1988 F250 diesel 7.3L

When engine is cold, truck is hard to start. Even in 80 degree weather. WTS light comes on and goes off every time. I have to crank it and crank it usually takes 2-3 minutes of cranking. This winter I would plug in the block heater and it would crank 2nd or third try. When motor is warm, it starts first crank. This started happening last fall. Before that, It always cranked first try. I thought it was glow plugs until reading threads on this forum.

Any Ideas?

 

how long is wthe wts on? have you checked the glowplugs?

 

does the wts light just flicker on for a second and then goes off?

 

Just timed it. 3 seconds. I thought it was staying on longer than that.

 

Just checked resistance on all glow plugs. the measured between 7 & 23 ohms. Most were around 15 with one @ 7 and two @ 23

 

What is the outside temp (air) where your at?? If 70 or higher it won't stay on very long

 

Temp was about 85 when I timed it. This winter it was more like 15-20 seconds and still wouldn't start without the block heater.

 

good plugs have a restance of 2 ohms or less, when they are cold. did you check them on a hot engine or was the engine cold?

 

you think about getting air into your fuel line.

 

truck was cold when resistance was checked. so the plugs must all be bad. Guess these ought to be replaced since they are probably all 18 years old.


I don't think it is air, as while cranking grey smoke blows out the exhaust.

 

Sounds like air getting into the fuel lines when the truck is turned off and let sit to cool down.

Have you upgraded all the rubber return fuel lines and return line fitting O-rings.

These lines and o-rings get hard over time and eventually let air get into the fuel system during cool down. If they get really bad they sometimes leak fuel out as well. Check for wetting around the return fittings and hose connections.

If your rubber lines and O-rings are more than 8-10 years old they should be changed anyways. A good way to tell if your lines are old is to see if they still have the factory gray paint on them. If they do, they are old and need changing.

Air in the fuel system will lead to long crancking before the engine will start. Usually only a problem during cold starts as there is not enough time for air to get into the fuel system during hot soaks.

From what I have read above your glowplug system seems to be working. As a minimum I would just check each plug with a 12V test light per procedure below just to be sure:

The practical and simple way to test glow plugs is as follows.

1.0 Pull the electrical connector off each plug.
2.0 Connect a standard 12V test light to the +ve terminal on your battery.
3.0 Touch the negative on your battery to test whether the light works.
4.0 Touch the glowplug at the tip were the electrical connector used to connect.
5.0 If the Test light lights up the plug is good.
6.0 If the Test light does not light up or is dim then the plug is bad.
7.0 If you find a bad plug replace them all unless you just replaced them all
8.0 Only replace with Beru/Motorcraft Plug (or maybe "Bosch" Plugs that say "Made in Germany" right on the body of the plug)

 

Fixed it.

I first replaced the Glo Plugs.

Nothing changed

I then ordered the fuel line/oring kit.

Nothing changed.

Then I replaced the glo plug relay.

Fixed it. Now it starts on a dime.

 

Someone else on here had a similar experience. In that case he said the ground for the relay was poor and it would pass enough current to light the WTS indicator, but not enough to really warm up the glow plugs.....

 

It might have not been here but in other areas I have mentioned that the glow plugs weren't heating fully or not at all. replaced controler. no change. added a ground wire from the ground contact for the controler direct to the battery ground. haven't had a problem since.

 

Correct me if I'm wrong, but the glow plug relay is the part that sends current to the glow plugs to warm them up?