3B diesel engine misfires above idle

[Jeff Hastie]

Hey Tom, I'm glad you don't think compression is the problem... those numbers seem acceptable to me, and the engine has lots of power once it's underway. When it's missing, there is a puff of white smoke for every misfire, and lots of white smoke when you rev it up to the point where it misses constantly. As for the EDIC, it stays steady throughout the misfiring, and I have run the engine with the EDIC arm removed with the same result. Also, I've tested the motor with the intake air hose removed from the engine, air unfiltered and direct, so unless there's a blockage inside the intake manifold, below the throttle apparatus, that can't be the problem. On Sunday I played with the timing a little bit {I didn't remove the injector or oil lines from the pump, so I couldn't tilt the pump more than a millimeter in either direction}, and advancing the timing a little from it's current position seemed to make the issue worse. It misfired and ran rough after starting at idle speed unless glow plugged constantly during my 3 min test, and when rev'd up it did the usual shaking with clouds of white smoke. I then retarded the timing a little past it's original position, and it ran great at idle, no need for any glow plug time after starting. It still missed when rev'd up, however. I'll have to try and time the engine properly when I have time, but do you think it's possible that the timing could be to advanced, and that is the cause of the problems? Would that make any sense?

 

[lostmarbles]

...When it's missing, there is a puff of white smoke for every misfire, and lots of white smoke when you rev it up to the point where it misses constantly. .As for the EDIC, it stays steady throughout the misfiring,..

Well it's getting the fuel OK then (and your EDIC isn't restricting fuel by wandering momentarily to the off position).

What's your ambient temperature there?

Perhaps it's just that your engine is so damned cold?

And I know you replaced your thermostat but where does the temperature needle sit when it's warmed up?

But then again, you're telling us it idles smoothly (and I'm assuming this remains the case even well after you've finished with the preheat). So if your engine were staying too cold I'd have expected it to be stumbling at idle too ...

and I have run the engine with the EDIC arm removed with the same result. Also, I've tested the motor with the intake air hose removed from the engine, air unfiltered and direct, so unless there's a blockage inside the intake manifold, below the throttle apparatus, that can't be the problem. On Sunday I played with the timing a little bit {I didn't remove the injector or oil lines from the pump, so I couldn't tilt the pump more than a millimeter in either direction}, and advancing the timing a little from it's current position seemed to make the issue worse. It misfired and ran rough after starting at idle speed unless glow plugged constantly during my 3 min test, and when rev'd up it did the usual shaking with clouds of white smoke. I then retarded the timing a little past it's original position, and it ran great at idle, no need for any glow plug time after starting. It still missed when rev'd up, however. I'll have to try and time the engine properly when I have time, but do you think it's possible that the timing could be to advanced, and that is the cause of the problems? Would that make any sense?

You've already fitted reconditioned injectors .. otherwise I'd have suggested that.

And you've owned this BJ42 for 2 years and it's always had this problem I see (but it's gotten worse recently)..

I guess you could try using some leverage to move the pump a bit more in the retarding direction...

But I'm a bit puzzled that's for sure.

Any chance of posting a video of its behaviour.. (You never know ... That may help us diagnose it ..)

 

[RufusTheDufus]

The average of 440, 380, 420 and 425 is 416. And 10% of that is 41.6. So your figures should range from 374 to 458 to comply with "no more than 10% variation. - And they do.

I always read the FSM 10% variation rule to be from maximum to minimum compression. Not from the average.

The 3B rocker arms will wear over time. The valve will create a divot in the rocker contact area which can make it difficult to properly adjust the valves. (Practically impossible to get proper valve adjustment using feeler gauges.)

A sticky lifter or a rocker arm with a warn bearing could cause this type of symptom on cold engine.

 

[lostmarbles]

......I always read the FSM 10% variation rule to be from maximum to minimum compression. Not from the average. .........

This is taken from the Aug 1980 B-series FSM (and is the same as appears in other Toyota B-series and H-series engine FSMs):

You can see that they give a blanket figure of 28 psi ........... which you are quite correct in saying is 10% of the minimum. But I'm afraid I've always considered this incorrect/inaccurate.

I think Toyota, in printing 28psi, is either assuming that a worn engine will always have compression figures around the lower limit, or else (more likely) is assuming that the average mechanic is too dumb to calculate the limits if they had printed "10%").

I was always taught simply that the individual-cylinder compression values shouldn't vary by more than 10%.

And my method of calculating whether this is the case or not is mathematically correct ... so I stand by it..

