[HELP]No fuel pump priming but fuel pressure is there when startup!? (video)
09-22-2016, 06:15 PM
#1
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[HELP]No fuel pump priming but fuel pressure is there when startup!? (video)
Hi,
I have a 94 4runner with 3.0 engine. The engine probably has 70k miles on it while the body has god know how many miles.
Straight to the point, the car wouldn't want to start right up. I would have to crank it like 10seconds to at least get it started but it would be about to die when started up.
The key on the 2nd run position multiple times, the fuel rail is not pressured so the pump is not priming according to the test gauge and my ear. BTW, the relay is good and the power to the pump should be good***.
***The reason why I say the power is getting to the pump is that the pressure gauge would read 50psi(unstable) on the fuel rail when I crank it. However, it would read 0 when the key is on the 2nd position.
Additionally, when the car starts painfully, the pressure would be unstably at 50psi.
Please refer to the video and please help me figure this out.. I have a brand new Genuine Toyota pump on hand. I want to know if it's a fuel pump problem or somethingelse so I can return the fuel pump if latter.
I have a 94 4runner with 3.0 engine. The engine probably has 70k miles on it while the body has god know how many miles.
Straight to the point, the car wouldn't want to start right up. I would have to crank it like 10seconds to at least get it started but it would be about to die when started up.
The key on the 2nd run position multiple times, the fuel rail is not pressured so the pump is not priming according to the test gauge and my ear. BTW, the relay is good and the power to the pump should be good***.
***The reason why I say the power is getting to the pump is that the pressure gauge would read 50psi(unstable) on the fuel rail when I crank it. However, it would read 0 when the key is on the 2nd position.
Additionally, when the car starts painfully, the pressure would be unstably at 50psi.
Please refer to the video and please help me figure this out.. I have a brand new Genuine Toyota pump on hand. I want to know if it's a fuel pump problem or somethingelse so I can return the fuel pump if latter.
Last edited by sam_KOR; 09-22-2016 at 06:37 PM.
09-23-2016, 02:24 AM
#2
You really need to check if your losing electric at the fuel pump .
As the Circuit opening relay has two sets of contacts one set is closed during cranking .
The second set closes when the switch in the AFM closes if you have the air intake off it will not run
Have you not jumped B+ and FP on your check connector to see if the engine runs ??
As the Circuit opening relay has two sets of contacts one set is closed during cranking .
The second set closes when the switch in the AFM closes if you have the air intake off it will not run
Have you not jumped B+ and FP on your check connector to see if the engine runs ??
09-23-2016, 03:49 AM
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No I haven't jumped those terminals yet. The reason being jumping two terminal didn't do anything for my car when I was doing the ignition timing. The check engine light didn't even come on that time.. But does it matter though? Shouldn't the pump be priming regardless on the 2nd position?
To check electric to the pump, I have to drop the tank right?
But then it's weird how the pressure reads 50psi erratically when start up.. which means there is power...
What do you recommend me to do? I really need to take this truck to Michigan from VA
To check electric to the pump, I have to drop the tank right?
But then it's weird how the pressure reads 50psi erratically when start up.. which means there is power...
What do you recommend me to do? I really need to take this truck to Michigan from VA
09-23-2016, 07:06 AM
#4
I am guessing at this Point you have physically checked the AFM switch is working
The Circuit Opening Relay has been checked for correct operation both coils and both sets of contacts .
On the Check Connector jump B+ and FP see if the engine runs.
This is Battery Positive and Fuel pump it bypasses all the relays the switch on the AFM
This has nothing to do with adjusting timing
No You can check the voltage at the plug that connects to the fuel pump on top of the tank
If I recall most 4Runners have Access through the floor under the back seat I could very well be wrong
It looks like the minute you release the key from start the fuel pump quits pressure drops
It is a older Runner who knows just what be worn allowing the pressure to drop even faster then normal
Best of Luck
The Circuit Opening Relay has been checked for correct operation both coils and both sets of contacts .
On the Check Connector jump B+ and FP see if the engine runs.
This is Battery Positive and Fuel pump it bypasses all the relays the switch on the AFM
This has nothing to do with adjusting timing
No You can check the voltage at the plug that connects to the fuel pump on top of the tank
If I recall most 4Runners have Access through the floor under the back seat I could very well be wrong
It looks like the minute you release the key from start the fuel pump quits pressure drops
It is a older Runner who knows just what be worn allowing the pressure to drop even faster then normal
Best of Luck
09-24-2016, 02:52 PM
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I am guessing at this Point you have physically checked the AFM switch is working
The Circuit Opening Relay has been checked for correct operation both coils and both sets of contacts .
On the Check Connector jump B+ and FP see if the engine runs.
This is Battery Positive and Fuel pump it bypasses all the relays the switch on the AFM
This has nothing to do with adjusting timing
No You can check the voltage at the plug that connects to the fuel pump on top of the tank
If I recall most 4Runners have Access through the floor under the back seat I could very well be wrong
It looks like the minute you release the key from start the fuel pump quits pressure drops
It is a older Runner who knows just what be worn allowing the pressure to drop even faster then normal
Best of Luck
The Circuit Opening Relay has been checked for correct operation both coils and both sets of contacts .
