Don't like the adverts?  Click here to remove them

Worth taking my injectors out?


Super Moderator
Feb 24, 2010
Country Flag
In the scheme of things, I have pretty much bottomed the mechanicals on my 80. Just a rebuild on the front diff to make it as good as new. But I still have doubts, concerns call them what you will over the fueling system. Accepting the fact that I am fine on the spanners but clueless on diesel injection systems what could I look at in terms of home mechanics that would make sense? The car starts fantastically well, 1/4 touch of the key. But I get a light grey pungent smoke from cold. This can go when warm, but not always. If I clog it, I get heavy bursts of soot. On top of the head near number one inlet from the manifold there always seems to be some dampness on there. There has always been a bit of a lack of power really. I'd expect a 4.2 x 6 to have much more go than this, but hey it's a 16 year old car. Fuel economy started out at 24mpg but will all the trimmings I am now at around 20mpg which show that it is probably working OK but there are some tweaks that could be done. Changed BEB recently everything still fine. My fuel pick up had no strainer on the end and I have changed two fuel filters now and pulled small trees out them each time. I gave the little nut on the pump half a turn and the click wheel inside got two clicks as well. That did make a difference not nearly so sluggish but it maybe soots a little more when revved hard. This week, the truck stood for several days and simply would not start. In the end I had to pour diesel into the fuel line and after a bit it fired up and throbbed for a bit until it fueled itself properly. I understand that the primer pumps can start to let air in. The pump on the top has never done anything when pumped even for several minutes.

OK Doctors, I'm not looking for an accurate diagnosis here, just some better understanding perhaps of what might be happening and what servicing I could do. It's done 100k of mixed care miles. Some care clearly being non existent. Is there any merit in pulling the injectors and simply looking at them like you would a spark plug? Is having them tested for spray pattern worth doing and expensive? Should I have my IP serviced somehow even though I don't suspect it of being faulty? I have run plenty of injector cleaner through the system.

So, what are your thoughts. I think that this really is an open thread on injection systems for the 1HD-T. As it is, it'll probably run to the end of the World and back. I haven't broken down, it's just that I would like the confidence of knowing what's what and where I might get let down just when I don't want to be. Plus any improvement in performance might be nice.

Chris said:
Is having them tested for spray pattern worth doing and expensive?
This is probably worth doing - I believe that it's not too expensive - biggest cost is probably the time to remove and refit plus shipping them off to someone who knows what they're doing. RVS in Swindon seem to be highly recommended. While the injectors are out and with RVS, you may as well have the tips replaced - again apparently not hugely expensive as parts go but your bill is starting mount :whistle: At this point, your injectors will be like new (assuming RVS found them all to be fine), so you can cross that off the list.

Chris said:
Should I have my IP serviced somehow even though I don't suspect it of being faulty? I have run plenty of injector cleaner through the system.
Hmm this WILL be pricey I suspect - personally I would check the other things first. The pump is complex piece of machinery and seems to be quite sensitive to settings, so I would nervous about flinging the spanners about near it - I'm sure you're a braver soul than me :mrgreen: Perhaps it's more cost-effective to add a fuel lifter/pusher pump, like a Walbro, to help the IP and see how the truck goes before you consider removing the pump and getting it overhauled. :idea:

That's a good start Andrew. I would take the injectors out myself so that's a zero cost. And in terms of testing, we have loads of diesel engineering places around here, mostly doing lorry stuff. It's the benefit of living in an area that still has some industry left. I like the idea of fitting a helper pump. Does the IP actually drag the fuel all the way from the tank or is there another pump somewhere else? I presume that this would be an on demand pump of sorts so that it stops pushing when there is a particular back pressure. I wouldn't want to 'burst' the IP.

I was referring to removing the injectors costing you time in that the truck is u/s while they're out, plus it's your time removing and refitting.

AFAIK the IP sucks the diesel, so no lifter pump or anything to help get the fuel from the tank to the IP. There is a diesel return line for excess fuel that's drawn through. I presume that any excess fuel flow delivered by the extra pump will simply flow back to the tank, so no risk of damage. Perhaps Jon or Julian can confirm the story here?

I think most of the "helper" pumps run continuously when the ignition is on and also have a "fail-open" design so that if they stop, they do not block the fuel flow. (Or if you wanted to be cute, you could add the helper pump in parallel with the original fuel line with a non-return valve in the original line and if your helper pump failed, the IP would simply pull fuel from the tank, bypassing the failed helper pump.)

