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F.ound O.n R.oad D.ead
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Discussion Starter · #1 ·
It started about a month ago and ive been covered in grease since then..
The truck is an 88 gmc s15 jimmy with 4.3 auto 4x4, ill be driving and it acts like its choking for gas. But my real reason for posting is a simple question and advice? I cleaned the fuel lines replaced pump and cleaned tank replaced injectors and filter, but i did not replace the regulator so when i went to clean the tbi i noticed that fuel has pooled in the upper part of the tbi where teh regulator attaches to does that mean its shot? ive also replaced pvc battery cv joints*irrelavant* map sensor*junkyard one* tps cleaned iac and entire tbi checked all vacuum lines and it idlesvery rough and when i get on teh gas it chokes down and stutters rapidly and it gets so bad sometimes i cant go over 30 mph. and teh only fuel pressure tester ive found for tbi is 130??? but im broke from parts for now..
 

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Get a TBI rebuild kit, the one I picked up at Advance Auto for $21 came with all the screens and gaskets plus the regulator diaphram, all but the spring. Sounds like the diaphram is leaking BTW.

Have you checked the distributor drive gear for wear? For excess play?
 

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F.ound O.n R.oad D.ead
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Discussion Starter · #3 ·
i was told it was previously rebuilt and i believe it cuz the gaskets are newish and clean and theres a phillips head screw on teh butterfly valve instead of torx haha. but not the dizzy is fine and sinces thats pretty cheap ill try it thanks i assumed it was way more.
 

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F.ound O.n R.oad D.ead
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Discussion Starter · #5 ·
Update, holley tbi kit including diaphragm. no change?
 

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You need to measure the fuel pressure. The TBI needs about 11 PSI to run well. However, there is no provision built in to the TBI engines to check fuel pressure. I have a TBI fuel pressure test kit that I can install in line at the frame where the fuel lines come through.
Have you replaced the fuel filter?
 

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I have a 1993 4.3, which is pretty similar to yours, as mine is also TBI. I had a problem very similar to your, new plugs, wires, distributor cap, and coil. It fixed it instantly.
 

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Sounds pretty similar to my problem actually, I'll let you know what ends up fixing it, lol. So far i've replaced the entire ignition, most of the sensors, the IAC and the EGR. Mine will clean up and run, though not well, if I can get it up over 1800rpm.
 

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F.ound O.n R.oad D.ead
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Discussion Starter · #10 ·
wow your sounds a little worse except mine clears up and drive like a champ 20 % of the time. thats what stumps me and ill do the same if i get it thanks bud
 

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F.ound O.n R.oad D.ead
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Discussion Starter · #11 ·
oh yeah new coil rotor cap plugs wires battery air filter also and no egr i got rid of that as soon as it acted up and new o2 sensor the pressure holds up fine while driving but the check valve is definitely gone( doesnt hold pressure with pump off) but i did get a tps sensor code after 3 ecm resets so the new tps is bad? or is mine adjustable? i replaced teh pigtails and soldered them nice and clean
 

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F.ound O.n R.oad D.ead
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Discussion Starter · #12 ·
triple post..
* the fuel pressure holds up fine
 

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Does your new TPS have the slotted screw holes or is it the newer one with the round plug and non-adjustable?

Mine is mostly fixed, the off idle stumbling is a fuel issue, the idle hunting and dieing is completley fixed with a junkyard ECM with the proper chips. I had tested my chips in a new ECM and that did not fix it, but new ECM with new PROM and limp chip and it's running, still stumbles off idle, but that is quite obviously a fuel problem now that the idle is fixed, it'll run and drive now, it's just a bit annoying.
 

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F.ound O.n R.oad D.ead
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Discussion Starter · #14 ·
not entirely sure..
 

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F.ound O.n R.oad D.ead
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Discussion Starter · #15 ·
sorry for stretch forgot completely about resizing..
but from what i see its not adjustable right?
well i was thinking why cant i just drill out the screw holes a little and make it adjustable after i check voltage.
comments?
 

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F.ound O.n R.oad D.ead
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Discussion Starter · #16 ·
glad to hear you got it mostly worked out, this one problems forced me to learn how tbi works so i got something good out of it haha
 

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Those are the part store replacements. GM\Delphi\AC Delco stopped making the ones with slotted holes for those a while ago, I have no clue why they did it, but they did. Those style need to be adjusted, though it's really a tiny amount. I would check it as is first, and see how far off you are from where it needs to be, and go from there. I know mine is off, it reads 2.1% with the blades completely closed, but it has been close enough to not cause a problem to date. Ideally you should be at 1.5%.

I've used TBI just a couple of times before, but today I started a rebuild on one, and found out why I've been told not to try and remove the blades on these TBs. The screws are idiotic one time use screws, from GM that you have to either grind down the back side, or break the head off(like I did) and drill and re-tap the shaft. >:/
 

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F.ound O.n R.oad D.ead
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Discussion Starter · #18 ·
wow that sucks the previous owner replaced the blades it seems , but they stick when i open the throttle like a squeaking sound like there slightly too big didnt notice it till i was moving the throttle with my ear beside it, but alright guess ill start on that thanks for all the help artos
 

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F.ound O.n R.oad D.ead
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Discussion Starter · #19 ·
tps is good now but i did notice one thing that im unsure off, the key was forward and i cant remember what i was doing but i know that when i tapped the distributor cap kind of hard the fuel pump kicked on and primed, everry time i hit it the pump primed. icm? i think thats what its called and if it is how do i get to it?
 

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F.ound O.n R.oad D.ead
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Discussion Starter · #20 ·
icm was coated with white gunk. fixed for now
 
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