Hard start. (This problem happened over night)

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Hard start. (This problem happened over night)

Postby jonny » Tue Apr 27, 2021 5:28 pm

1995 Isuzu Pickup 2.3L 96k mi. 2wd FI.
Suddenly, a month ago, I have a hard start issue, after the truck always started immediately.
If I use a "shot" of ether/starting fluid, the truck always starts immediately.
I've replaced:
Fuel pump
Fuel filter
Fuel pressure regulator
Spark Plugs
Distrbtr. cap (rotor was really STUCK ON, so I left old one in place)
Cleaned MAF with Alcohol & MAF cleaner. (MAF looked really clean)
I also put 2 check valves in fuel line running from fuel pump to fuel rail, although the fuel pump has a built in check valve that is working.
When cranking, fuel pressure goes to 42 PSI. then “if” or once the truck starts, PSI drops to 36 psi. & runs perfect. When I remove vacuum line from Fuel pressure reg., while it's running, fuel PSI jumps up to 42, as it should. There is no fuel in vacuum line (NEW Fuel pressure reg).
Once the truck starts, usually after 9 tries of cranking, it always runs perfect. The "Choke/Cold circuit" idles high until it warms up, then idles down & purrs. No hesitation while driving whatsoever. Once truck is warmed up, it starts immediately as well. If it sits for 4 hours or so, it is then 9 cranking tries to start it again. I noticed today, now that it's almost 70 degrees out, it started immediately after 4 hours while sitting in the warm sun.
I’ve spent about $200 throwing parts at it. It’s OBD-1 & the trouble code I got is #34. I get different information on, what #34 trouble code is?
Is 42 PSI a low pressure for truck to start up initially?
Any ideas? Any help?
THank you
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Re: Hard start. (This problem happened over night)

Postby Tentin » Tue Apr 27, 2021 7:25 pm

Code 34 on a pickup is a MAP sensor according to this list. Should be located on the passenger side between the battery and firewall.
1995 Isuzu Pickup 4WD aka Suzie Q. 3" lift, 32" A/T's
1998 Isuzu Amigo 4WD aka Smeagol The Amigo. 2" Lift, 31" A/T's
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Re: Hard start. (This problem happened over night)

Postby jonny » Tue Apr 27, 2021 10:15 pm

MAP was my next direction, though none of the symptoms of a bad MAP are what I'm experiencing... & I didn't want to spend another $50.
And i think that was an old fault code left over from 2017, the last time i tried to get the CEL to go OFF.
I will go that route, next,
Thanks
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Re: Hard start. (This problem happened over night)

Postby Tentin » Tue Apr 27, 2021 10:56 pm

Rockauto has them for a lot cheaper than that. You haven't reset/disconnected the battery since 2017? That's insane you would have a code stored that long
1995 Isuzu Pickup 4WD aka Suzie Q. 3" lift, 32" A/T's
1998 Isuzu Amigo 4WD aka Smeagol The Amigo. 2" Lift, 31" A/T's
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Re: Hard start. (This problem happened over night)

Postby jonny » Wed Apr 28, 2021 4:20 am

RockAuto sent me the 1st fuel pump that did n0t work, & I didn't find out until I had the fuel tank all buttoned back up.
The CEL has been ON since 2014. I've replaced the battery twice since then.
I've tried everything I've found on the internet to clear the codes & turn the CEL off.
As I recall, I let the codes cycle until they only read ''12''? That never worked.
Unhooked battery for a week, that did nothing as well.
How do you clear the codes & turn the CEL off? I've been trying to find the answer for 7 years.
http://www.isuzupup.com/viewtopic.php?f ... 08#p138808
8-)

Edit: I found a link that shows how to test the Isuzu MAP, & it states "Hard start (engine takes a long time to start)." is a symptom.
Feeling hopeful
https://easyautodiagnostics.com/isuzu/3 ... or-tests-1
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Re: Hard start. (This problem happened over night)

Postby Tentin » Wed Apr 28, 2021 12:38 pm

Yeah a fuel pump is one of those parts you don't want to cheap out on unfortunately. The map sensor I bought last year was the $20 spectre premium (MP102) and it's been working for me so far.

For my pickup just a simple battery disconnect resets my stored codes, so I have a clean bill of health until the next time I trigger a code. It sounds like it's just triggering again after you reset it, so a reset doesnt do anything until you solve the problem
1995 Isuzu Pickup 4WD aka Suzie Q. 3" lift, 32" A/T's
1998 Isuzu Amigo 4WD aka Smeagol The Amigo. 2" Lift, 31" A/T's
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Re: Hard start. (This problem happened over night)

Postby jonny » Sun May 02, 2021 10:53 am

Problem fixed?
The vacuum line to the MAP sensor (fault code #34), located on inner fender to rear of battery was MISSING.
It might have fallen off & "left" the vehicle? Where it plugs into the MAP is hiding underneath & where it T's in, was also hiding.
With the vacuum line nowhere to be found, it's kind of hard to see what to fix, when there's nothing to see.
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