| From | Message |
Greg
Dodge Dakota
JOIN HERE
3/12/2006
18:22:38
|
 Subject: 3.9 takes forever to start
IP: Logged
Message:
everytime i try to start my 95 3.9 whether cold or warm it takes 5 seconds to start, but when running idles good and runs perfect. Whats the problem please?
|
schmidtmike
Dodge Dakota
JOIN HERE
3/13/2006
00:11:34
|  RE: 3.9 takes forever to start
IP: Logged
Message:
is the MIL on? Can you hear the fuel pump run for a split second and then shut off with the key in the ON postion? If there are no codes, I would look into a check valve in the fuel pump that has failed. Is it harder to start the longer it sits? The check valve holds pressure on the system when the fuel pump shuts off, so the vehicle starts easier after sitting.
Fuel injectors do no "inject" fuel per-say, they simply act as electromagnetic valves that open and close. The amount of fuel pressure determines more than the pulse-width of the injectors, how much fuel goes into the engine. If there is very little or no fuel pressure, then very little or no fuel gets injected.
If the check valve fails to hold pressure on the system, when the key is turned and the engine cranks with no fuel pressure, the fuel pump has to raise the fuel pressure up to a minimum where enough fuel gets injected to start the engine. The fuel pump could take anywhere from 1-10 seconds to raise the pressure, depending on the fuel system and the volume of fuel the pump has to move.
Sadly, if the check valve is bad, the whole pump assembly has to be replaced and is around $150 from an aftermarket supplier.
|
schmidtmike
Dodge Dakota
JOIN HERE
3/13/2006
01:05:15
| RE: 3.9 takes forever to start
IP: Logged
Message:
If not the fuel pump maybe look into a laggy crank signal, or a malfunctioning ASD relay.
|
Greg
Dodge Dakota
JOIN HERE
3/13/2006
18:44:11
|  RE: 3.9 takes forever to start
IP: Logged
Message:
Yes the longer it sits the longer it takes to start, i noticed today that the fuel gauge is moving about a cm. back and forth, it just started today. ?. Also when i first start it i can smell gas heavily. I appreciate your time, but i am stumped. please help.
|
cuzindoug
GenIII
3/13/2006
20:27:54
| RE: 3.9 takes forever to start
IP: Logged
Message:
Like was stated above, get a pressure gauge to check fuel pressure at the rail. It should run around 45 psi (turn key on for fuel pump to cycle then off), if it drop down drastically, then you probably have a faulty regulator(check valve), if it leaks down slowly, then you MIGHT have a problem with an injector leaking by.
If it ain't broke, fix it til it is.
|
Greg
Dodge Dakota
JOIN HERE
3/14/2006
18:51:33
|  RE: 3.9 takes forever to start
IP: Logged
Message:
I will try that tomorrow, thanks. Thats the funniest thing i have ever heard. LMBO
|
| | P 1 |
|
Post a reply to this message:
Username Registration: Optional
All visitors are allowed to post messages
|
