Won't start unless I give it throttle. Why?

[LWilliams]

My 96 12v has developed a habit of not starting unless I push the accelerator about a third of the way down. Then it will start right up and idle just fine. It runs good with plenty of "bombed" power but I used to not have to give it throttle to start. I have had the fuel return line changed about 6 months ago so I don't suspect it. I have let the truck stand for 7 days while I was on vacation and it started right up the first time I tried it when I got back but I instinctively gave it a push on the throttle. I can start it every time but someone else that don't know about it can't get it to start. I am wondering if I have a problem brewing or if there is an adjustment I can make somewhere. Has anyone else had this problem with theirs and if so what did you do about it? Thanks.

 

[DSiemens]

Check your fuel return line for a leak and wet spots. Will it start after a few cranks or only when you press the pedel?

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95, Kitty dead, #6plate, 5speed.

 

[Rammin On]

Check your return valve ... if getting weak it can leak fuel by when you shut down.

 

[JJW_ND]

What is your idle set at??

Lower idle speed can effect startup.

I know this is kinda touchy on a autotrans, but I believe it should be around 750 - 800.

The engine data plate on my 96 (5sp) say 900 rpm low idle. It starts much better if it is close to that 900 ramge. If I turn my down to say 650, it will crank quite alot before it starts.

jjw
ND

 

[Rammin On]

The return valve (overflow valve) is located on the top front of your P7100 ... there is a fuel return line there with a spring loaded overflow valve.

Your idle speed if you have an aut trans should be 750 rpm with the trans in drive and the A/C on

 

[LWilliams]

I have a 5 speed and I am thinking the idle is set close to 600. I will check tonight when I get off work. But I have not changed the idle speed and it used to start ok.

 

[DHRA]

Larry, check your shut off arm (pin) that goes into the solenoid. They have a tendency to get soem rust on them and not want to start all of the time. Bosch changed them to a ball n socket because of this problem.

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Eric
GLTDR

 

[Rammin On]

For the 5 speed ... 780 rpm with trans in neutral and A/C on

 

[Red Rocket]

Larry,
If you would like exact directions on how to check the overflow valve, let me know, I did mine two weeks ago, so it's still fresh in my mind, email me.

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1998 2500, 12 valves, SLT, auto, 3. 54, 285/75-16, TST 230/605, t/c switch, DiPricol EGT/boost guages,K&N,camper special, 65,000 miles(2/01),
12 ton goosneck!
'01 Polaris EDGE-X 600

 

[Missouri Mule]

Larry,
Next time you start it, turn the key start position and let it turn over once or twice.
If it doesn't start which I fullly expect ot not to. Pop hood and prime pump, get back in and crank see if it will start with out puttng pedal down. If it fires up you have fuel leaking down(back to tank or onto ground), which could be following; return fuel valve, lift pump, fuel hoses or metal lines, injector pump. If you still have to put pedal down look for components clogged, filters mainly.

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Bill Thomas
Missouri Mule - 96 Wht 4X4 ST CC,5 spd, 3. 54, 8 ft bed, 1 ft high cheater boards.
99 Freightliner bl/wht FL60 ISB-5. 9 24v,215 hp,520 tq,6 spd, 3. 59 nsr,16 ft box, 19. 5 tires,Wt/gvw 11,000/23000

 

[Missouri Mule]

It could be air getting into fuel system also.

 

[Wilycyote]

I had the same problem. They replaced my return line and it didn't help. Checked the over flow valve. The presure was low, around 2 pounds. Should hold 22 to 26 pounds before it releases. Put in a new one and everything is fine. I also had a
2 mpg loss in fuel milage. It is also ok now. Good Luck

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1996 ram 4x4 ext cab. BD products, Oversize injectors,250 torque plate 4"cat back, torque lock. pressure lock, and BD Auto Transmission,Pac-Brake

 

[LWilliams]

What is the return valve and where is it located. How do I check it? Thanks.

 

[Red Rocket]

I just posted instructions on how to check the fuel return valve. Its free. look at the thread, got a whopping 10 psi fuel pressure.

 

[PBaker]

Probably a stupid question but are you guys using the tach to set idle or are you hooking up a tach under the hood and if so how?

Paul

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'96 2500 ext. cab, LB, 4x4, 5 speed, 3. 54, TST 280 cam plate, AFC spring kit ,pyro and boost gauges mounted on A-Pillar, tinted windows, 16x8 Eagle alloys series 1219, 285/75R16 Durango A/T's, stainless steel rocker panels and alluminum stirrup steps

 

[LWilliams]

Wow, thanks to all of you that replied. I came in to work this morning and there were a bunch of suggestions. Thanks. I checked my idle speed last night with the in dash tach. because I don't have an under hood tach and if I did I'm not sure how I would hook it up. Anyway, at a warm idle in neutral without the a/c on the needle is pointing straight at 9 o'clock. There are two marks between 0 and 1000. The needle is laying exactly on top of the second mark. Your guess is as good as mine on the exact speed. I'm guessing about 600-650. I looked at the pump to see how to set the idle up and I didn't find a set screw or anything I am confident will do it. There is a rod that goes from the front accelerator pivot to the rear pivot that is adjustable like a turnbuckle that I think would adjust the speed but didn't mess with it until I asked you guys. How do you set up the idle? I'd like to try that first and if that don't help then I will get into the fuel return valve.

 

[Strick-9]

Larry,

You found the front pivot and the adjustable arm that leads back to the rear pivot. The rear pivot has a tab that rests on a 10mm bolt head. This bolt has a 10mm locknut. It's tough to get your arm in there, but all you have to do is turn the bolt counterclockwise 1/2 turn or so. This picture might help:
#ad

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The idle set screw isn't labeled here, but you should be able to figure out what the linkage is resting on.

Tip: Move the throttle linkage to full throttle so you can access the bolt. Otherwise the stop tab will be covering it up.

-Chris

 

[LWilliams]

Thanks Strick-9, now that I know what to look for I will give it a try tonight.

 

[Joe G.]

Larry,

Another little tip. Put a screw driver in the linkage at the front of the engine to hold the throttle open. This takes the pressure off the adjustment screw and it's a LOT easier to adjust. When the lock nut is loose you should be able to turn the asjustment screw with your fingers.

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Joe George
Eureka, CA

'95 2500 CC auto 4X4,3. 54,Combo EGT/boost guage,custom switch panel,PacBrake,TST #5,Automatic motorhome steps on both sides,Foldacover hard bed cover,Cummins chrome kit,Black steel grill guard,Front hitch receiver

 

[LWilliams]

Thanks guys. I bumped the idle up last night and this morning when I started it I kept my foot off the peddle and it fired right up on its own. Joe G I used a screwdriver to prop the linkage open and thanks to Strick-9's picture I found the 10mm setscrew. You guys were a big help. Thank you very much.