Engine temp light on but does not overheat

check and clean both the pos. and neg. cables . also give the battery a good charge.

This is not to hard to solve. The outside airtemp determines how long the Glowplug timer works for absolute cold starts. Starting a warm engine is affected by underhood temps.

The Timer Relay will pulse power to the glowplugs. If the glowplugs are good, it is enough to preheat the cylinder for firing.

To tell if a glowplug is good is a matter of comparision between a new glowplug and a worn glowplug. YOU CAN MELT A GLOWPLUG WITH THIS TEST, but you remove the glowplugs, get a set of battery jumper cables and place one jumper to the base of the glowplug USING CARE not to ruin the threads on the glowplug.

You do not want to arc the spark on the glowplug threads. You want your fixed jumper connector locked on the base of the glowplug. The other battery cable jumper is touched to the top of the glowplug where the arcing occurs. This will not hurt the contact point if done properly.

You compare the "glow" of the old glowplug to the "glow" of the new glowplug. Bad glowplugs stay dark or operate at a darker color.

The Timer Relay gives you pulses and that is all the glowplugs get to heat up. This is what you simulate in your test. If a glowplug operates in a dull or dark condition, it is bad and throw it away. You want all glowplugs to readily light up when power is applied.

The other 2 parts to the system are the Timer Relay and the Power Relay. The timer gets its power from the Power Relay and the Power Relay is like a starter solenoid. The Power relay gets a tickler charge when the keyswitch is held to Start.

There are sometimes extreme cold Timers that hold the power longer tothe glowplugs. I do not have the Specs to tell you if your Timer is kicking out to soon.

I hope my solution helps. I have told you how to test your glowplugs. The timers are affected by air temperature and that makes it difficult to say if it is working long enough. If you know the glowplugs are good, and the timer shuts off before the glowplugs heat up, then you need a new or different type of timer.

Hello, The diesel engine relies on Glowplugs for the first start in the Morning or a cold start at anytime.

The Glowplugs themselves can be bad, but there is a Timer which determines how long the Glowplugs will stay on. Before the Timer is a Glowplug Relay which gives the Timer its power to operate. The Ignition switch provides power to the Glowplug Relay.

You disconnect a Glowplug wire, put on a test instrument (either a testlight or Voltmeter) and look to see what happens when you initiate a start. If the testlight lights and cycles a few times like a pulse, then the power supply is good. If not inspect the Timer and Glowplug Relay for continuity

If all the pulses seem to reach the Glowplugs, then most likely the Glowplugs are worn out. Test by removing then and connecting battery jumpers. Briefly touch the top terminal of the Glowplug with the Hot cable after grounding the negative cable on the base of the Glowplug, avoiding the threads.

You can melt a Glowplug. But if you find the Glowplug staying dark, then it is bad. Do this for all the Glowplugs and replace the bad ones. Remember the Glowplug only has the amount of time the Timer gives it to work. So if a few pulses do not make it Glow, then replace it. This should fix you up.

Follow your glowplug wires towards the Firewall. The glowplug wire goes into a Timer which is suppose to be internally regulated by outside Temperature and feedback from the glowplugs.

When you are in Cold weather, the Timer is suppose to keep the glowplugs on longer. When the engine is fully warm and you shut it off, you will notice it starts up like a gas engine. First you want to remove your glowplugs and check them by using Jumper cables and heating them up.

Be careful because they can melt or distort if on too long. I usually pull out 4 at a time because it is a comparison test and when you find the quickest, brightest glowplug you measure the others against it. When the glowplug stays dark or does not heat as quickly it is bad. Remember when it is in the engine the glowplug only has bumps of current coming from the Timer to warm up.

Once you are confident the glowplugs are okay, try starting the truck. Or for good measure, just change the Timer, but it will add to the cost.

As for the engine light, if you mean the "check engine" light, you can get that checked free at Autozone, Oreillys, or Advance. I believe Advance may be better equipped to test the PCM.

I hope my solutions are very helpful to you and thanks for using this service.

Hello, A diesel engine depends on the Glowplugs to start when the engine is cold. After the engine is running, it uses compression to continue.

This would mean you have a problem with the Glowplugs and the Glowplug Timer. The Timer is the device which works with the "Ready" light in the dash. The Timer will click off/on and can make the lights dim in sync with the clicks. The Timer is also responsive to temperature change; the colder the outside temperature, the longer the clicks cycle.

