Hard to Start then Runs Fine

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BravoDrew
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Hard to Start then Runs Fine

Post by BravoDrew »

Hello all! Have an 86 TD 2.2 pup that has become hard to start. Recently had new injection pump in. It runs great once it gets going, but I really have to push down on the fuel pedal for a long time before it seems to get enough fuel to cold start, especially if it's been sitting for a few days. What could the issue be? I've replaced the glow plugs with no change in performance.
New owner, '86 Isuzu P'Up Turbo Diesel SpaceCab, 5-spd, 2wd
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JoeIsuzu
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Re: Hard to Start then Runs Fine

Post by JoeIsuzu »

Tell us about your fuel lines. New, or old?

Sounds like classic air leak symptoms.

Jack
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spideypop
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Re: Hard to Start then Runs Fine

Post by spideypop »

My thoughts too. Especially since you had a recent injection pump change.
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puttputtinpup
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Re: Hard to Start then Runs Fine

Post by puttputtinpup »

I had the same issue with my 84 automatic after I disturbed the original fuel lines. The return line in particular was leaking air. I replaced them all and problem solved. You'll need to get different hose clamps.
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Paul
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Re: Hard to Start then Runs Fine

Post by Paul »

Is there a lot of smoke when it finally starts? If so, it is probably not a fuel problem but more likely a faulty glow system.

New glow plugs may not mean that they are working right or at all. See if you can get a clamp on current meter to watch the glow current while some one else does the glowing. You should see 140 amps initially, followed by a smooth decline to 40 amps over a period of about 4 seconds.

Failing the current meter, glow until the glow lamp goes off and then feel the current sensor part of the glow bus bar (be careful to not burn your fingers). The sensor should be hot, maybe too hot to touch.

Also, there is the tried and true method of watching the cabin lamp to see if it goes dim while glowing. Not definitive quantity wise but still useful.

Paul
'84 P'UP 2 wd diesel, 5 spd with 0.78 fifth gear and differential back to 3.73.
BravoDrew
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Re: Hard to Start then Runs Fine

Post by BravoDrew »

Hi Paul,
Yes, lots and lots of smoke. This sounds like what I might have. I am going to try to start it up this week and test it with a meter. What I do attach the clamp meter to?
New owner, '86 Isuzu P'Up Turbo Diesel SpaceCab, 5-spd, 2wd
BravoDrew
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Re: Hard to Start then Runs Fine

Post by BravoDrew »

JoeIsuzu wrote:
Mon Mar 28, 2022 2:23 pm
Tell us about your fuel lines. New, or old?

Sounds like classic air leak symptoms.

Jack
They're the originals... if it is a fuel line issue, how do I go about fixing it -- do I need to replace the fuel lines or is it possible they can they be repaired (looks like a hard repair, such small delicate lines? Would I have to find the lines off another truck?
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Duck
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Re: Hard to Start then Runs Fine

Post by Duck »

They're the originals... if it is a fuel line issue, how do I go about fixing it -- do I need to replace the fuel lines or is it possible they can they be repaired (looks like a hard repair, such small delicate lines? Would I have to find the lines off another truck?
[/quote]

Not the steel lines, Just the rubber ones.
90 Dakota with C223
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JoeIsuzu
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Re: Hard to Start then Runs Fine

Post by JoeIsuzu »

Well I didn't ask enough questions before weighing in. :oops:

Jack
dorf
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Re: Hard to Start then Runs Fine

Post by dorf »

I'm confused......just replace all rubber hoses and use screw type clamps and use Barricade rubber fuel lines. Easy but important fix....for a happy engine.

Don't mess wth the metal fuel lines.
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Re: Hard to Start then Runs Fine

Post by Newtron »

On those rubber line replacements, make sure you replace the smaller diameter line on the return side too. I had a crazy time once after I replaced all the delivery lines, only to be thwarted by that little one. Also dont try to cheat a too large diameter with a clamp, that also funked me once.
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1981 2x4 Diesel Pup DLX Long Bed
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Siegfried
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Re: Hard to Start then Runs Fine

Post by Siegfried »

I've also had a little trouble starting, at least when it's cold, and after reading this I thought I'd replace my fuel lines since they are old, just in case it might help.

When you replace these hoses do you have to do anything special to bleed the air out of the diesel fuel system or can you just replace them and start it up?
1985 Isuzu P'UP Diesel Long Bed
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JoeIsuzu
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Re: Hard to Start then Runs Fine

Post by JoeIsuzu »

Siegfried wrote:
Sat Dec 03, 2022 9:41 am
I've also had a little trouble starting, at least when it's cold, and after reading this I thought I'd replace my fuel lines since they are old, just in case it might help.

When you replace these hoses do you have to do anything special to bleed the air out of the diesel fuel system or can you just replace them and start it up?
We need to stay with BravoDrew's issue here, so I'll be brief:
Supply lines will require bleeding.
Return lines will not.

Jack
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Re: Hard to Start then Runs Fine

Post by hillbillie1 »

Bravodrew I feel your pain.
I had my voltage to the plugs and still got the smoke. I wasn’t getting fuel until the plugs cooled some causing the smoke.
Just for information check O Ring on butterfly drain on top of water separator. I was sucking air there. New Truck now. Mike
83 DLX 4x4 diesel pup
86 turbo space cab Ls pup
Cummins 3500 4X4 6 speed Manual
2011 Limited Ultra HD
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