Sluggish cold start, suspect fuel pump NEED ADVISE

[T4Rscott]

Hi all,

I have been experiencing a sluggish cold start in my 99 V6 SR5. I found an old thread that stated replacing the fuel pump helped. I am seriously considering this because A) I commute 150 miles round trip to work and B) the 4 Runner is just shy of 183K.

I have looked at the pumps online and was wondering do I need the pre-filter screen, and is one Denso pump better than the others listed for my truck?

If you have any other advise I should know, by all means share!

Thanks in advance,

Scott

 

[shootmymime]

Hi all,

I have been experiencing a sluggish cold start in my 99 V6 SR5. I found an old thread that stated replacing the fuel pump helped. I am seriously considering this because A) I commute 150 miles round trip to work and B) the 4 Runner is just shy of 183K.

I have looked at the pumps online and was wondering do I need the pre-filter screen, and is one Denso pump better than the others listed for my truck?

If you have any other advise I should know, by all means share!

Thanks in advance,

Scott

whats the temps there? is your batt getting old and slow causing your sluggish starts? have you tried turning the key to the on position for a few seconds to prime the pump and pressurize the fuel system before trying to crank the motor? does the vehicle cut out under heavy loads up hills?

 

[SilverRidgeRunner1]

Check your fuel pressure first thing in the morning with a fuel pressure tester. It the best thing to do. Once that checks out then move on to other things. What occurs does the engine turn over super slow first thing in the morning.

 

[T4Rscott]

Check your fuel pressure first thing in the morning with a fuel pressure tester. It the best thing to do. Once that checks out then move on to other things. What occurs does the engine turn over super slow first thing in the morning.

Once it fires, the RPMs drop for a second or two and then slowly climbs. The battery was replaced in October because of a bad plate. So far I have replaced the MAF with a know good one. Cleaned the IAC, replaced the plugs and wires, Witchhunter cleaned my injectors, cat is fine.

 

[T4Rscott]

whats the temps there? is your batt getting old and slow causing your sluggish starts? have you tried turning the key to the on position for a few seconds to prime the pump and pressurize the fuel system before trying to crank the motor? does the vehicle cut out under heavy loads up hills?

Vehicle does get numb once the tank is below a half and it does slow a bit on steeper inclines

 

[T4Rscott]

whats the temps there? is your batt getting old and slow causing your sluggish starts? have you tried turning the key to the on position for a few seconds to prime the pump and pressurize the fuel system before trying to crank the motor? does the vehicle cut out under heavy loads up hills?

Yes I have tried the priming trick, still the same. I do notice when the tank is between a half and a quarter, and I stop at red lights the RPMs drop and the idle isn't as steady. I have sprayed the vacuum lines and no change.

 

[gamefreakgc]

Yes I have tried the priming trick, still the same. I do notice when the tank is between a half and a quarter, and I stop at red lights the RPMs drop and the idle isn't as steady. I have sprayed the vacuum lines and no change.

Before you drop the tank a pay a lot for a new fuel pump (which rarely go bad btw) have you ever changed the fuel filter? If it's clogged it will mimic poor fuel delivery but have nothing to do with the pump. $30 and a little bit of time (and patience) and it's done.

 

[JRZEE2000TR4LTD]

Check your fuel pressure first thing in the morning with a fuel pressure tester. It the best thing to do. Once that checks out then move on to other things. What occurs does the engine turn over super slow first thing in the morning.

As far as I could tell, there's no way to use a fuel pressure tester, like the one in this picture, on our trucks as they don't have an access port. I believe there's some sort of SST that goes inline where the banjo fittings are, however I'm not 100% sure. Maybe someone else knows. I just didn't want the OP to waste $40 at AZ or PB for a tester that won't fit our trucks.

Edit: Here's the SST you need to test Fuel pressure.

 

[JRZEE2000TR4LTD]

Hi all,

I have been experiencing a sluggish cold start in my 99 V6 SR5. I found an old thread that stated replacing the fuel pump helped. I am seriously considering this because A) I commute 150 miles round trip to work and B) the 4 Runner is just shy of 183K.

I have looked at the pumps online and was wondering do I need the pre-filter screen, and is one Denso pump better than the others listed for my truck?
If you have any other advise I should know, by all means share!

Thanks in advance,

Scott

Oh another FYI. The fuel pump kit comes with a strainer. The part # is 950-0100. Here's one on Ebay. And yes go OEM. You don't want to do this repair twice.

Denso 950 0100 Electric Fuel Pump | eBay

 

[T4Rscott]

Before you drop the tank a pay a lot for a new fuel pump (which rarely go bad btw) have you ever changed the fuel filter? If it's clogged it will mimic poor fuel delivery but have nothing to do with the pump. $30 and a little bit of time (and patience) and it's done.

Yes I changed the fuel filter about a year and a half ago

 

[SilverRidgeRunner1]

Yea that's just a gauge that comes in a set I posted it up for a visual.

 

[xspsi6]

What brand if plugs? If anything other than ngk or denso twin grounded i would bet that to be your problem.

 

[lude and rude]

check plugs to make sure twin ground, NGK or Denso. have your battery tested at auto store (usually free). try pouring some seafoam or other cleaner in the tank. this is all cheap stuff to just see if anything changes.

our trucks DO NOT have cold start injectors so thats not the issue. a guy in this thread had a shop find the issue to be EFE (Early Fuel Evaporation) relay. but have no clue where that is. 4runner cold start issue - YotaTech Forums other than that you could try taking it in to a toyota shop and see if they can work some magic.

 

[xspsi6]

What brand if plugs? If anything other than ngk or denso twin grounded i would bet that to be your problem.