1989 5.0 Will not go in to closed loop, bogs when accelerated, no codes

[Dadpool]

Nice work!
Sounds like you are well on your way
Cheers

We got it back to the mechanics and now they are saying it is going in to closed loop from monitoring the O2 Sensor, but that it is now running too lean! Ugh! They are pointing at the injectors, but have tapped out. They can't find ones that they can say will without a shadow of a doubt, will work. We brought it home and I did some research and ordered in 8 Standard motor FJ712 after seeing it listed on multiple sites for a proper fit and flow rate. It will start and idle smooth as can be, and if you barely touch the gas pedal it will go, but as soon as you try to accelerate it feels like, well for a lack of better terms, something is holding it back, worse than before. Other than setting the timing back to 10 degs they didn't do anything else other than check to make sure it is going in to closed loop. I tried to set the timing back with the vacuum gauge and it would barely idle. TPS, MAP and IAC have all been re-replaced. The IAC did help, but not much. My son drove it last night after replacing and clearing memory and he said it ran great, until he shut it off at the gas station to put fuel in it, then on the way home it was back to poo. Maybe it's time to try that other distributor... IDK. There are no KOEO codes and the only code I got with a KOER was a Knock sensor, which it does have and I haven't changed it, but from what I found that shouldn't cause this kind of issue. There are 0 vacuum leaks, I bypassed the EGR with no improvement, and fuel pressure is steady and not losing pressure after 30+ minutes of being off. Any other ideas are appreciated.

 

[Tiha]

Kind of starting to wonder if the PCM is bad. Also having the timing off, or ******** because of the knock sensor I sure think could do that.

 

[Dadpool]

Kind of starting to wonder if the PCM is bad. Also having the timing off, or ******** because of the knock sensor I sure think could do that.

PCM had been replaced 3 times by the mechanics that had it, and it never solved the running rich issue, but I do understand that doesn't mean it's not causing this issue.
For the Knock sensor, looks like Amazon, Ebay are the options for replacements since no local parts store even has a listing for it. What would happen if it was unplugged for testing purposes only to see if that helped?

 

[L\Bronco]

PCM had been replaced 3 times by the mechanics that had it, and it never solved the running rich issue, but I do understand that doesn't mean it's not causing this issue.
For the Knock sensor, looks like Amazon, Ebay are the options for replacements since no local parts store even has a listing for it. What would happen if it was unplugged for testing purposes only to see if that helped?

Hey Dadpool, (sorry for the silence, been focussed on my mustang project)
Im struggling with the “mechanics” assessment.
If you did a koer test and the only code you have is the 25 for the knock sensor. Then is not running lean. (One of the koer tests is O2 resonse. Push it rich, pull it lean and check that the O2 sensor reading follows.)
Unless its lean during the bogging/ lack of power.
You verified fuel pressure, but, did you measure while the symptom was happening?
Tape the fuel press gauge to the windshield and watch it while it is accelerating with no power.
If you got a 25 for the knock sensor KOER, but no KOEO knock sensor code, then the sensor is probably ok.
The koer code just means it didn't ping during the “dynamic response” portion of the Koer test. (When the code 10 happens, you are supposed to goose the theottle briefly to WOT and off. It should ping as the timing is pegged at max advance.)
I dont feel the knock sensor is an issue

 

[Dadpool]

Hey Dadpool, (sorry for the silence, been focussed on my mustang project)
Im struggling with the “mechanics” assessment.
If you did a koer test and the only code you have is the 25 for the knock sensor. Then is not running lean. (One of the koer tests is O2 resonse. Push it rich, pull it lean and check that the O2 sensor reading follows.)
Unless its lean during the bogging/ lack of power.
You verified fuel pressure, but, did you measure while the symptom was happening?
Tape the fuel press gauge to the windshield and watch it while it is accelerating with no power.
If you got a 25 for the knock sensor KOER, but no KOEO knock sensor code, then the sensor is probably ok.
The koer code just means it didn't ping during the “dynamic response” portion of the Koer test. (When the code 10 happens, you are supposed to goose the theottle briefly to WOT and off. It should ping as the timing is pegged at max advance.)
I dont feel the knock sensor is an issue

No worries on the delay. I understand. I have been working on my 79 Cherokee getting it ready for a camping and wheeling trip. My son was hoping to take his Bronco, but it doesn't look like it's going to be up to par by Fathers day weekend.
Testing the fuel pressure while the symptom is happening, it does not change at all. It's at 30 at an idle and 30 when driving and it bogging down.
Also, pulling the vacuum line to the FPR while at idle makes the pressure jump up to 40.

 

[L\Bronco]

No worries on the delay. I understand. I have been working on my 79 Cherokee getting it ready for a camping and wheeling trip. My son was hoping to take his Bronco, but it doesn't look like it's going to be up to par by Fathers day weekend.
Testing the fuel pressure while the symptom is happening, it does not change at all. It's at 30 at an idle and 30 when driving and it bogging down.
Also, pulling the vacuum line to the FPR while at idle makes the pressure jump up to 40.

Ok cool, fuel press is right on point!
Did you say it was normal for your son after a reset then back to no power after a reset?
And does WOT act any different than heavy accell?(say…3/4 throttle)
Sorry for all the questions, its acting weird so I want as much data as I can get before any more suggestions.
Cheers

 

[Dadpool]

Ok cool, fuel press is right on point!
Did you say it was normal for your son after a reset then back to no power after a reset?
And does WOT act any different than heavy accell?(say…3/4 throttle)
Sorry for all the questions, its acting weird so I want as much data as I can get before any more suggestions.
Cheers

For grins and giggles, we warrantied the IAC, Cleared codes and then he said it was good up until he shut it off.
WOT It struggles to get up to speed, still bogging down. I'll mention that I did get a NAPA TPS sensor today and put it on to verify that I had a good part. No change.
I did a smoke test for grins, probably not the best type, but I put smoke in the break booster line with the intake ports blocked off and I am seeing smoke come out of the TPS sensor area. Could this be causing un-metered air to get in and cause the issue?

 

[L\Bronco]

For grins and giggles, we warrantied the IAC, Cleared codes and then he said it was good up until he shut it off.
WOT It struggles to get up to speed, still bogging down. I'll mention that I did get a NAPA TPS sensor today and put it on to verify that I had a good part. No change.
I did a smoke test for grins, probably not the best type, but I put smoke in the break booster line with the intake ports blocked off and I am seeing smoke come out of the TPS sensor area. Could this be causing un-metered air to get in and cause the issue?

Unlikely, leakage around the throttle shaft is unavoidable.
Your issue is not likely a vacuum leak.
At WOT pressure in the manifold equals atmospheric pressure, so leaks have little to no effect.
Yours is improperly measured air or improperly metered fuel.
A start would be, check the vacuum line to the map sensor, Sometimes they delaminate internally and delay the change in vacuum data so the truck goes lean intermittently and usually on hard accell.
For fuel, the only concern would be injector flowrate. (You have certainly verified pump volume and pressure)
Based on your symptoms, I wouldnt start there as it would act up consistently.
Another option could be that its not the engine at all. If the one way clutch on the stator in the torque converter seizes it will feel like the brakes are coming on the faster you try to go.
If that oneway freewheels, it will be an absolute dog off the line, but will start to normalize approaching hwy speed and up.
Lots to consider.
Hope that helps
Cheers!