AJatx

No, I didn't pull the EFI fuse after the changes. I thought about doing it since the ECU may need to relearn the new settings.

The lean fuel trims happen around >1.8krpm and > 20% throttle.

I'll reset the ECU and clean the MAF/TPS today and see if the condition is progressing in the right direction.

midiwall

Yeah... let's start there and see if the ECU still pushes to the +19 mark. If the ECU has been "up there" for a while, and something changes elsewhere, it can take a while for it to catch up.

(though the short term number should track quickly... hmm)

AJatx

Reseting the ECU definitely improved things.

I still have the low idle, which I think cleaning the throttle body/IAC valve should help.
Tip-in around 1.8krpm has a slight hesitation.
I have pretty good acceleration up to around 3.5psi, then it runs flat. Unfortunately, I didn't have the OBDII scan tool with me.

On a side note, I took an estimation on power output at 10psi (350bhp), BSFC of 0.6, and 45psi fuel pressure. At 80% duty cycle, I would need to run 42lb/hr injectors to support that power. Are my assumption completely off base?
Just curious since I have 318cc injectors and I thought Brian from URD said it should support the smaller pulley (10psi).

midiwall

Kick Arse!


[quote]I still have the low idle, which I think cleaning the throttle body/IAC valve should help.
Tip-in around 1.8krpm has a slight hesitation.[/quick]Have you ever ran SeaFoam through it? I'd bet it help that stuff...


Hmm... I'd bet on timing or fuel. (kindofa "duh")


Oh man... I'm running 305's and while I have room up top at WOT, I dunno that I'd be running anything smaller than the 2.2" I have now. I don't have THAT much room.

I got schooled on injector sizes in the midst of this thread:

https://www.yotatech.com/forums/show...835&post892835

There's a calculator here which I've been using:

http://www.rceng.com/technical.htm
Filling in your example numbers nets an injector size of 452cc/min. But, with the Walbro, the fuel pressure is around 65psi, so you're looking at 376cc/min.

I'm ready to push about 390bhp, which asks for 420cc injectors, but they won't idle, so I'll be running 375's at 90%.

AJatx

If I do any major updates to the maps on the FTC, I pull the EFI fuse from both engine compartment and under the dash.

I still have issues with WOT. I also noticed that when I floor the accelerator, my throttle percentage never go above 36% or so. Then again, I don't floor it that long and perhaps the BR diagnostics doesn't refresh the throttle percentage in time for me to catch it on the playback.

For TPS, I have not cleaned it yet... The truck is cooling off right now from my return drive from work. I have the parts cleaner ready.
I did calibrate my TPS using the shop manual method of taking impedance measurements at closed and WOT positions.

As for Seafoam, I researched the forum and I could not read the old BIG thread on it. Is it too old? I believe Mark reposted it in one thread, but I got an error claiming the thread doesn't exist. Anyhow, I tried it by pouring approximately 1/2 pint in the PVC location into the crankcase. I poured about 3 fl oz into the gas tank since I had about 4 gallons of gas. The truck was definitely warm when I poured in the Seafoam, a couple fl oz at a time. I shut off the truck for 10 minutes and start it back up.
No noticeable smoking after the start up, on lunch break, and after work.
Maybe my engine is already pretty clean from the times when I worked on it, but I never pulled the head, just intake manifold and injectors.

Getting an oil change soon just to make sure I get the old oil and stuff out. I'm due for an oil change anyhow.
Anybody use the Fumoto oil drain valve? My coworker recommends it, but I'm skeptical on the "idiot" proofing of the lock mechanism, especially if I do a little wheeling every now and then.
I definitely wouldn't use it on my track car since I want everything to be "gut n tite."

Back to the original issues....
I'll clean out the TB, TPS, MAF, and IAC valve tonight. I bet it'll help my low idle.
Not sure on the stumble. I guess the best way to describe this stumble is imagining a friend who has smoker's cough. A little cough every now and then, but subtle.

