Diesel Down!! 7.3 IDI No start

[taber45]

Having some issues here. 94 250 non turbo 7.3. 191000 miles. Recently purchased. Have reasonable knowledge of the diesel family and its history of glow plug/controller problems. The truck has started difficult while the engine was warm since I bought it. Actually, I have to dump a little fuel into the intake in order to start it. *This is problem 1* Second, today, I went to start it and it didn't even fire. It was cold here in NY, and the glow plug controller just clicks on/off every second. Probably have a few bad GP's but that shouldn't keep it from starting. I have installed a controller bypass switch and am manually lighting the plugs in leiu of the controller issue, but the darn girl still wont fire. Any suggestions?

 

[The Warden]

How many miles are on the injector pump?

If she isn't starting happily while warm, that indicates to me that there's either a fuel system or a compression issue. As an injector pump wears out, it can get to the point where, when the engine's warm, the tolerances are so loose that the truck won't start (but, as you pointed out, it'll run once started). Furthermore, bad glow plugs shouldn't affect a hot-start.

But, that wouldn't solve the cold-start issue. I would ohm-test the glow plugs and replace with Beru/Motorcraft plugs if any are bad, and then see if she starts. Keep in mind that a few bad glow plugs will make the controller act up, so your controller may be fine once you replace the bad plugs and make sure all connections are nice and happy.

Hope this helps some...good luck!!

 

[geonc]

There is also fuel drainback issues, bad inj "O" rings/caps,
the possibility of the pump innards inability to properly pressurise and deliver fuel :ie worn out pump from no additives.

94 250 non turbo 7.3. 191000 miles. Recently purchased.

possibility of pump removal and improper timing.

Start with the basics......

does fuel spurt out when you crack{loosen} the steel lines at the inj when trying to start? ---a 5/8" open end wrench--
For the $90 go to Auot Zone and buy 8 Motorcraft/Beru ZD9 glow plugs

On the right side fender is a wire bundle going to a plastic plug...about 8 wires--- disconnect and inspect----this is a problem area as some of the wires go to the GP controller/relay.

Trace the two 10 ga yellow{?} wires to the relay...if they are fried/loose at the plug you prolly have a damaged controller as well as the realy.
the fix {after buying damaged parts} is to disconnect the two small guage wires feeding the hot side of the GP relay and replacing them with 1 single 6 guage wire from the hot side of the fender mounted relay to the GP relay at the rear of the eng/top of the controller {has a "Z" shaped heat sink on it

Hope this is of some help and post back....there is a ton of info and quite a few helpful/knowledgeable souls here with more exp than I can give

 

[Exekiel69]

What about a good dose of stanadyne/power service? pour a hole bottle of this on the fuel filter, if it does Good then it may be the pump.

 

[budtoh3zo]

with the manual gp's you could have burnt the rest out, Sounds like new pump and gps are needed, If you get it started then when u shut it off and it does not start pour some cold water on it and try again

 

[geonc]

What about a good dose of stanadyne/power service? pour a hole bottle of this on the fuel filter, if it does Good then it may be the pump.

EZ...I must be slippn' in my old age, not first reccomending Freds hair tonic
{btw Fred, checks in the mail ;p }

Another trick is to fill up a new fuel filter full of "Seafoam" and split another can in in both tanks.
It really cleans out the system from the tanks,IP and nozzles
It is not "snake oil" and it has helped many

 

[taber45]

Good suggestions from all...thanks. I am going to try the new filter and seafoam first. I think that it wont hurt and is likely to be the cheapest. Next I am off to the glow plugs, but the price of an injector pump is hard to swallow...for now. I love my truck, but only having had it a month, that is a big bite to chew (even though I bought it for relatively cheap) I have tried to add stanadyne to the fuel. I haven't gone so far as to use a whole bottle, but I did double the recommended amount to the fuel, with no noticeable starting improvements.

