Rav 4 Poor Winter Starting

[alexr]

Hi all hoping someone has had this problem before or has any suggestions,here we go ,my daughters 53 plate rav4 d4d vx normally starts reasonably well (for a Rav4) but come a cold snap and it will just crank over and refuse to start,I have checked all the glow plugs and they have a supply and are within 1/2 ohm of each other in resistance (even pulled one at random reconnected to loom and shorted to block turned on ignition and watched it heat up) parralleling up Battery with heavy jump leads and tractor Battery make no difference ,only thing that seems to work is putting in garage with workshop turbo heater for 1/2 hour then cranking it over will start it,once its running its fine for the rest of the day,

other thing I have found and dont know if its related is that the idle up button makes no difference,have popped out swi and checked it (according to wiring diag' it shorts pin 25 of the engine ECU down to 0 volts) and it does in fact have about 11.6 volts from ECU which it shorts out when u press the swi',

is there a temp' sensor that tells the ECU that it needs to increase fuel supply for cold starting,and is this why the idle up swi has no effect as the ECU thinks its nice and warm outside ?

Help guys,is there anyone out there that has any clues to this before winter comes and my daughter makes my life hell again.

[bothwell_buyer]

Welcome to the forum. Dinna worry - my daughters make ma life hell too sometimes. Its a mark o the breed I think!

Hopefully an oil-burning expert will visit this post and give you advice. I run petrols and don't have any probs. The diesel trucks we have also start but they are kept inside a warehouse albeit cold. The only regular trouble we have is with batteries and its cos they needed topped up.

[Tech01]

HELP! HELP!

I'm trying to reply to this, but am unable to Upload any file to my reply.

Could someone take a look at the problem??

Chris

[anchorman]

I can't mend the forum but IF you can pm it to me I will attach it.

[dervdave]

You`ve only seen 1 glowplug actually working.... check them all.

[Tech01]

Hi Alex,

Sorry for delay in replying to your QQ - something odd happened to my "attach file" option!

You've already run lots of good tests. The IDLE UP switch will only function when the temperature is low. Cannot locate exact temperature, but it's in the region of 10degC, I think. Above this, pushing the button has no effect on idle speed.

Temperature feedback to the ECU for starting (and Idle Up) purposes is from the Coolant Temperature Sensor. This governs the length of time that the glow-plugs operate, both for pre-heat and post-heat.

m_st_0001.pdf

You can check the times out by using a meter/test-lamp attached to the glow-plug feed. Don't rely on the dashboard indicator - it extinguishes "as soon as starting is possible".

To check whether the glow-plugs are affecting the problem, with a cold engine simply switch on IGN, and allow an extra 5-10secs after the dash light goes out before cranking. If it improves things, then the glow-plugs need investigating further.

The coolant temperature sensor is bolted into the cylinder head. See Haynes (4750) manual, section 6B-5, 4. Unusually helpful description for location, testing, removal etc. If you don't have Haynes, I can scan and post the section for you.

You're using (2!) decent batteries, but do check earth connections to/from the Battery. Cranking with a bit of an ohm in the wrong place causes starting havoc, particularly for the glow-plugs. Textbook resistance for each of the original 'plugs is listed at 0.72ohm at 20degC, with a warning not to bench-test at more than 11v.

As Anchorman advises, check/renew fuel filter (frequent problem), and check for any air in the fuel line between fuel filter and HP pump. Air here causes starting havoc too.

Hope helpful.

Chris

[alexr]

Thanks all for replys you have given me further things to investigate,thanks Chris for your detailed reply,do you know if coolant temp sensor is the same one that drives the dash temp gauge ? (this appears to 'read' right so does it indicate sensor is ok ),have tried 3 cycles of cold start with ign then tried starting but has no effect !, in present weather its starts fine with no problems,and just had Battery checked with a load/voltage test while cranking and auto elec' says Battery fine so its ruled that out,will investigate further and let you all know result as this seems to be a common thread that crops up with the D4D in the Rav 4 on here ,thanks again guys

[alexr]

Chris can you tell me where you got info you posted as there is a reference to the temp sensor in there but refers to another doc' ie sect 5 , pub No rm697e,page ed-10,thanks alex

[Tech01]

Hi Alex,

Herewith the referred-to page of info about the water temperature sensor:

There are two official Toyota manuals that cover the 4.2 D4D engine (1CD-FTV):

Pub.No. RM697E (Aug.1999)

Pub.No. RM856E (May 2001)

The second updates the first, but refers back to it, so you need both.

Both available, but not cheap.

A wiring diagram (EWD......) is a separate publication, horrendously expensive, but beautifully printed in full colour. I only have the petrol one (EWD416F), obtained in error. Don't get this one!!

I'm uncertain whether this water temp sensor feeds both dash temperature gauge as well, or whether it's just sending info to the ECU for starting and other purposes. Probably easiest just to disconnect the sensor plug, and see whether the gauge stops working.

Chris

[alexr]

great thanks a lot Chris ,I will have a look at this this weekend,think I will start by dissconnecting and seeing if dash temp gauge 'dies',will check resistance anyway as this looks most likely culprit,I cant see anything else that tells the ECU to cold start,thanks for all yor help guys will let you know what I find,Alex