Starting issue when cold on 1997 2.5TD Bongo

Technical questions and answers about the Mazda Bongo

Moderators: Doone, westonwarrior

Post Reply
K8dtg
Junior Bongonaut
Posts: 14
Joined: Sat May 20, 2017 9:11 pm

Starting issue when cold on 1997 2.5TD Bongo

Post by K8dtg » Sat Dec 30, 2017 7:26 pm

Hello,

my bongo has started to cause an issue when trying to start for the first time after being left overnight.

our drive is steep and when facing uphill the starter is having to do a lot of work (3 or so 20 second cranks) to fire into life. and runs rough for a bit. if the van is facing down hill the engine starts first time with no problems.

It is asif the fuel is draining back to the tank, is there a diagram for the fuel lines to see if there is a 1 way valve that could be leaking? or an issue with the lift pump?

The problem has suddenly happened overnight and previously usually starts as soon as the key is turned the glow plugs have recently been changed. once the engine is started it continues to run perfectly

as any one had any similar issues?
User avatar
g8dhe
Supreme Being
Posts: 10642
Joined: Sun Apr 13, 2008 10:06 pm
Location: Worthing, West Sussex.

Re: Starting issue when cold on 1997 2.5TD Bongo

Post by g8dhe » Sat Dec 30, 2017 7:38 pm

It sounds like the standard diesel fuel pump seal problems, there isn't a one way valve in the system, some people have solved it by adding one, but I suspect that it might only be a temporary solution as if the seals are going then they will shortly start actually leaking diesel outside the pump.
Geoff
2001 Aero V6, AFT, full side conversion.
K8dtg
Junior Bongonaut
Posts: 14
Joined: Sat May 20, 2017 9:11 pm

Re: Starting issue when cold on 1997 2.5TD Bongo

Post by K8dtg » Sat Dec 30, 2017 9:08 pm

thanks for that info, I have has a quick search on here and seen the issue others are having. I will have a look at the fuel pump tomorrow as see if there are any obvious leaks around the dome caps on the fuel pump.I would imagine that if air is getting in fuel is getting out! I cant say I have noticed any diesel on the floor yet tho.
User avatar
Northern Bongolow
Supreme Being
Posts: 7722
Joined: Mon Mar 15, 2010 11:33 pm
Location: AKA Vanessa

Re: Starting issue when cold on 1997 2.5TD Bongo

Post by Northern Bongolow » Sat Dec 30, 2017 10:57 pm

K8dtg wrote: Sat Dec 30, 2017 7:26 pm Hello,

my bongo has started to cause an issue when trying to start for the first time after being left overnight.

The problem has suddenly happened overnight and previously usually starts as soon as the key is turned the glow plugs have recently been changed. once the engine is started it continues to run perfectly

as any one had any similar issues?
this could be the power supply to the plug tops that has developed a fault, relay or the insulated link bar between the plug tops is shorting on the fuel return rail beneath it to earth and maybe has taken out the fuse etc. also check the top screw on the plugs are tightened to the correct torque setting.

get yer meter out. :wink:
TheLongRoad
Bongolier
Posts: 480
Joined: Mon Nov 13, 2017 5:39 pm

Re: Starting issue when cold on 1997 2.5TD Bongo

Post by TheLongRoad » Sun Dec 31, 2017 10:52 am

Had exact same problem with a 1.6 d Ford Escort years ago. The answer is most likely air getting into system due to leaky fuel line. In my case one of the lines had been vibrating against the engine block and had a tiny oin hole. Enough to cause an issue.
2002 Friendee 2.0 ltr Petrol.
K8dtg
Junior Bongonaut
Posts: 14
Joined: Sat May 20, 2017 9:11 pm

Re: Starting issue when cold on 1997 2.5TD Bongo

Post by K8dtg » Sun Dec 31, 2017 1:16 pm

I have been out and had a look at the glow plugs, they are working as they should, so this further confirms my suspicion of air getting in to the fuel system as its OK starting down when facing downhill.

When checking the fuel system there seems to be no serious leaks apart from the dome cover being damp but as my drive is very steep guessing this is causing a strong vacuum when the fuel is trying to drain back to tank and causing air to enter but leaking externally excessively (yet), can’t see the other cover that is prone to leaking but from looking at photos of pumps on internet I am assuming this is directly behind the domed cover and is flat?
are both seals the same green seal part number 2 460 223 001?

Thanks all for your speedy input over the new year period, Happy new year all \:D/.
User avatar
mikeonb4c
Supreme Being
Posts: 22877
Joined: Sun Nov 05, 2006 10:49 pm
Location: Living with Mango Bongo in the North West but with a tendency to roam
Contact:

Re: Starting issue when cold on 1997 2.5TD Bongo

Post by mikeonb4c » Sun Dec 31, 2017 1:35 pm

K8dtg wrote: Sun Dec 31, 2017 1:16 pm I have been out and had a look at the glow plugs, they are working as they should, so this further confirms my suspicion of air getting in to the fuel system as its OK starting down when facing downhill.

When checking the fuel system there seems to be no serious leaks apart from the dome cover being damp but as my drive is very steep guessing this is causing a strong vacuum when the fuel is trying to drain back to tank and causing air to enter but leaking externally excessively (yet), can’t see the other cover that is prone to leaking but from looking at photos of pumps on internet I am assuming this is directly behind the domed cover and is flat?
are both seals the same green seal part number 2 460 223 001?

Thanks all for your speedy input over the new year period, Happy new year all \:D/.
I think you're right on all counts and the symptoms don't really point to glowplugs. I seem to recall it being established that there are (at least) 3 seals that can influence fuel leak out or air leak in, also (from dodgy memory!) that its the third one and not the ones under the domed covers that is often implicated in air leaks. However, no doubt a techie can correct me on this.
K8dtg
Junior Bongonaut
Posts: 14
Joined: Sat May 20, 2017 9:11 pm

Re: Starting issue when cold on 1997 2.5TD Bongo

Post by K8dtg » Sun Dec 31, 2017 4:10 pm

plonkatronix wrote: Sun Dec 31, 2017 2:35 pm
Interesting, not read about a third seal... Hi there K8, sorry to jump in on your post but we have had the same with our recent purchase, so far we have replaced the 2 seals which stopped the fuel leak but the fuel was still dropping back, then I read about leaving the fuel cap unscrewed to prove a blockage/vacuum was pulling it back to the tank (not breathing behind)... since leaving cap unscrewed we have reduced the not starting to only once in a blue moon (will get round to clearing breather pipes when it's warmer) but I'm hoping this 3rd seal mentioned may sort the moon

... unscrew your cap and try, worth a shot
Thanks that’s brill advise, I have also heard of a one-way valve before the tank breather that can block that may also be causing vacuum, I haven’t looked for this yet but will check it out.

Cheers
Danny (Sorry I didn’t introduce myself very well) #-o
User avatar
g8dhe
Supreme Being
Posts: 10642
Joined: Sun Apr 13, 2008 10:06 pm
Location: Worthing, West Sussex.

Re: Starting issue when cold on 1997 2.5TD Bongo

Post by g8dhe » Sun Dec 31, 2017 5:33 pm

There is a valve in the cap itself meant to allow air in this often gets gummed up and needs cleaning;
Geoff
2001 Aero V6, AFT, full side conversion.
Post Reply

Return to “Techie Stuff”