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So I guess I thought I was too cool...

VitaminC

VitaminC

Registered Member
Joined
May 3, 2011
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Wichita Ks
I'm going to break down and buy an aldl cable, fuel pressure gauge adapter, psi gauge, and a membership.
This tbi is kickin my ass.

I'm to the point where "I think I fixed it" -> "thought I fixed it."
This all started with a heat soak issue (which I still have).
I've already bought two things I didn't need and I'm done with that.

So I guess what I'm saying is I'm here for the long haul guys, I love the truck and I don't quit. But I ask for some forgiveness for my ignorance in the future. I'm near Wichita Ks if anyone else is. I will start a build thread shortly.
Ps... Best place to buy an aldl?

-Cody
 
Did you post about the heat soak issue somewhere? Is it the starter or fuel or what?
 
Russell said:
Make one! They are cheap and easy to make :)
Click to expand...
:sign17:

The WINALDL interface cable I built is pictured below. Parts were about $10 from Radio Shack. I think WINALDL is a useful program.

DSC01338.jpg
 
Here is the one I built!

The black wire is a ground wire, the brown wire is the serial communication wire, and the yellow wire either shorts A and B together to make the ECM flash error codes, or it provides 10K of resistance to set the ECM into ALDL mode. The third switch position disconnects A and B. I stripped and soldered the ends of the wires to make them easy to slip into the ALDL port without the wires getting all messed up on the ends.

The switch and the project box made me spend about $20 on the whole thing, I had the rest of the components sitting around already :waytogo:

I've also attached the wiring diagram for an ALDL adapter. I added the switch on my own accord. You'll find other diagrams that use only 1 transistor, and while they work fine, this one is a bit more robust and can handle much faster communication speeds without loosing any data. If you don't know what one or more of the symbols mean, let me know and I'd be happy to explain it better.

aldl2.jpg

DSC04402.jpg
 
Update.... I broke down and bought another part... Ignition coil, I use the excuse as " it's in the tune up section"

But anyways I'm working on the truck right now. This greenhorn at work owns his own shop and lent me his fuel pressure adapter... It's pretty cool, goes in place of the filter and has a shrader T.

It's installed and i kicked the truck on for a second. ( don't want it too hot, I've got some other stuff to do) 10 psi with some leaking at connections even. I still need to test it when the truck is acting up, which is fairly easy to accomplish. Noticed some funky braided stuff under there I need to look at though.

Today I looked at some aldl cable build threads when i decided 105 outside was a bit hot for work outside (lasted 10 minutes)

One more thing... This thing has an open element filter. I know tbi hates that shtick, but how badly? I also think it's coming into contact with the top of the plug wire heads on the dizzy.

I've decided to trace grounds as well.

Just an update on how cool I feel covered in gas, and noticing all the leaks I have under the sob tonight

-Cody
 
Okay guys... Tonight's progress. It was a lot.

At start fuel pressure at the filter is 10-11 psi. After 10 minutes of idle 10-11 psi. It's only 87 degrees outside right now. I left the gauge hooked up to check tomorrow at 100* plus outside, to check heat soak issues with the pump (I'm thinking doubtful at this point).

I installed MSD's "street fire" coil tonight. I know it's 8mm friendly. I wouldn't have ever bought a "performance" part, but I hated the fit and finish of the auto store brand.

Had to remove dizzy cap to get the coil in and out. I noticed some corrosion on the pickups in the cap...hit them with emery cloth, i did the same with the dizzy rotor spindle connection head. I believed the PO when he said he replace all of that 2 years ago (must have been having the same issues as I am now). The cap and wires ARE newish. On the other hand. The rotor looked crusty.

And for the life of me I could not find a screw to remove it... Suggestions??

I also noticed the gasket for I'm assuming a pod spacer (top of the tbi, surrounding the injectors approx. A 1 in. tall, thin metal surround with a "vacuum" line running to the valve cover, hope that make sense) that gasket is split. Logically to me it shouldn't make too much of a difference.

