So my 1994 s10 blazer with the 4.3 vortec cpi (w vin number) broke down on me last week. I was driving when it started hesitating like it wasn't getting enough gas. It stalled and would not start. I got it home(towed) and changed the fuel filter thinkinng it might be a stoppedd up filter. Wasn't all that dirty but already had the part so changed it. That didn't do anything so i got a fuel pressure gauge to check the pressure. Getting about 52-58 with key on so i assume im good with that. Took the plenum off and found the clean/golden passenger side of the engine which indicates a bad regulator. Put a new regulator on and everything back together and ran great for a little bit. Took on a test drive and filled up the tank and back home about 10 miles all together. Then later that evening went into town and after driving about 15 miles had the same issues as before and stalled out and had it towed home.
After it sits for a day I can start it up and it will idle fine, but when I give it gas is stumbles real bad and will die.
I have good spark with the timing light, good pressure with the gauge, what could it be???
I had a check engine light but was the knock sensor on the back by my distributer cap-plugged it back in and it fixed the light, but nothing else.

recent work:
sythetic oil/filter-about 3000 miles ago
platinum bosch plugs-about 3000 miles ago
k&n high flow filter-about 1500 miles
serpentine belt/tensioner pulleys-1500 miles
fuel filter
pressure regulator

It almosts acts the way that my 89 did when I had a kinked fuel line but couldnt find anything kinked up
Any help would be great!

 

well I checked my trouble codes on the computer via jumper from a to b (didnt realize i would have any because the light was off, so some must have been stored) and have codes 12(engine was off so is normal) 22, 34, and 43. I know 43 was from the spark control module being unplugged for so long so now I have 22 and 34.
my haynes manual say the following:

code 22- throttle posistion sensor/voltage low

code 34-vacuum sensor or MAP sensor

for code 22 it recomends changing the tps is there a way to test the sensor before doing so?

and also for code 34 it recomends i replace the MAP sensor-any way to test these?

Changing the TPS would make sense to me-well it would explain the good idle and bad accelerating, but not the stalling out and not starting up

 

You can test the TPS with a multimeter. Connect the probes to the sensons pins, and set it on Ohms. The resistance should change smoothly up as you turn the throttle open. I dont know what values though, but they are in a thread on here... You can also use some carb cleaner to remove junk from inside the MAP sensor too. I would only change the sensors if there is something rattling in them.

You seem to have very similar problems that I had. I got a mess of codes, but servicing the EGR valve fixed it and cost next to nothing. If you take it off its usually full of crap. A new EGR is about 200 bucks, but all you really need to do is remove all the carbon from inside it and make sure the plunger moves open and closed without sticking.

My truck would crap out and not start once it was warmed up. Its cause the EGR was sticking open from crud in it. I put one from the wreckers on instead of clean it cause I had the part handy. I did however get an EGR code, which you do not have there. I also had some triggered for TPS and MAP which were just made as a result of the EGR buggering up.

 

I did find a way to test the TPS after i had asked (ohmd the sensor pins and turned the throttle and recieved a steady change) and found it to pass the test.

Im gonna try and check the MAP in the morning before work as well as the EGR

When I had the plenum off it didnt seem to have a lot of crud in the EGR hole but i guess its worth a try, right?

 

Check the hole in the plenum AND the EGR valve. You should be able to run a small brush up through the EGR passage in the plenum with no problem. Mine was solid (small chisel and a lot of Berryman's B-12 - great stuff by the way). I just soaked my valve in B-12 and really cleaned the interior of it. Worked like a champ after that. You can get an EGR gasket with a screen in it that keeps a lot of the garbage out of it. By the way, how are ya Ohsofly? Haven't seen you post too much in a while.

 

Gimpy, thats cause I had alot on my plate. Im also no longer living it up on the west coast in sunny Abbotsford either. Had it out with the ex and packed my things and moved back to Edmonton. Blazer hauled my 2360 pound trailer full of tools through the mountains no problems, and my dad pulled a large Uhaul with my household belongings in it with his big RV. Got my old job back, got my old life back, got my single income back, getting the young chicks back too! Ive always beleive the best way to get over someone is to get into someone else! Ive got plenty to do on my truck now, the place I have has a double garage too! Just been setting up my toys and shop. Ive been trying to pop in at least once a day and have a snoop.

I also took my digital dash apart and cleaned the orange rust off the connections for the plug and creamed it up with diletric grease real good and seems to work just fine now, no blinking out, but the speedo still isnt working. Couldnt take pics as I dont own a camera, I used "hers" all the time before. Will be grabbing a pile of parts every pay period to keep myself busy. Did the rear brakes and axle seals to find that I have grooves worn into the backing plates that I filled with JB weld, and I also have loose wheel cyls, they are sloppy on the backing plates. So backing plates and wheel cyls are next things I get. Then front calipers, pads, lines and rotors. Then balljoints, tie rods, idler and 4 shocks. Then shackles and tires and wheels. Somewhere in there Ill do all the painting to it too. I have many cans of black boxliner waiting to go on it. And probably new torsion bars and rear springs so that I can have new everything under there. Then out of province inspection so I can get cheap insurance here and put my OHSOFLY alberta plates back on. Then find a winter beater and try and get a V8 in it over the winter months.

Sorry bout the thread jack, any updates on the fix OP?

 

Well the EGR was clean, did a little extra cleaning for it but didnt gettta put everything back together with having to go to work
Needed to move it befor working on it and couldnt get it to start at all so i guess what ever it is thats wrong is getting worse/not intermitent at all now. Needless to say had to push it quite a bit lol
But idk what to do now
I cant find any sort of fuel leaks with the plenum off and am completely lost
Cant be anything to complicated...

 

What you really need to do is get your hands on a pressure tester and hook it up. Borrow or buy for about 50 bucks. Its a handy diagnostic tool and you can use it on anything. You can have the fuel leak back into the tank so the only way you are going to see that happening is with a test guage.

 

Yeah I have a fuel pressure gauge I got from advanceauto for like 44 bucks after tax
Im getting around 55-60 with the key on

I did some cleaning of the plenum and all the electric connectors and all that good stuff and got it to start up
Was idling real high but sounded good. Took for test drive and was hitting 35 without pushing the gas peddle but no missing or feeling like i have no fuel. Computer threw 2 codes 34(map/vaccume) and 54(low fuel pump voltage)

Found the high idle was caused by the IAC or whatever not being plugged back in cleared the comp and everything seems right. Took for about an 8 mile test drive and let it iddle for a while and so far no issues. No computer codes and no lights on

As of now as long as nothing decides to come back its fixed i think. Will know for sure later when I go for a further drive.
Thanks everyone and hopfully its fixed for good :]

 

well the bitch is back to its tricks :/
Same **** as before so I took the egr off cleaned it up(wasnt too bad) but everything back together no help
good fuel pressure good spark same symptons
I can start it up and it will idle fine but touch the gas and it dies and wont start for a while
Im thinking maybe my CPI unit but dont really wanna throw $300+ on a new one
checked around the yards and nobody has them and nothing on craigslist.
I took the injector out soaked it and put everything back but no improvement
I have no codes and good pressure/spark.
Could it still be the EGR and how could i test it? Also is there a way to test the CPI spider?