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93Dak
Dodge Dakota
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7/14/2004
10:11:07
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 Subject: Fuel pressure
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Message:
I just bought a set of 19# injectors from fiveomotorsport.com for my 93 Dakota 3.9. They make the engine run smooth, but occaisionally the engine will misfire. SOmetimes it will get so bad that the check engine light comes on. Yesterday, I drove it for almost an hour and it missed the entire time.
I bought a fuel pressure tester and with the engine idling, the fuel pressure is at 32 psi. I thought that I read somewhere on here that it is supposed to be at 40 psi. If it is supposed to be at 40, could low fuel pressure be causing the misfire?
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?
Dodge Dakota
JOIN HERE
7/14/2004
10:52:13
| RE: Fuel pressure
IP: Logged
Message:
More probably spark plug gap
or egr failure !
If engine light on = should be codes !
What are they ??
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93Dak
Dodge Dakota
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7/14/2004
11:21:10
| RE: Fuel pressure
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Message:
By the way, that is 32 psi with the vacuum line still connected to the pressure regulator. Fuel pressure bleeds off pretty quickly after shutting it down. Sometimes hard to start when hot.
Code is 27 which when I looked it up is something related to the injectors. None of these problems showed up until two weeks after I installed these injectors.
I ran out of gas about a week before these problems got bad. Not sure if I damaged the fuel pump or not.
I pulled the fuel rail out with the injectors attached and let the pump pressurize the fuel system. I had no leakage at the injectors, so my guess is that the check valve in the pump is bad. I can't find any other leaks in the fuel system.
EGR code (32?) has never shown up. It is original, but I've cleaned it a few times.
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Dodge Dakota
JOIN HERE
7/14/2004
13:25:53
| RE: Fuel pressure
IP: Logged
Message:
You have not mentioned if you recently replaced plugs / type used / gap setting !?
Check for about .045 gap = will probably
eliminate "misfire "..
Computer ' control ' bahhh!!!!
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93Dak
Dodge Dakota
JOIN HERE
7/14/2004
14:08:03
| RE: Fuel pressure
IP: Logged
Message:
Plugs have 15,000 miles on them. No trouble at all before I changed injectors. They are the Autolite 3923 or whatever everyone on here recommends. They are gapped at 0.040. When gapped at 0.045, the truck had no power.
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J and J Auto
GenII
 
7/17/2004
01:24:31
| RE: Fuel pressure
IP: Logged
Message:
The presure should be between 40 to 50 psi
If it misses all the time and code 27 heres what
you need to do
Start and let idle
unplug 1 injector at a time untill you find the
1 that is not working, call Bruce and he will
send you a replacement ASAP
Each one should drop engine speed and make it run
rough may even die.
The 19# injectors Bruce buys in bulk and he has
gotten a few bad ones I got one myself, just use 1
of your old ones untill Bruce sends a replacement
Bruce is a great guy and will not give you any
problems he will galdly get one out to ya.
It will run at 32 psi but that is not good it
decreases atomization and will give you poor gas
milage this should also be fixed
Also check all the connections on the injectors
you may have a bent pin on one and not making good
contact
The time I got the bad one it was the third one
in a few thousand he sold
Larry
J&J Auto
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93Dak
Dodge Dakota
JOIN HERE
7/19/2004
09:20:46
| RE: Fuel pressure
IP: Logged
Message:
Larry:
The Haynes manual says that the fuel pressure should be 31 psi at idle with the vacuum line connected to the fuel pressure regulator. Since mine is showing 32 psi on the gauge, that seems correct to me. If I turn the key to "on" without starting it (about three times), I can bump it up to almost 45 psi.
I found the problem with the injectors. I changed them in the dark when I put them in, and I didn't notice that two of the old injectors left their o-rings in the fuel rail! I pulled those extra o-rings out, and the injectors work perfectly now... ooops...
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