starts but dies under 30ish degrees
#1
01-09-2016, 12:32 PM
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starts but dies under 30ish degrees
Ok so Im looking @ a 78 power wagon with a 12 valve out of a 90 that has had i/c ran to it off of another rig first off.Iirc people say to stay away from the 89-90.5?Or so is that correct?This is what he says about it I copied & pasted it.
It has a intercooler on it now from a 91 it is a non I/c motor meaning it has the 9mm injector nozzles instead of the 7mm nozzles that the 90.5-93 have.
Then he said.... No it does have the grid heater I think the mechanical lift pump my be getting weak it will fire and run for a few seconds then dies and that's it
Then.... I know when it's fourty or above it lights right off as soon as you breath on the key but if it idles a lil bit it will fuel haze....&then.... Yah the grid heater cycles on you can see the volt gauge dip and I didn't wait for it to heat up wanted to show how easy it starts up at this temp even with out the grid heater heating up......
Then..... If is a rotary pump and the lift pump is a mechanical one on the side of the block looks like s small block Chevy one I know in the winter it. Will fire right up like it did in the video after the grid heater cycles of course and will run for some times 5 some times 10-15 seconds then slowly losses rpm until it dies and won't restart have had several people tell me that that is the lift pump cause when the rubber diaphragm gets cold it won't pump if the pump is going bad .
Now I know little about 12 valves & still fairly new to cummins I have a 24 valve.I askes over on another forum but Im looking@buying it soon if this doesn't sound like it's going to be trouble to you guys that know these things?So I figured Id reach out as much as possible.Any ideas would be great thank you.
It has a intercooler on it now from a 91 it is a non I/c motor meaning it has the 9mm injector nozzles instead of the 7mm nozzles that the 90.5-93 have.
Then he said.... No it does have the grid heater I think the mechanical lift pump my be getting weak it will fire and run for a few seconds then dies and that's it
Then.... I know when it's fourty or above it lights right off as soon as you breath on the key but if it idles a lil bit it will fuel haze....&then.... Yah the grid heater cycles on you can see the volt gauge dip and I didn't wait for it to heat up wanted to show how easy it starts up at this temp even with out the grid heater heating up......
Then..... If is a rotary pump and the lift pump is a mechanical one on the side of the block looks like s small block Chevy one I know in the winter it. Will fire right up like it did in the video after the grid heater cycles of course and will run for some times 5 some times 10-15 seconds then slowly losses rpm until it dies and won't restart have had several people tell me that that is the lift pump cause when the rubber diaphragm gets cold it won't pump if the pump is going bad .
Now I know little about 12 valves & still fairly new to cummins I have a 24 valve.I askes over on another forum but Im looking@buying it soon if this doesn't sound like it's going to be trouble to you guys that know these things?So I figured Id reach out as much as possible.Any ideas would be great thank you.
#2
01-10-2016, 06:02 PM
#3
01-10-2016, 11:22 PM
There are a few things that can be going on, as mentioned above, it sounds like you don't have a primed system. Either air getting in, a small leak, or it never was primed in the first place. (I don't know the history of the truck- was it running with the swapped engine before and stopped running?)
Are you giving it any throttle, and how many times have you tried?
Typically from what I've experienced if these trucks don't have any fuel leaks or issues they fire right up. On the other hand when the system sucks air in or loses prime its difficult to get that air out. Once the air is out it should fire immediately.
In regards to general cold starts mine will take a few tries if I forget to plug in the block heater and will be hard starting and rough idle for 30 seconds or more. Have you tried the block heater plugged in for a few hours and see if there is a change?
The lift pump is quick to replace but running the truck without fuel can damage the rotary pump which will cost quite a bit. If you are losing prime or have air in the system It can be difficult to get out and takes 100's of pumps of the primer just to fill the pump and a line. So good places to start:
-First make sure there is no water in the fuel, that can seize the rotary pump (should be a bleeder on the filter)
-Make sure the fuel filter is tight
-Check the system for leaks visibly
If you do remove or replace the filter, make sure it's full. If its not your truck it sounds like but you want to go this far you can attempt to prime the system. If there is no resistance on the priming lever then there is probably air in the system.
You can cracl open the lines at the injectors, (I think these are 17mm).. If these lines are cracked off the seat a little when pumping you should have fuel bubbling out ad come to a solid stream. If you have them all cracked and tighten them you should only need to get 2 or 3 liquid full and the truck starts to fire. Once I get mine firing on 3 or 4 cylinders and stumbling I have had to bleed a little more or just give it some throttle to get the remaining air out.
Some people have mentioned crack the lines while having someone crank the truck. I hesitate to advise anyone to ever open these lines unless they understand the pressure that's in them once that pump is turning. If you go that route do not open the lines very far at all and be very careful of the fan turning and other things.
Are you giving it any throttle, and how many times have you tried?
Typically from what I've experienced if these trucks don't have any fuel leaks or issues they fire right up. On the other hand when the system sucks air in or loses prime its difficult to get that air out. Once the air is out it should fire immediately.
In regards to general cold starts mine will take a few tries if I forget to plug in the block heater and will be hard starting and rough idle for 30 seconds or more. Have you tried the block heater plugged in for a few hours and see if there is a change?
The lift pump is quick to replace but running the truck without fuel can damage the rotary pump which will cost quite a bit. If you are losing prime or have air in the system It can be difficult to get out and takes 100's of pumps of the primer just to fill the pump and a line. So good places to start:
-First make sure there is no water in the fuel, that can seize the rotary pump (should be a bleeder on the filter)
-Make sure the fuel filter is tight
-Check the system for leaks visibly
If you do remove or replace the filter, make sure it's full. If its not your truck it sounds like but you want to go this far you can attempt to prime the system. If there is no resistance on the priming lever then there is probably air in the system.
You can cracl open the lines at the injectors, (I think these are 17mm).. If these lines are cracked off the seat a little when pumping you should have fuel bubbling out ad come to a solid stream. If you have them all cracked and tighten them you should only need to get 2 or 3 liquid full and the truck starts to fire. Once I get mine firing on 3 or 4 cylinders and stumbling I have had to bleed a little more or just give it some throttle to get the remaining air out.
Some people have mentioned crack the lines while having someone crank the truck. I hesitate to advise anyone to ever open these lines unless they understand the pressure that's in them once that pump is turning. If you go that route do not open the lines very far at all and be very careful of the fan turning and other things.