 

[lostmarbles]

One thing I guess we're all avoiding here is suggesting that there could be a fault with

• the automatic timer (pressed into the timing cover), or
• the injector pump

And the former is definitely a reasonable possibility (but it is such a pita to get at).. We don't hear of them playing up much but perhaps it's happening here?

 

[RufusTheDufus]

Jeff are you in the U.S. or Canada? I have a Kent-Moore timing light adapter you're welcome to borrow. It clamps onto the #1 injection pipe and senses the fuel pulse. It triggers a regular spark ignition timing light. It makes the process of checking pump timing as easy as a spark ignition engine. PM me if you're interested.

 

[Jeff Hastie]

Hey guys, thanks for the comments. The ambient temp has been ranging from -20 to -5 Celsius the past week or so, and I don't know my engine temp, because my temperature sender has been broken for a little while now, and I am planning on fixing it soon. This engine has always been a little slow to warm up in winter, partly due to the non-electric radiator fan, which spins right from when the motor is started {I don't think it's supposed to do that, but oh well}. Cardboard in front of the rad helps a lot, and while the above may contribute to the issue, I don't think it's the main problem. After all, a properly functioning, but semi-warm engine wouldn't misfire and shake like crazy when raised above idle, would it? All I know is that my other, older 3B has no such problem at 630 thou km. Anyway, since I tilted the pump a hair toward the engine {retarded}, it has significantly reduced the needed glow plug time, and greatly reduced the noticed engine misfiring that used to occur when the vehicle was first driven after starting. It still has the problem, but it seems a little better, anyway. I'll look into retarding the timing some more, or just timing it properly, as soon as I can. I'll also see if I can post a video, but I've never tried that before and don't yet have a u-tube account, so don't hold your breath. Also, Rufus, thanks for the offer of the timing light, but I live in Alberta, Canada... a little out of the way, shipping wise. I should be able to manage the hard way, but I guess time will tell. Hopefully that fixes the problem, and if not, then I'll turn to the pump, timer, or rocker arms, as suggested.

 

[yotahed]

I believe you've advanced your timing if you tilted toward to the engine. Slightly advanced will start quicker and smoother.

 

[Dieseler]

Jumping in here a little late with the new upgrade with MUDD....have you tested your glow plugs to make sure they are all functioning at 100% it sounds like you are just experiencing a cold cylinder and in cold climates what you describe is common.
I have many diesels that all respond differently in cold weather some fire up instantly no jumping around and some are real jumpy till I get some heat into the cylinders.
You should not rev it up just raise the RPMs aprox to 1000 RPMs and hold it for a few minutes till you get some heat buildup I use the throttle cable to hold it there till I am ready to drive .

 

[Jeff Hastie]

My service manual indicates that tilting the injector pump towards the engine retards the timing, but I suppose this could be a misprint. Out of curiosity, can anybody confirm that this is correct? As for the suggestions about glow plugs, engine temp, and bad cylinders, those have been pretty much ruled out in previous posts Dieseler, but thanks for the feedback. Also, just raising the rpm to 1000 causes misfires in my engine, but it starts and idles great.

 

[lostmarbles]

I believe you've advanced your timing if you tilted toward to the engine. Slightly advanced will start quicker and smoother.

My FSM agrees.

My service manual indicates that tilting the injector pump towards the engine retards the timing, but I suppose this could be a misprint. Out of curiosity, can anybody confirm that this is correct? ....

Are you sure your FSM says that?

Here's what the Aug 1980 B-series FSM (36047) says:

 

[Jeff Hastie]

The manual I'm referring to is the "MAX ELLERY'S FACTORY WORKSHOP MANUAL, LANDCRUISER DIESEL 4&6 CYL, 1972-1990", and it says "If the injection timing is retarded, advance it by tilting the pump away from the engine. If the timing is advanced, retard it by tilting the pump toward the engine." The diagram shows the injection pump of a 2H engine, but the the book says that the instructions apply for B, 3B, 13-BT, 2H, and 12H-T engines. Anyway, I think I'll go with your FSM on this one, given that it is B-series engine specific. Anyway, given the symptoms of the engine, it would make more sense to me that my timing is over retarded, rather than over advanced. Thanks for the post.

 

[RufusTheDufus]

Interesting that it says it applies to both the B and H series engines. The injection pumps are on opposite sides of the engine.

 

[lostmarbles]

Interesting that it says it applies to both the B and H series engines. The injection pumps are on opposite sides of the engine.

Ha ha

You've hit the nail on the head Rufus.. And this is a good example of why the Toyota FSMs are so superior to all alternatives..

