No start w/o throttle blip
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Joined: Mar 2011
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From: Manitoba Canada
I set my idle at 950rpm last night. It definitely starts better, but still doesn't just jump to life like some of them. I hat the 950rpm idle, waaaay too high for this cowboy. So I idled it back down to 750rpm. I'd rather use pedal to start it than idle it that fast! lol That said, I've GOT to find out why!!
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From: Seymour Tn
Is this fuel system designed to retain any fuel psi at all with the engine shut off? am i wrong? because i thought the only "check Valve" in the whole system was the OFV. ive thought about adding a low psi electric pump for those stupid moments i have when i run out of fuel from time to time. and yes Im with Infidel on the WW2 technology. eliminates alot of headache and operating costs
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Joined: Mar 2011
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From: Manitoba Canada
Is this fuel system designed to retain any fuel psi at all with the engine shut off? am i wrong? because i thought the only "check Valve" in the whole system was the OFV. ive thought about adding a low psi electric pump for those stupid moments i have when i run out of fuel from time to time. and yes Im with Infidel on the WW2 technology. eliminates alot of headache and operating costs
Anybody have a fuel press gauge? Does it drop to nada right away whey you shut it off?
Infidel: I'll take that timing advice, and thanks!
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From: Airdrie, Alberta
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.
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.
If you want it to start easier, loosen your gov springs off a click or two, and readjust the idle to proper setting.
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From: Manitoba Canada
You've over complicated the whole system. If the fuel system has no air leaks, it doesn't really matter if the system doesn't hold pressure, as if any fuel moves, it is replaced with more fuel. Unless your tank is extra low and its sucking air. If the OFV is leaking, and any air gets up that high, it should still not affect much, as it is the high point of the low pressure system. My VP had a OFV that was leaking, and it cause hard starts, but it is on the bottom of the pump, not the top.
If you want it to start easier, loosen your gov springs off a click or two, and readjust the idle to proper setting.
If you want it to start easier, loosen your gov springs off a click or two, and readjust the idle to proper setting.
- basically all the chip is doing is advancing timing and upping injection pressures right? More pressure = more fuel delivered in the same amount of time, but I forgot that those are electronically fired injectors. Guess I should have thought it through a little more.
As fuel does not compress any real amount, the fuel system will pump the exact same amount of fuel whether under pressure or not. Anyways, I revamped my whole fuel system and the truck definitely starts/runs better than it did, plus I got rid of some leaks so it wasn't a total loss!
What will loosening the governor springs do exactly? There's always a trade off - what's the down side to doing this?
Thanks
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From: Airdrie, Alberta
Your max governed engine speed will be slightly lower, and will desensitize the throttle pedal a bit. Going to the next stage GSK will fix both of those issues though. I was maxing out at 4300 rpm with the 181 dv's, its now closer to 4k. But it drives so much better, and it starts in half a revolution with zero throttle input. Its been quite a while since it would do that.
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From: Montana
Anybody have a fuel press gauge? Does it drop to nada right away whey you shut it off?
I think the only reason the pressure doesn't drop instantly is because of the almost closed needle valve used for a snubber restricting the pressure drop.
A snubber would do the same thing.
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From: Manitoba Canada
Does that mean going to a 3k gsk?
I stuck a liquid filled gauge (no needle valve) on mine to check FP at idle - 41psi. When I shut it off, I watched it drop but I didn't see it go to zero 'cause I was getting impatient and finally took the gauge off before the press was that low. I just installed an in-cab Isspro gauge with a needle valve tonight. It takes some time but it definitely drops to 0 when shut off. I guess the pressure does bleed off through to OFV.
But.... none of that likely matters though as pointed out earlier.
Tate, thanks for the advice. I'm going to try backing that governor off a click at a time and see where I get.
I also still plan on advancing the timing to 16* but I haven't got time for that at the moment.
But.... none of that likely matters though as pointed out earlier.
Tate, thanks for the advice. I'm going to try backing that governor off a click at a time and see where I get.
I also still plan on advancing the timing to 16* but I haven't got time for that at the moment.
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From: Bethel Acres, Oklahoma
Mine was sucking air at the fuel heater. It had always liked a little pedal to start. Then it wouldn't start at all without some pedal. Then it wouldn't start. This took place over a 6 month period. The heater was shorted out and the connector was a little burned. I eliminated the heater and put the pre-filter screen bowl back on and it starts easier, with no pedal, than ever before.
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I had a 97 that started almost by just showing it the key (honestly, you could not let go of the key fast enough). My 94 is not the same way, but still good...no pedal, but turns over probably 1-2 revs and that's with the timing at 16 which I've heard causes them to start slightly harder....Next project is to replace fuel lines from tank to pump and see if it's any better. (already removed heater and replaced OFV)...it's fine, but miss the 97..
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From: Fresno
So just an update, went out today and fiddled with the idle, not sure what I set it at cause I was working by myself, but once I got everything back together and took it for a drive it started right up no problem and no throttle blip. BUT, its about a quarter inch away from the 1000 mark, is that too high?
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From: Manitoba Canada
Ya, what he said. Far too high for my taste though. I idled mine back down to just over the 750rpm mark. I didn't like the sound of the big C humming that fast at idle and with my tighter TQ and shift kit it hammered into gear too hard going from P or N to D at idle.
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my truck alway starts between 1/2 -1 crank, 2 cranks if it was below 0. im still on the original lift pump at 280 000 km. i found the gsk made no difference in starting, at least not in the summer. we'll c what winter has to say. idle is 800rpm since gsk install-i would recommend a gsk to anyone whether they say they need it or not. its just plain good to have
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