It smells really really rich. Like stupid rich. Yeah, it's rich, don't don't do that. happenings he Hood Hello everybody, good evening to you and I say evening because it's a current point in time.

It is in fact my evening. The sun is getting long, the Shadows are starting to stretch and I uh I'm wrapping my head as much as possible around this situation right here. I'm doing my best to try to figure it out. We're going to do a little bit of a walk through.

you're going to see a few new parts on here and we're going to go through all that stuff and I'm gonna explain to you why I have not reached a point of a confirmed diagnosis. There is no confirmed kill going on with this just yet. It does run and here let me show you we'll just start the thing up. It will run.

It runs very, very badly. It runs very very rich and it won't stay running for long. You get a couple minutes out of it and then she dies All right now. I Pulled the spark plugs out already I Mentioned that earlier, found them extremely fuel fouled and we're about to die.

Found the plugs very very fuel valve I Found a bunch of corrosion underneath of the distributor cap I Cleaned everything off in there sandpaper to all of the the contact points I found what are you gonna do? You're gonna? Yeah. We're just gonna go ahead and shut this down. I Can't hear myself think or talk I Certainly can't heal, hear myself talking and think powering down. but you get the point.

runs like garbage. Okay, so while I was tinkering with this unit I pulled the idle air control solenoid off and the IAC had no seal in it so that IAC was just running wide open. The thing had broken the little rotating shaft that runs the seal up and down or the shaft that runs the seal up and down. That thing was seized in position I attempted to actuate it electronically with some jumper leads and it was just a dead shorted unit.

The thing was was no bueno. so I went ahead and ordered an idle air control. Uh, that helped but did not solve the problem. but now it at least uh, it runs for longer before it shuts down.

I connected my smoke machine which I believe I have it right right there. Yep, I took the smoke machine, locked off the intake and I plumbed the uh, the smoke into the throttle body right here at this little port. After that I located one port in the back that was not connected, there was another one I think one for the EGR that was not connected. so I had two more vacuum leaks there and there's also a vacuum leak right down here at the throttle position sensor.

Really tough to see. there's not much light. so I fixed a couple. found and fixed a couple vacuum leaks.

but again, that's not the problem, it is a problem with this engine. but it is not the problem with this engine point being. slowly but surely I'm starting to to kind of figure out and narrow down what the issue is well or what it isn't. Rather, now this pipe right here.

this thing goes to the air injection pump, which is an emissions device off of that air injection pump. There's supposed to be a crossover that goes over to that other side exhaust manifold and it's got a fitting on it just like the one that we're looking at right here on the manifold. See that where the uh, the Bolt's been welded into the manifold and same situation on the other side. There's supposed to be an air pipe going into that that's welded into the manifold.

That's not the problem I'm just letting you know what I found I found a couple other vacuum leaks uh at one of the ports right here. Apparently they had used like golf tees, you know, little wooden golf tees. They were using those to plug up vacuum lines and um, well, that wasn't going to work. So I actually put vacuum plugs on there I Parts cannoned I Parts Canon a fuel pressure regulator because of all the debris that I found in the fuel pump and all the debris that I found in the fuel filter.

So I figured, uh, there was a chance that some of that debris has made its way through the system I pulled off the regulator. It appeared to be okay, but uh, since this is a Parts Canon diag I figured I would just toss one of those in there while it was removed. So we've eliminated fuel system as the issue now. I have an ignition system at all times no matter what it does.

I have spark. Good spark at the coil and I've got spark at all of my spark plug wires. No arcing or anything like that. So I do not believe the the ignition system is the issue here which moves us on to fuel injectors.

It does not have eight bad fuel injectors. That's that's nearly a mathematical impossibility. and I'm not even going to entertain the idea that we need to put fuel injectors in it because it I mean it may have one or two bad injectors. but as for all of them being bad or having enough of them bad to cause the symptoms that we have, that's not going to happen.

And the reason that I say that is all of the plugs were fuel fouled. every single one of them like some of them even come out wet. So that moves us on to Fuel Control. Now this being a pre-obd2 vehicle, I don't have scan tool capability so what we need to do is retrieve codes manually through this connector here and what we do is we take a jumper pin and connect this unit right here to I believe it was.

is there that one or that one? um I knew which one it was when I did it now I tried to retrieve trouble codes from the ECM and I wasn't able to do that because when I set up the jumper this check engine light. actually, you know what? let me just do that. right now. let's let's fetch a paper clip.

