4.3 TBI Chubby nightmare

85ragtop · Dec 20, 2007

If it's not the ECM then I (my dad) have no idea. This is very strange.

Darkwriter77 · Dec 20, 2007

It's a GM product. NOTHING about this damned vehicle seems to make sense, mechanically. I mean, really, whose idiotic idea was it to make the COOLANT SENSOR have the potential to cut off fuel (or dump it)? Or to cut the fuel pump off if there's no oil pressure reading? What, one sensor goes buggy so the whole thing has to shut down? ARRRRGHHH!

Going to try a few final things first, then I'm gonna bite the bullet and waste $70 or so on a new ECM. If it still won't start ... screw it, I'm selling it. I've already wasted $450 in parts on this turd.

Darkwriter77 · Dec 21, 2007

Redid the crappy connections for the fuel injector sockets. No change.

Replaced the oil pressure switch, the housing of which was broken, anyhow. No change.

Screamed and ranted and raved and threw a hissy fit, slammed the door, and went back inside to pout. No change.

timeless2 · Dec 21, 2007

Wait, so you did test different injectors already?

Darkwriter77 · Dec 21, 2007

Yup. This bastard's had THREE pairs of injectors swapped in/out of it. They've all tested good for continuity, so at least the coils on 'em aren't fried, but I find it hard to believe that three sets of injectors from three separate engines would all be so completely clogged up that they won't even let a dribble of fuel out, at all.

This damned Chevy just needs to frickin' DIE! ... er, wait. It's already dead. Okay, it just needs to go away from my driveway!

Next on my planned list of wasted funds is an ignition switch - a couple of other S10 dudes have had the same problem, and that's what it turned out to be in their case after they similarly spent forever trying to figure it out. But, of course, I'm sure this will not apply to my situation, because my luck with this frickin' GM turd is just horrible. Yayyyy, another $12 to throw away to the Chevy gods! Wheeeee! Next thing y'know, I'll be checking the air in the tires or something to try to make it start...

Ooh, I know! Why don't I just install my frickin' wallet in the intake and see if it runs, then! Maybe some sacrificial offerings? Lay open a vein or two, dribble it into the TBI unit, and see if it runs on blood, by chance? Seriously, I'm going nuts trying to make this thing work. It's almost like a quest, now. I almost CAN'T quit, because then I'll go the rest of my life wondering what the hell stupid little thing was preventing it from starting all this time...

'13_ImpactBlue_GT · Dec 21, 2007

Darkwriter77 said:
Yup. This bastard's had THREE pairs of injectors swapped in/out of it. They've all tested good for continuity, so at least the coils on 'em aren't fried, but I find it hard to believe that three sets of injectors from three separate engines would all be so completely clogged up that they won't even let a dribble of fuel out, at all.

This damned Chevy just needs to frickin' DIE! ... er, wait. It's already dead. Okay, it just needs to go away from my driveway!

Next on my planned list of wasted funds is an ignition switch - a couple of other S10 dudes have had the same problem, and that's what it turned out to be in their case after they similarly spent forever trying to figure it out. But, of course, I'm sure this will not apply to my situation, because my luck with this frickin' GM turd is just horrible. Yayyyy, another $12 to throw away to the Chevy gods! Wheeeee! Next thing y'know, I'll be checking the air in the tires or something to try to make it start...

Ooh, I know! Why don't I just install my frickin' wallet in the intake and see if it runs, then! Maybe some sacrificial offerings? Lay open a vein or two, dribble it into the TBI unit, and see if it runs on blood, by chance? Seriously, I'm going nuts trying to make this thing work. It's almost like a quest, now. I almost CAN'T quit, because then I'll go the rest of my life wondering what the hell stupid little thing was preventing it from starting all this time...

That last paragraph was funny as hell.

Sorry about the S10

Go consume several beers and try again tommorow, you might have a brainstorm in the meantime.

timeless2 · Dec 22, 2007

Time to take it to Chuck.

Darkwriter77 · Dec 22, 2007

Chuck's on his way to look at it today, as I type.

timeless2 · Dec 23, 2007

Darkwriter77 said:
Chuck's on his way to look at it today, as I type.

What was the outcome of the visit?

Darkwriter77 · Dec 23, 2007

No luck with Chuck.

He did manage to get the thing to *ALMOST* run, but it's still the same issue: No fuel coming through the injectors. It's getting fuel TO the TBI unit, it's getting spark, it's getting signal to the injectors, it's spotlessly clean all through the TBI unit itself ... AAAAAAAARRRRRGGHHHHHHH!!!!!

Seriously. I need to either just hope for a miracle to make this thing run again, or just put it up for sale on Craigslist and take a huge friggin' loss on the bastard.

85ragtop · Dec 23, 2007

Darkwriter77 said:
No luck with Chuck.

He did manage to get the thing to *ALMOST* run, but it's still the same issue: No fuel coming through the injectors. It's getting fuel TO the TBI unit, it's getting spark, it's getting signal to the injectors, it's spotlessly clean all through the TBI unit itself ... AAAAAAAARRRRRGGHHHHHHH!!!!!

Seriously. I need to either just hope for a miracle to make this thing run again, or just put it up for sale on Craigslist and take a huge friggin' loss on the bastard.

I'm in the same shape with the Camino.

