Greetings everyone,<br><br>Lately my 1st gen. has been acting a little strange after I fueled up yesterday. I cannot get it to idle consistantly. When the truck is in *Park* it idles at 690-700 rpm. In *Drive or Reverse* it tends to idle at 590-600 rpm. In the past, the truck consistantly idled at 800-825 rpm in *Park or Neutral*, and 700-725 rpm in*Drive or Reverse*. All rpm readings were taken at operating temperature, not cold start up.<br><br>Before I performed any adjustments to the low speed limit screw, I checked the following items: Air filter (cleanliness), Injectors (possible air in fuel system), Fuel filter (possible water), Turbo Boost, EGT's, Valves, throttle linkages, and throttle lever travel. All items check out with flying colors.<br><br>After my inspection, I did go ahead and make an adjustment. I set the idle to 800-825 rpm in *Park or Neutral*, and 700-725 rpm in *Drive or Reverse*. The engine was warm during the adjustment.<br><br>After the adjustments were performed, I test drove the vehicle. The idle slipped up to 900 rpm in *Park or Neutral*, and 825 rpm in *Drive or Reverse*.<br><br>Does anyone have any idea as to what would cause the inconsistant idle??? Bad Fuel, Fuel filter clogged, Malfunctioning Fuel Selonoids, Injection Pump??? I hope not another injection pump, I just replaced it 4 months ago.<br><br>Any help, advise, ideas, or information would be greatly appreciated.<br><br>Thank you in advance.<br><br><br>Respectfully, <br><br>Nicholas R. Gajewski

 

I had the same thing happen to me after fueling at a IGA fuel station. Mine was so bad it would hardly start in the morning. I complained to the store manager and he said there is nothing wrong with their fuel so it must be a problem with my truck. I said yea, there is, it shouldn't have ever been in their place of business, and not to worry, it will never be there again.<br> I ran a double dose of fuel treatment through it and it seems to have cleared up.<br> so my guess is you got a bad load of fuel like I did.<br><br> dave

 

Nicholas, knowing you attend to details with a vengence I'm thinking you are seeing the same thing as me..... fuel..<br><br>I have found that in the winter months my idle speed/quality is best described as slightly &quot;unstable&quot;.<br>I see the very same fluctuations, and twitching.<br>In fact the numbers are almost an identical copy of my experience here.<br>I also think that with our 'tweaked' systems they are a tad more prone to this fuel quality issue too...<br><br>bob.

 

Thanks so much for the speedy responses, and great information! ;D I will continue to monitor the idle situation for possible changes. <br><br>Thank again guys!<br><br>Respectfully,<br><br>Nicholas R. Gajewski

 

I would think fuel too. Try to find a vendor that moves alot of fuel and good quality. In the winter, fuel conditioner can help to smooth out a rough idle as well.<br><br>I have a favourite vendor I used to go to, but now his fuel quality isn't great. Hard decision as he is a good friend, but now I buy my fuel elsewhere. It does make a difference.<br><br>J-eh

 

Nicholas,<br>I second the bad fuel theory. I am with Jason, I only purchase fuel at high volume outlets. Thats the beauty about our trucks you can fill up at the same pump where the big boys get there fuel (not like those other wannabe diesels).<br>---<br>Al

 

BTW, Nicholas,

I've had a bit of success treating this by using fuel additive like Stanadyne PF in &quot;double dose&quot; proportion. It doesn't totally rid it of the fluctuation but it helps. In fact I can tell if the fuel has been treated or not by the RPM.
Without it, my idle is about 800 and slightly irregular, with it, my idle is 850 and smoother.
Give that a try and see how it works. Also, you could try Howes Meaner Power Cleaner, but I did not have as much success with that as it leans more toward lubrication and cleaning additive than the SPF.

Last thought.... I had the chance to use some of the Amalgamated fuel additive my brother bought.
It is even better than the SPF.
I like it, but you have to order it in minimum 5 gallon pail.

bob.

 

Bushy,<br><br>Thank you for the reply. I used the &quot;double dose&quot; of Stanadyne PF as you suggested, and it indeed helped. Currently, my idle in park ranges from 850-875 rpm when at operating temperature. In drive, my idle is at 750-775 rpm at operating temperature. I must admit, the Stanadyne PF is some amazing stuff. I use Stanadyne PF on every fill up. It gives me &quot;piece of mind&quot; so to speak. With today's low sulfur, low lubricity diesel fuels I wouldn't want to run without it.<br><br>Thanks again.<br><br>Nicholas R. Gajewski

 

Good deal Nicholas, glad it works for you....<br>Again, BTW, I see that same discrepancy in idle no matter if it's winter or summer fuel. With the SPF I have an idle about 50-60 RPM's higher, without it, less obviously.<br><br>bob.