New to diesel - rough starting?

Allow me to introduce myself, or more importantly, my truck.

I'm a recent convert to the diesel world, in the form of an imported 1990 LJ78 (yeah, the one with the head problems). I knew what I was getting into when I purchased the truck, and I have to say that in these last 1500km I've been very pleased. I went out of my way to find a 5 speed, as I've heard the tranny cooler in the autos can be somewhat responsible for the overheating and consequent head cracking (and I just plain prefer to shift my own gears, thank you very much). I bought the truck to run on vegetable oil, and I'm quite nearly done the conversion.

The issue with the truck is that it is a bit rough starting sometimes. The previous owner recommended two cycles of the glow plugs, which certainly helps the start. Still, it takes up to 5 seconds of cranking to get it started sometimes, regardless whether it's warm or cold, block heater plugged in or not. It will also cough out a large cloud of smoke (I'm fairly sure this is normal diesel behaviour, though). If it's been started cold the engine will also idle a bit rough for the first few minutes. It will sort of misfire every couple of seconds, causing the engine to lurch on its mounts and belch out a bit of smoke from the exhaust.

The really strange thing is that for the first week or so after I first filled it with B20, it started like a dream. I was very pleased, thinking that the B20 had cleaned things up and that the starting problems were over. It was not to be so, unfortunately, as the following week (still on B20), the starting difficulty returned.

I was at first concerned that this might be related to a cracked head, but it doesn't seem to have any of the other symptoms one might expect with that. I certainly hope this isn't a sign of a dying head - but I knew what I was getting myself into when I bought it.

Once the engine is started and warm, it runs great. I'm really pleased with this truck - I'll be even more pleased when it's running on veggie.

I've never owned a diesel before this truck, nor had much experience with them. I understand that they're a bit more difficult to start, generally, but is this normal? Most other diesels don't seem to have to crank this much, nor do they stutter after starting. The double glow plug cycle seems a bit odd, as well.

If you double glow it does it start better?

First thing with any new to you diesel IMOP is to buy a set of glowplugs and start fresh. Just like changing the oil if you have never known when it was last done.

ALso a really good mod is to remove the timer and run with a manual push button, you control the glow times. Cycling the keys is annoying.

When you are absolutely sure your glow system is 100% and you still have problems then you can look further.

If it runs fine warm, doesn't have excessive smoke when warm, and isn't gobbling up coolant, then a good chance your fine.

If you have the Factory engine manual( FSM 2l-t) then you could see how to test glowplugs. They have a ohm rating and you could also pull them and put power to them.

But again I would just replace. 20 bucks each at napa maybe. Maybe someone on here knows the part number for a NGK. Toyota will be like 99 bucks a plug..... But you could try them.

Congrats on the new truck, you will be a complete Diesel convert once you get the starting issues sorted out.

I second Brownbear's opinion that the glow plugs are to blame. I recently went through some rough startup, and eventually no start problems due to glow plugs on my troopy. It turned out that the temp sensor that tells the timer how long the plugs should stay lit had become disconnected, and the plugs stayed on for way too long, burning them out one by one. I now have the sensor locked in place, all new glow plugs in the truck, and a spare set of new glow plugs for the next time (since it took two weeks for the new plugs to reach my dealer!)

So, go ahead and get a new set of glow plugs ordered, and on their way to you, and while you are wating, go through the factory service manual, and test every component of your glow system with a meter. Make sure that the glow plugs really are to blame before you put new ones in.

On the B20, I don't know that it would clean out your system that quickly. I have been running bio for the past year, first at B20, then at B50, and when summer hit , I made the jump to B100. I have never really felt a change in performance that would lead me to think that my injectors were now clean. It just continues to run as great as ever.

Good luck

Could also be fuel starved. As I recall b20 kindof scrubs the fuel system. Have you drained the sediment filter (if it has one) and changed the filter?

Karl

Mattse.cx- Do you have an automatic choke or a manual? During the first few minute when it has a rough idle what's the RPM? I used to set the manual choke on my old '88 Hilux Surf to between 800 and 1000 RPM when I first fired it up. After a few minutes, when it was warm, I would turn it down to around 600 to 800 RPM.

Mattse.cx said:

Still, it takes up to 5 seconds of cranking to get it started sometimes, regardless whether it's warm or cold, block heater plugged in or not. It will also cough out a large cloud of smoke (I'm fairly sure this is normal diesel behaviour, though).

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On the contrary toyota diesels are quite clean . The emmisions standards have been quite high in Japan for some time.

If you take the steps the others pointed out it should start almost immediately with just half second puff of greyish white smoke.
The instant start will also extend your battery life.

Another area to look into is the injectors .When the tips become clogged it affects the spray pattern causing black smoke when its revved,even when warm.
Rebuilt injectors give better fuel economy and more power.

Once a diesel is running right it usually only needs filter and oil changes which can be done by almost anybody and you get the true money saving benefits of diesel power.
Dont forget the workshop manual and welcome to the club.

I had a problem with my 3B doing the same thing when cold. I noticed that the problem went away once I had the injectors rebuilt, a bit more expensive then glow plug but worth it. If the glow plugs fix it then that's great. If not then look into at least getting the injectors tested. If they need rebuilding then make sure the place that does it knows the specs for you motor and gives you the proper shims (washers) with the rebuilt injectors.

Wow, I leave for an hour or two and look at all these replies! Thanks, guys. I'll definitely yank out those plugs and replace them - hopefully that will fix things up before the cold gets here.

Do you have an automatic choke or a manual?

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It's a manual, but the control knob is broken and has been on my 'to fix' list for a few weeks. It generally idles at about 800-900 when it's warm, though.

the LJ78 does start harder than other Toyota diesels, one thing that helps is diconect the cold sensor at the block for a longer glow. doesn't fix the problem but does makes a difference.
although i have not done it yet, i am thinking of a manual over ride for the wifes daily driver LJ78...

Another possibility...air leak in the fuel system. I'm having some starting issues as well, I think I'll dealing with a piece of loose fuel line that allows air to leak in slowly. The injection pump then has to do extra work to get fuel up to the injectors. I just put some hose clamps on there today, so we'll see if that helps.

Worth checking into anyway.

Robin

agreed, always start cheap and work your way up...

I thought it might be an air leak at first, but since multiple glow cycles seem to help, I'm betting on the plugs.

NorCal Cruiser said:

Mattse.cx- Do you have an automatic choke or a manual? During the first few minute when it has a rough idle what's the RPM? I used to set the manual choke on my old '88 Hilux Surf to between 800 and 1000 RPM when I first fired it up. After a few minutes, when it was warm, I would turn it down to around 600 to 800 RPM.

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It's not a choke--diesels often have a hand throttle though. I use mine when starting a dead cold engine. I start it, let the oil pressure come up, then crank the hand throttle to get rpm's up to just under 1000. Once the temp comes off the peg, I set the throttle back to rugular idle.

Factory turbodiesels usually have a lower compression ratios than normally aspirated diesels. This works fine once the engine is up and running and making some boost; however, for starting, the lower compression ratio of the turbodiesel can make the initial compression ignition just a little more difficult. This is not unusual. It means that good glow system is ever more important. I'm with all the others who have mentioned to start fresh.

You can check the glow plugs without removing them. After you remove the 12V wires that connect to the glow plugs, take a resistance reading from where the wire was connected to ground. Not sure what the Toyota resistance specs are, but if you have low resistance and no opens, the glow plug is usually good.