Previous difficult cold start > Now it seems like not getting fuel and won't start at all

[Baxter]

@IDIBRONCO any recommendations for next steps in trying to solve this sucker ... FSS seems good. still not getting fuel as you mentioned from the IP but the return lines spit fuel so the lift pump seems good as you mentioned before ... must not be getting power to the IP huh?

 

[IDIBRONCO]

see pic. the one behind it is the high idle connector correct?

No. That's for the timing advance.

@IDIBRONCO any recommendations for next steps in trying to solve this sucker ... FSS seems good. still not getting fuel as you mentioned from the IP but the return lines spit fuel so the lift pump seems good as you mentioned before ... must not be getting power to the IP huh?

What happens if you use a jumper wire to put power directly to the FSS? If you do that and it pumps fuel, then you know that everything is working with the IP and you need to figure out why there's no power going to it with the key.

 

[Baxter]

ok got it. the red arrow in my last picture is where the power comes into the FSS correct? I found my test light finally and there indeed is NO power in that wire with the key on. therefore it's not powering the FSS as normal. Is it feasible to actually power up the FSS with the jump wire straight from the battery and get in cab and start the truck? would it only pump fuel while the engine is turning over or would it be constant? then could I shut engine off at the key and unhook the wire from FSS.. thanks for the help!

 

[Rdnck84_03]

Yes you can power the FSS from the battery to start the truck from the key. No you cannot shut the truck off with the key. It will only shut off when wire to battery is removed.

James

 

[Baxter]

Interesting. so while it's running leave key in on position and go under under hood and disconnect? then back to cab to turn key off?
thanks @Rdnck84_03

 

[Rdnck84_03]

Yes that is the correct order. I'm not sure on a vehicle since they weren't designed to function this way, but diesel tractors with manual kill levers this is the correct way. It is supposed to be ******* the alternator to be running with the switch off.

James

 

[Rdnck84_03]

Well I guess " hard on" is a dirty thing in all context now.

James

 

[Baxter]

ok I hooked up a semi-permanent fused wire from battery to FSS spade ... pain in the ass to attach on and off every time of course but the truck starts perfectly fast cold and runs strong. Now I know 2 things, the manual gp harness and switch I installed works and that I need to run a new wire from the FSS to the ignition because I still can't figure out where the OEM path is broken, my guess is that it ran through the old relay that was controlled by the key on/off somehow ... anyways without pulling apart the whole engine wiring harness it is what it is. Anyone know if I can simply run a wire from FSS through the firewall to fuse box? find an open slot that has power only when the key is on, same as the manual gp switch is set up. ..run an inline fuse on the wire and plug it in to the slot. Anything else I should do? thanks again for your help on this thread to get me to this point.

 

[IDIBRONCO]

I don't see why not. I would put a fuse in that wire though.

 

[Baxter]

Welp I'm still running the hard wire from battery to FSS. Seemed to be working fine for now until I can permanently fix the wiring (**see below, I tried!) ... Now I am experiencing randomly every 4 or 5 cold start attempts the very same symptoms as before installing the manual gp harness kit ... clip wire to FSS, get in cab turn key on and hold gp button switch for about 5-8 sec. (I've tried different time lengths up to about 13 sec) I'm holding the button on while cranking starter and when the truck starts to idle I release the button. Starts cold as normal, but every once in a while the truck fires up for a second sputters then dies, like I have no glow plugs. Then I have to crank the starter for 10 sec. getting nothing, with a minute break then try again, nothing for about 4 of these cranking sessions, then she fires right up and runs smooth and strong. Sorry I know this isn't rocket science but am I doing this correctly? Is this operator error? On my other truck I just hold the button on for same amount of time then release it before I crank the starter ... it starts up quick when cold as normal with this procedure.

Also when I lost power to the FSS now that other switch behind the power-in spade, cold advance I think it is, is not working as the truck used to high-idle for a while cold until it warms up a bit then the rpms drop. Could this have anything to do with it?

