92 Hilux Surf 2LTE - Rough idle and starting issues

[92Surfivor]

I’ve been running and wrenching Toyotas for years, but this is my first diesel.

When I got it (with 320,xxx kms) the T. Belt light was illuminated, so that was top of the list. I replaced the timing belt, idler, tensioner, crank and cam seals, water pump, and thermostat. I also replaced the coolant at this time, but I did not perform a coolant flush.

From the start, it has had difficulty starting. Plugging in the in-line coolant heater helps, especially when the thermometer dips below 0*C. Multiple glow plug cycles helps as well, regardless of temperature. I have to depress the throttle pedal to half or full throttle and crank for 15 – 20 seconds before the engine starts to fire. Once it does, it blows a huge cloud of light blue smoke that smells very strongly of raw fuel and will only run on high idle and has a regular miss.

Once the engine has been running for a minute to a minute and a half, the miss and the smoke clear. After this, the truck seems to run great and is a real pleasure to drive and has plenty of power at all RPMs (although delayed by the turbo lag). However, it will only idle smoothly in high idle. In regular idle the engine shakes more than I would expect it to, despite maintaining ~800 rpm; after a minute or two of this, it begins to develop a miss and run rougher and rougher unless I switch it back to high idle. In addition, no matter how warmed up the engine is when I shut it off, if I let it sit for more than a couple of minutes it starts almost as crappily as it does when cold.

This vehicle had been sitting for at least 6 years prior to this, so I replaced the fuel filter and did a “deep clean” with snake oil (SeaFoam). This had zero affect, and the starting and idling issues have gotten slightly worse since then.

I have also tried bleeding all the injectors as well as pumping the fuel pump rock hard prior to starting, but neither had any affect.

I am looking for suggestions on:

• Simplest and most effective way to troubleshoot for fuel leaks / loss of prime
• Best replacement injectors
• What else to look for

Thanks in advance, and apologies for the long post.

 

[92Surfivor]

Also, we all like pictures, so here is a poser shot taken while driving across a frozen lake on my ride to work today.

 

[duncanrm]

• Its possible your glow system is not working at all.. during a glow cycle I suggest you monitor your battery voltage and ensure that there's a substantial drop in voltage (> 1V for example) - the voltage drop indicates that a substantial load has been put on the battery. If you had a DC Current Clamp Meter that'd also offer some insight.
• The poor starting when hot can be indicative of an injector pump that is old and tired. The tolerances open up when they warm up.
• At 320,000klms its likely due for injector rebuilds - a poor spray pattern on the injectors can cause a poor idle. The injectors on these are generally rebuilt, not replaced.
• It doesnt sound like a loss of fuel prime issue to me.

 

[92Surfivor]

• Its possible your glow system is not working at all.. during a glow cycle I suggest you monitor your battery voltage and ensure that there's a substantial drop in voltage (> 1V for example) - the voltage drop indicates that a substantial load has been put on the battery. If you had a DC Current Clamp Meter that'd also offer some insight.
• The poor starting when hot can be indicative of an injector pump that is old and tired. The tolerances open up when they warm up.
• At 320,000klms its likely due for injector rebuilds - a poor spray pattern on the injectors can cause a poor idle. The injectors on these are generally rebuilt, not replaced.
• It doesnt sound like a loss of fuel prime issue to me.

Thanks for the feedback! I hadn't thought of checking for voltage drop when cycling glow plugs.

Any tips on how to troubleshoot a weak injector pump?

I am trying to cover as many of the simple things as possible first, and in the meantime either sourcing new injectors or else finding a reputable place in my area who rebuilds them.

 

[duncanrm]

Thanks for the feedback! I hadn't thought of checking for voltage drop when cycling glow plugs.

Any tips on how to troubleshoot a weak injector pump?

I am trying to cover as many of the simple things as possible first, and in the meantime either sourcing new injectors or else finding a reputable place in my area who rebuilds them.

Putting aside odd electrical issues.. and provided the cranking speed is good there's not much else that will cause a problematic hot start on a diesel with a rotary injection pump than a worn injection pump in my experience, especially if the engine compression is still good. There's no real trouble shooting that can be done on the pump itself that I'm aware of.

 

[92Surfivor]

Putting aside odd electrical issues.. and provided the cranking speed is good there's not much else that will cause a problematic hot start on a diesel with a rotary injection pump than a worn injection pump in my experience, especially if the engine compression is still good. There's no real trouble shooting that can be done on the pump itself that I'm aware of.

