145 hard to start cold

[mo5]

my 1971 145 b20F is a bit hard to start when its cold,could it be the temperature sensor causing it?i reckon its broken,the temperature never goes above the first line on the gauge. it runs fine after a couple of seconds idling and starts first click when its warm..any ideas?
thanks!

[Clan]

I think you have two temp sensors , the larger one for the gauge , (your thermostat is probably stuck open if its not warming up )
The second smaller sensor is the fuel injection , which is probably also faulty . you should find resistance values for different temperatures in a manual if you want to check it yourself .
Does the cold start improve if you pump the throttle pedal when cranking? This will inject extra fuel ... and may compensate . I bet its using a lot of fuel!

[john h]

You might have a specific fault, but don't overlook the basics.

Make sure that your spark plugs, HT leads, distributor cap and rotor arm are all fresh and perfect condition. Then check timing is right and no blockage in fuel filter, etc.

John

[mo5]

is that the sensor thats at the front of the engine? ive found a replacement temp sensor,will i need a thermostat aswell? it really likes petrol...pumping the pedal helps when starting..the plugs,leads and distributor cap are new as is the fuel filter.fuel pump seems to be fine too..

[Clan]

yes the smaller one near the thermostat area . certainly worth swapping and check the resistance with the one you have when it is cold ...

[mo5]

so that sensor only tells the injection system the temp not the gauge in the dash?would it be a bit of a co-incidence that theyre both faulty? would a faulty coolant temp sensor make it hard to start cold? maybe its my cold start valve?
thanks for the help by the way

[Lesky]

If your 140 has D-jet, you might find something here:

http://volvo1800pictures.com/documen...lt_tracing.pdf

You can check your cold start valve by removing it from the intake and, while a helper turns the key, see if the valve sprays fuel. This is best done holding the injector in a jar with a rag over the top to prevent petrol from going everywhere. If it doesn't inject, it could be a bad valve or a bad thermal timer.

I would also check resistance values on the ignition coil to make sure that you're getting a strong spark. I think the specs for the coil are in the D-jet manual I posted.

[B20F]

so that sensor only tells the injection system the temp not the gauge in the dash?would it be a bit of a co-incidence that theyre both faulty

The sensor for the gauge is at the other side of the head at the firewall side. It has nothing to do with the injection part, it's only function is the signal for the watertemp.gauge. If the gauge is working but indicating a too low temperature I would suspect the thermostat is stuck open. You can check it with a cold engine, take of the radiator cap, start the engine and watch if the coolant is pumped around through the rad. If so the thermostat is stuck open. You should only see the coolant be pumped around through the rad when the coolant is hot.

[mo5]

Thanks for the info! Next day off is Monday,I'll investigate it then..