Weird/Different Glow cycle and hard start

[waynep]

Hello All:

My 97 Sub 2500 has allways cycled on/off the "Wait to Start" lamp about seven times, then goes out copletely and then starts no problem.
Now, when I turn the key on, the "WTS" lamp stays on for a bit,does not cycle on/off, then goes out, and the engine is very hard to start with a lot of white smoke when it does. Any ideas? Thank you all. Wayne

[Iain]

I had a similar problem on an 86' 6.2L. It ended up being the controller was shot. On the newer models I am not sure if they have a controller anymore or if the computer controls it all. Check for good grounds on the engine and check your batteries as well. If they are getting a bit weak it may be creating the hard start.
Iain

[waynep]

Hello All:

I believe that the 97s did not use a seperate controller???
Could it be bad glow plugs?? I have 120k on the plugs and injectors. Is it time to change them and to what part numbers are best?

Thank you all for your replies. Wayne

[JohnC]

What time frame are you seeing with all this cycling? The first cycle should be the longest by far and you should try to start the engine immediately after it ends.

On the later trucks the glow cycle is controlled by the PCM and only if the relay is flakey will the cycles differ from those called for by the PCM

One explanation my be a bad power connection to the relay causing the relay to drop out as soon as the load of the glow plugs is applied. Just a WAG, though...

[waynep]

Hello All:

The wait to start light allways blinked on/off about 6 times, with on/off times about 3 sec. each. No problem starting.

Now the WTS stays on for about 8 seconds, and then goes into it's on/off cycle, and will not start. Weird.

Any suggestions appreciated. Regards, Wayne

[rameye]

I had a similar problem a couple times last year. Check all connections, my relay connections were loose. After that,I suggest that you disconnect the temperature sensor and then see what happens.

It is my understanding that the temp sensor tell the pcm how long to keep the glow plugs on.

good luck!

[waynep]

Hello All:

Well I checked and replaced 6 out of 8 glow plugs. Only one was good. I could not easily get to 7 and 8, any suggestions???. Now it starts fine, but still has the weird glow cycle. Is it OK also to run with 2 bad glow plugs? Do they do anything after start up? It seems like it is running smoother and with less noise?
Thanks to all for answering, Wayne

[MTTwister]

waynep - #8 I got to from underneath, reaching up - surprisingly easy. ( But I have "skinny" arms - your results may vary).

#7 ( Drivers rear )- I got to from up top - a little kinky , but not bad.

If you mean #6 ( second to rear on the passenger side) - I undid the down-pipe ( turbo and Cat connection ( might have been overkill). I think if I had pulled the glow plug connector, then undid the heat shield thingy and slid it out of the way - I could have gotten that one out. Certainly not if they had expanded, but fortunately that wasn't the case.

[5.7L oldsdiesel]

On the 6.5TD i repaired last week with the help from the guys from this forum has a glow plug light issue.On a cold start sometimes,when the key is switched to "RUN",the glow plug light comes on for 2 seconds and then goes out.I have to cycle the key back and forth to get a longer glow cycle.What could be happening here?

[rameye]

try unplugging the coolant sensor..see if the same thing happens..

cost of this test=$0

[5.7L oldsdiesel]

Thanks Rameye.

I unplugged the connector and have a glow plug light which stays on longer.Bad coolant temperature sensor?

Thanks again. smile.gif