Rover 25 02 1.6 poor starting

Possibly a leaking injector or two causing flooding ? To check for this, before turning the engine off with the ignition, pull the fuel pump fuse / relay and let the engine stall. Replace the fuse / relay and see if that makes a difference. I once put a switch in the cabin to kill the fuel pump because I had those symptoms.

David

Possibly a leaking injector or two causing flooding ? To check for this, before turning the engine off with the ignition, pull the fuel pump fuse / relay and let the engine stall. Replace the fuse / relay and see if that makes a difference the following day. I once put a switch in the cabin to kill the fuel pump because I had those symptoms.

David

A duff coolant temperature sensor making the ecu think the cold engine is warm would cause this. Easily tested for resistance with an ohmeter. Usually about 3000 ohms cold and 300 hot from memory but I'm sure you can check.

True - but the common failure mode is open circuit making the engine run fully rich. I've never come across one failed short circuit. However, easily proved by unplugging it which should set the mixture for the coldest start. For a GM spec sensor - which most seem to be - a 175 ohm approx resistor replacing the sensor will set it to fully hot mixture.

If the fuel rail is depressurizing overnight, you could try switching on and off a few times before attempting a start. This will run the pump in short bursts and build up the pressure. Also, how is a cold start in the morning if you let the engine cool down at night, then start and stop it? Fuel evaporation due to heat soak can sometimes be the reason.

However, it could be something else. Loom etc connectors could be getting dirty with age and introducing resistance to a circuit. So although the battery is good, all of its volts ain't getting where needed. A voltage drop test to the ECU and pump etc would be easy enough to do.

Open circuit or short will cause ecu to use default value (normally 80deg C) OR use the air temp sensor for an approximate reading and then use an algorithumn to calculate expected engine temp based on time running / load / speed etc.

Newer ECU's are *very* accurate at this !!!

Tim

Thanks a lot to all, for the various suggestions. I'll start working my way through them on Monday, when I'm not on 'Christmas shopping duties' and post back if I come up with anything. Cheers.

I've now ruled that out. 250 > 4.5K which agrees with the spec.

Thanks

I'm still working on this one. I thought removing the fuse had improved it a bit but now I'm not convinced. Need more time. I tried leaving the fuse in and then removing the plugs first thing and looking with a torch. Might any leaked fuel be able to be seen or is the amount so small that it makes no difference. All cylinders looked perfectly dry.

The odd thing after putting the plugs back the car started immediately, with no hesitation whatsoever. Odd. I'll see how it goes on from here.

Andy

Best of luck then.

regards

David

Oops, I've realised I've missed out what could be a fairly critical sentence.

After letting the engine stall from removing the fuel pump fuse / relay, turn the ignition off before refitting the fuse / relay.

Apologies.

David

Hi David

Yep, that makes sense ! ;-) I'm not sure now which way I did it. I'll have another go next week. This morning it started almost immediately, but it's not at all reliable. It would be good to get it sorted as I hate things that don't work.

Thanks for taking the trouble, Andy

Andy,

I hope you get it sorted at minimal cost.

seasons greetings

David