24 Valve 2nd Gen Dodge Cummins 98.5-02 Discussion of 24 Valve 5.9 Liter Dodge Cummins Diesels with VP44 Injection Pumps
Sponsored by Trailer Plus

Losing prime. What else is there to check?

Thread Tools
 
Search this Thread
 
  #11  
Old 11-19-2010, 11:16 AM
kingbrad89's Avatar
Diesel Wrench
Thread Starter
Join Date: Jan 2010
Location: MEADVILLE PA
Posts: 500
Likes: 0
Received 36 Likes on 28 Posts
Default Losing prime. What else is there to check?

I'm still iffy on that though because it varies with the level of incline the truck is on. If the nose is very very steep uphill, it's almost like trying to start the truck after new injector install haha. It'll crank for ever, even if the key is bumped and the lp primes it in this case. Once running it's fine and it'll always start eventually
 
  #12  
Old 11-19-2010, 11:36 AM
01quadcab's Avatar
Diesel Bomber
Join Date: Jun 2007
Location: Shingletown ca
Posts: 2,664
Received 153 Likes on 136 Posts
Default

sounds like you need to do something for fuel pickup I agree I would sump it and be done then you wont have to worry about buying a factory fuel module or doing a draw straw that seem to also be problematic.
 
  #13  
Old 11-19-2010, 11:57 AM
kingbrad89's Avatar
Diesel Wrench
Thread Starter
Join Date: Jan 2010
Location: MEADVILLE PA
Posts: 500
Likes: 0
Received 36 Likes on 28 Posts
Default Losing prime. What else is there to check?

Well the 1/4 tank issue doesn't bother me as much as the losing prime issue. If the prime issue is being caused by the fuel module then a draw straw would fix it in theory. I would imagine if you are very careful with draw straw placement and cutting the straw, you would be able to beat the 1/4 tank issue and keep on a low budget.
 
  #14  
Old 11-19-2010, 03:17 PM
crzycummins's Avatar
Diesel Bomber
Join Date: Mar 2010
Location: forsyth il
Posts: 1,186
Received 87 Likes on 69 Posts
Default

yes very careful with the cut
 
  #15  
Old 11-19-2010, 05:39 PM
navy_welder's Avatar
Diesel Enthusiast
Join Date: Sep 2010
Location: sulphur, la
Posts: 134
Received 3 Likes on 3 Posts
Default

I just made me some fittings and drilled a hole in the bottom of the tank and it doesn't leak and never loses prime and the only thing I do have to worry about is the 1/4 tank issue but I just made a protector plate that bolts to the cross brace and it all seems to work great it was just a quick fix for me cause my tank unit was screwed bad and I was driving long distances so I would have to stop every 250 miles instead of every 600 like now
 
  #16  
Old 11-19-2010, 06:04 PM
mysterync's Avatar
Diesel Bombers Sponsor
Join Date: Mar 2007
Location: Blowing Rock,NC
Posts: 3,791
Received 367 Likes on 251 Posts
Default

Are you loosing prime before the VP44?
If not, And considering it must be pointed up hill , I always start with connector tubes and overflow valve!
 
  #17  
Old 11-19-2010, 07:27 PM
kingbrad89's Avatar
Diesel Wrench
Thread Starter
Join Date: Jan 2010
Location: MEADVILLE PA
Posts: 500
Likes: 0
Received 36 Likes on 28 Posts
Default Losing prime. What else is there to check?

I don't know where I'm losing prime. That's what I'm trying to figure out
 
  #18  
Old 11-19-2010, 07:50 PM
mysterync's Avatar
Diesel Bombers Sponsor
Join Date: Mar 2007
Location: Blowing Rock,NC
Posts: 3,791
Received 367 Likes on 251 Posts
Default

But Obviously if you know your loosing prime you've verified that it's loosing prime, If you bucket test the truck after it's been setting and you dont have any fuel for a few seconds it's before the VP-44 if It's after the VP-44 you'll have plenty of fuel coming out when you take the lines off. Does it crank when bled? if you bleed the lines and it fires right up it's obviously somthing like a connector tube. Cant really help you past that, We just tear in and go looking for the problem. These fuel systems are the most simple of just about any modern vehicle
 
  #19  
Old 11-19-2010, 09:31 PM
kingbrad89's Avatar
Diesel Wrench
Thread Starter
Join Date: Jan 2010
Location: MEADVILLE PA
Posts: 500
Likes: 0
Received 36 Likes on 28 Posts
Default Losing prime. What else is there to check?

I know they are very simple. Very. But pinpointing this is a pain in the ***. I figured that somewhere in all those replacements I did that I would have found the problem. I guess I just kinda figured that the problem was near or at the motor because of the pointing uphill/downhill issue. I haven't really thought about the module in the tank. It's just weird that it varies so much by positioning of the nose of the truck. It can sit for weeks with the nose down and will fire right up no problem. But face the nose uphill or on flat ground and it'll crank for the length of time dependent on the steepness of the hill. Like I said earlier, if the nose is facing very steep uphill, it's a bear to get started
 
  #20  
Old 11-19-2010, 10:12 PM
kingbrad89's Avatar
Diesel Wrench
Thread Starter
Join Date: Jan 2010
Location: MEADVILLE PA
Posts: 500
Likes: 0
Received 36 Likes on 28 Posts
Default Losing prime. What else is there to check?

You know what, now that I'm thinking about it, it must be before the vp. You would figure that if it was after the vp, the time of pre-prime cranking would be generally the same length of time, and wouldn't vary with the steepness of the hill it's on. If it's before the vp, there is much more room and volume for that to vary depending on hill steepness and length of time parked. The only thing that gets me now is, if there is fuel at the motor, after the vp, and it's not losing prime there, you think it would kick over or stumble at least a little and then die. Then it would crank over until it gets fuel again
 


Quick Reply: Losing prime. What else is there to check?



All times are GMT -5. The time now is 04:09 PM.