TD5 warm start problems

[philchan1974]

Hi. Having issues with a hot - warm start on my TD5.

Cold start when sitting for 1 hour plus or over night no issues.

But when left for short periods (such as filling up either gas or running in for a short errand) it does not fire up straight away. Has to be left.

Not only that, i stalled at a light and it took forever to get going again.

Anyone have any thoughts?


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[Tony4921]

Filling it with gas can not help too much!

[philchan1974]

Right. Should have used “fuel”.


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[landcrabmechanic]

Sounds to me that when the fuel is warm/hot the pump may not be creating the pressure required for the injectors? Where are you located?

[philchan1974]

Right now travelling back to Mission.

I had the fuel pump replaced in Calgary and am travelling back with it.

Thoughts?

I just left it for an hour while eating dinner. Difficult start but fired up.

I am getting nervous every time I turn it off.

Thought it could be the copper injector seals and air getting in to the fuel system?


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[Tony4921]

Have you checked the injector harness/ECM plug under the passenger seat for oil?

[philchan1974]

No but I will. If I find anything what’s the plan with that?

I’ve noticed it’s very temperamental. This is what worries me.

Is there a “proper” starting procedure for these engines? Ie) key turn on, glow plug light out then full crank?


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[Tony4921]

Oil ingress in the ECM harness causes all sorts of wierd issues and is very common. You can try to clean it out, but a new harness under the valve cover will be needed. You can also try to start it by turning the ignition on when hot and press the throttle pedal to the floor 5 times. The CEL will start to flash and the fuel pump will run constantly. This is a fuel prime procedure. Give it 30s and see if it starts any better. You should not need glow plugs at all when hot. Mine starts ok cold without them, as the wife keeps demonstrating to me.

[InterMechanico]

When diagnosing a hard restart in a diesel engine, I often find the culprit to be air ingress into the fuel system.

There are a few ways this can happen, but the two listed below are the most common faults I see.

1) Air entering the fuel system on the low pressure side. The low side is the portion of the fuel supply circuit between the tank pickup and the fuel transfer pump. This portion operates at something less that atmospheric pressure, so if there is any area that air can enter, it will do so. Since fuel will likely leak back out once the engine is shut off and the pressure in this portion of the circuit equalizes with the atmosphere, you'll often see wetness or an accumulation of dirt and grime in the area of the leak.
- The easiest way to see if this is causing your issue is to install a glass eye as close to the transfer pump as possible, run the engine and watch for bubbles in the fuel passing through. Through trial and error, you can locate the cause and see when it is resolved.
Edit: TD5 engines have a fully pressurized supply circuit, so this is unlikely.

2) Air enters the return circuit through leaking injector nozzle cups or sealing washers-
-If your fuel system has a fuel return circuit from the injector nozzles, AND that return is connected to the injection pump, leaking injector cups or sealing washers can allow the return fuel to become saturated with combustion gas (air, essentially) as it returns to the Injection pump for reuse. It has the same effect as air entering on the low pressure circuit, but is not as easy to detect.
-To check for this fault, I will remove the return line (injector return port to fuel cooler in this case) at the injection pump. I will place it in a suitable (2 liter, clear) container. I cap the port on the (fuel cooler in this case) injection pump. I then run the engine at idle and allow some fuel to accumulate in the bottle, always keeping the line submerged so as to observe any air bubbles as they exit. If the truck is an automatic transmission model, proceed with the next step in a safe and careful manner.
- Block the vehicles tires, set the park brake and ensure there is nothing in front of the vehicle. Have a trusted companion/helper sit in the driver's seat with their seat belt on. Have them perform a light stall test by pressing firmly on the brake pedal, placing the transmission in drive and applying a load to the engine. At this point, you are watching the clear bottle closely, because as the engine loads up, the combustion pressure will rise, and if combustion gas is leaking into the return circuit it will be most apparent now.

Be safe!

Neat! The TD5 has MEUI's (Mechanically Actuated Electronically Controlled Unitized Injectors). These are normally found only in larger engines.

In my experience, if the engine starts after a sustained period of cracking, it's not likely to be a basic electrical fault.

In basic terms, diesel engine injection pumps force a small volume of fuel through a tube and into an injector nozzle, which is essentially a valve that only opens at a very high pressure. MEUI'S do the same thing with pump and nozzle combined in one assembly.

Important- Fuel is not compressible, and works well to open that valve. Air is mushy and lazy. It will just compress when forced to do work, and will not open the valve.lol

Good luck Phil. You can do it!