Buttoned it all back up and it idled good.

While idling I noticed... PVC valve is making an a$sload of chattering noise.

Before I finished I jumped A & B and looked for codes... None besides 12.

While I had A & B jumped I checked out the iacv. With key off I couldn't see it. With key on, I could see a little of the cone, but what was weird is it was making noise, like slipping gears.

Ice done a lot of homework and a lot of hours under the hood. I will do some more diaognostic in early afternoon before work and update.

Please help:)

-Cody
 
VitaminC said:
At start fuel pressure at the filter is 10-11 psi. After 10 minutes of idle 10-11 psi. It's only 87 degrees outside right now. I left the gauge hooked up to check tomorrow at 100* plus outside, to check heat soak issues with the pump (I'm thinking doubtful at this point).
Click to expand...

10PSI is too low despite its being within range; I make adjustments for anything under 12. This is the potential issue: The fuel pressure is regulated by returning excess fuel to the tank. This returning fuel also keeps the fuel in the lines nice and cool. It is possible that your fuel delivery has dropped below the regulator setting and you no longer have return fuel. Disconnect the return fuel line and run it safely to a gas can then jumper the fuel pump relay and verify you have a solid steam of return fuel. If you do not have good return fuel this may well be your problem. If you do have good return fuel, shut off the engine, cap the return line, jumper the fuel pump relay and observe the fuel pressure. It should climb significantly higher than 14 PSI, probably into the 20s.

VitaminC said:
I installed MSD's "street fire" coil tonight. I know it's 8mm friendly. I wouldn't have ever bought a "performance" part, but I hated the fit and finish of the auto store brand.
Click to expand...

Pointless but its your money. :-)

VitaminC said:
Had to remove dizzy cap to get the coil in and out. I noticed some corrosion on the pickups in the cap...hit them with emery cloth, i did the same with the dizzy rotor spindle connection head. I believed the PO when he said he replace all of that 2 years ago (must have been having the same issues as I am now). The cap and wires ARE newish. On the other hand. The rotor looked crusty.
Click to expand...

White oxidation on aluminum conductors is normal and while unsightly to us is invisible to the high voltage jumping across to get to the plugs. Knowing that, I still feel the need to scrape it off when i have the cap off.

VitaminC said:
And for the life of me I could not find a screw to remove it... Suggestions??
Click to expand...

Small cap DISTRIBUTORS have rotors that lift off, sometimes with great difficulty. I suggest it be left alone unless a replacement is necessary (very rare). There is a metal clip in there that will almost certainly go MIA as the rotor lifts off abruptly.

VitaminC said:
I also noticed the gasket for I'm assuming a pod spacer (top of the tbi, surrounding the injectors approx. A 1 in. tall, thin metal surround with a "vacuum" line running to the valve cover, hope that make sense) that gasket is split. Logically to me it shouldn't make too much of a difference.
Click to expand...

Oreilly has the air cleaner gasget you refer to for $1.69.

The hose is the crankcase vent.

VitaminC said:
Buttoned it all back up and it idled good.

While idling I noticed... PVC valve is making an a$sload of chattering noise.
Click to expand...

I suspect you mean the PCV (Positive Crankcase Ventilation) rather than PVC (Polyvinyl chloride) valve.
The valve can be noisy but it is possible you have the wrong or generic valve. Not a huge issue but worthy of investigation. Doubtful it is associated with your issues at hand.

VitaminC said:
Before I finished I jumped A & B and looked for codes... None besides 12.

While I had A & B jumped I checked out the iacv. With key off I couldn't see it. With key on, I could see a little of the cone, but what was weird is it was making noise, like slipping gears.
Click to expand...

When in diagnostic mode (Pins A and B Jumpered) and the engine not running, the ECM commands the IAC (Idle Air Control) to extend. It will continue to send extend commands while in Diagnostic mode and is harmless.
 
