PROBLEM: hesitate on quick acceleration

[glenn_a]

Hello fellow Explorers....

Just need your opinion or expertise or maybe you had this issue and solved that problem....

When ever I accelerate quick (gas pedal to the floor) I get this hesitate and it clears up in few seconds soon it pick up speed or rpm, if I accelerate slow like a normal human being then its all good...

I previously changed my coil pack, spark plugs, high tension leads, 02 sensors, MAF sensor last year and 6month after I get this problem and don't know where to look first...

I have checked my vacuum leak and exhaust leaks which is all good but all I can think off is my 02 sensors again because it smells like running rich also ( would the 02 sensor make the car run rich..? ) no engine light on the dash nor faulty codes

please help if you have anything for me thanks!

 

[2000StreetRod]

O2 sensors ignored at WOT

When you floor the accelerator the PCM detects WOT and switches from closed loop (using O2 sensors) to open loop (using factory stored tables). I doubt that your O2 sensors are causing the hesitation. However, if your engine has been running rich for a while when the PCM is in closed loop the cats may be clogged which can cause hesitation.

I assume that you have the SOHC V6. Have you checked your fuel pressure? See Ford Explorer Ranger Fuel pressure test procedure You could have a weak pump or restricted flow causing the fuel pressure to drop (instead of increasing) when vacuum is low (WOT).

Your vehicle has the variable induction system (VIS) that changes intake runner length at 3,000 rpm. See Variable Induction System Sometimes the linkage to the vacuum motors comes loose so VIS doesn't work properly.

 

[glenn_a]

if your engine has been running rich for a while when the PCM is in closed loop the cats may be clogged which can cause hesitation.

I assume that you have the SOHC V6. Have you checked your fuel pressure? See Ford Explorer Ranger Fuel pressure test procedure You could have a weak pump or restricted flow causing the fuel pressure to drop (instead of increasing) when vacuum is low (WOT).

Your vehicle has the variable induction system (VIS) that changes intake runner length at 3,000 rpm. See Variable Induction System Sometimes the linkage to the vacuum motors comes loose so VIS doesn't work properly.

oh thank you!

yes I may check the fuel pressure and yes I will double check that VIS vacuum too.... thanks!

ill keep you up to date many thanks!

 

[glenn_a]

2000StreetRod yeah just goin through my previous thread just realized I had same problem before and we discussed this issue and found out it was my 02 sensors...

http://www.explorerforum.com/forums/showthread.php?t=398735&page=5

I may have to buy this and see if it will fix the issues. But yeah I will check the fuel pressure too just waiting for my pressure kit to arrive...

thanks heaps 2000StreetRod for all your help, Just noticed too that you always there to help...

by the way 2000StreetRod, just a quick question too what do you think about the SCT Performance tuner? is it worth to buy just to give an extra boost for performance?
if so which one would you recommend because I am guessing you are into performance and you may able to guide me which one is better and more options....

http://www.ebay.com.au/itm/111217723250?_trksid=p2055119.m1438.l2649&ssPageName=STRK%3AMEBIDX%3AIT

or

http://www.ebay.com.au/itm/230921162918?_trksid=p2055119.m1438.l2649&ssPageName=STRK%3AMEBIDX%3AIT

thanks again for your time my friend!

 

[2000StreetRod]

different symptoms

Your previous problem was the engine was running rich. Now your engine hesitates when the accelerator is floored.

I doubt that just changing the tune will make any significant (very noticeable) performance improvement. I'm not familiar with the X4 but 4PointSlow probably could help you. About three years ago I purchased an X3 from Henson Performance that included a custom tune for my 90 mm MAF sensor. Unlike the SF3, the X3 does not have any preloaded tunes. About a year ago I purchased the Advantage III software tuning package so now I do my own tunes. That way if I make a mechanical change to my engine I can change the tune to match. If you want noticeable performance improvement you have to make mechanical changes (higher flow heads, more aggressive camshaft, forced induction, etc.).

 

[glenn_a]

thanks 2000StreetRod.....

I end up replacing my 02 sensors because its seem leaking and showing black exhaust residue but that did not help the problem....

