'01 EB Ex V8 bogging at full throttle

[Turdle]

I think you are on the right track.

 

[JCase]

Anyone have a pre and post 97' vacuum diagram handy?

 

[rickybobby]

The fact that it is only throwing a lean code for bank 2 virtually eliminates the possibility of a lack of fuel pressure or flow. Being that it is a single bank throwing the code the 1st thing i would do is remove the upper intake and inspect the gasket. Also, on the 5.0 does the fuel rail sit between the upper and lower intake like the 4.0? If so then that gasket could also be causing the issue. Does your scanner give you the option to datalog? it would help me a fair bit to get a snapshot of the data while it is experiencing the problem. It kinda sucks that we both moved farther away from each other. I would love to come up there and give ya a hand but its a nearly 2.5 hour drive each way now.

 

[rickybobby]

What brand/type of brake clean are you using, not all of them are flammable anymore. It may very well just be crappy timing. I had a car come in to work the other day for a crankshaft position sensor and then crap the ignition cylinder an hour after the guy picked it up.

 

[JCase]

The fact that it is only throwing a lean code for bank 2 virtually eliminates the possibility of a lack of fuel pressure or flow.

Bingo!

 

[Joe Dirt]

Using gumout carb and tb cleaner.

I was thinking about the fuel thing after that code threw- it did seem odd that it was only throwing on one bank. Even the vac thoughts- wouldn't that show up on on both banks?

The rail is under the intake, so to service it, the intake needs to come off anyhow. I'm thinking that as easy as the intake is to remove if I just unbolt the TB from it so I don't have to mess with the EGR pipe, I may just take a new upper intake gasket over and put it on.

I am going to check that vac tree though, and I think I have a spare regulator just for giggles. If that doesn't do it, I'm tearing the intake off. I'm assuming now that if it isn't vac related, a leaky gasket on one or two ports may be letting enough air in to create a lean condition on one bank, whichever of those ports is leaking...

It's a quest, I tell ya...

If all of that is ok, can the cam position be off enough to do this? I mean the sensor on top was not removed, but he probably spun the rest of it in the lower intake putting the thing back in there. If it's off say 1/16", would that create this condition? Could it be a bad injector? Maybe a broken brittle connector when he unhooked them and one connector slip up and it's not firing? It runs so well up to 75%.

 

[JCase]

Sharing some thoughts...

Initially, it sounded like the problem I had with mine with a weak fuel pump, would not rev over 4,700rpm/ felt "bogged down" as you described.

But, considering your friend didn't have this problem before swapping intakes, and considering he's "customizing" the vacuum routing by using two different year trees/vacuum routing, and considering the mishap with the tree and gasket installing the intake the first time, and the point rickybobby bought up about it throwing a code only on one bank, it has to be a vac issue.

My opinion would be to get a post 97' tree from a junk yard, buy a new intake gasket, tear it down and take your time installing everything again.

 

[FIND]

Cam sensor should only affect idle and start up.

The code is for the bank 2 sensor, so passenger side, so a leak on the EGR could affect that side. Have you gotten a good look at the EGR pipe?

Fuel and vacuum can easily only show up on one side, and I've seen fuel pressure issues that did only trigger codes on a single side, especially on returnless fuel systems, since pressure is lower the further you are from the FPR.

Remember, air entering the engine is a fluid, it only flows so fast, and flows in the directions it is easiest to move in, so vacuum issues tend to cause larger problems nearest the source of the leak. Also, this is the side EGR is on, so there is that for consideration. Plus, these are narrow band sensors, and a number of years old, so they only give the ECU a gross estimate anyway. Besides, the code may just be a bad sensor, and unrelated to the issue, which may not even be throwing a code.

 

[Joe Dirt]

Great info... This is turning into a very interesting thread...

The EGR pipe is good, I did look that over. It also was not cracked open, as when the intake was removed before, he just unbolted the TB from the intake and slid it off so as not to have to mess with the pipe.

It is also interesting that the tree was apparently crunched through the rear of the intake, towards the passenger side he said.

I think the course of action will be to pull the tree and check to see if it is leaking at all through any of the hoses, which I suspect it is not. Then, we will replace the intake gasket. If that fails to fix anything, we'll replace the fuel filter. If no dice, we set the truck on fire and drink beers.

 

[rickybobby]

Joe, when you pull the intake, pull the fuel rail too and check that gasket and the injector o-rings. I chased a lean code on mine for nearly a year and it was the gasket between the fuel rail and lower intake. I never had any luck using carb clean to find a vacuum leak, traditional brake clean has always worked better for me.

 

[colintrax]

Great info... This is turning into a very interesting thread...

The EGR pipe is good, I did look that over. It also was not cracked open, as when the intake was removed before, he just unbolted the TB from the intake and slid it off so as not to have to mess with the pipe.

It is also interesting that the tree was apparently crunched through the rear of the intake, towards the passenger side he said.

