TBI Adjustable Pressure Mod

[mudbuggy]

Running MAP and FPR off the same vacuum line is perfectly fine. Many OEM applications are set-up this way.

People forget that vacuum in this sense is not flowing air, but more like a spring or cushion of air, that only moves a little bit, or rather gets stretched under more vacuum.

I'm not trying to to a vacuum regulated fuel pressure thingy, I'm attempting to make mine adjustable with a thumbscrew underneath the unit so I don't have to take the upper part off to adjust it. I wouldn't know how to do that

[JeepsAndGuns]

I have made the regulators adjustable on about 4 diffrent tbi units, all of them that little screw was brazed into the part sticking down. And that part is held in with a snap ring and then glued into place. I have simply grabbed it with a pair of vice grips and spun it, only one I had to heat just a touch to loosen the glue. Once freed I could spin it all the way up or down.
The tbi unit on my engine right now is like that, all I have to do is remove the air cleaner and turn it with some needle nose plires.
All the machine work and custom screws and whatnot seems like the hard way to do it Just my $0.02 worth

[EagleMark]

Or you could buy one, or copy one...



Have you ever checked the fuel pressure with a test gage? Wonder if that electric is lieing?

[mudbuggy]

Before I installed the electric gauge I installed a mechanical set. Dead on! The adjustment tab is all the way on the bottom of the hat. That is the one that is one the truck!

[gregs78cam]

I have thought about getting a pair of these, they might help in your case but those steel lines can be pretty tough. I had a heck of a time getting a couple of them out of one of my TBIs.

http://www.eastwood.com/ew-brake-formin ... liers.html

http://www.harborfreight.com/tube-bendi ... 95782.html

I know two ends of the scale.

[EagleMark]

I've got flare tools and tubing benders but sometimes it's not sharp enough bend. Would really like a set of those plier type benders for 3/8 and 5/16... the ones listed do 3/16 and 1/4///

[mudbuggy]

When I get home I will try and adjust the tbi that is on the truck how you said. No heat, don't feel like going in orbit (just filled up this morning). I am having a brain fart on the map fitting can't remember when I stored those elbows, only 10 of them. I as of yet have been able to remember to dig out test info for the tps and iac. Hopefully ill do that before the weekend

[EagleMark]

http://www.thirdgen.org/tpimod2

[mudbuggy]

I attempted to move the base of the fuel regulator this evening with needle nose pliers, didn't budge, but I didn't crank the shit out of it either. I did pay attention to the tps and the map. I realized that the tps that is on the other tbi is of another style, and the map is nonexistent, I mean it's not there. I have an 89 I should have one if not in that position, then someplace right? My back was knotting up on me so I didn't spend a lot of time, but I will look tomorrow at lunch, I have a much larger flashlight and my meds will be in full effect at that time too...

[JeepsAndGuns]

The map sensor is there to the left of the tps in the 2nd pic, it has a green connector on it.
When I said I had to apply heat to one, I ment when it was out of the truck and on the bench, tbi and fpr disassembled. I dont think you gonna break it loose when its still on the truck using needle nose plires. I have always had to remove the top of the injector pod and put some vice grips on the nub to break it loose. Will probably needa new gasket.

[mudbuggy]

I understand, I wasn't going to use heat on the truck anyways, I just filled the tank up and I don't feel like ending up in orbit!!! I am thinking that I might this weekend just rebuild the top half of the tbi unit, depending on the weather and how I feel, I need to get a flat tapered head torks 1/4" x 28 tpi bolt idk maybe an inch or 3/4" long. Once I have the bolt then I have all of the parts. I'll just use the back up tbi upper pod section, I have a leak from the upper pod or from the regulator so I'm only a breakdown away from having to rebuild it anyways. Besides firewood season is coming up and I'd hate to miss a day of playing at the cabin because I have to rebuild the tbi.


If that is the map then it is plugged into the fittings on the front of the tbi. The line that comes off of the back is to the 'service' equipment, cruise, hvac, vacuum gauge. The one with a green plug, I thought was the egr solenoid, I'm going out to look I'm curious now! Nope your right, but it is tied into the intake vacuum port. Now I'm wondering who said the map was suppose to be in the rear port of the tbi that is slowing me from installing the adjustable fuel regulator knob on the back. idk I'm so confused now?

[EagleMark]

Sure looks like the MAP vacuum line runs to back of TBI from here. The port between fuel lines is for MAP.

[mudbuggy]

Mark,

That line from the back of my tbi goes to the cruise, vacuum guage, vacuum ball (?), and the hvac. That's it. That's how I bought it too, for 25 bucks!!! I put a battery in it and drove it the next day to work!!!

[EagleMark]

The line on the back of TBI goes to MAP sensor only!

[mudbuggy]

Ok, look at the last post that I made that has two pictures in it. The first picture has a green glove holding the vacuum line from that fitting. Do you see the white tee, then the cruise control can, then the smaller vacuum line that runs to the left in the picture? So what now is a person to do? What does this mean, that someone has really redone the vacuum lines on my truck? I am starting to wonder how it is suppose to be from the factory? If it's working I'm not really sure I want to mess with it too much, then again, if it is less then effecient then I would rather it be better. I really am getting more and more confused on what to do?