Bongo fuel fixing – weekend #1
So at the end of August 2025, I decided to take on the Mazda Bongo and to get it running again. It has been suffering from poor starting/running for quite some time, but things came to ahead earlier this year when it failed to start and since struggling back into my driveway has sat there waiting to be fixed.
My previous attempts of adding redex seemed to have worked, as shown in the video I took earlier this year, sadly now its back to failing to rev over 1500 rpm.
I am none the wiser as to why it would have worked, but now its back to not revving over 1500 rpm. My plan as per mentioned in the video was to the basics first, that was change the filters and glow plugs, its been sometime since that was done. I ordered a full filter kit and a set of new glowplugs from bongo spares, which arrived promptly.
As I knew I wanted to change the glowplugs, I followed several videos on youtube, all offer different perspectives, but collectively help. I started with doing I had never done before, removing the engine cover, this went really well and I kept a good visual record of the things I removd and unplugged.
I was pleased that the cover came off as planned and I could access all the necessary nuts as shown in the various videos. I then set about replacing the fuel filter. I have done this before and was pleased it was quite routine/easy to get on and off. The filter didnt look too bad, but it has been on the bongo for about 4 years, and I think the root cause of the fueling issue is that the tank ran on empty and introduced alot of particulate to the fuel system, so replacing it was a no-brainer !
With the fuel filter fitted, the next step was the diesel fuel pump and the banjo filter – its been many years since I had this out – I even questioned if I had re-fitted it the last time I had it open, after several fiddiling and using my phone as a ‘zoom stethescope’ i could see the banjo was indeed still in place ! I took it out and it was full of conaminents – i was half hopeful this was the source of my issue with the bongo.
I gave the bongo a crank, sadly still not going above 1500 rpm – my next step was to change the glow plugs for this i wanted easy access to the glow plugs and removed the vacuum pipes and removed them from the fittings, the use of a ‘swivel’ joint on the socket set really helped in this situation to get to the tricky bolt.
I noticed on the tutorials just how small the bongo glow plug bolts are – whilst i have many spanners and sockets, i had none which could fit the bolts and the depth required. I headed to amazon and got a deep socket set, but that would take time to arrive. This was a good time to take a break and do some more research on youtube and the forums to see what my plans ahead could be.
The good news is the socket set arrived in the evening, having already settled in for the evening, it gives me plenty to do next week.
One of my favourtie and most impressive youtube channels has been ‘steve’s machines’ – his videos have really inspired me to take on things I would otherwise think not possible. I am facing the real world issue that the bongos diesel fuel pump may need switch out, in the mean time I’m going to try all the other things, e.g. new glow plugs, flush the fuel system with cleaner and then see where I am at, but I am determinted to get my bongo up and running reliably and enjoying my ham radio hobby out on the road again !