Let's just jump it right now. I'll show you what I'm talking about powering down paper clip in hand. Uh, we can use a jumper wire, but paper clip's supposed to fish supply some fish. Paper clips will suffice.

So what we do is we jump these two connectors right here. Then we'll go into the cabin, key the thing on and it should flash to us the uh, the codes that are present. But let me show you what it does. See that self-check will not work, see how it tries to flash but it won't flash like there's a flash.

But this is not how it's supposed to be doing this. Oh, we're actually a little bit better off than it used to be. It was just doing this. uh, like that half faded right here.

It was just doing that the entire time. Well, anyway, so I proceeded to attempt to diagnose this without uh, without retrieving trouble codes. I Kind of disregarded that for the time being and it went on to try to diagnose this in a more analog fashion. which yeah, that's how we're doing this one.

Here's what we're gonna do if you recall from the first video, there was a time when this, uh, this relay. the fuel pump relay right here was buzzing I can't see I've heard a fuse box making a pumping noise. um I can feel it. It's this relay right here in that a bunches pop that thing out of there I know it's tough to see, there's bad lighting.

sorry yeah, we take the relay out and the noise stops I don't know what that's about and right now the buzz is back. which is good. You guys hear that? maybe if I zoom in, you can hear the sound of the buzz I turned off the fans. You hear that buzzing.

That buzzing is the coil in this relay going open circuit closed circuit open circuit closed circuit. So that buzzing is not. uh, or that relay is not making good connection. Now again, if you recall from the first video, I swapped around these relays thinking maybe it was just a bad relay.

Turns out, that's not the case. So in my frustration I got myself to pondering and I noticed something while attempting to troubleshoot I realized that was a problem. Maybe not the problem, but since I'm in business right now fixing some of the problems, eventually, I'm going to get to the problem. But watch this.

We keyed it off. We'll keep it back on. Okay, now with that relay up there buzzing, we will not get a restart. Watch this, see that it's not happening.

Let's try it again. Okay, let's go check our relay one more time and we're gonna hear that. that relay is buzzing back and forth. Hear it.

So here's what we're gonna do: I'm gonna shut this thing down, key it off, disconnect the battery that way Everything Powers down fully. We're going to come back, power it back on when we reach the state where that relay is no longer buzzing and the thing will immediately start. Okay, so let's go ahead and shut the power off. I'll be back in a minute.

When I think this thing is going to do its, uh, its reset. While I'm letting that thing cool down, let's run inside to the AC and I Want to review a couple things on this wiring diagram with you guys. Put that over here, huh? So what we're looking at here is the power and ground distribution for the engine management system. What we have right here: This, uh, this representation is the fuel pump relay.

That's the relay that is over there buzzing. We can see from this uh, this chart that that relay has a fuse 30 amp power supply it's going to run up and when this relay is closed, it sends that power supply down. This wire right here runs it over to the fuel cut off inertia switch. That's the one inside of the cabin at the kick panel on the passenger side.

That's where we tapped into the system in the first video to manually power the fuel pump and then drain all the bad gas out of the tank. This is where we should find our uh, our fuel cut off switch. it runs on over Powers the motor in the fuel pump and the fuel pump runs going back to the relay. Once this circuit is energized, that power also splits right here if this, uh, if this splice and it's going to run all the way over to our PCM However, that circuit the load Circuit of the relay is not the cause of that buzzing.

That buzzing is being caused by the actuation circuit represented right here which is going to be the red wire and the light blue was that light blue with an orange Tracer Okay, let's go ahead and back up that red wire and make sure that that is a power supply that runs over to our other page turns into a splice right here. Get some power at the PCM Power relay splices back over and ultimately again ends up at PCN. Okay, so that leaves this side of the circuit to cause that buzzing or it leaves the other side the ground side of that circuit to cause that buzzing. Because again, if we follow the light blue and the orange Tracer wire to our other graph, that's uh, was that number eight right there? I think that's eight you get T Now you can see we follow that one on over.

