STILL having issues....

[rusty ol ranger]

Loseing my shit over here...

New intank pump and tank. Thought i had the issue beat this time. After about 15 miles right back to the same shit. Motor changes tune, loses power, pops when you let off the throttle...

Overall it runs great untill it takes to these fits. 60-65mph all day and power for days off the line.

I shut it off for 10 minutes, fire it up, itll run good for another 5 or 10 miles.

It acts like its running out of fuel. Has no power, motor kinda "hums" and it breaks up at higher RPMs.

Im getting a code 41, lean O2. Which i was NOT getting with the old O2, but i changed it trying to cure this issue. I unplugged the O2, (which i tried before to no avail, but now that the rear pump is working...) but this time it seemed to help.

I could hear the motor still doing the same thing, but to a lesser extent and only at higher RPMs....It also seemed to idle better for some friggin reason...

Any ideas???

Could it be a damn ignition issue?? Its seeming more and more that way. But i dont know anymore.

Can an FPR fail lean?

 

[PetroleumJunkie412]

Loseing my shit over here...

New intank pump and tank. Thought i had the issue beat this time. After about 15 miles right back to the same shit. Motor changes tune, loses power, pops when you let off the throttle...

Overall it runs great untill it takes to these fits. 60-65mph all day and power for days off the line.

I shut it off for 10 minutes, fire it up, itll run good for another 5 or 10 miles.

It acts like its running out of fuel. Has no power, motor kinda "hums" and it breaks up at higher RPMs.

Im getting a code 41, lean O2. Which i was NOT getting with the old O2, but i changed it trying to cure this issue. I unplugged the O2, (which i tried before to no avail, but now that the rear pump is working...) but this time it seemed to help.

I could hear the motor still doing the same thing, but to a lesser extent and only at higher RPMs....It also seemed to idle better for some friggin reason...

Any ideas???

Could it be a damn ignition issue?? Its seeming more and more that way. But i dont know anymore.

Can an FPR fail lean?

My thoughts are tfi, O2, or ECM.

My factory ECM started doing this crap to me before I ditched it. Haven't had issues since.

Other thing that comes to mind is crap blocking the fuel lines, or a few plugged injector baskets.

 

[RonD]

Computer code "lean" means injectors are having to be opened 15%-20% longer than computer calculated
Computer bases it calculations on having 30psi fuel pressure, so yes if FPR was going bad and only holding 15psi pressure then you would get Lean code.

 

[rusty ol ranger]

My thoughts are tfi, O2, or ECM.

My factory ECM started doing this crap to me before I ditched it. Haven't had issues since.

Other thing that comes to mind is crap blocking the fuel lines, or a few plugged injector baskets.

TFI is new. Distributor is not new but a known good one. O2 is new. Was going to replace the ECM but guy at o reiley sold me one for an auto trans. So i said f it because i found out it was an EGR issue (this was the first round of issues i was having.

I doubt its the fuel lines as when i changed the filter it was clean and i was able to suck fuel through them by mouth.

Injectors possibly? I mean it idles kinda rough, but rusty #1 always did to. But id think injectors would act up constantly. This thing only acts up after a bit of highway cruising. I can bang it around town all day and nevee have an issue.

Computer code "lean" means injectors are having to be opened 15%-20% longer than computer calculated
Computer bases it calculations on having 30psi fuel pressure, so yes if FPR was going bad and only holding 15psi pressure then you would get Lean code.

I know you said before that when it shows lean that means that the ECM will try to compensate by dumping fuel. So the fact im getting a lean code, AND lean symptoms tells me that something in the fuel system is not putting out the proper volume. Correct? Even with the O2 unpluged, which i read should throw it into "drown myself" mode, its still acting lean...

I know in THEORY the FPR could cause this, but has it ever happend? In my close to 20 years on this board ive only seen the old "fuel in the vacuum hose/rich" FPR failure.

 

[Dirtman]

Id be looking at the chinese fuel pump you installed. They are DOA more than half the time.

 

[fastpakr]

Agreed. You really need a fuel pressure gauge to see what's happening rather than guessing.

 

[rusty ol ranger]

I got one.
Iv checked it over and over and its been in spec...

BUT...

I can never check it when it starts acting up. Thats the issue aa far as fuel pressure goes.

 

[fastpakr]

No way to rig up the pressure tester to be visible as you drive?