I don't know whether the Walbro is an on-demand pump or not. Not even sure what makes a Walbro preferred over any old diesel fuel pump? We're talking about moving diesel a few metres with a hydrostatic head of maybe half a metre...

EDIT: Some interesting info on how a rotary injection pump works here

Andrew, I generally give myself a generous discount on my hourly rate so that's not a problem. Whilst I am doing that I am not out mugging old ladies or dealing in stolen clothes pegs or whatever. I shall look into the pump idea. These pumps are good I'm sure but 16 years on they have done plenty of work haven't they. I think that there will be a series of measure here that can improve an old warhorse. None of them on their own will likely be a show stopper.

Is there any merit in looking at IP timing and that sort of stuff, to make sure that injection is just right. If you've a puff of blue on start up it could be oil smoke from worn valve guides, or similar, or fuel smoke from worn injectors. Only a sniff of the smoke will confirm which blue smoke it is. My money's on the injectors. Also, maybe the IP is just not producing the pressure required for good clean ignition.

As AP says, the injectors is a good starting point and start ruling out the bits one by one.
Don't like the adverts?  Click here to remove them
The light grey smoke is not a puff on start up, it is a continuous mist for some while leaving a light fog behind me. It is an eye watering sort of acrid smoke and smell. Not at all like a fuel smell or like say, soot. It's very unpleasant actually.

I think that starting at the injectors and working back is probably the right thing to do. Does removal and replacement require any consumables, like crush washers or anything?

There may of course be other issues here like worn rings or as you say valve guides. We may not crack everything in the end but eliminating all variables is good. Some people might simply not be bothered. it runs pretty good, but why have a project and stop short? If it was an 80 on a trailer for off roading at the weekend, I simply would not bother with this.

The light grey smoke is not a puff on start up, it is a continuous mist for some while leaving a light fog behind me. It is an eye watering sort of acrid smoke and smell. Not at all like a fuel smell or like say, soot. It's very unpleasant actually.

:thumbup: Fuel smoke from worn injectors....(I'd put a tenner on it) when the engine warms up I bet it disappears pretty much totally. When the engine is nice and hot the combustion is at its best, that's why the smoke is less of an issue. When cold, ignition can be poor, with injectors that have droplets of fuel rather than the ideal mist, and as such it will smoke. Will also account for an increase in fuel consumption too.

Get the injectors done and you'll be well on the way. Dunno if the 80 has heater plugs but if it has I'd be checking those too when you have that area of the engine stripped. Bung in a new set.

Not sure about the consumables, but I'd be surprised if the injectors didn't have crush washers or similar. However, they may be captive like on a sparkplug and not replaceable. Injector people will best advise there. Or speak to Parts King in Lindop and he can check those bits.
Top fellas, both. Many thanks. Cheers for the search. I hadn't got that far as I am actually working (truthfully)

I would not be surprised if the codger that owned this prior to me ran it on goat's wee or something. The cyclonic filter trap on the airbox had enough wheat in it to make a loaf and there was even rat droppings under the battery trays. So Lord knows what has been through it over the years.

The light fume does generally disappear when hot, yes. It can be variable.

Hi Chris, Not sure what area you are in, there is a good diesel specialist in Hoddesdon called Wade diesels that I have used for the last 30 something years & they have always been honest on their testing & reporting on injectors/pumps.

I would say from what you have said the injectors will need testing & over hauling.
Before even contemplating IP and injector service.
I'd personally would give it a brand new thermostat, if you haven't done that allready ;)

It does a lot more than keep the engine from overheating.
A long way from Hoddesden, that's for sure. Thanks, but plenty of injector people around here. Big on transportation and haulage. Was sure that my signature had my location in. Not noticed that it was missing. I shall stick it back in again.

Done the thermostat, radiator and coolant already. Appreciate what you say, but I don't think that the initial smoke that comes out of my exhaust is related to that. I am going to start with the injector service I think.

If your cooling circuit is up to spec. Then IP and injectors are the cherry on the cake.

After the front end engine work and the valves I simply rolled mine into a diesel place.
They worked on the injectors and tuned the IP to spec.

It still has a faint blue smoke in the morning.
These trucks love to work all day, but don't like being woken up in the morning :D

Before you tear into the IP and such, run your usual stretch a couple of times and record MPG.
When the work is done, run that stretch again and you'll notice the difference in MPG. In the longrun your wallet will surely profit from having the work done, or diy :thumbup:
Cheers Chris. Great inspiration! I love the quote about getting up in the morning. Cooling is tip top. I am going to drop in on a local injector place next week and see what they have to say.