Glow Plug Issues

[Andre Steyn]

Hello everyone
I need help with the glowplugs on my TD42, basically what happens is that even after replacing all 6 the relay switches on then off then on then off and then on and finally off completely. Therefore not giving enough time for them to heat properly. Any advice??????

[ricster]

Hi Andre,

Mine does exactly the same thing. If I recall it does 3 cycles. Once you crank the engine it re initiates the "3"cycles ( I may be wrong on this when the engine is running ). The glow plugs are supposed to stay on whilst the engine is running until either the engine oil or coolant temp reaches 50 deg C. ( again not sure which). Thereafter the glow plugs switch off and are inactive.

When I did my glow plugs I checked them by running a wire to the battery, they glow red hot within a second.... and I mean glow RED hot, so the cycles shouldn't make too much of a difference.

Hope this helps.

[bogeyman]

Andre
Do you have cold start issues?

If the glow plugs you replaced were the correct Nissan part , it should work perfectly.
These fast glow plugs will burn out if powered for too long.
Some older vehicles used plugs that can get power for a minute without burning out.
You can check the plugs by isolating them from the feed wire and measuring the resistance to earth. It should be very low (less than one ohm)
Chris.

[Andre Steyn]

I do have cold start issues yes, replaced the glow plugs and the relay, even after the 3 cycles of on off on off it still starts with white smoke and rough idling. The plugs I used are ngk, same as original nissan part.

[ricster]

.... Mine on a really cold day needs the 3 cycles to start if I want it to take first crank. My motor might take one full revolution before firing up. On an average day like todays JHB wet cool rainy day, if I just bang the key in and turn, then no ways will she start. I need at least one cycle and then crank and off we go. On a hot day, while its on its first cycle I crank and off I go.

But how to solve your patrols problem..... Just some food for thought, and it did make a difference on my Iron Maiden. These motors have a compression ratio of 22.7:1, where as petrol motors are maybe in the 8 to 9:1 ratio mark. So to crank those 6 cylinders under that kind of compression..... with 6 glow plugs also sucking the life out of the battery, the glow plugs are probably not getting to the glow rate that is needed to achieve a good clean burn inside the cylinder. If you have a second battery ( must be fully charged ) connect it up in PARALLEL and try starting the Patrol, and see if there is a difference in starting time and amount of white smoke coming out the exhaust. Your patrol was sitting for a long time and I'm thinking the battery is maybe not as good as it used to be.

White smoke ( not whitey blue smoke) is saying that there is un-exploded diesel coming out your exhaust.... your Patrols exhaust I mean....hahaha. So why isn't that diesel being used. Diesel needs compression and heat to explode. If the battery test thing doesn't cure it, then check each glow plug for a second or 2 on a battery to see if it glows. If they glow red hot all should be well there. Then do a compression test. If around the 22:1 mark, then all is cool there. If not, you may have the rings with the openings not in the opposite directions, or maybe a broken ring ( but then there will be other k@k happening like oil loss and blue smoke out the exhaust.) but this is unlikely. Is the head torqued correctly. you may have pressure leaking between cylinders. Remember your sleeves were skimmed if I recall flat with your block. "Piano wiring" the block could solve this, if it is indeed the problem. The head torquing for me was amazing..... you tightened those bolts with a torque wrench to some ridiculous setting then still cranked that bolt more than 90 deg..... I used a 1.5m long tick steel tube just to get the leverage to crank the bolts.And then you have to re-torque again after a few 100 Km

Good luck mate .... keep us posted

[Andre Steyn]

Hmmm ok the fact that the newly rebuilt motor was sitting for a year isn't good yes,I've done about 6000km since everything finally came together,slight oil usage about 1l for the whole distance. Besides the bumpy starts in the morning she runs really good, no water usage no overheating,turbo spooling up from 1900rpm already and at full at about 2200-2500 and keeping up until about 3850rpm. My mind is telling that just maybe besides the glowplugs not reaching full tempreture that the pistons are struggeling to seat in the sleeves. I took it really easy on the motor for the first 1500kms even the first dyno we set her at only 90hp to be safe. Oh yes forgot the battery is new had to replace it due to standing so long.