Just went to the truck... Lit a match and threw it at the truck. Problem solved. Jk

Well it's 101* outside. It fired right up, sounded great. But within two minutes it started hunting for an idle again. I watched the fuel pressure gauge the whole time. When the Rpms would dip, the needle vibrated erratically. When the engine recovered I would get a solid 11 psi.
Eventually when the truck shut itself down, the fuel pressure slowly dropped to zero.

I don't feel like working on it today before work (aside from getting that gauge off to return to the guy). I'm going to ask him if I can borrow it through the weekend but I bet he'll need it. I hope he let's me because I really want to try what Texas said to do.
 
I wouldn't spend time chasing fuel pressure if it's 11psi. That's what stock trucks run. Your problems would be at higher rpm and not idle if 11psi was too low.

Sounds more like a vacuum leak to me. Check all the egr stuff.

-Brian
 
Kinda what I was thinking about the fuel pressure. I mean I understand it's on the low side of the spectrum, but i wouldn't think enough to kill the truck. I plan on replacing the pump anyway as the sending unit apparently isn't communicating with the gauge. I will try to solve this issue first.

The EGR is currently unhooked and all vacuum ports to and from blocked. I need to get ahold of a GM EGR valve as in my last topic, "EGR rant" the piece of crap i bought at Autozone wont even allow the truck to idle for some reason.

I have checked and checked for vacuum leaks, but only visually. I'm sure there is one somewhere. The strange thing is I have fixed about 10 obvious ones and now it doesn't like it.

I'm beginning to seriously think I have a bad ground somewhere, or a bad cell in the battery. I want to do a voltage test on the battery tomorrow to see if it is losing power under heat load. Can I just hook a volt meter to the terminals or is there a better method? I know my questions are elementary and most of them I will read on and figure it out myself. Mainly using this space here as a diary almost of what I've done and what I should do from you guys.

I've also given thought to the fuel pump relay. The way the pressure dropped today in the heat was like it lost power or something... PSI was direction correlating to the rpm drop right before it died.

Good grief I need an ALDL cable. I will order one.

BTW...Contributing member now baby!
 
With the fuel pressure already lower than the factory 13-15, and you say the pressure was dropping before it died, depending on how old that pump is, I wouldn't rule it out.

I have seen them run good for a bit and the longer they run, the worse they went. I have also seen one fail within an hour of install, good 'ol Autozone junk.
 
I would pull the pump and check/replace it and make sure that the submersible fuel hose that attaches the pump to the sender isn't cracked/split like many people have had issues with (which can cause your problem). Just remember, that short piece of fuel hose MUST BE submersible fuel hose NOT standard fuel hose.
 
I am almost convinced to drop the tank tonight. But I had a brainstorm walking out the gate at work... I am not hearing the pump kick on when the key is in the "on" position. I know some body has mentioned that the computer needs to sense oil pressure in order for it to activate the pump. I'm probably over generalizing this, but I hope I have the jest of it.

Well last night when I had the fuel pressure gauge hooked up, with the key ON, engine off... I got zero fuel pressure. Engine had to be running to achieve a reading

I know there is a way to test the fuel pump relay by running 12v to the red wire hanging by it. So I will do that first.

To really monkey the situation.... I had an issue a week or so ago with the coolant temp sensor. Problem was the PO had pulled the sensor out to "install a temperature gauge" the sensor was left hanging by it's wires in the front of the engine.

Well guess what other gauge is "installed" in the truck... Oil pressure gauge. I can only imagine the hack job on my poor oil pressure sensor back there
 
Sure as ****... Oil pressure sensor is removed, adapter and sending unit with a hard copper line in it's place... Unbelievable. No place I can buy one at this time of night, but tomorrow I will...

I could only find one loose wire. It is brown and has a female spade connector attached. It is factory and brown/tan in color. I cross referenced my chiltons. It says there are supposed orange and grey wires. I guess orange could age to brown, but no grey? If any one gets a chance to look at theirs please let me know...

Will update
 
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