This circuit gets its ground directly from the PCM that right there and it's even labeled Fuel Pump. Okay, so when the PCM decides that it wants the fuel pump to turn on, it's going to ground this circuit which is going to ground this circuit because we already have power here that's fused power. It's going to ground that and that is going to close this circuit right here. Okay, so I believe that this circuit right here is the cause of the buzzing fuse box.

Now applying a little bit of logic to this: I Don't think that the issue the circuit fault is on the power side because I don't have any odd relay activity over here at the Uh the PCM power relay. So what I'm thinking is that the ground side from the PCM is not a good ground I think it's just going open, close open, close up and close. and that's the buzzing sound that we're hearing is that relay turning on and off and on and off quite rapidly? So what I think I want to do is I'm going to go ahead and we're gonna figure out which circuit I'm gonna go ahead and disconnect PCM and I want to test this circuit from was it pin 22 all the way over to our fuel pump relay. So we're going to check resistance on that circuit.

We're going to make sure it's uh, it can carry a load and we're going to make sure it's got good resistance and kind of go from there. but I think that there's an issue going on with this circuit. It's either going to be the wire or I even speculate that there's a grounding issue at this PCM right here. So let us run back up to the Chuck and check to see if that relay in there is still buzzing because I think that that buzzing is like The Smoking Gun in this situation.

Reason being is that if we start this thing or if we try to start this thing, it will not start. Oh, batteries disconnected. Okay, it it will not restart when that relay buzzing symptom is present, but it will restart when the buzzing is not present. So right now there's no relay buzzing.

Key it back on and do not hear the buzzing. but let's go back out and check. I Know we're walking around a lot and it's probably annoying now. We heard the fuel pump.

Come on, no buzzing at that relay. It's gonna restart. Watch this all right. Back out to the relay.

Got my hand on it. You can't hear it but I can feel it and it is not buzzing. Did you hear it start? As soon as it stalled, that buzzing symptom showed back up. So let's try to make the buzzing stop.

That's what I want to do again. This is silly analog stuff. but I've got to figure out how to troubleshoot this without. uh, without good info or in good backstory because basically I'm resurrecting a junkyard car All right meter here.

We're gonna need that later. Put that up there out of the way for now and I'm gonna go ahead and I'm gonna pull out this fuel pump relay because I want to check circuit relay gravity I want to check the circuit ah on the other side recovered and again, we swap relays here already. So I know that the relay is an up cause of the buzzing. so it's got to be the uh, the circuits that support it.

So we know that that relay gets connections over here at the PCM PCM is right back here by the brake booster. So I'm going to go in and unbolt this thing and uh, try to get some access to the pins and we'll see if we can't uh, resistance? check that ground wire. There you go. Oh no, it took my wobbly socket from here.

We're disconnected. I need to move some of this stuff out of the way. Let's see. Get rid of that.

We'll pull this connector out here so we can manipulate it some. There we go, All right. let's move over here so we can see what we're trying to see. Pull this little Shield thing back some I need to see the number plates that are on the back of this so I can identify the circuits.

It should be numbered like you know, 1 through 90 or something like that. Okay, so far so good. What I want to do before we do anything is I'm going to check all the grounds at the CCM since we're here. so everything that supplies any kind of ground to this unit, we're going to go ahead and check that with the meter first.

So again, grounding, grounding a test lead and then grounding my negative lead that way I don't have to hold it if I can hang out over there. Yes, the battery's disconnected and we're going to set the meter to resistance continuity and we're just going to check for these grounds. and I've already mapped them out earlier. We've got I think there's three or four of them 60s a ground and 40 is a ground 20s case ground I think that was all of them.

It's yeah, 60, 40, and 20.. So taking a look at our connector right here, let's try to really get some zooms on that. Maybe you can read it? Maybe not. How far do we go? Maybe you can't read it.

It's pretty far out there. We've got pin 41, 21 and 1. so it starts here, goes that way and counts up, Uh to 20.. So at the very end we have pin 20.