I think the course of action will be to pull the tree and check to see if it is leaking at all through any of the hoses, which I suspect it is not. Then, we will replace the intake gasket. If that fails to fix anything, we'll replace the fuel filter. If no dice, we set the truck on fire and drink beers.

Instead of wasting time checking for vac leaks, why not go ahead and do the fuel filter? Pretty easy to replace, and it should be changed every so often anyways.

Find, when my cam sensor went bad it caused a miss at all RPMs. Idle to WFO. I think you're right about the EGR valve. That would explain it being lean on 1 side. And EGR valves are a pain in the arse to work with so it's probable he fudged it up.

I'm not convinced it's an air issue. Fuel pressure drops at higher revs, and vac leaks cause all kinds of problems. Stalling, stumbling idle, no power.
So IMO, replace the fuel filter and see what happens. Low PSI will cause it to run lean

 

[Joe Dirt]

Yeah, I have one waiting to go in... After I replace the intake gasket. Just got it out, this is what was in there, the line is from the crushed vac line that was in there...

We'll see shortly if this was it. Going to pull the intake and replace the fuel injector o-rings and zip tie the broken fi connector tabs as well. Then tossing on the fuel filter regardless...

 

[JCase]

Yupper, that gasket is toast.

Good work Joe! I see an ice cold Miller High Life in your future!

:biggthump

 

[4rd4life]

damn he routed that vacuum hose all through that intake lol nice one!

 

[Joe Dirt]

I know- it was smack inside.

No dice though- replaced the intake, tested the tree, air flowed fine, no leaks. O-rings in the fuel injectors were replaced, connectors are tight, then replaced the fuel filter.

Same issue. Unless it's a bad DPFE, TPS (which did test fine) or some other sensor, I have no idea what could be causing it. It will rev fine in idle, it will accelerate fine under partial throttle, above 3,000 rpm. It is only if you kickdown that it will go nowhere. Could something be fishy with the kickdown? Transmission problem?

Grasping at straws here.

 

[JCase]

WTF!?

Dirty Crank Position Sensor?

I assume you've already cleaned the Mass Air Meter.

If its left in 2nd gear and you rev it past 4,500rpm, does it still bog or is it just when the trans kicks down? Full throttle and part?

He didn't have this problem before the intake swap, correct?


I know this may sound silly because vacuum is vacuum, but you might want install the correct tree back on it. They way it's routed could be making one of the vac lines cavitate at full throttle/high rpms. Just a thought...

 

[Turdle]

I know- it was smack inside.

No dice though- replaced the intake, tested the tree, air flowed fine, no leaks. O-rings in the fuel injectors were replaced, connectors are tight, then replaced the fuel filter.

Same issue. Unless it's a bad DPFE, TPS (which did test fine) or some other sensor, I have no idea what could be causing it. It will rev fine in idle, it will accelerate fine under partial throttle, above 3,000 rpm. It is only if you kickdown that it will go nowhere. Could something be fishy with the kickdown? Transmission problem?

Grasping at straws here.

Just because--

Time to verify the timing of the cam sensor. (times fuel injectors)

 

[Joe Dirt]

Yup. Cleaned the mass air meter, that's nice and clean.

Assuming I need to pick up a sensor and tool so I can try to align it... If the sensor never was loosened from the shaft, can I just loosen the keeper holding the shaft to the lower intake, and turn the shaft to see if anything changes, kind of like messing with the timing via old distributor?

Also- check this video, and more specifically the comments... CLICK ME

 

[Turdle]

Yup. Cleaned the mass air meter, that's nice and clean.

Assuming I need to pick up a sensor and tool so I can try to align it... If the sensor never was loosened from the shaft, can I just loosen the keeper holding the shaft to the lower intake, and turn the shaft to see if anything changes, kind of like messing with the timing via old distributor?

Yes, it will rotate like a distributor. When setting this it is important to have the #1 cylinder at TDC for the compression stroke. Once there, take a look at the sensor flag. The flag should just be getting around to the actual sensor--this may help you to see if it is out of adjustment, and how far. I would do this before loosening --moving it. The sensor will rotate 1/2 turn for every one rotation of the crank. ( but you already know this)

 

[Joe Dirt]

The odd thing to me is if the vane is inside under the sensor, and the sensor wasn't removed, how would it have gotten out of alignment? The keeper was removed, and the electrical connector was still pointing forward, but when the keeper was tightened, he said it didn't really rotate at all, it just went back down into the lower intake. Oil pressure is fine, everything still lined up.

If the sensor is still on top, and I loosen the keeper, will rotating the entire assembly change how the injectors are timed?

I'm curious if anything would be damaged, i/e burn a piston, if I rotate the assembly a little either way with the cam sensor still mounted to see if it changes anything before I pull the cam sensor off since I don't have the tool yet. Want to be careful, since it isn't my truck...

In other news, my hands really hurt and my forearm is raw from messing with this thing. Whomever's idea it was to change the fuel filter and let fuel run down over my freshly scraped raw arm- thank you. Made my Sunday...