[bogeyman]

Andre

The two non turbo 4.2 engines I run both have 100k km on and both will only start second time in colder weather. With white smoke for a minute.
The manual instructs you to rev the engine slightly until it runs smoothly. They have never failed to start in severe cold.

Something easily overlooked is the battery connection clamps and cables.
A good test is to feel for heat on the cables and connections directly after a long starting crank. Also check the bonding strap.

Chris.

[ricster]

Hmmm.... I'm a bit stumped.... If the motor is running nicely, and a litre of oil usage over 6000Km, I believe is fine. Here is another train of thought...... Being a new rebuild engine, you may have driven it gently ( running in ), which is why there are many different views on "running an engine in".

I do a LOT of stop start short trips with my Patrol. I work 7Km from home, and have had similar white smoke issues from time to time, so here is my train of thought and I do find that this works for me. My motor has done about 70 000Km since I did my rebuild and all is well with my motor.

With Alfin pistons and rings you need compression to press the ring up against the side of the sleeve to get a good seal. There is a cross pattern on the sleeves when they are, I presume honed to create and hold a type of oil film over the entire sleeve, so as the piston ring slides up and down there is always a thin film of oil between the two. If the compression is low, by not putting your foot down on the accelerator and pushing the revs to the 3000rpm mark under load, the Alfin piston ring is designed to push out and up against the sleeve. More compression will make the ring push out more, and less compression = less pressure on the sleeve.

Where am I going with this??.... Maybe the sleeves, or bores have become slightly glazed. I think a slight glazing of the sleeves can be burnt out with a good aggressive long ( more than 80Km )drive. On start up, DON'T let it idle !!!. When you pull away do an aggressive pull away..... don't wheelspin obviously, but don't pull away like driving Miss Daisy, do a good average to just above average pull away. Keep the max revs to MAX 1500 rpm ( The motor is still COLD ). Don't be scared if you see HUGE plumes of black and/or white smoke coming out your rear.... again I mean your Patrol... ...... so you want to get short crisp quick gear changes with rpms at 1000- 1300 rpm put your foot flat on the accelerator ( obviously if safe to do so ). You want to push the motor to get the biggest explosion at the lowest rpm while cold.

The temps will rise to normal operating temps quite quickly. Now don't baby the motor.... this TD42 is a BIG donkey and an handle punishment better than you think, so put your foot down and push the motor a bit. That motor is more than ready to take a bit of hard work.

Get the EGT's up into the 550 deg C mark ( pre turbo) and let it stay there for a short period of time UNDER LOAD!!. 550 deg C is still well under critical temps of 700 deg C. When you are returning home don't let the engine idle for 2-3 minutes, but rather slack off the power to allow the oil to cool down via the oil cooling system you already have. If you stop at a robot, and pull away ...... floor it to 2000rpm and change gear and repeat till 60Km/h is achieved then hold it there. Do this at every pull away.

Your EGT's will not shoot up high doing this and your oil temp will also not go up too high. When you are at home the turbo will be spinning at a reasonable rpm and oil temps will be acceptable. Idle for about 20 - 30 seconds MAX and switch off. next day start up and repeat process.

Check if on day 2 there is an improvement, and if there is a difference on day 3 after the second hard drive. If you decide to do this, let us know the results.

You can ease "this style" of driving up a bit but continue to drive this way on start up. Don't punish the motor when cold, but don't baby it either, you need those Alfin rings to do what they were designed to do. You will have to assess how to drive the Patrol under whatever the weather conditions are. What I'm saying is if its snowing let it idle for 30 odd seconds before driving away, if you are in the Namib desert drive it almost immediately after start up.

Please note that this is only my opinion, and it is working for me..... this is your decision if you do try this, as I assume there will be differences in opinion on this matter with other Patrollers and enthusiasts.

[ricster]

I agree with Christo, rev the engine for 2 seconds ( about 900-1000 rpm) on start up and AFTER the oil pressure lamp has turned off, then let it idle to see if there is still smoke out the exhaust.

Is there a continuous stream of white smoke, or just a few puffs at different intervals, or at the same intervals?

[Grant]

Andre,

Who did the dyno for you ? How high do your EGT's get under full load ?

Also was it set at 90hp or KW ?

I have the old GQ 4.2 D with Safari turbo and Inter cooler and with 400k km, all is still well. You can also call me on zero eight three six double zero four zero two three.