The TOYOTA August 1980 2H FSM (36048E) correctly
shows that when the IP is slung on the other side then the opposite applies:

 

[Jeff Hastie]

Good news... it's fixed! I decided to time it properly, made an inspection pipe out of a spare injector line, and found that the current timing was retarded just under 1/2 inch from the timing notch on the pulley. FYI, this is after I advanced the timing last weekend as an experiment, so my timing must have been really retarded in its original state. Anyway, after I advanced the timing to the correct position {by tilting toward the engine... you guys were right}, re-installed everything, and fired up the engine, it ran great. No need for additional glow plug time, even though it wasn't plugged in at 0 degrees. It could rev up to about 1000 rpm, right away, without missing a beat. After a 3 min warm-up, it could rev up much higher without missing, and after a short drive, it was perfect. I'm considering it fixed at this point, and thanks to everyone that responded to my posts.

 

[roscoFJ73]

The average of 440, 380, 420 and 425 is 416. And 10% of that is 41.6. So your figures should range from 374 to 458 to comply with "no more than 10% variation. - And they do.

So I don't think compression is to blame..

You haven't mentioned smoke.

Is that how you are supposed to do it? I thought it was max of 10% variation between the highest and lowest reading ,rather than the average reading.

But I don't think compression is the problem either.

 

[lostmarbles]

Good news... it's fixed! I decided to time it properly, made an inspection pipe out of a spare injector line, and found that the current timing was retarded just under 1/2 inch from the timing notch on the pulley. FYI, this is after I advanced the timing last weekend as an experiment, so my timing must have been really retarded in its original state. Anyway, after I advanced the timing to the correct position {by tilting toward the engine... you guys were right}, re-installed everything, and fired up the engine, it ran great. No need for additional glow plug time, even though it wasn't plugged in at 0 degrees. It could rev up to about 1000 rpm, right away, without missing a beat. After a 3 min warm-up, it could rev up much higher without missing, and after a short drive, it was perfect. I'm considering it fixed at this point, and thanks to everyone that responded to my posts.

Good news...

BEE-JAY42 had it sussed early on in the thread (see his post immediately below) and the rest of us just muddled our way through to proving him right...

Sounds like text book retarded timing, mark where your pump sits then advance the timing on it to see if it makes any difference. If it doesn't you can then return your pump to it's original position no harm done. It's the first thing I'd do and won't cost you anything.

Is that how you are supposed to do it? I thought it was max of 10% variation between the highest and lowest reading ,rather than the average reading....

Well maybe my method is just the kiwi way....

 

[Awl_TEQ]

Nice timing with this thread. That was a pun.

I'll post this here rather than start a new thread with the hopes it will be easier for future searchers to find the info.

I have just installed a 3B that was rebuild 4 years ago and I just fired it for the first time last weekend. I have been dealing with the same or very similar symptoms as Jeff. But I am also getting air. I have been swapping parts from the engine I pulled (which ran fine BTW) in an attempt to stop the air ingress while also adjusting timing and taking test drives all day. I believe I have the timing figured. I advanced it as far as I could and got all black smoke all the time so I brought it half way back and it seems decent. I can stop the black smoke by backing off of the throttle. Still low on power though.

It is difficult to identify the problem when dealing with two separate issues that cause similar symptoms. My symptoms have been changing throughout the day but here is where I am at now. She starts great, idles fine. I back out onto the road and as I start off in first she's "OK" but a little weak on power. I get a few random misfires as I go through the gears accompanied with white smoke each time. I'm a block from a minor highway with a bit of a hill. So as I climb the hill I am quite low on power with continuous black smoke. I can only muster 70km/h up the hill where the other engine had me up to 90 by the crest. As I drive around on level ground she's smooth but weak. After about 15 to 20 minutes I get serious white smoke and rough running at all RPM. If I pull over and stop she will stall. The only way to start her again is to bleed the fuel filter which gives lotsa bubbles and then she'll fire right up.

In an attempt to stop air ingress I swapped the two fuel hoses and banjo sealing washers over from the good engine. I also put a gear clamp on the fuel line where it enters the primer because it seemed loose. My thinking is that I am getting air build up at the filter so the air must be entering before the filter. I am considering swapping over the primer pump and its housing. That is the only thing left that wasn't part of the previous engine setup.

Except the fuel return line from the injectors. And possibly the line that joins the injectors together.

With all of that laid out I invite input from the brain trust.

