Engine/Transmission (1998.5 - 2002) Hard start in cool weather

[roundabout]

I have a 98.5 3500 with approx 230,000 miles on it. Living in Florida problems with cold starting are not usually a problem until now. Lately if the temperature is at 68-66 degrees or below the truck will not start. If the temperature is above this there is no problem. Eventually it will start with enough cranking. The fuel pressure guage shows 14# prior to attempting start. The engine will sound like it wants to start then nothing. After the engine starts and gets warm, it does not matter what the temperature is it will start normally and run great.

The grid heater solenoids click, and a test light shows power through the heaters (from power in side to the ground on the manifold). This works the same on both the heater input cables. There is no drop voltage on the dash gauge which would indicate the grid heaters are drawing the correct power.

The other odd things about this is that when this happens the fuel pressure shows 14#, and normally goes right to 0 when the key is turned to start. When this no start happens it goes to 14=15# then does not go right to 0, but bounces around eventually going to zero. Here also once the engine is started and warm the fuel pressure acts normal.

Is it possible the grid heaters are just good enough to allow 12 volts across but will not pull a decent load. Or is there a part of this system that I do not have a clue about. ( PCM, ECM, a sensor some place.)

 

[DavidC]

Guess I will get it started. The grid heaters according to a service manual do not activate until 60 or below. This number could be subjective but I would think they are not your problem. The fuel heater on my 99 does not activate until 45 +/- 8 degrees. If you have voltage across the grids does not mean they are working, you would need an amp check to show that or use an ohmmeter from the hot side to negative which should show continuity if the elements are not burned out. So now if the heating system is ruled out as a problem maybe the fuel is siphoning back to the tank from a break in the return line or the return T on the back of the block leaking ?. Excessive cranking before a start is usually a fuel problem.

Dave

 

[roundabout]

I have been over the fuel system at least 3 times attempting to find anything that would cause an air leak. I have had no luck so far.

 

[SAndreasen]

I had an 01 do that once and it was An o ring on the cross over tube

 

[NIsaacs]

When did you change your fuel filter? When they start to plug up they will flow when the fuel is warm but not when it is cold. At 60* they will start without the grid heaters so never mind that.

Nick

 

[roundabout]

Just a quick reply as I will have to do some checking. In answer to NIsaacs, the fuel filter was changed last week, I believe wednesday. I could not see problem with the O ring or the seal on the old filter. The problem has been going on for some time, I just have not posted a thread while I was attempting to locate the problem. I will have to do a better job of attempting to locate a possible air leak some place.

Does anyone know if there could be an air leak or back flow problem with the Carter fuel pump?

For SAnderson, thanks for your suggestion, but were exactly is the cross over tube?? Need to check that also.

 

[DavidC]

There is also the overflow valve on the VP44 that has a check ball internally that is suppose to open on over pressure and return fuel to the tank. I have not seen one go bad but you never know. I would look at that portion and follow to the T on the back of the block and make sure there are no problems there also. Good luck.

Dave

 

[hcole]

Why don't you try parking the truck downhill (front end much lower than rear) and see if it makes a difference? Sometimes the rubber hoses leak and it's not apparent to the eye that they're leaking. Parking it downhill will keep the fuel in the hoses and won't let air in. It's an easy check.

 

[Vaughn MacKenzie]

roundabout, you commented when you hit the key the fuel pressure shoots to 15 then is slow to fall. It is true too much fuel pressure will cause starting difficulty. I think DavidC is onto it, could be a sticking overflow valve. When you turn the key to start it for the first time of the day wait for the fuel pressure to drop to 5 or less then try cranking it. Or try starting it like a gas rig, don't wait for the light, start cranking it immediately the moment you turn on the key.

I am sure the grid heaters have nothing to do with your issue. When I had my grid heaters disconnected one year mine would start right up with temps in the low 20s (although it would sputter a bit and take a moment to smooth out). That was without the block heater being plugged in.

 

[roundabout]

Ref above, the overflow value was changed on 1-7-16 and the truck sets on a hill facing both up hill and down hill depending on how it ends up for the day. It does not seem to make any difference which way the truck heads up or down hill. Where I live this is the best grade I have. The truck will not start until after the wait to start light comes on, it has not for years. I checked the "T" and lines on the back side of the engine yesterday, could find no problems there. I'll have to wait for the morning temps to get down so I can check and see if letting the fuel pressure on the guage drop down helps. Right now the morning temp is above the mid 60's and the truck starts with no problem. The weather man is guessing the temps will be down in the 50's this weekend. If so I can say for sure it will be a bear to start.

I want to thank everyone for their suggestions, I'll keep trying. Have to stumble onto the answer eventually.

 

[DavidC]

OK, so lets say your truck is picky as below 60 is getting into grid heater territory. Did you ohm across the grids to make sure you have continuity ?. They are just like a toaster, if the element is burnt out you can have all the voltage in the world across them but open in the middle, thus no heat. Just throwing this out there.

Dave

 

[DClark]

Ck the sealing washers on the banjo fitting on the fuel line. There are several. I had one that would not seal and was letting air in the line. It did not cause a hard start problem, but it sure didn't run good. Hope this helps.
DClark

 

[SAndreasen]

Cross over tubes are on each injector between the injector line and the injector it goes into the valve cover you have to take the lines of the injection pump and then pull them from the engine to check them I changed every fuel line and sealing ring on my truck before I finally found the problem i wasn't making oil when it happened either I ended up taking it to a shop and they found the problem the dodge dealer wanted to replace all the cross over tubes when I called the dealer when I was doing a head gasket to see if they could get new o rings for the cross over tubes they said no you have to buy all new tubes to get the o rings well that's a lie