Smoking Bongo 2.5 diesel 1997

Technical questions and answers about the Mazda Bongo

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Ryan S
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Re: Smoking Bongo 2.5 diesel 1997

Post by Ryan S » Fri Apr 13, 2018 7:49 pm

So here’s a Over due update, I have now replaced fuel filter,injectors and cold start solenoid (white connector) and have improvement especially since changing cold start solenoid but still smoke, I have yet too change the bottom seals on fuel pump, but I doubt this will cure the problem. Van is running a lot smoother since I have done these jobs, any other ideas as too what I could take a look at?
Thanks!
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Northern Bongolow
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Re: Smoking Bongo 2.5 diesel 1997

Post by Northern Bongolow » Sat Apr 14, 2018 2:07 am

check the function of the cold start solenoids carefully as described above and the position of the throttle peddle/cable, if the solenoid was duff then someone may have altered the throttle position adjustment on the pump to get it to run sweeter when cold. this could result in overfueling which is correct when warming up, but wrong when the engine has warmed up. is it heavy on fuel generally. think of it like the old fashion carb/choke set up.
Ryan S
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Re: Smoking Bongo 2.5 diesel 1997

Post by Ryan S » Mon Apr 16, 2018 1:01 pm

Ok so I discovered my father adjusted my throttle cable which I have now put back to original position and slapped him on the hand but it now has a bit of slack, so on cold start I’m idling at approx 900rpm (the first line under 1000rpm) the van drops slightly to about 880rpm and when I put the Aircon on it drops even more approx 800-850, from what Iv read idle speed should rise when the Aircon is on? I have now replaced both cold start solenoids. I’m thinking I am going to have to pass this too a specialist :(
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Northern Bongolow
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Re: Smoking Bongo 2.5 diesel 1997

Post by Northern Bongolow » Mon Apr 16, 2018 2:01 pm

if the idle speed goes down when the aircon is switched on something isnt quite right.
the aircon compressor maybe seizing up, or the right hand solenoid (the one with the white plug isnt working, or the pipework to it or from it is leaking, or collapsing under vacuum and closing as they are old and hard, or the wrong grade pipe has been fitted.
are the 2 pipes that come down from going to the vac actuator on the correct stubs, and is the actuator free and not stuck or leaking.

once you get a grip of what should be happening you should be able to trace the vac/airflow through the system. bare in mind that the 2 solenoids only work at all when the temps of coolant are below warm up temps, then they turn off via the ecu/temp gauge.

if the throttle is up at above about 900 950 revs the glow plugs also turn off via the ecu, best to wind the throttle as low as you can get away with and do the job when the coolant is really cold, say first thing in the morning after a cool night.

the 2 solenoids work approx as follows left one with the black plug works from below zero deg c to approx +10 deg c then turns off, the right one with the white plug works only from approx +10 deg c to about +50 deg c ,(when the glow plugs turn off anyway). then turns off as the bongo is then warmed up. if you start the bongo with ANY THROTTLE you will alter the ecu controlling of the cold start process as you will lift the revs and confuse the ecu.

the 2 cold start solenoids can be swapped over to test either at the plug or via the pipework to test, you can also remove them and put 12volts to the plug to test them mechanically, and to see if the vac flow is being blocked off like they should when operating.
hope this helps.
teenmal
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Re: Smoking Bongo 2.5 diesel 1997

Post by teenmal » Mon Apr 16, 2018 3:24 pm

Ryan S wrote: Mon Apr 16, 2018 1:01 pm Ok so I discovered my father adjusted my throttle cable which I have now put back to original position and slapped him on the hand but it now has a bit of slack, so on cold start I’m idling at approx 900rpm (the first line under 1000rpm) the van drops slightly to about 880rpm and when I put the Aircon on it drops even more approx 800-850, from what Iv read idle speed should rise when the Aircon is on? I have now replaced both cold start solenoids. I’m thinking I am going to have to pass this too a specialist :(

Yes It cold be more cost effective in the long run rather than buying unnecessary parts .

Take care
Ryan S
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Re: Smoking Bongo 2.5 diesel 1997

Post by Ryan S » Wed Apr 18, 2018 12:17 pm

So a big thankyou too everyone for all your advice especial Northern Bongolow, it seems that now I have changed both the solenoids adjusted cold start ever so slightly the smoking has stopped! Happened slightly when I didn’t let the plugs warm for long enough but since leaving for 5/10 seconds longer has been fine. As for the idling not going up with the AC on it pretty much stays at the same revs I’m idling. Maybe I just got lucky here but I am happy with that!
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Northern Bongolow
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Re: Smoking Bongo 2.5 diesel 1997

Post by Northern Bongolow » Wed Apr 18, 2018 2:28 pm

the settings are quite important to get right as one affects the other etc.

but if your happy, were happy toooooooo. 8)
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