 

[lostmarbles]

....I have just installed a 3B that was rebuild 4 years ago and I just fired it for the first time last weekend. I have been dealing with the same or very similar symptoms as Jeff. But I am also getting air. I have been swapping parts from the engine I pulled (which ran fine BTW) in an attempt to stop the air ingress while also adjusting timing and taking test drives all day. I believe I have the timing figured. I advanced it as far as I could and got all black smoke all the time so I brought it half way back and it seems decent. I can stop the black smoke by backing off of the throttle. Still low on power though.

It is difficult to identify the problem when dealing with two separate issues that cause similar symptoms. My symptoms have been changing throughout the day but here is where I am at now. She starts great, idles fine. I back out onto the road and as I start off in first she's "OK" but a little weak on power. I get a few random misfires as I go through the gears accompanied with white smoke each time. I'm a block from a minor highway with a bit of a hill. So as I climb the hill I am quite low on power with continuous black smoke. I can only muster 70km/h up the hill where the other engine had me up to 90 by the crest. As I drive around on level ground she's smooth but weak. After about 15 to 20 minutes I get serious white smoke and rough running at all RPM. If I pull over and stop she will stall. The only way to start her again is to bleed the fuel filter which gives lotsa bubbles and then she'll fire right up.

In an attempt to stop air ingress I swapped the two fuel hoses and banjo sealing washers over from the good engine. I also put a gear clamp on the fuel line where it enters the primer because it seemed loose. My thinking is that I am getting air build up at the filter so the air must be entering before the filter. I am considering swapping over the primer pump and its housing. That is the only thing left that wasn't part of the previous engine setup.

Except the fuel return line from the injectors. And possibly the line that joins the injectors together.

With all of that laid out I invite input from the brain trust.

Let's get the air ingress problem out of the way first..

I'll assume this is a 3B with an inline pump and no fuel return back to the tank (as per BJ42).

I'm busy re-roofing our house right now and have been moving my BJ40 every day so I can dump the old iron onto the driveway (where it usually sits). Well the day before yesterday I noticed it "stumble a bit" when I fired it up. Then it appeared to come right so I drove it out and parked it in the street. But that evening (after an exhausting day up on the roof) I went to try and start it and it would fire up but then die after about 10 seconds or so. So I immediately knew an air ingress problem had suddenly developed. (The fuel level in the tank is very low at about 1/8 full which means the fuel pump will be sucking more vacuum than normal ... which is probably what caused the leak to develop at this time.) The most obvious sign was when pumping my little Bosch primer to get the air out. Sure I could get diesel to come out of the bleed nipples (and the cruiser would run for a bit longer before dying again) but the primer never really became hard to push. So the first point I'd like to make is that having a primer that's hard to push is a good sign that your fuel system is leak-free.

So I went around tightening all the hose clamps on the recently-replaced sections of my fuel lines. And while I was doing this (with a torch in the dark in my worn-out state) I knew exactly where the most likely culprit would be. And this proved to be the case..

It was the lower fuel hose clamp in my leakage line as shown in this image:

So my second point is that this clamp is likely to be your culprit because it is so hard to get at. (Why would it leak somewhere where access is easy?) Besides that, it is a small diameter line so if you've used an ordinary hose clamp on it, it's not likely to be doing a good job of strangling the hose properly onto the tubing.)

Here's one of those horrible things:

 

[Awl_TEQ]

Hi Tom, Thanks for posting. Yes, 1981 BJ42 CDN spec inline pump. Actually, come to think of it, the pump is 1983 but still inline.

I'm working from the basis that the fuel delivery system I pulled was working fine. Furthermore, the system I put in was rebuilt by a competent shop. So for now I will not worry about injectors or the IP itself. I will also leave the injector lines out of the equation because they are a) downstream of the pump b) not leaking and c) real shinny.

On the suction side I will ignore the tank and hard lines up to the rubber jumper at the steering box (LHD, I did not touch any of that during the engine swap). From that point to the inlet of the IP is where the issue lies IMO. That includes the leakage line. All of the clamps on both rubber lines are of the stock spring type clamps. These clamps are adequate from new but in light of a hard to find leak I will change them all to something more positive like what you posted above Tom.

The primer pump is new and does pressure up pretty good so my leak must be small to require 15-20 min of run time at hwy speed to develop bubbles enough to stall.

My leakage line was a junkyard find (as were the injector lines). I had them re-plated and they were acid etched as part of that process. They were nice looking lines and much better than my "mine truck" originals but it is possible the hard line of the the leakage line has a crack. This is less likely than a rubber line/clamp leak though.

As I stated above I swapped out my large lines and sealing washers on the fuel filter already.

If I can't get the rubber lines to seal and solve the problem then I will have to move on to the primer pump. Although rare, I have read a thread here on mud where a new primer pump was letting air into the system.