C2 1.6 VTS not revving when left overnight

[mmd78]

All
recently when I first start the car after it has sat for 9-10 hours she stall after the usual rpm overshoot.
If I restart the engine she will idle fine, but cannot revv over 2000 rpm, run rough and I can hear some backfire from the exhaust.

Instead if I leave it in idle for less than one minute, then I accererate it revv up fine.

It looks to me engine runs in excess of fuel

Any idea? how to test Canister purge valve ?

Thanks
Marco

[c2gt16]

sounds like one of the sensors may have failed, just guessing but worth checking these type of things

[Trek]

Temp sensor sounds like it needs changing , diagnostics will confirm , sounds like it sending an average warm signal and not telling the Ecu it’s cold on start up

[mmd78]

Hello Trek and C2GT16,
nope.... both coolant sensor and air sensor mesure 29 or 27 degrees, with outside temperature of 29 Degrees. Warming up the enigne coolan ride to 80 and air intake to 34.
looks normal to me.

I noticed also that the engine struggle to go past 2500 rpm when cold.
I replaced the sparkplugs (former set was 40.000 km old) and now it cranks at the first turn. but still struggle to increase RPM (some light pop to the exhaust).

Any other ideas?

Thanks
Marco

[Trek]

Hello Trek and C2GT16,
nope.... both coolant sensor and air sensor mesure 29 or 27 degrees, with outside temperature of 29 Degrees. Warming up the enigne coolan ride to 80 and air intake to 34.
looks normal to me.

I noticed also that the engine struggle to go past 2500 rpm when cold.
I replaced the sparkplugs (former set was 40.000 km old) and now it cranks at the first turn. but still struggle to increase RPM (some light pop to the exhaust).

Any other ideas?

Thanks
Marco

I have had a car a gt 2004 which did something similar to this , problem was the crank sensor .

[mmd78]

Trek you mean that the probelm disappeared after some time the engine was running ?

[Trek]

Trek you mean that the probelm disappeared after some time the engine was running ?

I changed the crank sensor and the problem disappeared , it was actually a car I bought that the owner gave up on as it had this problem ,was well unhappy when I cured it 😹😹😹😹Simples😹😹😹

[mmd78]

Sorry my question was wrong.
My car cant rev past 2500 for the first minute or less.
After that it revvs up normally.

Did your 2003 Gt has the same probelm ?

[Trek]

No, it just would not rev past 2500rpm

[i lunn]

Sorry my question was wrong.
My car cant rev past 2500 for the first minute or less.
After that it revvs up normally.

Did your 2003 Gt has the same problem ?

If you don't have proper diagnostic unit I would be going down the change crank sensor route as it looks like it is quite likely to be cause. but as mentioned diagnostic could find the problem before spending a fortune on parts.

[mmd78]

Ah ah like when I bought my former Mondeo. It was not pulling and throwing pcodes for Air/fuel mixture.
It was the MAF that was installed in the wrong direction by some assh@le.
Dealer discounted me the cost for new fuel pump and injectors..ah ah

[mmd78]

Gents
I need your help again.
Car: C2 VTS 210.000 km on the clock, not mapped.
Issue: after leaving the car parked for 8-9 hours, next start is difficult, engine stumble stall, and trying to accelerate sounds like a flooed engine.
after 1 minute in idle problem disappear
accelerating for 5-10 seconds rpm barely reach 2000-2500 rpm

Actions:
1) check manifold for snapped bolts-> is ok
2) checked hoses for air leaks (vacuum line to brake booster, canister valve)-> all good
3) measured the injector leaks on bench, all good spray equally, leakage at high pressure within limits
4) Ultrasonic cleaning (from a professional), re tested on injector bench, small improvement in spray and little less leaking
5) replaced injector o-rings -> problem still there
6) replaced: coolant temperature, engine speed sensor -> problem still there
7) swapped coil pack from another car-> problem still there

Any other suggestions?
Is there any pressure regulator for the fuel pressure somewhere on the fuel line or any non return valve than may check?

Thanks
M.

[Trek]

Gents
I need your help again.
Car: C2 VTS 210.000 km on the clock, not mapped.
Issue: after leaving the car parked for 8-9 hours, next start is difficult, engine stumble stall, and trying to accelerate sounds like a flooed engine.
after 1 minute in idle problem disappear
accelerating for 5-10 seconds rpm barely reach 2000-2500 rpm

Actions:
1) check manifold for snapped bolts-> is ok
2) checked hoses for air leaks (vacuum line to brake booster, canister valve)-> all good
3) measured the injector leaks on bench, all good spray equally, leakage at high pressure within limits
4) Ultrasonic cleaning (from a professional), re tested on injector bench, small improvement in spray and little less leaking
5) replaced injector o-rings -> problem still there
6) replaced: coolant temperature, engine speed sensor -> problem still there
7) swapped coil pack from another car-> problem still there

Any other suggestions?
Is there any pressure regulator for the fuel pressure somewhere on the fuel line or any non return valve than may check?

Thanks
M.

As this car runs a single line pressure system with a fuel vapour return valve( check this is functioning correctly) , the pressure is controlled in the tank by the pump/filter assembly
You could try a low pressure back blow up the fuel line in case this is the filter blocking up , and I mean low pressure , also check the tank breathers are not blocked , run the car a while and then remove the fuel cap
Crank sensor can cause issues , it’s cheap to replace so change it and start from a known good point
If you have lexia/diag then have a look at live engine data fuelling and spark

[mmd78]

Hi Trek
I had a look at fuel timing and spark with LEXIA and the traces in idle and accelerating with no gear: are the same both when the engine runs bad or good. Also MAP and coolant are comparable.
2.5 Bar of fuel pressure measured plugging a meter on the fuel hose and commanding fuel pump by lexia (btw fuel pump is activated by commanding FAN on...)
Reinspected spark plugs (Bosch super-4) all good.

Anyway past two days the car has started perfectly like new and I'm happy -- but I have not got the cause of the problem...most likely will come out again...

thanks all for helping