The second row is pin 40 and then the third row should be Pin 60. And according to our chart, those are the grounds. So let's probe those guys. this is 20.

that's grounded 0.4 Ohms. Oh, you can't see I'm too far zoomed sorry 1020 that's ground at 0.4 Ohms. Pin 40 Ground at Point Four Ohms and Pin 60. So the PCM is receiving Good Grounds from its wiring harness.

Now back to our our chart here. We are going to be looking for the ground circuit for the actuator on the fuel pump relay. That's the one that's making the buzzing. So we're a few.

Circuit Eight that's a light blue with an orange Tracer Okay, that runs over to our other sheet. Circuit number Eight: light blue with an orange Tracer Run straight to the PCM and that's it. Pin 22. Okay, so we're going to locate 22.

So this is one. This is 20. That means this is 21, confirmed by the 21. And right here we have a light blue with an orange Tracer That's Circuit 22.

This is the ground circuit for the fuel pump relay. All right. So what I'm going to do is we're gonna probe and these are round pins and no, I'm not hurting them with this. Uh, this.

Pro right here. I'm gonna go ahead and probe 22 to make contact with it and we're going to find the other end of that circuit down here in the fuse box and we're going to check resistance on that circuit I Believe, not that one, not that one. There we go. Found it.

So this is the circuit that the PCM uses to actuate fuel pump relay and that's hanging out at 0.4 ohms. So that's a good wire. Okay, I'm not going to load test it I'm assuming that's a good wire I probably shouldn't assume, but is what it is. So thinking about this I'm I'm of the opinion that PCM is is messing up.

it's got an issue with it. It's got a fault somehow. maybe the fuel pump is not the actual fault that causes it to stall, but I know there's an issue there because that relay should not be buzzing. Okay, so what I'm going to do is I'm going to back probe that circuit, not a needle.

I'm not poking a hole in the wire I'm going past the steel and we're just going to make some contact with the connector on the inside of uh of the larger PCM connector. gonna ground that probe circuit to my meter. negative and I'm going to test that connection I just attempted to make by checking continuity on pin 22 on the other side and I don't have it, make sure I've got the right one. Yep, 22.

Okay, so now what I'm gonna do is I'm gonna connect this connector back to the PCM and effectively what I've done is identified the circuit in question, verify that it's good, and then I've tapped into that circuit with this jumper lead which is going to allow me to test a little bit further. So let's plug this guy back in. we'll get it fully secured. Come on, get in there.

It's my, uh, my gun. I'm sure you guys are freaking out in the comments right about now over this blowing up engines and stuff. but the way I see it? uh, can't make this thing any worse. Anyway, so we just, uh, we just reconnect PCM and I'm just going to probe down there at that relay pin one more time to make sure my connection that I just made is still valid and it is.

Ohms are good. 0.8 changed a little bit, but who knows. Anyway, so that just simply confirms that my jumper lead right here is tapped into the grounding circuit for the fuel pump relay. So what I'm going to do? we're going to put that relay back and I am going to reconnect the battery, put that guy on right there, reconnect the battery.

We have no buzzing at the relay. All right, let's go inside. Restart: Z Engine This is guaranteed going to start as long as that relay is not buzzing. This is what I have come up with so we're key on I Hear no buzzing start.

Here's what we're gonna. we're gonna I Do Not think I Do not think that a bad circuit or a faulty ground on this relay circuit right here is going to cause the horrendously poor running condition because right now I know that that fuel pump's running, it has good ground and it has good power it always has. I've checked that multiple times the fuel pump is totally 100 working. Therefore I Do Not believe that this circuit is causing any of those symptoms that this truck has been experiencing.

What I'm trying to determine here is does this: PCM have a fault of any type whatsoever And if I can prove out that fault, I'm going to go ahead and move on replacing this. PCM Because this unit right here is the only device on that car that's going to cause the symptoms that it has at this point in time due to what we know it's not. We know it's not ignition. We know it's not spark plugs.

We know it's not a distributor. We know it's not vacuum leaks. We know it's not engine timing. I Check that.

