Engine/Transmission (1994 - 1998) Early morning - idle then dies...

[USMCBay]

My 97 has always needed to be pedal to the floor at start and it fires right off. If no pedal it turns and turns...



When I first start it - it needs to be warmed up with a 1200rpm idle to get my normal 900rpm. This takes two - three minutes.



Does this sound like a rubber fuel line sucking air?



All help and comments appreciated. I'm trying to get this truck on the top side of Maintenance.

 

[kenny61]

Does it run rough when it first fires?

 

[Joe G.]

You should check to see that your grid heater is working. You should see a voltage fluctuation after you start it. If that is not happening check the big relays below the driver side battery.

 

[mfburns]

I had the fuel line leaking problem and just holding the pedal to the floor was not enough to start it. I would have to depress it several times, and it would run rough at first then smooth out. I am not sure your issue is the same.

 

[EKlem]

This sounds to me like a fuel delivery problem when cold. The fact that you have to use the pedal for several minutes indicates that you are not fueling enough then. The likely culprits are low idle, low fuel pressure, and air in your lines. What is your idle when warm, in drive, with the ac on? It should be 850 or so(and the dash tach isn't always accurate). Do you know what your fuel pressure is? Since this is a long term problem, I would not suspect your fuel filter unless you neglect to change it. You say that it starts very quickly which indicates that you do not have air in your lines, you will need to crank for a little while if you do.

Is this problem related to the outside temperature? Knowing this will help rule some things out.

The best way to diagnose this in my opinion would be to start it with a fuel pressure gauge hooked up and see what happens. It is possible to diagnose it without one but it is a bit harder.

 

[Missouri Mule]

It seems your low idle mite to be low.

If you were sucking air you would most likely would have to re-prime the fuel system.

 

[USMCBay]

This sounds to me like a fuel delivery problem when cold. The fact that you have to use the pedal for several minutes indicates that you are not fueling enough then. The likely culprits are low idle, low fuel pressure, and air in your lines. What is your idle when warm, in drive, with the ac on? It should be 850 or so(and the dash tach isn't always accurate). Do you know what your fuel pressure is? Since this is a long term problem, I would not suspect your fuel filter unless you neglect to change it. You say that it starts very quickly which indicates that you do not have air in your lines, you will need to crank for a little while if you do.



Is this problem related to the outside temperature? Knowing this will help rule some things out.



The best way to diagnose this in my opinion would be to start it with a fuel pressure gauge hooked up and see what happens. It is possible to diagnose it without one but it is a bit harder.

Well - now it sounds like it is fuel pressure or heater grid because it fires off instantly with some pedal depression. My normal idle is a bit high @ 900rpm after the 2min of warm up (maybe 1min). Its just where I backed the rpm's down to after the 4k install... I like it there because its a little quieter at idle. I will have a fuel pressure on it shortly - thats easy. I will let you know... I know that when its just about to achieve a descent idle if you let off the pedal you can tell theres an electrical draw (alternator?) that cycles and draws the idle down almost to die status (not a/c - its out:{)... so not sure what that's all about. It isn't an issue after warm up. Now that sounds like heater grid. Cold weather seems to effect it more.

 

[USMCBay]

Something obvious but is you shutoff solenoid being drawn in all the way?

It no Got-e one!:-laf

 

[USMCBay]

Does it run rough when it first fires?

Never runs rough... ever - RPM's just go go go - gone. But this is just the first minute or two.

 

[EKlem]

I highly doubt that it is your grid heaters if it starts fine. Once it is going, the grids are not necessary to keep it going. They continue to operate for emissions purposes only. I think that a fuel pressure test should shed some light on this even if it rules out a fuel problem.

 

[Dieseldemon]

Some of the trucks built in old Mex did not have the fuel heater hooked up which made for hard start and white smoke on start up if thats the problem chrysler made a kit to hook it up there was also a recall on that problem.

 

[Joe G.]

The grid heater might have caused that problem but I really don't think the fuel heater could have. It's actually worthless and a potential failure that will make you walk. Many people have removed then with no starting problems at all. If the fuel heater fails it can be a very hard thing to diagnose because of an air leak in the electrical connection. One guy on another forum who lives in Juneau, AK has removed five of them. All of the fuel heaters had burned up. None of those trucks have a starting problem now.

 

[Dieseldemon]

My grid heater has never worked since the truck was new and it never caused this problem the relay was never installed fron the factory we get down to -4 where I live and if I let the fuel heater cycle starts just fine. If I do not let the heater cycle I get a lot of white smoke and rough run for about 3 min. But what ever works for you keep doing it.

 

[USMCBay]

I don't really get too much white smoke... I probably get more on hard acceleration after the black smoke clears out.

 

[Devan Manis]

you get white smoke on accelleration? Your pump probably needs to be phased and timed. i don't know if that is your hard start problem though.

 

[USMCBay]

you get white smoke on accelleration? Your pump probably needs to be phased and timed. i don't know if that is your hard start problem though.

Phased??? Wwwwwhats that?



It's not a lot of white smoke. Also I may need to adjust the screw on my diaphram in the back of my AFC... I screwed that in slightly until it touched and then backed it off a standard smidgin'... or was it a metric smidgin'?



Not really sure why I did that but read about it here somewhere.

 

[kenny61]

If its not running rough when it does start its probably not a fuel leak. (or at least air leaking in to the system. whats the lowest rpm it will stay idiling at?

 

[USMCBay]

If its not running rough when it does start its probably not a fuel leak. (or at least air leaking in to the system. whats the lowest rpm it will stay idiling at?

Last night our weather was 70+ and humid. I started the truck and 30sec after 1100rpm warm up it idled @ 700rpm's then 600, 500, 400, 300died. Then @ 45sec it idled at 700rpms and by 1full minute had climbed to my 850/900rpm range.



I will make sure the Fuel Shut Off arm is full open. I have a static pull cable with a spring load to keep it open. It should be full open but I will check there Marine.

 

[kenny61]

Well than its simple... I aint got a clue

 

[KCraft]

my 95 was always hard starting in the am. thought is was natural, did some reading on TDR an found out that i might have a bad over-flow valve. went to cummins and they wanted over a $100 for it. bought mine off ebay for $30. put the new over flow valve in and WOW what a difference. ps when i took the old one out the insides were all broke. spring and check ball all came out in mutipple different busted pieces.