TheNeckasaurus

Ever since I had my truck it will not turn over unless I blip the throttle. Any ideas why this might be?

Hodge

Are you talking a cold start, or anytime you start it?
What RPM's does it idle at? You probably need to adjust the set bolt for the throttle stop, increasing the idle a little. That should help it to start easier.
But, if the label is still on your sun visor, it will tell you that on a cold start, you need to depress the throttle a little. Not out of the ordinary.

greasy

mine is that way too, not as bad since I added a 3k GSK and bumped the idle up a bit

you don't need to pump the throttle, just depress it a touch and hold it


sounds pretty normal

TheNeckasaurus

It does that all the time, I live In fresno california, averaging 95 and up in the summer time.
It always starts right up when I give it a tap but I just wanna know if I can fix it. Ill remind you I live in fresno, the most boring place on earth, I need something to do!

9812vram

I know exactly what you mean - mine does the same. I know guys with trucks like these that can reach in the window and it'll fire right up cold or not without pedal.

Personally (this is my opinion) I think the label on the visor means COLD when it says to give it some peddle on a "cold start". "Cold" to me would be 0*c and colder, where a diesel engine doesn't run quite right for a few seconds. I don't think it means when the engine is not warmed up.

I believe the problem is that the fuel pressure bleeds off from the check valves in the pump and/or the overflow valve. The injectors need some back pressure to fire properly (that's why they're plumbed back into the fuel system on the pressure side of the pump) and the pistons in the p-pump are filled by lift pump pressure also. Take the pressure away and the injectors will not fire and the pistons in the injection pump will not fill with fuel. This is my theory on the issue anyways. I'm currently revamping my fuel system - new lines and filtering system all home made. I've installed a new lift pump and added a check valve for the injector return to keep them pressurized and one between the filters and pump to ensure the pump stays pressurized. A fuel press gauge will tell me if the overflow valve is leaking off pressure, in which case I'll add a check valve inline there also to see if that makes the difference, but I don't think it should if it's sealing properly. Guess we'll see if this makes mine fire up without adding pedal!

The debate is always whether this condition is normal or not - I say no - not when there are a plenty of trucks out there that don't need pedal to start. Something's different.

mechmagcn

I thought I was the only one with this problem On my truck you can press the pedal all the way to the floor and it still won't start, just roll over. But once you hit the starter, just tap the pedal and it will fire off right away.

infidel

Consider it a blessing if you have to give it a little bit of throttle for a cold start.
It means it isn't idling too high and wasting fuel.
As long as it idles fine after starting leave it alone and get used to giving a little throttle.
The 12 valve P-pump is WWII technology that doesn't automatically adjust for a cold start like modern vehicles.
Just the way I like it.

TheNeckasaurus

Its not just cold start, it anytime I start it! I could drive it 10,000 miles and turn it off, then go to turn it on and it would do the same thing. Where Im at the coldest Ill see is high 30's at night and that is rarely.

98fargo

Mines the same, needs a little bit of throttle to start, hot or cold, doesn't matter, like infidel said it's old technology, that's what I love about them!

dieselman97

My 97 is like this, my 94 is not just hit key. From the words of Jim jessup its a curb start feature so it doesn't blow smoke on the suits n lift the ladies skirts. So depending on year is whether your truck does it or not.

9812vram

Ya, must be! I installed my new filtering system and check valves yesterday and same thing. Fuel pressure could still be bleeding off at the pump overflow... I havn't hooked up my fuel pressure gauge yet. It may be cool old technology, but in my opinion, there's something to be said about a truck that starts instantly. The technology is in these pumps to start that 5.9 instantly. I'm going to look into this further...

infidel

I think it may have more to do with idle rpm plus timing rather than the model year if your engine starts instantly.

9812vram

Ya, you're probably right. I know my idle is too low and I will adjust that yet, but what do you figure? Idle it up to 900-950rpm and advance the timing? 16* maybe? I want to advance the timing anyways.

Hodge

Original poster- what does your truck idle at? It should be 750 or so. If it is lower than that on mine, then it needs pedal to start. A tiny adjustment makes a difference. I'd suspect that yours is idling too low.

TheNeckasaurus