ECU for 3.0

After a long cold winter of cold start problems and killing a battery, plus way too much money for a diagnostic check which found nothing the throw away line was must be the ECU that is shot.
Well I did not even bother calling Toyota, breakers on-line search not come up with anything.
I'd thought I'd ask if anyone had one or if anyone could let me try theirs in mine to rule it out/in.

Before I take mine apart and really mess it up.!

that's a big jump from bad cold start to ecu trouble, take it you've already checked heater plugs and connections etc.

anytime Clive..

Thank you Mr Admin I may well take you up on it.

Right I've had it diagnostic checked and no fault found. I've had the fuel system checked, no fault found.
It starts fine from warm. It runs fine, and fires well as that was part of the fuel system check.
Glowplugs changed, relay and leccy connections all ok.
Water temp sensor ok, air temp sensor ok, throttle position sensor ok (been removed and de-gunked)
It will fire after 10 seconds of cranking.

So everything checks out ok, which leads to the ECU, if it does not know it is not workig ok it can't register a fault.

All the ECU does is regulate the fuel flow rate in relation to the air flow, except for the cold start when it increases fuel - and this I guess is not happening.

I'll unearth it at the weekend and have a look for any burning on the board. Re seat all connections. If nothing then I'll call on Admin.

Not such a grim picture, I've found a company who will repair it if faulty for about £100, way cheaper than the $2,000 listed on the Toyodiy site

Is it just starting thats a problem or is it running badly too..

If the ECU was fried i have thought it would have been more obvious than just the starting? What about the leads to the glow plugs, maybe they are a bit tired?

I had a problem on an old Pajero a few years back, turned out the diesel pump was gelled up, needed stripping and cleaning and ran like a dream

Are you leaving it long enough for the glow plugs to do their job?
I usually wait until i hear the alarm(usually about 5-10 secs) before cranking.You can hear a relay click off just before the alarm.

Starts from warm first touch of the key, runs fine no matter what temp srarting (once started!).

Glow plug, relay, busbar and wiring all tested and found faultless.

On turning ign 11v are fed to the glowplugs for around 14 seconds, then they have an after glow of 8v. Diesel specialist suggested 3 ways of starting, straight in cranking, turn key wait for relay click crank or 3 heat glowplugs to relay click twice then crank.

I'm finding the straight in works best.

Loads of connections to break and make this weekend and an ecu cover plate to remove. I will check glowplug power again. A further spanner thrown in by an Army mechanic is perhaps the starter motor is not in A1 condition and not spinning as fast as it should?

hmmm, reallt sounds more mechanical than an ECU issue, but the ECU's are a black art to themselves....

What about the thermovalve thing on the side of the pump if you have one...

I was thinking fuel as I run on veg oil, but that checked out ok. Timing ok. Rev range as in the book and power output within range. It is just cold starting and if i did not know that the glow plugs are working I would say it was them - changed them anyway way back at the start of problems.

No cold start thermovalve - all run by the ECU.

Does resetting the ecu help?...ie: disconnecting the battery a while?

does heating the veg oil help?I've read some where that the oil needs to be heated ?

hmmm, may have hit on somethin with the veg oil mebee?

If it runs fine warm i wouldnt have thought it was the ecu.Have the glowplugs been taken out and a checked for build up around the tips?Could be the injectors are dirty and the spray pattern isnt quite catching the glowplug.

Changed to 100% Diesel to rule out fuel, now back on 50/50 symptoms the same.

Glow plugs have been changed.

Injector cleaner used, no change. Diagnostic check on power output and exhaust gas indicate all ok. No erratic idle cold or hot.

Just want to rule the ECU out as two technicians have mentioned it and the Toyota manual even suggests checking/replacing ECU where there are cold start problems. Today -3, eleven seconds of cranking and he fired up.

Nice dry day and I've got to be the family taxi so no time to tinker!

Well I bet your'e glad you have a good battery.....

Think I've cracked it.

Coolant level has allways gone down by a cupful each time I check. I fill up the neck until it starts to overflow into the expansion bottle.

The last few weeks it has started without too much hassle, maybe warmer weather, maybe going back to 100% veg oil.

Well no, I had to top the coolant up by almost a litre, the very next morning was it a pig to start, yes it was. My thinking is the level had gone down below a crack in the head. When topped up coolant seeps into the cylinder(s) and leads to bad starting. On the strength of this I bought some Kalimex Seal-up as a quick fix/diagnosis.

I can report that it does what is says on the tin, well plastic bottle. Starting easy from cold, even in the frost this morning, no coolant loss so far.

Oh well now I'm confident I know what it is and can start saving for a new head. It came with a new head and it is a cheap copy one so I'll not bother getting it fixed.

Time will tell how long the fix lasts.

Oh and the battery - the extra oomph must have cleared the hydro lock?