Darkwriter77 · Dec 24, 2007

If I didn't have to worry about emissions, I'd just convert this stupid thing to a carb'ed setup and be done with it.

Darkwriter77 · Dec 26, 2007

UPDATE: Still no luck. Going to redo the connections to the injectors with soldered connections instead of crimped ones, just to be on the safe side and make sure they're getting full voltage.

Also going to pull the return hose to the tank to make sure fuel is being sent to the TBI and then looping back, which would indicate everything else up to that point is good and flowing right (probably a bad FPR, then). Probably going to rebuild the TBI ... AGAIN ... and hope that I simply got a bad FPR by some random chance. I pulled the turd apart when I tore the TBI down completely last weekend and everything was completely spotless, with no signs of foreign (or domestic) debris, damaged/leaky gaskets, or tears or holes in the FPR diaphragm.

If all this fails, my only remaining hopes are to replace the TBI injector pod as a full unit, and swap out the ECM at last (expensive final resort). If none of this gets me up and running again ... screw it. The Chubby will become someone else's problem as I put it up for sale and hope to recoup at least a portion of my losses.

woaixiaoxiao1 · Dec 26, 2007

I'm a spam bot and have since been removed.

Darkwriter77 · Dec 26, 2007

woaixiaoxiao1 said:
The injectors are, in fact, getting signal to spray - I verified this with the noid lights - so it's not likely to be the computer.

I think the chances of it are astronomically distant, but maybe I replaced two bad injectors with two more bad injectors? Either that, or I have a blockage somewhere in the TBI unit's passages between the fuel pressure regulator and the injectors. Thing is, HOW would something big enough to block it get past the fuel pump sock, the fuel filter, and then the fuel pressure regulator, too?

I had a weird thought: Maybe someone previously put sugar in the gas tank? How would I verify this? Besides tasting it, of course...

Hmmm. Those words sound familiar...

Darkwriter77 · Dec 28, 2007

IT LIVES!

Turned out to be a combination of several things:

1. Crimped rubber fuel supply line by the tank - my fault, I made them long for ease of tank removal and such, but when putting the tank back up, the supply line got pinched almost completely shut. It was letting just enough fuel through to tease me and mess with my emotions.

2. Lower TBI unit injector pod was cracked. It was sucking air and not letting fuel go into the injectors, so the regulator was just shipping the stuff right back toward the tank. When I fixed the kinked fuel line, I was getting so much fuel to the TBI that it was just GUSHING right out of the bottom of the injector pod and flooding the intake.

3. Timing was WAYYYYYY off after piddling around with the pickup coil and whatnot. I lined it back up with the marks I'd made before I'd pulled the dizzy and it smoothed things out quite a bit. When I double-checked the timing, I was then only 2* off.

Sooooo ... now it runs like poo, but at least it runs well enough that I was able to drive it around a little and get a feel for what all else it needs ... which ... is ... a lot. It still lugs and chugs and misses a lot when it's in gear, and it still gags when it's given more than 25% throttle input, but it idles smooth as silk in park or neutral. Probably a sensor issue. My list of suspects:

1. TPS (going to check the voltage tomorrow, now that it's in running condition)
2. EGR valve (going to pull it and see if it needs cleaning)
3. EGR vacuum solenoid (not sure how to test it, yet)
4. Knock sensor (ditto)
5. MAP sensor (doubtfully this, as it looks brand spankin' new, but who knows)

Many, many thanks to those who've offered suggestions to get me looking in the right direction and have this sucker running again. Y'all rule.

timeless2 · Dec 29, 2007

Wow, get this little guy running (better) and then start running from it.

Glad you're in action now.

hhead · Jan 9, 2008

I know you said the exhaust needed work. Just a thought. A clogged catalytic converter will cause the same problem. no power when giving it gas sound like it's missing, idles okay, when it gets fully clogged the car won't start at all. simple to remove exhaust if it is clogged. no need to buy parts yet if it's not the culprit. i guess you can just go to the tailpipe and see if exhaust is coming out.

Darkwriter77 · Feb 5, 2008

EXTENDED UPDATE:

The Chubby lives, and it lives well, now. The full tally of items that I had to clean/fix/replace/adjust or otherwise tinker with to make the thing run right were as follows...

1. IAC valve was sticking
2. TPS was bad (even though it tested good with a voltmeter ... go figure)
3. Timing chain was sloppy
4. Cam timing gear had a broken/wiggly tooth
5. Harmonic balancer had spun (although it still doesn't wobble)
6. Rotor button on BRAND NEW distributor cap was broken/improperly manufactured
7. TBI injector pod was cracked
8. Two plugs on the driver's side were barely screwed in even finger-tight by the prior owner
9. Incorrect EGR valve was installed (was borrowed from a 4.3L full-size Chevy truck, or the whole motor was transplanted from one)
10. Five separate vacuum hose leaks (cracked/broken plastic lines and missing/disconnected rubber hoses)

Just thought I'd put a final update on this thing, in case anyone was curious. Unfortunately, this wasn't one of those "I replaced this one thing and it fixed all my problems" kinds of deals. It was A LOT of stuff that had gone horribly, horribly wrong due to the prior owner being an incompetent douche.

timeless2 · Feb 5, 2008

Geez, did that thing emerge from a body of water or did someone actually neglect it that bad?

Just hard to believe a person could be that dense.

4.3 TBI Chubby nightmare

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