You also should pull the glowplugs and individually check them. Usually do 1 Bank at a time so you have 4 to chose from. Take a Battery jumper cable and connect one end to the base of the glowplug without damaging the threads and ground the cable end. Then take the other cable and connect one end to the hot post of the battery.

Touch the top of the Glowplug with the Pos battery jumper and be careful not to melt the Glowplug. When you get a good one it will glow quick and bright. When the glowplug stays dark or takes a long time to glow, it is bad. This is why I recommend doing 4 at a time. It is a matter of comparision. The short time is the real world example of mimicking the Glowplug timer. If you can not heat the Glowplug, the Timer will not either.

Once you get all the Glowplugs working like they should, you can evaluate the Timer. It may need replacing too! If you turn the Key to Run and let the "Ready" light work, the truck should start. If it does not, turn the Key and cycle the Timer 2 or 3 Times. Then try it. By repeated cycling of the Timer, if the truck starts better, it means your Timer is not staying on long enough for the glowplugs to work. Replace the timer.

Keep clean oil in the engine and consider "Flow" products to help the fuel and oil work better in Cold weather.

There is also a TSB 08-18-6. It is about low pressure on the Injection devices. Exhibits hard starting, no start condition.

I hope my solution is very helpful to you. You could give me feedback on the end solution for your problem.

Best way to check the glowplugs is to remove them and connect each one to a set of Battery jumper cables. You connect the Neg side to the metal sides of the bottom of the glowplug taking care not to mar the glowplug thread. Then take the POS to the top of the glowplug and touch it.

You can actually melt the glowplug. But judging if the glowplug is good is a matter of comparision. Once you get a good one that lights up quickly, you can judge the rest by how quickly it lights up or if it stays dark.

You can test the individual wires to the glowplug with a test light. You will be limited by the timer which will vary the length of time it powers the glowplug by outside temperature. The timer will also respond to engine heat. That is why the timer does not cycle when the engine has just been restarted.

Once you determine if the glowplugs are good, you can work your way up to the timer. You could have a sticking solenoid inside the Injector pump and be getting a dry start. I hope my solution gives you a very good idea on how to check your system. You can use the reply feature for more questions.

It sounds like your Glowplug timer or the Glowplugs are bad. The reason that turning the Key 4 or 5 times helps, is that everytime you put the Key to RUN or START you are energizing the Glowplug timer and reheating the Glowplugs.

You can check the Glowplugs by removing them and remove at least 1 bank at a time. Get some jumper cables and put the NEG post on the plug without smashing the threads. Take the POS cable and touch the Glowplug till it starts to Glow. You can mess up and melt the Glowplug so watch it. BUT, as you test you will find the bad Glowplugs will not light or will take longer to light up.

This is the reason I said to take out 4 plugs at a time, minimum, because you need to compare bad and good, visually.

The timer is not as easy to test. It is a variable timer and the warmer an engine is, the less time it will work. Obviously if the Glowplugs are not Hot, the timer is cutting off too early. But you check your Glowplugs first. The Glowplugs help to give a Feedback loop which tells the timer to stay on.

The rough idle is because the glowplug is not hot or the compression is bad in the cylinder.

It sounds like the "Timer" for the glowplugs, but you may want to prime the Fuelfilter to provide a draw for the fuel. One of the problems is you lost the fuel in the lines as soon as the fuelpump was disconnected.

If you installed the fuelpump because of a "NO start" condition it may have been the Glowplug timer all along. You may have taken a wire loose for the Timer or broken a wire. The Timer box needs feedback from the Glowplugs.

Disconnect one of the Glowpug wires and put in a test light to the wire. Observe when you put the engine in RUN position if the Testlight will light up. If the Testlight does not light, you are not getting power to the Glowplugs.

Diesels need Glowplugs only for starting. After that, the compression operates the engine. The Timer for the Glowplugs regulates how long the Glowplugs work each cycle. You may have to test the Glowplugs if they get power but do not work.

Each Glowplug is like a sparkplug. You would need to pull them and connect 12 Volts to each. Use a jumper cable and do not touch the threads. Use power sparingly or you can melt them. But 1 by 1 you can see a difference in a bad or good glowplug by how each gets hot.

I would test the glowplugs themselves...Just hook a test light to the positive side of your battery and touch the probe to the top of the glowplug. It should ground out through the glowplug and turn the light on. If it doesn't then you have a bad glowplug.

sounds like you may have some bad glowplugs. Does wait to start light come on and stay on for about 10 seconds? Could be relay issue also