'm driving and I don't have the accelerator all the way to the floor, it gets no fuel and splutters or it won't accelerate. All the way to the floor and it goes. Taking off is a nightmare for me, the engine and the clutch as it involves learner style revs to go :bang:

I am at my wits end as it is very difficult to get around anywhere in this car. Has anyone experienced this problem in their own car or can anyone shed some light on this situation? I don't want to have to send it to the local Fiat dealer, 50 miles away

Any help or input is much appreciated!

 

[fabiomsouto]

Check the fuel pump first (being new does not garantee you that it's working) and change the fuel filter.
Does the injection light turn on on the dashboard?

 

[m20b25]

Check the fuel pump first (being new does not garantee you that it's working) and change the fuel filter.
Does the injection light turn on on the dashboard?

The pump was put in about 5 months ago. I took the cover off and listened to it as I was driving, its working correctly. Fuel filter is incorporated in the pump, can't be changed. The injector light does not come on while driving, just the usual check at the start and off again as normal

My dad had a look yesterday evening. He cleaned up the maxi fuses and said it was running great, just a splutter here and there. He suggested that I went round and cleaned the maxi fuses thoroughly, which I did and its still not working right

I decided to take a video of what I'm talking about. It does not idle right. Its as if the car is getting no fuel at any throttle position but wide open it works fine. This happens after about a mile of driving.

The video and sound become un-synchronised at the end, don't mind the rev counter and the noise not matching up


Could it be the injectors? Faulty ecu? If it needs a new ecu so be it, I just have a feeling its something simple I've overlooked

This is becoming very irritating. I just want my car back working alright again

 

[Adrian Bravo]

That looks very annoying, the ECU light is not on so the car doesnt have a clue it must be something simple

Have a look at the fuel cut off/inertia switch and I guess you have double checked the crank sensor gap and positioning is correct.

Seems your fairly certain its fuel related though, so double check everything in that system. Maybe the fuel pump wiring been damaged in your boot/rear seat floor area?

 

[m20b25]

That looks very annoying, the ECU light is not on so the car doesnt have a clue it must be something simple

Have a look at the fuel cut off/inertia switch and I guess you have double checked the crank sensor gap and positioning is correct.

Seems your fairly certain its fuel related though, so double check everything in that system. Maybe the fuel pump wiring been damaged in your boot/rear seat floor area?

Thats what I'm thinking and its looking like when I find out I'll be asking why I didn't check this first

I had a look at the cut off switch, it hasn't been disturbed or damaged and looks to be in good working order...

I got fuel pump relays, I remember on the Tempra when the pump went it destroyed the fuse and holder too, meaning we could use it on lpg only untill we found out what was the problem.

Does this system have a fuel pressure regulator? Or is it built into the pump? Is it possible the wires are faulty going to the ecu?

I've left the car unplugged all day, maybe a simple ecu reset might work?

Scratching my head all day... :bang:

 

[Adrian Bravo]

The fuel pressure regulator is built into the casing of the fuel pump assembly.


The inertia switch cuts off the ground supply to the pump.

 

[m20b25]

I'll try a different pump later this evening

 

[m20b25]

I didn't have to try a new pump

Problem is sorted AT LAST!!!

Now in true fashion, I'm not sure what caused it but I have my suspicions.

First I changed these relays and cleaned up the holder

Then I changed the lambda sensor for a known working part

Finally I took out the ecu plugs, cleaned them up and drowned them in wd40

And after a test drive it worked fine. Another longer test with different throttle positions and flat driving, still working great. Finally a 50 mile round trip, running perfect

In my opinion, I think the relays were to blame. I took them out and the ends were black. I actually bought new ones earlier today by chance its just my opinion though.

The main thing is its sorted and back to happy motoring Thank you all for your help!!!

 

[Bravo16VSpoonz]

the car would have a cut off switch, maybe when flooring it, its injected too much fuel, and ecu maybe thinking it being a fault, nd would off the fuel...just a thought of course..not sure if it works like that though...



edit:- didn't read the above:/

 

[m20b25]

It's happened again people

But I have the answer

The exact same nonsense: no response until full throttle, very annoying to drive. So I narrowed it down to 2 components this time due to my last post on the issue: pump relays or the oxy sensor. Swapped the relays 1st, they made no difference. So I disconnected the oxy sensor. Started up normal, ran faultlessly, accepts half throttle. 150ish miles later the car is returning faultless driving

What caused it? Over here were very fond of cheap, unbranded fuels. Here is the result of this cheap petrol in action on a bad day. At its worst it can destroy an engine

I'll get a new oxy sensor and place the results here

Beware everyone!

 

[paultaylor6003]

iv been havin issues sounds as if wants to cut out when runnin normal fuel. when i use shell super unleaded it runs perfect not a flutter, bit of a f****r tho paying £1.50 a litre. lol but curing it. i suppose your cars only as good as the last owner kept it. its a shame.

 

[iancrofty]

It's happened again people

But I have the answer

The exact same nonsense: no response until full throttle, very annoying to drive. So I narrowed it down to 2 components this time due to my last post on the issue: pump relays or the oxy sensor. Swapped the relays 1st, they made no difference. So I disconnected the oxy sensor. Started up normal, ran faultlessly, accepts half throttle. 150ish miles later the car is returning faultless driving

What caused it? Over here were very fond of cheap, unbranded fuels. Here is the result of this cheap petrol in action on a bad day. At its worst it can destroy an engine

I'll get a new oxy sensor and place the results here

Beware everyone!

Hello m20b25,

so you have changed the lambda sensor? or is the oxy sensor different?

cheers
ian

 

[m20b25]

Hello m20b25,

so you have changed the lambda sensor? or is the oxy sensor different?

cheers
ian

Lambda sensor. Caused by poor quality petrol. Budget £60 ish for a new one

 

[varesecrazy]

Lambda sensor. Caused by poor quality petrol. Budget £60 ish for a new one

as they said = the diagnosis for this being faulty is unplug it's lead to the loom, ( so the ECU uses a "standard reading"),
and see if the engine runs better = no improvement = save yourself £60!!,
Charlie

 

[m20b25]

as they said = the diagnosis for this being faulty is unplug it's lead to the loom, ( so the ECU uses a "standard reading"),
and see if the engine runs better = no improvement = save yourself £60!!,
Charlie

I have all the aforementioned parts to change anyway so no costs there for me