New 1988 R30 Classic Custom owner, need help

[SirRobyn0]

I've replaced everything (fuel filter, pump ) and those sensors. Same issue. Even after disconnecting and reconnecting battery.
Sprayed all of under the hood with starter fluid to search for vacuum leaks, didn't find any. I'm checking fuel pressure next "just because".

Running a lean condition, definite power issues/won't get above 35 at best.

Any forums you suggest I take this to for expert advice, or is this the place?

I would say this is the place. If you want more input from more of the members you might want to post your problem in engine performance or ask an admin to move this thread.

 

[gotyourgoat]

I've replaced everything (fuel filter, pump ) and those sensors. Same issue. Even after disconnecting and reconnecting battery.
Sprayed all of under the hood with starter fluid to search for vacuum leaks, didn't find any. I'm checking fuel pressure next "just because".

Running a lean condition, definite power issues/won't get above 35 at best.

Any forums you suggest I take this to for expert advice, or is this the place?

First off welcome and calm down. The weekend is actually some of the slower less trafficked times on here. Don't freak out, we'll help you get back on the road.

I'll bet you code is related to not having an o2 sensor. Guessing those headers don't have a bung for an o2 sensor. There should be at least one.

Need more info. Won't go over 35 because it won't shift or? What's it sound like? What else is it doing?

 

[SirRobyn0]

First off welcome and calm down. The weekend is actually some of the slower less trafficked times on here. Don't freak out, we'll help you get back on the road.

I'll bet you code is related to not having an o2 sensor. Guessing those headers don't have a bung for an o2 sensor. There should be at least one.

Need more info. Won't go over 35 because it won't shift or? What's it sound like? What else is it doing?

He's got a good point about the O2 sensor. Of course a bad O2 sensor could be the problem as well. I'll also add that a bad O2 sensor alone shouldn't cause the drivablity problem your having. Additionally the computer ignores the O2 sensor during the warm up period which is called open loop mode. If and I know you don't but if you had access to a hand held scanner for the system you could monitor it and see if symptoms are occurring in open or closed loop. That could be a clue as well. Maybe you should do a video of the engine when it's acting up. Seeing and hearing it act up could help us point you in the right direct as well.

 

[af77]

First off welcome and calm down. The weekend is actually some of the slower less trafficked times on here. Don't freak out, we'll help you get back on the road.

I'll bet you code is related to not having an o2 sensor. Guessing those headers don't have a bung for an o2 sensor. There should be at least one.

Need more info. Won't go over 35 because it won't shift or? What's it sound like? What else is it doing?

It won't go over 35 because it (seems) it can't get enough "power". I can punch the gas and it won't take off, it'll big or slowly get up to about 25mph. Top speed is around thirty. It's like it's not getting enough gas. But then sometimes it backfires so it could be an air/fuel ratio thing.
The one thing we know is it's reporting a lean exhaust condition.

I hate sensors; I got an old truck thinking they wouldn't be part of the problem. I'm learning it isn't quite old enough.

 

[Big Chip]

Did you check to see if you're getting good spray from the injectors? I think with those you should be able to look down the throttle body and just confirm everything is good there.

 

[af77]

He's got a good point about the O2 sensor. Of course a bad O2 sensor could be the problem as well. I'll also add that a bad O2 sensor alone shouldn't cause the drivablity problem your having. Additionally the computer ignores the O2 sensor during the warm up period which is called open loop mode. If and I know you don't but if you had access to a hand held scanner for the system you could monitor it and see if symptoms are occurring in open or closed loop. That could be a clue as well. Maybe you should do a video of the engine when it's acting up. Seeing and hearing it act up could help us point you in the right direct as well.

So that's part of the problem; after I start it and give it some gas it idles pretty well. It only has the problem when driving it above 15mph. It's really just like it's not getting enough gas/air.
However, if I leave it in park I can rev all the way and down and it's smooth (with Maybe a backfire or two at most as it settles).

 

[Big Chip]

What transmission do you have?

 

[af77]

When doing a fuel pressure test , the T connector goes after the fuel filter right? Any clever way of connecting the T connector up without spraying gas all over the place?

By the way, my target psi should be 13+ psi for the fuel pressure right? Should that be at idle, with gas pedal punched, or both?

 

[af77]

What transmission do you have?

Automatic. I have no idea beyond that. Need pictures or more details?

 

[Big Chip]

Automatic. I have no idea beyond that. Need pictures or more details?

It wouldn't hurt.

 

[af77]

Did you check to see if you're getting good spray from the injectors? I think with those you should be able to look down the throttle body and just confirm everything is good there.

I did with it shuttle still manually actuating the throttle, yes. Both were spraying. I'd be happy to rebuild that TBI with the rebuilt kit, but that all seems good honestly.

Haven't checked it while driving it, obviously. That's why I'm doing the fuel pressure test next. Just need those last questions about it answered above: never done one before.

 

[gotyourgoat]

Needs to be 86 or older to not have sensors, the tbi in 87 brought them into the mix.
Not having o2 sensors shouldn't be the cause of the current issue. Worse fuel mileage but not this.


Revs good while being in park but doesn't drive right in gear. 350t with a bad vac modulator?

Snap a pic of the underside of the trans so we can identify it. Here’s an id chart

You must be registered for see images attach

 

[SirRobyn0]

So that's part of the problem; after I start it and give it some gas it idles pretty well. It only has the problem when driving it above 15mph. It's really just like it's not getting enough gas/air.
However, if I leave it in park I can rev all the way and down and it's smooth (with Maybe a backfire or two at most as it settles).

T-ing in after the fuel filter is just fine for the test. Yes you will probably have some gas leakage when your hooking up and disconnecting but it shouldn't leak while you are actually running the test.

Again a bit of video of it acting up could help us. Even if it is just from the drivers seat as it act up. At least that would give us somewhat of an in person feel for what it is like.

 

[af77]

Needs to be 86 or older to not have sensors, the tbi in 87 brought them into the mix.
Not having o2 sensors shouldn't be the cause of the current issue. Worse fuel mileage but not this.


Revs good while being in park but doesn't drive right in gear. 350t with a bad vac modulator?

Snap a pic of the underside of the trans so we can identify it. Here’s an id chart

You must be registered for see images attach

Here is a video of everything under the truck. The exhaust and the transmission.

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Transmission is:

TH400/3L80
The thirteen bolt one.

You must be registered for see images attach

 

[af77]

SirRobyn,
Per your request I made a video of me starting it, driving it, and even under the hood. I have commentary throughout.

Thanks for all the help.

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Edit:
Is this what you guys are telling me the issue is? Replace this?

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