Classic wont start hot
 

Hello,

I bought my 1995 Impreza WRX STi about 3 weeks ago. It was due for a cambelt change so I changed the cambelt kit, waterpump and thermostat about 3 days after. Also changed oil and filter.

About 2/3 days after that I got in it to move it after doing a 10 mile journey and it wouldn't start, turned over but wouldnt fire up. Tried it again and it started. A couple of days after that it started happening more often when hot and on a couple of occasions would just cut out when idling.

I bought a walbro 225 fuel pump and checked and blew out the filter with an airline and it seemed okay for a day then came back. I took it to a local subaru specialist and plugged a diagnostics reader in and came up with crank sensor, I replaced that and was fine for a day. Came back again and he said that the plug to the fuel pump under the rear drivers side seat sometimes melts which mine had so I bypassed the power and earth cable and again was fine for a day then happened again, wouldnt start when hot. I also noticed that when it turns over the fuel pump keeps clicking in and out.

I then changed the fuel pump relay and again was fine for a day. Yesterday has been the worse its been, undriveable. Started up normal when it was cold in the morning, took it to the garage for fuel, filled up and wouldnt start again, 30 mins later it started.
Got home and did some tests on it, it would start perfectly when cold and I left it sitting there idling and when it reached temperature it would just die. Wouldnt restart again till it was cold.
It did this 3 times.

Im running out of things, I've checked the earths and all seem fine but will give them a clean today. I had a friend come with a multimetre and he testes the coolant temp sensor and on cold start up it was at 1.7ish (meant to be between 0.9 - 1.5) but slowly when down to 1.1. We did think it was the temp sensor but surely a faulty sensor should turn the fans on which doesnt...

Another thing I drove it hardish a few days ago on that hot muggy day and the temp gauge went between half and 3/4, when I stopped the top and bottom hoses were red hot so not a stuck thermostat (had a new one last week).

It starts absolutely fine cold and it turns over normal, not slow.

Another thing we checked was the voltage to the starter motor which was meant to be 13-15 but it was 10ish but remember it starts fine cold.

I have checked many forums and a few people have this problem but haven't actually posted a solution. Also the CEL is not on.. I did thinknit could be the cam sensor but surely shouldn't there read a fault about it?

There is no performance problem when driving it, no boost problems or anything.

Does anyone have any ideas? Thanks.

might be worth trying a CTS then.

I plan om getting one from importcarparts and also I just did the diy dianostic read by plugging two plugs in the bottom and got temp sensor and crank again. Though the crank sensor was second hand.

The fault codes may be old one's stored in the ecu - clear the ecu then drive the car and recheck for fault codes.

Mick

Yeah I'm taking it to stuart hopefully tomorrow in east sussex so he can plug it in. I tried to reset the codes myself but cant as one of the steps includes starting it which it wouldn't do.

Managed to do the diy reset and theres now no codes...

Disconnect the battery for half hour to reset ecu. Then once in fails again check codes.

Update: I removed and cleaned all the earths and the crank sensor. Reset the codes, now theres no codes showing up.

Yesterday we checked some of the voltages with a multimetre, mainly the engine temp sensor and starter and the temp sensor was out and the starter was under what it should be.
Just checked them all now and the voltages are all spot on in the brackets...

Hopefully should be all fixed... car was also driven, heated up, switched off and it started fine several times.

'Driven'

Yeah sorry I'm on my phone and was typing quickly. Fixed now.

LOL..... no worries, its just a pet hate of mine chap..

Glad you've got the motor sorted.