Thanks, I guess I'll rule that out for now then until I eliminate a few other variables like the injectors and running a compression check.

 

[92Surfivor]

Related to that last one, after reading multiple threads on here about the 2LTE overheating / head cracking / head gasket issues, I am now understandably paranoid about this possibility. After the coolant change I mentioned in my first post, I have had a couple of occasions where the coolant overflowed out of the expansion tank. There are no other symptoms of head issues, and the bubbling coming out of the overflow had no odour of exhaust. The temperature gauge never moves past a bit under half way, and it doesn't happen until the engine has been running for some time under normal conditions. The engine seems to reach operating temperature and stay there, which suggests that the thermostat is working properly.

At first I thought it was possibly a symptom of air still trapped in the system and working it's way out, but it's happened a couple of times now. This is leading me to suspect that either there is a very small leak from the combustion chamber into the coolant system letting gases build up until they overcome the rad cap and blow into the overflow, or else air bubbles are working their way through the system and causing hot spots and boiling.

I have tried a few different things to remove all of the air from the system, including the "2L pop bottle trick" (actually a 4L milk jug). This seemed to be very effective, but even after 20-30 minutes of idling, massaging all the coolant lines I could reach, and running at multiple different RPMs, I started getting foaming in the coolant.

My next step with this is to do a full coolant flush, but can anyone give some perspective on what exhaust gasses getting into the coolant actually looks like? Could my intermittent overflowing of coolant be caused by anything else that anyone can suggest?

 

[duncanrm]

Related to that last one, after reading multiple threads on here about the 2LTE overheating / head cracking / head gasket issues, I am now understandably paranoid about this possibility. After the coolant change I mentioned in my first post, I have had a couple of occasions where the coolant overflowed out of the expansion tank. There are no other symptoms of head issues, and the bubbling coming out of the overflow had no odour of exhaust. The temperature gauge never moves past a bit under half way, and it doesn't happen until the engine has been running for some time under normal conditions. The engine seems to reach operating temperature and stay there, which suggests that the thermostat is working properly.

At first I thought it was possibly a symptom of air still trapped in the system and working it's way out, but it's happened a couple of times now. This is leading me to suspect that either there is a very small leak from the combustion chamber into the coolant system letting gases build up until they overcome the rad cap and blow into the overflow, or else air bubbles are working their way through the system and causing hot spots and boiling.

I have tried a few different things to remove all of the air from the system, including the "2L pop bottle trick" (actually a 4L milk jug). This seemed to be very effective, but even after 20-30 minutes of idling, massaging all the coolant lines I could reach, and running at multiple different RPMs, I started getting foaming in the coolant.

My next step with this is to do a full coolant flush, but can anyone give some perspective on what exhaust gasses getting into the coolant actually looks like? Could my intermittent overflowing of coolant be caused by anything else that anyone can suggest?

A few points:

• I have a 2L powered LN85 Hilux.. the temperature gauge is also rock solid at 50% even after a massive hill climb. The gauge is in fact very suspiciously stable at 50%. I suspect there's a factory zener diode and resistor setup to lock it in at 50% until a very dramatic rise has occurred. Toyota have pulled this stunt on other similar models, and the "jump point" is set ridiculously high. My LN85 is not a tourer for me and is great condition so I am not too concerned. One day when I'm bored I'll make the effort to pull the dash apart and remove the cluster to "fix" it. In your case, I'd be fitting an Engine Watchdog or similar to give an accurate indication of coolant temperature via a thermocouple bolted to the thermostat housing or similar
• I dont think its air in your system
• Bubbles in the coolant is a clear indication of a head issue - getting the vehicle up to temperature with a specialist big filler bottle attached to the radiator fill point is the best way to see these.
• Your description of "foaming" in the coolant does not bode well for it being anything but a head issue.
• After considering everything you may have some success with products like Chemiweld to seal the head if this is in fact the issue, such a fix can often last for years.

 

[92Surfivor]

Thanks for all your help, @duncanrm !

At this point I've been driving for a week under normal / mild load (mostly highway with minimal change in elevation) and I have not lost any coolant. I'm inclined to agree that the coolant symptoms are pointing to a head gasket or head failure, however it seems to only force air into the coolant under heavy loads at this time.

I am going to focus my attention on resolving the hard starting and idling issues for now as that is the only thing impacting the drivability at this point. Hopefully any issues with the head are minimal enough that they are a.) not affecting the starting or idling issues, or b.) going to cause any further damage to the engine.

I am aware that both of these options are possible with a head failure, but as you can see I have successfully transitioned from denial to ignoring the problem...