With my current map, 1st and 2nd are a little sluggish at 30% throttle and 3psi as if it was rich. When hitting 3rd (or D), it really picks up. No use in spanking the throttle on Overdrive since I'll be past the speed limit around my area.

Anybody try using different A/F sensors for the pre-cat sensor? I know Honda has wideband A/F sensors (5-wire) that run around $150 or so. I may have the part number laying around in my mess of parts.

AJatx

So good and bad news after cleaning out the TB, IAC, TPS, and MAF today.

Good news, first:
-WOT feels great now. I was only able to test around 2krpm, but it doesn't feel flat.
-Idle is more consistent at around 800rpm.
-Idle sounds a little more quiet.
-Throttle response seems a bit better.

Bad news:
-Erratic idle still present. It's a small stumble of 100rpms or less that is always present at a frequency about every 4 seconds once up to operating temperatures.
When warming up, it's very subtle, but still present. The frequency of this stumble is not dependent on rpm. I'm starting to suspect the fuel filter even though it has been replaced about 13kmiles ago. The injectors are new as well as the fuel pump and pick up.

So far, so good... now I need to get back on track with tuning.

AJatx

I didn't re-calibrate the TPS after cleaning.
At no throttle input (idle), I'm seeing as high as 11%.
At full throttle input (WOT), I'm seeing around 75%.

Does that correlate with your settings in the BR tool?

Also curious if you have some map A values for +6psi in the ballpark of 15.

midiwall

Yeup, sounds about right.


Not I... I don't run the FTC.

AJatx

Where do you install the wideband O2 sensor?
Do you drill out a hole in the cross pipe and weld a bung in place?

I read in another thread about the thickness and double layer of the exhaust manifold makes it difficult to use a bung.

midiwall

It needs to be in front of the first cat, and after the Y pipe that merges the left/right manifolds. That usually doesn't give you a lot of options...

Just_Me69

hey guys, his TPS maxes out at 75%. The ECM doesn't recognize WOT until 80%. If he is having high RPM lean out, it is because the computer isn't going into open loop when he smashes on the gas. Have you tried another known good TPS yet?

midiwall

Page DI-37 of the 3rd gen FSM disagrees with you...

AJatx

A couple of questions:
1) Can you use the BR tool to diagnose the wideband O2 sensor for 99+ Runners? There is an O2 sensor #2 voltage monitor and I'm assuming it's for the wideband sensor.

2) When I'm WOT, the truck appears to be hitting a wall in acceleration in the range of 2.5krpm to 3krpm until Drive or Overdrive is engaged, then the truck flies through the rpms. At first, I thought it was lean and I added fuel. Any suggestions to check for transmission control? I've only tuned with manual transmission cars. I know there are maps for the transmission in the ECU. Just wondering if some of the FTC settings can be optimized for all gears in the rpm range.

jeremys73

I have the exact same problem but with a completely stock engine. At WOT it acts like it's hitting a rev limiter or not getting enough fuel. Sometimes it's fine. It seems to be doing it after driving 15+ miles. Planning on changing fuel filter, cleaning MAF...

AJatx

Yeah, something is up with either a major vacuum leak or broken solenoid because i'm getting real lean readings now on idle and vacuum levels throughout 500rpm - 3krpm with my current map and Gadget's original map that came with the URD kit.

AJatx

Does the fuel map values have a linear relationship to the injector duty cycle (i.e. 10 = 40% so 20 = 80% at a particular rpm and load OR map values: 0 = 0% and 25.5 = 100%)?

Just curious since I see significant changes in fuel trim in closed loop mode when I barely change a value (i.e. delta of 0.1).

The reason for my question comes from my concern that I think I'm setting high duty cycles for 5-6psi even though my short term is showing lean in open loop mode and heavy throttle input (70% and datalog shows closed loop).

I've also noticed a little lag between datalog on the BR3 values compared to real-time (i.e. watching the tach and values on the portable side-by-side).