And "geonc"...what about the orings on the injectors? I think it stands to be possible that I am getting air in the system, but am unsure at this point. I didn't get it to fire today, and have run the batteries down so I am awaiting them to charge. Will tackle it again tomorrow. But how is a good way to tell the condition of the orings on the injectors short of taking them all off and replacing them? And what is the right oring to replace it with?

I have no idea how many miles are on the pump, but I do see a sticker on it says it is a reman pump. I have no idea how long they typically last, but I think they should go around 150000, leaving only 40000 on this pump if my theory is correct.

 

[aaklingler]

did you plug the block heater in?

 

[geonc]

taber45, inj pumps have gone +200k and as little as 75k so without prior correct knowledge of the previous owners fuel maint habits....it really cannot be pinpointed.

re; the inj "O" rings......there are 2 rings per nozzle, located under the plastic "T" caps that are connected via cloth braided hose and pinch clamps.

Is there any sighns of fuel around these areas? Altho that is not a concrete indication of condition, sometimes we all overlook the obvious
Worn caps, bad "O" ring will allow the fuel to drain back or leak etc.....
There is also a check valve at the filter head...some one will chime in and give you the "inside" tip on troubleshooting/correcting it.

For under $30 GO HERE and get the kit contains all nesc caps,"O" rings, hose,clamps

Save the link! DIS is one of the places you will become familiar with

Hope this is of some help!

GEO

 

[wtom24]

I have had a similar problem with my 93 7.3 engine. The glow plug controller reads the temperature of the glow plugs by measuring current. If one or two glow plugs are open then the controller thinks the plugs are up to temperature. I usually have to cycle the glow plugs 3 times on a hot start to get er going. Cold it takes some cranking. Works fine when all of the glow plugs are alive....I seem to lose one about once a year.

 

[taber45]

Still patiently awaiting the "chime in" regarding the check valve at the filter head. I just replaced the filter, and am in the process of replacing the starter. I currently have the Mitsu starter(think its from the factory) and I think the soleniod is weak, dropping voltage/current. Problem is, a new solenoid is near $50 and a new rebuilt mitsu starter is only $130, and comes with a new solenoid. By the way, the top bolt wasnt that bad....once I could see it. The starter literally had 3 solid inches of mud/oil/grease caked around it! When I replaced the filter, I filled it with fuel, and am hoping that with a new starter, it will fire right up. From there, I am going to replace the return caps on the injectors and their orings. I haven't seen any signs of leaks there, but they have more movement then I expect, and am afraid that the orings are bad. Still hoping not to go for that injector pump, and a little TLC is not gonna hurt the truck. I have hinted towards the check valve at the filter in the return line. I removed one of the fittings on the filter body for the return line to try to overfill the filter and there was a spring in behind the fitting. Not sure if there was anything that fell out I may have missed, but I think I am in the neighborhood of the check valve...Any words of wisdom on this sucker?

 

[94f450sd]

http://community.webshots.com/photo/298744815/1344176923067175480xBMwQQ

in that picture you will see my injection pump.on top of it you will see a brass fitting with a black hose with a red clamp comeing from it to an injector.that brass fitting is the check valve these guys are talking about.if it happens to stick open it will allow fuel to drain back to the tank.also dont go monkeying around with the return lines and caps.they will leak if you look at them the wrong way.with one leaking i went through 1/2 tank of fuel to go 30 miles

 

[taber45]

So the injector pump has the check valve, not the fuel filter assembly? Is that standard or just for your application? I'm sure I can check it, but wonder if anyone has any additional input.

 

[taber45]

So, today, I replaced the starter after the fuel filter the other day. I thought it was spinning kinda slow, and after the batteries were charged up, it still was slow. $140 later, and a little greasy, the thing fired up! YAY! First diesel I've heard in days!. I haven't had a chance to see if it starts better warm yet, but it turns atleast twice as fast as it did. However, I have another problem now. The things shuts off when I let off the pedal. If you let the RPMs come down slow, it will stay running, but if you let your foot off too quickly, it shuts right off. What is my problem now?

 

[aaklingler]

it sounds like you need an injection pump, you can try running some fuel additive. WHat does it idle at when you let off slow? You could also try turning the idle up a little.