 

[92Surfivor]

Current plan is to replace or else have my injectors rebuilt, install a combination EGT/coolant/boost gauge to better understand what my engine is doing in different conditions, and perform a thorough coolant flush and change, as well as adding RedLine Watter Wetter.

I'll update here to let everyone know how I make out!

 

[duncanrm]

Is the Turbo on a 2L-TE water cooled? This it outside my area of experience.. I wonder if this could be the source of frothing/air if that is the case? I only run NA diesels.

 

[92Surfivor]

I have not confirmed it personally, but I have read that the turbo is liquid cooled. However, from the description I read it didn't sound likely that air could be introduced at that point. I haven't ruled it out however. I'm mostly doing keyboard speculation at this point, as I've been on night shift for the past 7 days, and I've had no opportunity for troubleshooting. However, I'll be off tomorrow so I should be reporting back with some actual information soon.

How do you find the power on your 2L? I may have a line on a running 2L, but at this point I am really enjoying this engine/transmission pairing (2LTE/auto). I'll likely rebuild the engine if it comes to it, however, I also love the idea of the rugged simplicity of a naturally aspirated, mechanical fuel pump diesel engine. I also have a 92 Toyota pickup with 750,000kms on the old faithful 22re. I don't think I'll ever swap the engine in the old girl, so I don't have much use for that 2L engine, but...

 

[duncanrm]

How do you find the power on your 2L?

The power on the 2.4litre 2L diesel engine in this little ute is more than adequate.. I can hold 100kph up a steep hill on my daily commute and its reasonably nimble off the mark. I really dont feel it needs more power at all.

 

[4Ruster]

I suspect there's a factory zener diode and resistor setup to lock it in at 50% until a very dramatic rise has occurred. Toyota have pulled this stunt on other similar models, and the "jump point" is set ridiculously high

There absolutely is a zener in there. I actually removed mine and the gauge was very acurate. I could see exactly when the thermostat opened up and see it regulary fluctuate throughout the drive. When you simply bypass the diode the needle reads higher. 205F was right about under the red mark.

 

[Squash]

If she starts fast once warmed up definitely the glow system. Normally one will change all of the glow plugs. Just one bad plug will leave smoke and rough idle until that cylinder warms up. Not certain about you system but chances are that it has two temp sensors, one for the gauge and the other for glow plug pre-heat. You can unplug this sensor and/or hot wire the Busbar and see if things change.
Rough running normally means that your pump is sucking air. Try a clear piece of hose from the IP(pump) to your filter outlet. If you see air bubbles replace / repair your way towards the tank.
Fuel pump creates a vacuum, so you will almost never see a leak.

 

[Toyo Boyo]

I had the 2LTE engine in a Hilux Surf many years ago with most of the issues you described.

Change all the glow plugs resolved my slow starting. Replaced the hose to the fuel filter as it was allowing air to bleed in.

The bad news - it sounds like the head might be cracked. Mine was and it was replaced with the 2.8 litre NA head. It fits but is stronger than the 2.4 head. Do some research on this. You still run the turbo even though it runs the 2.8 head.

I also engineered an intercooler for my Surf, that helped with power.

Intercooler fitted to my old diesel Toyota - HomemadeTurbo - DIY Turbo Forum

Forced Induction - Intercooler fitted to my old diesel Toyota - Hello Newbie here, enjoying the banter and reading all the FAQ threads. Just thought I'd post up some pics of the intercooler I fitted to the 222,000km diesel in my old Toyota Surf 2.4TD. It has better torque and has been a really...

www.homemadeturbo.com

 

[92Surfivor]

Thanks for all the great responses everybody.

For a quick update, it is looking like I have a cracked head (gasp! surprise!). The engine puked out a bunch of it's coolant again and started to overheat the last time I ran it. This is the third time this has happened, so I am not running it again now until the issue is resolved.

Does anyone have any suggestions on ways to definitively confirm that the issue is a cracked head/gasket? Anyone have any experience with those testers that detect exhaust gases in coolant?

Also, for those who know this forum better than I, what is a better place for a build thread: "Diesel Tech", or "95 - Older Minitruck / 4Runner"?

 

[duncanrm]

Does anyone have any suggestions on ways to definitively confirm that the issue is a cracked head/gasket? Anyone have any experience with those testers that detect exhaust gases in coolant?

I dont think there's much doubt. Also those testers can deliver false positives.. When the problem occurs the definitive signs for me are visible gases coming out of the radiator and/or lots of large bubbles.