Cold starting problem - another permutation of the problem!

Technical questions and answers about the Mazda Bongo

Moderators: Doone, westonwarrior

Locked
steveyd
Bongolier
Posts: 168
Joined: Tue Mar 16, 2010 9:10 pm
Location: Wantage

Cold starting problem - another permutation of the problem!

Post by steveyd » Mon Nov 29, 2010 12:28 pm

Hi All,

My Bongo won't start when its really cold (ok it does after a lot of cranking and lots of white smoke) - its ok when its warmer, but not when its frosty.

My first thought would be glowplugs, but I've followed all the other threads but this seems to be different in that once its running there are no running issues, idle speed is fine etc etc.

I have checked the glowplugs - all show a low resistance as expected (not open circuit), there's 11.97V at the rail on all of them, the glow plug relay works (after ~ 30 secs I hear a click and I can see the rail voltage drop to 0V). It has a new 95 ah battery. I have tried it with a jump lead straight from the battery to the rail, no difference and also one to give a better ground to the engine in case of a defective earth strap. The cold start also seems to be fine - when I turn the ignition on, there's a click and the pump cable gets pulled in a bit. There's no cracks etc in all the those little cold start valve pump type things above the glowplug rail.

The Bongo starts no problem after a few hours - just overnight frosts seem to get it? If it was a fuel system problem, why is it ok when its a bit warmer (starting did seem to get a bit lumpy in October time). The engine runs just fine when upto speed and idle is fine too. I cant see any obvious fuel leaks.

My suspicion is that even though the plugs are registering voltage and consistent resistance they may be a bit weak? I'm assuming the inline fuse and the one by the drivers knee are ok as all the voltages seem to be right in all the right places? What else COULD it be? The Bongo did have all new glowplugs recently when I bought it last Feb (and it started fine when I got it in the cold). Maybe they just put in naff plugs...? They just LOOK like they're working...?

.. and I just noticed a NEW coolant leak! Why does my Bongo hate me so? I'm having to sell my other car as this Bongo is bankrupting me! New hubs, arms etc etc - are they all like this?

Cheers,

Steveyd
321Away
Tribal Elder
Posts: 783
Joined: Mon Oct 26, 2009 1:45 pm
Location: Berkshire
Contact:

Re: Cold starting problem - another permutation of the probl

Post by 321Away » Mon Nov 29, 2010 2:05 pm

taking a reading of resistanse or continuity of a glow plug wont always show faults, i've seen loads (by that i mean hundreds) that give a resistance and show a ground that dont work, the only true test is to pull them out and power them up, should take approx 4-5secs to see glowing tip, any more and the plug isnt necessarily on its way out but it means its not reaching full temperature quick enough, just beacuse you've had them replaced doesnt mean they're any good either, have seen customer cars with week old sets where all 4 plugs have failed, use only NGK, others will recommend other brands but NGK is the only brand i've seen that hasnt had a failure new out of the box.

Also consider fitting a 1 way valve to the fuel line, may be fuel draining back down?
Julian
User avatar
mikexgough
Supreme Being
Posts: 6158
Joined: Mon Sep 08, 2008 9:02 pm
Location: Cambridgeshire - where the all the Slodgers reside
Contact:

Re: Cold starting problem - another permutation of the probl

Post by mikexgough » Mon Nov 29, 2010 4:48 pm

steveyd wrote:
.. and I just noticed a NEW coolant leak! Why does my Bongo hate me so? I'm having to sell my other car as this Bongo is bankrupting me! New hubs, arms etc etc - are they all like this?

Cheers,

Steveyd
Nope they certainly are not all like that.....
Conversant with Bongo Top Pinion Oil Seals

Bongo owning Velotech Cycle Mechanic
steveyd
Bongolier
Posts: 168
Joined: Tue Mar 16, 2010 9:10 pm
Location: Wantage

Re: Cold starting problem - another permutation of the probl

Post by steveyd » Tue Nov 30, 2010 11:15 am

Thanks - I made a concerted effort to give the plugs a chance - did 3 cycles of waiting the relay to shut off and it did start quite a bit easier - still some churning but not the ~1 min yesterday.. So maybe I really do just have weak plugs - esp as everything else seems fine.. When I get a chance I'll also put in a one way valve - it could do with a new fuel filter so may as well combine the jobs!

Cheers,

Steve

p.s. leaks turned out to be what I was hoping - the jubilee clips needed nipping up - new hoses all round in the summer!
steveyd
Bongolier
Posts: 168
Joined: Tue Mar 16, 2010 9:10 pm
Location: Wantage

Re: Cold starting problem - another permutation of the probl

Post by steveyd » Mon Dec 06, 2010 10:36 am

Fixed - glowplugs were weak - set of 4 new NGK's and now starts a treat!
Locked

Return to “Techie Stuff”