On the Check Connector jump B+ and FP see if the engine runs.
This is Battery Positive and Fuel pump it bypasses all the relays the switch on the AFM
This has nothing to do with adjusting timing
No You can check the voltage at the plug that connects to the fuel pump on top of the tank
If I recall most 4Runners have Access through the floor under the back seat I could very well be wrong
It looks like the minute you release the key from start the fuel pump quits pressure drops
It is a older Runner who knows just what be worn allowing the pressure to drop even faster then normal
Best of Luck
Another question is... my fuel pressure was reading yesterday when I jumped, at 50psi but today when I jumped the terminal again, pressure gauge was reading 0.. I checked the regulator and all the fuel was coming straight from the return line from the regulator. I'm wondering that's because the engine was not running, creating 0 vacuum, which in turns doesn't close the diaphragm in the regulator, causing it stuck open? I hope you understand what I'm saying. Long story short, would I have to have the engine running to create vacuum for the regulator to operate properly to read proper pressure from the fuel rail?
Thank you very much.
09-25-2016, 01:32 AM
#6
Lets go back in time
I hope at some time this started and drove acceptable for the 3.0 ??
Then you started getting hard starts .Anything you might remember at this time.
CEL on at all ?? (check engine light)
When was the last time the engine had a tune up fuel filter ??
As to not compound the problem by lack of a simple tune up.
With this Ethanol gas rust is a major problem lifetime filters are clogging in a year
It is very important to be using the correct year information as things do change
Also it is important to keep your battery charged during all this trouble shooting
First when the engine is not running all the fuel does is just circulate pressure side to the FPR and back the return line
No Vacuum the fuel pressure regulator will not open if it is working like it should
Relays do fail it might be something as simple as that I just had A COR (circuit opening relay) that was getting water in till it just quit
The contacts in the AFM can wear or even break .
Might be physical damage to the wiring
This grounds on the left door post never hurts to check
The ECU main ground on the cam bearing cover bolt another good place to clean and tighten
I hope at some time this started and drove acceptable for the 3.0 ??
Then you started getting hard starts .Anything you might remember at this time.
CEL on at all ?? (check engine light)
When was the last time the engine had a tune up fuel filter ??
As to not compound the problem by lack of a simple tune up.
With this Ethanol gas rust is a major problem lifetime filters are clogging in a year
It is very important to be using the correct year information as things do change
Also it is important to keep your battery charged during all this trouble shooting
First when the engine is not running all the fuel does is just circulate pressure side to the FPR and back the return line
No Vacuum the fuel pressure regulator will not open if it is working like it should
Relays do fail it might be something as simple as that I just had A COR (circuit opening relay) that was getting water in till it just quit
The contacts in the AFM can wear or even break .
Might be physical damage to the wiring
This grounds on the left door post never hurts to check
The ECU main ground on the cam bearing cover bolt another good place to clean and tighten
09-25-2016, 05:49 AM
#7
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Well the fact is I bought this a few weeks ago. I have never been able to run it right so I got screwed with used car purchase. Let's not talk about how I screwed up.
The engine is supposed have only 70-80k miles because this guy who sold me swapped it.
Thinking that the engine would be fine, I bought it and here it is, 30psi in cyl#2. I'm wondering if cam timing off by a tooth have such big effect like that to cause one cylinder to have 30psi?
Is that possible?
The engine is supposed have only 70-80k miles because this guy who sold me swapped it.
Thinking that the engine would be fine, I bought it and here it is, 30psi in cyl#2. I'm wondering if cam timing off by a tooth have such big effect like that to cause one cylinder to have 30psi?
Is that possible?
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09-25-2016, 08:02 AM
#8
It happens one most often gets what you pay for
Cam timing would effect all the cylinders not just one .
So in essence you have a vehicle that really does not run.
The only thing you can do is start at the beginning air spark fuel
Being this is a 3.0 the first thing that comes to mind is head gasket or gaskets
then just over all neglect
Cam timing would effect all the cylinders not just one .
So in essence you have a vehicle that really does not run.
The only thing you can do is start at the beginning air spark fuel
Being this is a 3.0 the first thing that comes to mind is head gasket or gaskets
then just over all neglect
09-25-2016, 09:14 AM
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I understand..
Wouldn't piston ring or damage cause the car to smoke from the exhaust? I don't have that.. Do I still have hope that it's only cam timing that's causing the issue?
The car costed me 3500 and now I might either have to rebuild it or swap a rebuilt engine on it. I don't even know that's worth it. It's like 3000 loss for me either way. I dont' really know what to do at all.
Wouldn't piston ring or damage cause the car to smoke from the exhaust? I don't have that.. Do I still have hope that it's only cam timing that's causing the issue?
The car costed me 3500 and now I might either have to rebuild it or swap a rebuilt engine on it. I don't even know that's worth it. It's like 3000 loss for me either way. I dont' really know what to do at all.
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