I finally got my Fuel pressure kit and did the procedures but yeah its showing very low pressure and yes maybe its time for me to change the fuel pump which Ive been planning for ages...

 

[glenn_a]

here's what it looks like on IDLE.... and even though I REV the engine to 3000rpm the needle did not move at all...

I noticed too soon I turned the ignition on it took time to get up the pressure....

 

[glenn_a]

 

[glenn_a]

I assume that you have the SOHC V6. Have you checked your fuel pressure? See Ford Explorer Ranger Fuel pressure test procedure You could have a weak pump or restricted flow causing the fuel pressure to drop (instead of increasing) when vacuum is low (WOT).

may I ask what is (WOT)...?

I checked all the vacuums and I think its time for the pump and see how it goes......

 

[Flash]

may I ask what is (WOT)...?

Wide Open Throttle

I checked all the vacuums and I think its time for the pump and see how it goes......

Not a good time to be buying from the States at the moment, our dollar has tanked.
Try Amazon, you can often get cheap delivery from them.

 

[glenn_a]

Wide Open Throttle



Not a good time to be buying from the States at the moment, our dollar has tanked.
Try Amazon, you can often get cheap delivery from them.

oh thanks!....

 

[Flash]

Carter P74178 Electric Fuel Pump
$84.94USD
Items: AUD 119.51
Shipping & handling: AUD 13.13
Total before tax: AUD 132.64
Estimated tax to be collected: AUD 0.00
Order total: AUD 132.64

Bosch 69131 Original Equipment Replacement Electric Fuel Pump $56.45 USD
Items: AUD 79.42
Shipping & handling: AUD 11.02
Total before tax: AUD 90.44
Estimated tax to be collected: AUD 0.00
Order total: AUD 90.44

This one is a Walbro, good stuff and free delivery.
The only other one that comes close for price on Ebay is an Airtex, only recommended for throwing at kids on your lawn.

 

[Flash]

oh thanks!....

I did your shopping for you, there's one in Brisbane free delivery.

 

[glenn_a]

I did your shopping for you, there's one in Brisbane free delivery.

lol.. thanks heaps

Flash! just noticed your in Brizzy... are you in Ford Explorer Australia in Facebook too...?

 

[Flash]

are you in Ford Explorer Australia in Facebook too...?

No. I haven't seen it.

 

[glenn_a]

finally got the fuel pump.....


[AEROMOTIVE 340 STEALTH FUEL PUMP ELEC EFI IN-TANK 340LPH @ 90 PSI ARO 11142]

 

[2000StreetRod]

fuel pump overkill

That's the same pump I installed prior to my supercharger installation. It has way more flow capacity than I could ever use even if I had 20 psi of boost instead of 6 psi. The majority of the pumped fuel will be returned to the fuel tank. It draws considerably more current than the stock pump but did not blow my fuel pump power fuse in the month or so I drove my Sport before adding a an electronic fuel pump controller.

 

[Flash]

finally got the fuel pump.....


[AEROMOTIVE 340 STEALTH FUEL PUMP ELEC EFI IN-TANK 340LPH @ 90 PSI ARO 11142]

No doubt it's a good one; Why did you go for this one rather than the Bosch OEM or the Walbro?

 

[glenn_a]

That's the same pump I installed prior to my supercharger installation. It has way more flow capacity than I could ever use even if I had 20 psi of boost instead of 6 psi. The majority of the pumped fuel will be returned to the fuel tank. It draws considerably more current than the stock pump but did not blow my fuel pump power fuse in the month or so I drove my Sport before adding a an electronic fuel pump controller.

I was thinking the same but I have built this engine stage 3 and thinking this pressure may help a little for performance...

see how we go and Ill let you know the verdict

 

[glenn_a]

No doubt it's a good one; Why did you go for this one rather than the Bosch OEM or the Walbro?

yeah I was planning to go with a bosch high flow pump but where I get all my engine parts recommended me this for my application...
As I built the engine above standards, I fitted a custom over sized piston .40thou and port polished heads and fitted just slightly bigger valves plus balanced crank shaft and stage3 tuned cams...

let u know and see if it made any difference lol...