Engine Pre-heating

[Paul Woods]

Ah there's usually a separate cold start injector time switch for that, the EFI one is a constant temp reading for enrichment when cold, i guess it all depends where that pump/heater is plumbed in too.

[MMaddict]

I would have thought the EFI sensor would also be in the the engine coolant loop so the thermostat would not need to open for it to see hot coolant, if it was outside the engine loop then the cold start fueling would remain engaged for quite a long time. A lot of the time isn't it located pretty close to the cylinder head so will heat up pretty damn quick.

No expert myself but the old Mk1s used to start up no problems with the cold start injector unplugged.

The thing is, that if the thermostat isn't opened there is no loop out side the engine block. the EFI sensor is usually screwed somewhere in the engine block.

Technically it would be very hard to install a pre-heater unit between te EFI temp sensor and the block it self without moving the EFI sensor.

So I guess a pre-heater is only helping, and not leading since it never even gets close to thermostat opening temp.

[sketchy]

given the water is in the block, if the water temp is 60 degrees, most of the block will be getting close too. as you wont have a near cold block with warm water in it...but given there is no flow. will take a while for the temp to increase all over. would be talking probably hours, especially in near zero temps..

there is no reason why you couldnt add a loop of steel coolant pipe through the sump to aid with preheating the oil too though, seems a bit over the top to me, but you COULD...like "t" off one of the manifold coolant lines. Ill get my coat...

probably better off just putting an electric heater under the sump before bed...and turn it on as you get up...

[MMaddict]

given the water is in the block, if the water temp is 60 degrees, most of the block will be getting close too. as you wont have a near cold block with warm water in it...but given there is no flow. will take a while for the temp to increase all over. would be talking probably hours, especially in near zero temps..

there is no reason why you couldnt add a loop of steel coolant pipe through the sump to aid with preheating the oil too though, seems a bit over the top to me, but you COULD...like "t" off one of the manifold coolant lines. Ill get my coat...

probably better off just putting an electric heater under the sump before bed...and turn it on as you get up...

[weegaz22]

I can see the appeal, my E39 has an option to plug in a webasto telestart module and have the diesel pre-heater warm the block off a remote with an (allegedly) 1km distance, and after 5 mins it'll activate the climate control turn up the heat and turn on the blowers to defrost the front and rear windows, dunno if you could have space retro fit one in an mr2 bay, maybe the boot? (especially one thats been.. ahem.. brutalised) and then have it supplied by its own diesel resevoir and pump, its the better option than running a cable out to your car IMO, but i guess it depends on your circumstances as well, between garage/driveway/street parking on whether its conveinient enough for you

the cable operated one is only going to offer that extra bit of protection and nice and toasty comfort 50% of the time, cos when you drive to work or the shop in winter by the time you come back your car is stone cold when you have to drive back home, so from that point of view that's why i wouldnt pay for one of the plug in electric ones.