Also, we know all of what it is not, but we do not know what it is I Do not believe it's ignition coil because the ignition or I'm sorry Ignition Control module, where's that ICM Yeah Yeah yeah yeah, that's the coil ICM I Don't believe it's the ICM When these things fail, it has no spark. But if this thing eventually stalls and shuts down, which it will, I will still have spark I'll still have injector pulse or still going to have a fuel pump. So we have everything that we need or that the engine needs to support it and make it run, but it doesn't run for long and then it dies. And on that same topic, we know it's not the coil because I've witnessed and verified that the coil runs I know it's not the distributor cap and I know it's not the plugs and wires because I checked all that stuff and made some improvements.

We know it's not the idle air control because there's a new one. We know it's not fuel delivery, but again, all we have is this relay buzzing which it should not be buzzing. That is a it's kind of a red flag to me, so it's none of this stuff. It's not the injectors.

Actually, it could be the injectors because the injectors are constantly powered and they receive their ground signal to fire again from our ECM and I'm aiming to prove that the ECM has an internal problem where it fails to ground its circuits when it's supposed to. and if I can catch this thing in the ACT that's exactly what I'm going to prove. now. Stall.

But watch. It's going to stay and run all day. now. Watch Now you guys! Oh I Love what I did I left.

it left the vacuum line off. Hang on. I Thought it was louder than normular and maybe it'll stall now. Okay, good we stalled.

That's what we want because I think we have really crappy fuel control. Look at here. that relay is buzzing again. You hear it.

fans off, relays buzzing. Now you can hear it. I'm sure there's also some other stuff kind of buzzing over there, which it shouldn't be. But watch this.

We know that that is a grounding circuit. the one we just tapped into. Listen to this relay when I Ground All done. Ground Off Ground On Ground Off Ground on.

So what does that tell us that tells us somewhere inside this: PCM the device used to cause ground for that fuel pump relay is faulty. Whatever it might be mosfet, say it might be a relay. Whatever is going on in this PCM that supplies the ground on it. The circuit that we're tapped into is a faulty component in the.

PCM Now that tells me that if we have one fault in the PCM extremely likely it's extremely likely that there are additional faults in that. PCM Now real quick. just to prove my theory one more time, we're doing the buzzing thing. Let's go try a restart.

see what it does. Nothing key off. Kion In fact, I Would like to prove that the circuit that we are spliced into is not the cause. Relay lushes, We're gonna ground it.

The circuit's grounded again. Still isn't going to start. Now watch. No buzzing, buzzing and all.

I'm doing is artificially supplying a ground to that relay because I do not believe that the PCM is capable of Performing that function. What I think is happening here is when this: PCM runs for a little while and it heats up. That's when the fault occurs because if I were to walk in here first thing in the morning, or walk in here in an hour, or maybe even in 15-20 minutes, walk back in here. It'll start right back up and run for a couple minutes, not long, and then it craps out and dies again.

So we don't have a confirmed kill. but I have confirmed. There's an issue with that powertrain control module, so that is what I'm going to order that's next on my parts Cannon that's how it's going to be so no repair today I have to order one I don't know where they're at, but uh, we're kind of getting somewhere because it runs longer than than it did run and uh, you know that's that's where we're at so far or right now. So let me pull my my test leads out: I'm going to power down the vehicle, let my little trickle charger charge my battery back up because that thing's been working.

its butt off. Today there we go. put that down there. Oh, we're still in testing mode.

I Could probably try to retrieve those codes, but yeah, I've got Direction and we're going to go with that. I Really don't care if this thing says that the EGR is disconnected. Oh yeah about that. I found a piece of a Coke can blocking off the EGR because I I actually thought at some point that perhaps this uh EGR valve was stuck open which it is and somebody put a Coke can Where It Bolts to the intake to uh to seal that up.

Also, so it's not the EGR valve, that's that's all. Also on the list of things that is not wrong. Well, the things that are wrong with the car but are not the cause of our problem I Think that I think the problem is in the PCM and it always has been. so that's what I'm going to order.

that's what I'm going to change next. So uh, as always like thank you guys for watching this video. Let me know. If you guys think that I'm on the right track, let me know.

If you guys think that I'm on, let me know if you guys think if I'm on the right track or not, maybe I am maybe I'm not. but uh I mean eventually with enough Parts it will run again. It just takes enough parts so I just got to figure out which ones I want to put in next. I guess so.

Anyway, again, thank you guys for watching and most importantly, do not forget to have yourselves a great day! See you guys later In deferred.