 

[rusty ol ranger]

No, the tester Hose has to be straight up and down to work properly. Its a cheap ass harbor freight pos.

But something interesting today, i talked to my mechanic, hes thinking its an ignition issue of some sort even with the code 41.

I thought horseshit so i took it for a drive, got it to act up, for shits i pulled the SPOUT connector out while it was running. No difference in idle or how it ran. Plugged it back in, same thing.

Now, after the engine cools for 10 min or so, it does make a (slight) difference.

I was reading online of other guys with this issue and it was the ECM. If it was the PIP or TFI then it would quit or not run at all period.

Thoughts?

 

[fastpakr]

Didn't you swap the ECM previously with the one from Rusty 1?

 

[rusty ol ranger]

I did.

However, rusty #1s ECM turned out to be junk to. Years ago before the interwebs the fuel pumps quit. I wired them directly into the key switch.

When i plugged rustys #1s ECM into Rusty #2 the fuel pumps wouldnt run. Pulled codes and got a (cant remember the number) but something pertaining to a failed fuel pump circuit.

So no, rusty #2 still has the original ECM.

At this point every single thing in the ignition system is new or known good. As are all the stupid little sensors (ECT. IAT, MAP, etc).The only things left in the fuel system are the injectors and regulator.

Besides some sort of huge mechanical issue the ECM is really about all thats left. I, as well as my mechanic has gone over the wireing, really it looks pretty good yet. I swapped EEC relay today, no change.

The ONLY thing thats made a slight difference is unplugging that O2 sensor, and all it did was make the problem less pronounced. But its still there.

 

[PetroleumJunkie412]

If only they made a way to relocate that tfi module and get it off the back of that distributor...

 

[rusty ol ranger]

If only they made a way to relocate that tfi module and get it off the back of that distributor...

You think thats whats goin on? Its a brand new TFI..

 

[RonD]

The 1991 to 1994 3.0l use remote mounted TFIs, usually on the rad support

The SPOUT is the "vacuum advance" for the spark timing, which is why you need to unplug it to set base timing, same as you would unplug Vacuum hose on distributor to set base timing.

The distributor has weights and springs inside for RPM advance, same as all distributors, but even with electronic points you need a way to change spark timing based on engine LOAD not just RPMs
Thats what Vacuum advance did, vacuum in the intake changes with engine LOAD.
Computer sees throttle position(TPS) AND RPMs so it can calculate LOAD, it then sends spark advance or retard data to TFI on the SPOUT wire
Engine should run OK with SPOUT unplugged, maybe lower idle
And it can be driven but would seem sluggish on acceleration because you are only running on RPM spark advance, no "vacuum advance"


Lean for O2 and computer is high oxygen in exhaust, so computer adds more fuel to burn it up
Misfires means no oxygen was burned in that cylinder, so it gets dumped into the exhaust.........computer, thinks "lean"

Actual Lean condition will always cause pinging/knocking in an engine

 

[rusty ol ranger]

The 1991 to 1994 3.0l use remote mounted TFIs, usually on the rad support

The SPOUT is the "vacuum advance" for the spark timing, which is why you need to unplug it to set base timing, same as you would unplug Vacuum hose on distributor to set base timing.

The distributor has weights and springs inside for RPM advance, same as all distributors, but even with electronic points you need a way to change spark timing based on engine LOAD not just RPMs
Thats what Vacuum advance did, vacuum in the intake changes with engine LOAD.
Computer sees throttle position(TPS) AND RPMs so it can calculate LOAD, it then sends spark advance or ****** data to TFI on the SPOUT wire
Engine should run OK with SPOUT unplugged, maybe lower idle
And it can be driven but would seem sluggish on acceleration because you are only running on RPM spark advance, no "vacuum advance"


Lean for O2 and computer is high oxygen in exhaust, so computer adds more fuel to burn it up
Misfires means no oxygen was burned in that cylinder, so it gets dumped into the exhaust.........computer, thinks "lean"

Actual Lean condition will always cause pinging/knocking in an engine

Thats the thing though. I notice NO difference in performance/idle with the spout unplugged. Which is why im thinking its distributor/ecm related. It does feel real sluggish once these issues take hold.

Im gonna spend tomorrow with a DVOM doing my best, once again, to try and diagnose the damn thing. Im doin my best but this is so far above my knowledge spectrum it aint funny.