2005 zafira brainteaser

dodzy

Ok folks, a few pints for the problem solver! Zafira 1.6 petrol starts on the button. Ticks over lovely. Once you rev past 1500-1600 it'll stutter and cut out. Starts fine immediately after. Drives fine under 1500-1600 rpms. Again, once you hit above this it'll die. Baffled! Suggestions?

dodzy

Anyone ?

XsApollo

Are you accelerating hard past 1600?
Does it cut out if you go really gently past 1600?
Maybe change the fuel filter and see if any improvement.

dodzy

XsApollo wrote: »

Are you accelerating hard past 1600?
Does it cut out if you go really gently past 1600?
Maybe change the fuel filter and see if any improvement.

No not hard, anyway you choose, it'll die, soft or hard acceleration. Fuel filter changed. No difference.

My gut is an ECU fault.

_Brian

We had a 2006 model of same car. Sometimes rough running and odd revving behaviour illustrated was sorted on the service by a "carb clean" to remove buildup.

dodzy

_Brian wrote: »

We had a 2006 model of same car. Sometimes rough running and odd revving behaviour illustrated was sorted on the service by a "carb clean" to remove buildup.

As luck would have it, there is a donor car there so all the obvious ones have been swapped out, bar the ECU. Coil packs, throttle body, cat, new fuel filter. It idles so smooth, which suggests to me that it is mechanically sound.

jimgoose

Has anyone clapped an OBD-II scanner on it?

dodzy

jimgoose wrote: »

Has anyone clapped an OBD-II scanner on it?

Yep, fuel pump relay voltage low. The lad who has both vehicles bypassed the fuel pump relay; pump is apparently working fine.

martinr5232

dodzy wrote:

Yep, fuel pump relay voltage low. The lad who has both vehicles bypassed the fuel pump relay; pump is apparently working fine.

Is it pumping enough fuel though to keep the pressure up might be worth trying a fuel pump if you havent already.

jimgoose

dodzy wrote: »

Yep, fuel pump relay voltage low. The lad who has both vehicles bypassed the fuel pump relay; pump is apparently working fine.

There are two core powertrain codes for fuel-pump relay voltages - P0230 and P0231, control and feedback respectively. Which one exactly do we have here?

REXER

dodzy wrote: »

As luck would have it, there is a donor car there so all the obvious ones have been swapped out, bar the ECU. Coil packs, throttle body, cat, new fuel filter. It idles so smooth, which suggests to me that it is mechanically sound.

Old cat may have self destructed and clogged up the down stream exhaust box thus choaking the exhaust flow?

dodzy

jimgoose wrote: »

There are two core powertrain codes for fuel-pump relay voltages - P0230 and P0231, control and feedback respectively. Which one exactly do we have here?

Hey Jim, P0230.

REXER wrote: »

Old cat may have self destructed and clogged up the down stream exhaust box thus choaking the exhaust flow?

Nope, this was checked and ruled out.

jimgoose

dodzy wrote: »

Hey Jim, P0230...

As much as it annoys me to even talk about it, the ECU in those things develops brain cancer and starts screwing up the switched-earth on the fuel pump relay. So it could well be the ECU, as per your gut. Stupid thing!! :mad:

dodzy

jimgoose wrote: »

As much as it annoys me to even talk about it, the ECU in those things develops brain cancer and starts screwing up the switched-earth on the fuel pump relay. So it could well be the ECU, as per your gut. Stupid thing!! :mad:

Thanks very much for the input guys. Jim, I guess the ignition will have to be swapped out of the donor car along with the ECU ( key match to ECU ) ?

It's not mine so not the end of the world for me. As you seen from the AH thread, that letter from the bank has me pretty happy today

jimgoose

dodzy wrote: »

Thanks very much for the input guys. Jim, I guess the ignition will have to be swapped out of the donor car along with the ECU ( key match to ECU ) ?...

Most likely, yes. The words "ECU" and "replace" cropping up too close to each other usually makes me want to kick things.

dodzy

jimgoose wrote: »

Most likely, yes. The words "ECU" and "replace" cropping up too close to each other usually makes me want to kick things.

Cheers again Jim.

Last Q: Would you even bother swapping out the fuel pump (based on my previous posts), or just head straight for the ECU ?

jimgoose

dodzy wrote: »

Cheers again Jim.

Last Q: Would you even bother swapping out the fuel pump (based on my previous posts), or just head straight for the ECU ?

I'd probably clap a cheap used one from a breaker's in there just to rule the thing out.

dieselbug

dodzy wrote: »

Cheers again Jim.

Last Q: Would you even bother swapping out the fuel pump (based on my previous posts), or just head straight for the ECU ?

Why not just check the fuel pressure under load at the point where the problem occurs.
If it remains within spec at that point then that rules out the pump

dodzy

dieselbug wrote: »

Why not just check the fuel pressure under load at the point where the problem occurs.
If it remains within spec at that point then that rules out the pump

Doner car there so only time. No expense. The lad is swapping it out tomorrow.

Mar4ix

timing ? camsaft, cranchaft and speed sensor faults would also cause similar behavior .

dodzy

Mar4ix wrote: »

timing ? camsaft, cranchaft and speed sensor faults would also cause similar behavior .

Crankshaft sensor replaced. Problem sorted. Cheers folks