94 350, 7.3 turbo, 97K. The wait to start lite does not come on, since the malfunction milage has gone down, black smoke on MILD acceleration. Are the problems related? What is the best approach to diagnostics? Turbo waste gate seems to be functioning.

 

1st thing we need to know is if its an idi or a powerstroke.Both engines were offered that year.

 

pre power stroke the international idi

 

re powerstroke, the black smoke shouldn't have anything to do with the glowlugs. he was saying that a sensor on the powerstrokes will make the light not come on and the same sensor will make the motor run like junk, but not on idi. there isn't any computer diagnostics on these bad boys. how bad is your fuel milege, drop from what to what?? it may be something about your turbo locked up or soemthing? what do you mean by the wastegate seems to be working?? how can you tell?

 

If its starting good then it could be just a blown bulb,Does the volt meter pull down to show gp operation?The smoke and performance is not related to the gp's,they are for ease of starting only.Could be time for injector testing.

 

It seems that the problems are not related THANKS. Was concerned that the lite problem was doing damage. The truck starts fine (*in warm weather/ or heater on)
The black smoke/lower milage (minus4 mls/gal). How to test inj? Re turbo - was told that waste gate problems could cause Black S./lowerMls.
THANK YOU.

 

(*in warm weather/ or heater on)
The black smoke/lower milage (minus4 mls/gal). How to test inj?
QUOTE]

What about cold weather and heater not on.Im sure there will be times you wont be able to plug it in. Injectors need to be removed and taken to a shop to have them pop tested.

 

bulb not blown
yesterday got cold 43 deg was really difficult to start. 30sec try to start leave for 1min try again took 10mins and did not run very well untill warmed up (t guage off C)
Ran fine rest of day except for excessive black smoke on mild acc.

 

can you hear your turbo whistling at all??? could you ever hear your turbo whistling, if i remember right, they don't make much noise. it could be locked up and choking the motor. is your air filter dirty?? did ou replace it with a motorcraft or whats the other one that is real restrictive??? baldwin i think even when clean will caust air starvation to the motor. do you have a little thingy that says your air filter is dirty? is it sucked all the way together??? my friends did this, and he had a brand new filter and it said the filter was REALLY dirty but it was new and it was making it blow smoke. we replaced it with a k-n and it ran like a champ. just some things to look out for.

 

deanj,
On the back of the engine to the right of the turbo you should see a black box about 3 x 5 inches. You should be able to follow the glow plug harness to it.
First thing is while you are out front have someone turn the key to run. Do you hear the relay clicking? I am going to assume you do not.
The top pops off with a little effort. This is the glow plug relay/controller. The top portion is the relay, there are four terminals that have wires on them. The two big terminals are the battery and glow plug terminals. One of them should have battery power on it at all times. The small terminals are the ignition terminal and the controller terminal. One of them has two wires on it, this one should be the ignition terminal. Remove both of those wires and check to see which has power on it when the key is turned to run. Replace that wire only. With the key in the run position ground the other small terminal with a piece of wire. This should cause the relay to close (loud click) turning the glow plugs on so do not hold it on for more than 10 seconds. If you do not get the loud click the relay is no good, if you do get one the controller is not working. One reason may be a bad ground, look for a wire, white I think that is hooked to the engine probably under one of the controller mounting screws. Make sure it is clean and grounding good. Hook the other wire back up on the ignition terminal and see if it works now. If it does you are good to go, if it does not you can either buy a new controller which is about 175 dollars at Ford or you can hook them up to a manual momentary switch. To hook up the momentary switch run a wire from the terminal you grounded to get the relay to close to the inside of the cab. Hook it up to a momentary switch, then run the other terminal on the switch to a chassis ground. Now all you have to do is hold the switch down for about 5 seconds when it is chilly and start the engine. Latter when it is real cold increase the time to 10 seconds before starting.
The great thing about a manual switch is you only need to use the glow plugs when you need them, not every time you turn the key on. Makes them last lots longer.

 

It seems I have 2 problems. 1.Wait to start lite and 2.excessive black smoke on accel.
1.relays etc work fine 'clicking' sound with ign on.
2.All filters are replaced with ford every 5k + I donot trust idiot guage on air filter cover it has allways lied to me.

 

Excesive black smoke under hard acceleration is reasonable,could be the pump is turned up a tad too much.You need to get a test light and check the glo plugs.Clamp the clip to the pos batt,pull wire off glo plug and touch probe to the gp,if it lights,its good,move on to the next ones.Im thinking you will find a couple of bad ones.Btw,replace with beru's and save yourself some future headaches.

 

There is a blue wire that comes out of the controller that hooks to the truck harness. This is for the "Wait to Start" light. Check that connection.

 

Thanks for all your suggestions (more informative than Haynes!) Will try suggestions this week-end. THANKS AGAIN