** I ran a clean in-line fused wire from the FSS thru the firewall into the cab to fuse box. Found a slot that had power only with the key on. It will not get the fuel pump to pump fuel. However the FSS does click on when I touch the spade with the new wire. Is it not getting 12V? Why did I even go inside with the wire? Couldn't I just run it to the starter relay or somewhere under the hood to get 12V when the key's on?? Thanks for your help as always on this as I stumble around on what I think is still a simple problem I just can get right.

 

[Rdnck84_03]

Ok there is alot going on here. First off, the starter relay will not work for the FSS. One side of the relay is always hot, the other side is only hot in the start position.

If it starts and then dies, the glow plugs are not the issue. I think you have a fuel issue, either drain back or a leak that is letting air in the system. Glow plugs working or not after it starts it will continue running unless it runs out of fuel.

James

 

[Baxter]

Thanks James. So can't I connect to the side of the relay that is hot only in start position?

I would agree with you on some sort of fuel issue but the truck runs strong and healthy always has except for a few years back when I needed to replace the injectors, been all good ever since. ... it's only giving me hit & miss problems on a cold start up. I'm suspecting that cold timing advance switch, whatever that thing does because I know it's not working and maybe it needs to be working properly to fire up the truck easily when cold. Not me just holding the throttle open a bit trying to recreate that little brass pin that extends to hold it open when cold, then drops rpm as it warms up ... thoughts?
thanks again for the feedback.

 

[Rdnck84_03]

No because then the FSS would only be energized while the starter is cranking. So basically the truck would start but would immediately die when you release the starter.

The cold advance being non op should not cause any issues starting the truck. I have my cold advance and high idle on independent switches in the cab. Only time I use the cold advance is when temps are down below 15 degrees. I do use the high idle frequently for jump starting other equipment.

Where did the new injectors come from? Was the pump timing set after injector install?

James

 

[Baxter]

Yep my bad, I realize now it would only be hot when cranking starter ... ok I was just wondering if that other switch on top of the FSS was critical to get the right about of fuel to injectors when cold. ok if not that's good.

..and I knew this was coming ... arghh! no sir in fact I was pretty new to idi's an diesels in general and just swapped out the injectors with new ones not thinking the IP needed adjusting. I have to ask though, it's probably been about 4-5 years now after I put the injectors in, truck immediately cleared up knocking and rough running scenarios so I figured it was good to roll. Would setting the timing now make any difference on a perfectly well running engine? and would having not set the timing back at install all of a sudden be causing a cold start only issue? Did I screw the pump up slowly over time and is cold start hit and miss a sign of the IP going bad? sorry for the 20 questions ... thanks

 

[IDIBRONCO]

Would setting the timing now make any difference on a perfectly well running engine?

It could be that you think your engine runs fine now and will be surprised at how much better a properly timed engine will run. YES! Check/set the timing.

would having not set the timing back at install all of a sudden be causing a cold start only issue?

Possibly, but it would more likely be from internal wear in the pump causing the timing to be more retarded than it was when you put in the new injectors.

Did I screw the pump up slowly over time

Probably not, but the timing will retard over time as the pump internals wear. This can cause other issues.

is cold start hit and miss a sign of the IP going bad?

I'm not going to say yes or no here because there's WAY too many variables involved for me to give an accurate answer. I'll just answer "maybe". What you have to remember, and it's also something that most of the online "experts don't mention or don't know, is that the pumps and injectors wear at the same rate. Ideally, you want to replace them as a set. You can replace just the injectors, just the pump, or worst of all (unless there's a known problem, you can replace just some of the injectors. I know that, often times, cost is a factor, but you should still try to replace the pump and injectors as close to each other as possible. Yes, you will need to set your timing for each replacement. If you doubt what I've said here, just ask one of the known quality pump and injector rebuilders.