Discovery1 hard starting when warm

[rickl]

Hello

I recently had the fun of changing the head gaskets and doing a top overhaul on my 1997 Discovery 1 3.9. Before I started this work the car would start ok cold or hot no worries.

I have found since putting it all back together I am having trouble starting when the engine is the slightest bit warm, even on a really hot day. The engine turns over quite fast but will not fire. I have found that if I turn the key on and off so the fuel pump runs a few times then turn the engine over it coughs a bit and eventually if I keep trying it will fire.

If this were an older holden or ford I would almost say there was no 12 volts getting to the coil while it was cranking.

While I was doing the top overhaul I changed all the filters, including the fuel filter. The car had a new fuel pump only a few months ago and I have plenty of fuel pressure. I also put a new genuine fuel pressure regulator on while doing the top overhaul.

I have had a look at the spark while the engine was being turned over on the coil lead and there seems to be spark.

The engine bay was extensively pressure cleaned and degreased when the top overhaul was done.

I would appreciate it if anyone could guide me on the best way to trouble shoot this problem. I have checked all I can think of. I need to get this sorted as I have a registration inspection due in the next week.

I appreciate any help

Regards

Richard

[LandyStu]

Hi Richard,
It sounds like the fuel temp and coolant temp plugs are reversed, both run off the same part of the harness and are easy to get plugged in wrong.
Just had a quick look the coolant temp plug is green wire / red black wire.
Hope that's somewhere to start.

P.s the fuel temp sensor is the one on the fuel rail :-)

[rickl]

Thanks LandyStu

I checked and the plug on the coolant temp sensor was green and red wires. I swapped the plugs on the coolant and fuel temperature sensors just to be sure and the car would not even start. I put them back and it was back to starting with difficulty when warm

Regards

Richard

[rickl]

Well after a frustrating weekend and the inevitable breakdown in the middle of nowhere the fault was finally found and fixed. It was simply the coil was dying. This coil was only about 3 months old. Anyway a new coil fitted and the car is running as good as it always has.

[chazza]

Was the new coil the correct type?

I found this in my notes from AULRO:
"COIL -Bosch part No/ 0221 122 392 straight from Bob Tait Bosch technical support Australia"

Check yours, because if it is the wrong one, a failure will happen again,

Cheers Charlie