First Diesel: Looking For A Faq For Hard-start Help

[Fozzy_Bear]

Hi all.

 

I am comfortable with my knowledge of gasoline engines, but I just bought my first diesel (a 96 Chevy 3500, crew cab 4x4 ) and I am kinda lost. I know it will need some work, since I bought it for a pretty low price, and I've already identified a issue I need to address.

 

But before I go into details, I was wondering if anybody knows where a good FAQ is that is written for somebody comfortable working on gas engines showing primarily the differences between them.

 

As for my issue, at its heart it's a hard-start issue, but with a twist. the engine starts just fine and then runs totally smooth for about 45 seconds. then it coughs and dies unless you floor the pedal, and even then it will only manage 1200 or so RPMs for about 15 seconds. While the engine is struggling, it sounds pretty bad. Then, the Service-Engine-Soon lite comes on and it instantly smooths out and is fine until you turn off the engine. I've driven it for over 100 miles at a time (at 65mph) without a single issue... once that initial what-not is done.

 

And just to check, I started the truck back up right after I got home (after 100 miles, it was certainly up to temp) and I had the exact same problem, but the coughing/struggling was not as intense... but still bad. Only for 15 seconds and only after it ran perfectly for 30-45 seconds after starting.

 

 

Any ideas or links to good sources would be appreciated.

 

thanks

 

 

.

[merlin5577]

Your best bet for in depth details on the difference between gasoline and diesel would be to search Google or Wikopedia. In a nutshell; gasoline is a spark ignition, diesel is a compression ignition.

 

As for your problem, I would find a place to scan the truck when the check engine light is on and go from there. It could be a number of things, and I can only guess. When you have a code(s) they will point you in the direction of the problem. On a side note, if your diesel has a MAF sensor DO NOT use ether on it. The hot wire on the MAF sensor can ignite the ether in the intake and cause a backfire. Hope this helps, good luck.

[Fozzy_Bear]

...

On a side note, if your diesel has a MAF sensor DO NOT use ether on it. The hot wire on the MAF sensor can ignite the ether

...

 

Ok. important safety tip... Thanks.

 

But I was hoping for a little more than just "search google"...

 

anybody else?

[95Sierra2500]

In all honesty, the similarities between a diesel and a gasser are this: They are both engines, both use ignited fuel to move a piston, turning the crank. They share similar nominclature about parts involved. Beyond that, their similarities end. They are two completely different animals with completely different characteristics that would take FAR too long for one of us to type up. So the answer of 'search google for a good write up' is the easiest way to find what you're looking for.

 

As for the CEL and hard start issue, I'm going to take a guess (hard to say for sure unless you get the code #) and say that your glow plugs are bad, and you're not letting them/they can't heat up properly to provide an ignition source for the fuel at startup. Remember that diesels don't have a constant spark to ignite the fuel, but ignite the fuel via intense compression. The glow plugs are only there for the initial startup to add a little heat. Once the engine is running they shut off. If you turn the key and immediately start cranking on a diesel, it won't start very well. You have to turn the key on, let it sit for anywhere from 3-8 seconds, THEN start. Don't go much past 8 seconds or you can burn out the glow plugs and will need to replace them.

[Fozzy_Bear]

...that would take FAR too long for one of us to type up. So the answer of 'search google for a good write up' is the easiest way to find what you're looking for.

 

As for the CEL and hard start issue, I'm going to take a guess (hard to say for sure unless you get the code #) and say that your glow plugs are bad, and you're not letting them/they can't heat up properly to provide an ignition source for the fuel at startup.

...

You have to turn the key on, let it sit for anywhere from 3-8 seconds, THEN start. Don't go much past 8 seconds or you can burn out the glow plugs and will need to replace them.

 

Well, that's what I figured... That's why I asked if anybody had a link to an existing FAQ or such... I didn't expect somebody to type it all up just for me... but I guess there's not one out there. - odd; I had thought that wouldn't be a rare request--

 

...

 

I have a basic idea of what glow plugs are and how they work. But the fact that it starts up smoothly and runs for a few seconds seems to rule them out. - unless the problem is that they are shutting off too soon and as soon as they go out, that's when the problem starts - Which is what I suspected from the beginning based on my limited Diesel knowledge. However on a few other boards where I posted this question I've got answers ranging from a leaky fuel line/pump to bad batteries .

 

 

.

[merlin5577]

Well, that's what I figured... That's why I asked if anybody had a link to an existing FAQ or such... I didn't expect somebody to type it all up just for me... but I guess there's not one out there. - odd; I had thought that wouldn't be a rare request--

 

...

 

I have a basic idea of what glow plugs are and how they work. But the fact that it starts up smoothly and runs for a few seconds seems to rule them out. - unless the problem is that they are shutting off too soon and as soon as they go out, that's when the problem starts - Which is what I suspected from the beginning based on my limited Diesel knowledge. However on a few other boards where I posted this question I've got answers ranging from a leaky fuel line/pump to bad batteries .

.

 

Like 95Sierra2500 stated, the differences between gasoline engines and diesel engines are vast. To type them up would take a long time. Its not a rare question, just long in the tooth. I went to wikipedia, typed in "diesel engine" and got;

http://en.wikipedia.org/wiki/Diesel_engine

I did the same with "gasoline engine" and got;

http://en.wikipedia.org/wiki/Gasoline_engine

These will give you a good understanding of there differences and similarities.

 

As for your problem; you really need to get the computer scanned and the codes read.

 

*Edit* I went back and read your original post. If I had to guess, I would say your lift pump is going bad and unable to supply enough fuel to the injection pump, causing the engine to go into "limp mode" to prevent damage to the injection pump. Thats the only thing I can think of with the symptoms you have described.