Elk Posted June 29, 2009 Share Posted June 29, 2009 The truck has had a problem starting for a while. You have to turn it over for a long time to get it started if it’s been sitting for a while. The guy that drives it says it’s a fuel check valve problem. And now it’s losing power, would that be caused by the check valve too?We have a 99 Mack parts truck out back but I don’t know what part I should be replacing. Quote Link to comment Share on other sites More sharing options...
fjh Posted June 30, 2009 Share Posted June 30, 2009 The truck has had a problem starting for a while. You have to turn it over for a long time to get it started if it's been sitting for a while. The guy that drives it says it's a fuel check valve problem. And now it's losing power, would that be caused by the check valve too?We have a 99 Mack parts truck out back but I don't know what part I should be replacing.Its likly one of 2 things the check valve at the out let of the block Or the fuel transfer pump at the front.If I was a bettin man my call would be the transfer pump havig said that if you have any filters with plastic bowls on them eliminate them from the system first! Quote Link to comment Share on other sites More sharing options...
Elk Posted June 30, 2009 Author Share Posted June 30, 2009 No fuel filters with plastic bowls, just the normal all metal kind. And they where replaced a few days ago. It made no difference in performance. Any other common problems I should be looking for? Quote Link to comment Share on other sites More sharing options...
fjh Posted July 1, 2009 Share Posted July 1, 2009 No fuel filters with plastic bowls, just the normal all metal kind. And they where replaced a few days ago. It made no difference in performance. Any other common problems I should be looking for?The fuel pump is the most common! loss of power blu smoke and stumble. If ya got a parts truck remove and replace block check firstthe pump should put out no less than 60 psi. Quote Link to comment Share on other sites More sharing options...
Elk Posted October 4, 2009 Author Share Posted October 4, 2009 The transfer pump was replaced and it made things a little better. The main power problem ended-up being that the throttle lever on the injection pump was striped out. And the main part of the starting problem ended-up being a small fuel-line that went form the injection pump top of the head (I’m not talking about the fuel injection lines this was a small plastic line going to the front of the head). It had a hole in it that was letting air back into the system. Quote Link to comment Share on other sites More sharing options...
Gambi80 Posted October 11, 2009 Share Posted October 11, 2009 The transfer pump was replaced and it made things a little better. The main power problem ended-up being that the throttle lever on the injection pump was striped out. And the main part of the starting problem ended-up being a small fuel-line that went form the injection pump top of the head (I’m not talking about the fuel injection lines this was a small plastic line going to the front of the head). It had a hole in it that was letting air back into the system.After reading this post a few days ago I did some investigating on my truck. I found that this small line you're talking about was bad on mine too, it was worn right where it goes into the head...not a big leak, but it was moist when the engine was running. Also, I checked the fuel pressure and it was averaging only 20lbs, but was varying wildly. I replaced the transfer pump and it seems to run quite a bit better and starts like it used to...with the 1000 rpm smoke show when cold. Quote Ever wonder how a blind person knows when to stop wiping? Link to comment Share on other sites More sharing options...
jzack Posted October 13, 2009 Share Posted October 13, 2009 After reading this post a few days ago I did some investigating on my truck. I found that this small line you're talking about was bad on mine too, it was worn right where it goes into the head...not a big leak, but it was moist when the engine was running. Also, I checked the fuel pressure and it was averaging only 20lbs, but was varying wildly. I replaced the transfer pump and it seems to run quite a bit better and starts like it used to...with the 1000 rpm smoke show when cold.Gambi- you must have missed my posts from a few weeks ago. I had that same line go bad in my truck too! Took quite a while to track it down. Moist up at the head where you have to crawl up there and look straight down to see it. Quote Link to comment Share on other sites More sharing options...
Elk Posted October 22, 2009 Author Share Posted October 22, 2009 After reading this post a few days ago I did some investigating on my truck. I found that this small line you're talking about was bad on mine too, it was worn right where it goes into the head...not a big leak, but it was moist when the engine was running. Also, I checked the fuel pressure and it was averaging only 20lbs, but was varying wildly. I replaced the transfer pump and it seems to run quite a bit better and starts like it used to...with the 1000 rpm smoke show when cold.Glad I could be of some help. Quote Link to comment Share on other sites More sharing options...
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