Hello All, Been lurking a while and can't seem to find a suitable solution to my latest issue by way of search, so here goes.... Forgive me for being long winded....
The vital stats of my truck are:
'01 Tacoma Ext Cab TRD 4x4 3.4L Manual
TRD S/C, URD 7th Injector, 2.2" pulley
Doug Thorley Headers/ Exhaust
De-Cat, URD O2 Sim
NGK AFX wideband O2
160,000......
I installed the TRD S/C about a year ago and, aside from running the truck with no fuel upgrades and the low rpm ping issue, had a good running truck...
My problem begins at the process of attempting to eliminate the low rpm/ high load ping issue. I ordered the URD 7th injector kit, Headers, Exhaust, and 2.2" Pulley this fall and installed the components as I had time, as the truck is driven on a regular basis.
First I installed the higher volume Walbro pump and drove the truck for a few weeks with no new problems. I then installed the Headers and exhaust (de-cat was done way before all of this) to get the shiny parts out of the view of my wife.... No noticeable problems that evening, but the next morning with the engine not fully warm I got on the highway to head to work. As I accelerated in third gear to 3200 rpm or so, the truck essentially would not allow me to rev any higher. The truck warmed up and the problem seemed to disappear.
Over the next couple of weeks, the truck began to do it more often, more so when the truck was cold, more so in the higher gears....
I finished the 7th injector install and installed the 2.2" pulley because I figured this problem may go away with a final tune and more fuel. It did not.... at least the high load ping was easy enough to tune away!
With the truck fully warm, it does not seem to "bog" unless I am in 3rd, 4th, or 5th at WOT and right around 3200. You can get through the hesitation and by about 3700 and the truck seems to run strong from there until redline.
What it is doing is pulling a lot of timing out right there ( I have graphed it out with a scantool, I do not have a screen shot to reference now...)
The AFR's dip way low through this area (sometime in the 9's) as well, but I am told this would be consistent with retarded timing and inefficient burn... From 3800 to redline the AFR's climb into the mid 11's.
I have installed a new upstream O2, cleaned the MAF sensor, checked timing belt tension and timing, crank timing, greased the driveshaft, washed the truck, etc...
I have not checked the knock sensor signal or fuel pressure (with the engine running strong up top, I don't see it being a fuel problem).
Any ideas about where to go next? I was thinking about getting some timing plots snapshotted, and maybe a video of the occurence just for clarification.
The vital stats of my truck are:
'01 Tacoma Ext Cab TRD 4x4 3.4L Manual
TRD S/C, URD 7th Injector, 2.2" pulley
Doug Thorley Headers/ Exhaust
De-Cat, URD O2 Sim
NGK AFX wideband O2
160,000......
I installed the TRD S/C about a year ago and, aside from running the truck with no fuel upgrades and the low rpm ping issue, had a good running truck...
My problem begins at the process of attempting to eliminate the low rpm/ high load ping issue. I ordered the URD 7th injector kit, Headers, Exhaust, and 2.2" Pulley this fall and installed the components as I had time, as the truck is driven on a regular basis.
First I installed the higher volume Walbro pump and drove the truck for a few weeks with no new problems. I then installed the Headers and exhaust (de-cat was done way before all of this) to get the shiny parts out of the view of my wife.... No noticeable problems that evening, but the next morning with the engine not fully warm I got on the highway to head to work. As I accelerated in third gear to 3200 rpm or so, the truck essentially would not allow me to rev any higher. The truck warmed up and the problem seemed to disappear.
Over the next couple of weeks, the truck began to do it more often, more so when the truck was cold, more so in the higher gears....
I finished the 7th injector install and installed the 2.2" pulley because I figured this problem may go away with a final tune and more fuel. It did not.... at least the high load ping was easy enough to tune away!
With the truck fully warm, it does not seem to "bog" unless I am in 3rd, 4th, or 5th at WOT and right around 3200. You can get through the hesitation and by about 3700 and the truck seems to run strong from there until redline.
What it is doing is pulling a lot of timing out right there ( I have graphed it out with a scantool, I do not have a screen shot to reference now...)
The AFR's dip way low through this area (sometime in the 9's) as well, but I am told this would be consistent with retarded timing and inefficient burn... From 3800 to redline the AFR's climb into the mid 11's.
I have installed a new upstream O2, cleaned the MAF sensor, checked timing belt tension and timing, crank timing, greased the driveshaft, washed the truck, etc...
I have not checked the knock sensor signal or fuel pressure (with the engine running strong up top, I don't see it being a fuel problem).
Any ideas about where to go next? I was thinking about getting some timing plots snapshotted, and maybe a video of the occurence just for clarification.