not a ford, but still need help. 2000 Chevy Blazer

[nunan]

my buddy has a 2000 blazer with the 4.3 and the spider injectors. he had a leaking lower intake gasket, and i had never done one before so i figured i'd take on the challenge. pulled the motor apart, replaced the gaskets and got it back together. initially, i had timed it wrong (thats what i get for not using a compression gauge the first time, and relying on a buddy to help me), but i didnt realize at first it was timed wrong. so i was cranking it all together for probably a good 5 minutes (over the course of trying to figure out what was wrong). well the next day i pulled the distributor, timed it according to the chiltons manual, and fired it up...only problem is it ran like crap. sputtering and misfiring and just plain running rough. so i shut it off because it wreaked of fuel, and had a check engine light on. so i left it until today to check the codes, i got a p0135 for the b1s1 o2 sensor. went underneathe, didnt see any corrosion or burned wires. so i reset the code, and it did not return. i restarted the vehicle, and it had a stft b1 of 50%. so i shut the truck off immediately, as i did not want it pouring fuel down the exhaust pipes. here's a few things about it just to add on to my book i've got going:

 

cap and rotor were replaced with intake change, wires were replaced 6 months ago (duracrap. the cap and rotor were bad, so i may have to replace the wires too) plenum gasket was changed with lower intakes. ive sprayed the area down with 2+2 to check for vacuum leaks, could not find any.also used propane as well to check. intake gaskets were torqued in sequence, but not with a good torque wrench (good one is at shop) so i may bring that home and retorque the intakes. not sure where else to look, may try to reset timing yet again, couldve sworn i had it right this time though. any other ideas what may cause this?

[joshbuys]

These spider poppet injectors are known for issues with leaking fuel, you can check for an external fuel leak at the spider or pressure regulator, if no external leak, possibly running some cleaner through the injectors could help if one is sticking. Chevy updated these injectors and the replacements are supposed to be better and not stick, but a replacement spider can be pricey.

[Bruce Amacker]

My memory is really weak on these, but I'll give it a shot.

 

Did you mix up the spiders where they are supposed to go in the ports? They won't run for shit if you did.

 

Does yours have a "flapper valve" motor on the rear of the plenum,(electric dual plane manifold) or an EGR? You can pull them out and look inside for leaks, it's really common to have bad (stuck) injectors or leaks under the plenum. Look for wetness or puddling, which is not normal. Cycle the key and look inside, the large tubes toward the rear will split.

 

Standard has an update where the injector assy is changed and the tips now have the electrical portion built in, but you have to buy the assy and I doubt it's cheap.

 

P0135 is O2 heater, do an amp test at the fuse or do a voltage drop across the fuse terminals while the key is on, a drop of .1 or .2v will indicate it's working.

 

STFT of 50% makes me think you have a poppet stuck or switched the tubes around. Does it smooth out if you feed it propane or ether?

 

I have a lot of pictures of this system but not your model year.

 

Good Luck!

 

[Mbl35]

I remember these having fuelpump issues, had a 96 or 97 once fouling up plugs and the fuel pump fixed it.

[Bruce Amacker]

Damn, you're right, I forgot about that, it's REALLY important for it to be correct. IIRC it should be above 63psi. If it's below 58 it won't run right- the poppets don't open.

 

 

[Jim Warman]

My only experience with these systems was on the V8s long before I moved back to a Ford dealer... but I do recall poppet valve concerns....

 

To the subject at hand... STFT on one bank is 50% (FWIW, this means it is TRYING to add fuel to that bank but not accomplishing what it wants... you should be OK to run it). What is LTFT and what is the other bank doing for fuel trims?

 

Does the thing just run rough or does it have any misfires? What are the O2s doing?

 

Checking for vacuum leaks... don't forget that there is a bottom to the lower intake gaskets... Disable the PCV system and flood the crankcase with propane vapours to check the bottom seal of the intake...

 

However.... knowing that bank 1 is trying to add fuel without knowing what bank 2 is trying to do is a little like watching ICP without knowing what IPR is doing...

[Matt Saunoras]

is the spider hard to change? our parts guy has a 99 sonoma and it's the only thing I haven't replaced trying to hunt down a random miss under load. we finally gave up on it because he doesn't wanna pay for a spider assembly. The plugs were never fouled up so it's not overfueling and probably not hurting anything

 

 

 

btw he's throwing parts at it in order from cheapest to most expensive, so guess what the only thing left is.

[Bruce Amacker]

Buy a reman assy from Jim Linder at Linder Technical in Indy. He ships everywhere daily.

 

http://www.lindertech.com/

 

Good Luck!

 

[Brad Clayton]

Bubba's tek tips are pretty funny on that site.

[Bruce Amacker]

Jim Linder is a pillar in the training community, perhaps one of the most accomplished trainers around. He has been the driving force behind numerous national training conferences and one of the key people to launch my training career. He's slowing down toward retirement now, well into his 60's and has redirected his focus from high tech training to hot rod training, now doing classes at his Indianapolis facility on carbs, point ignition, distributor advances and similar stuff, and a line of Bubba's food products that he sells online. He has several 50's style rat rods in his stable as well as a Bonneville salt flats racer with a flathead Ford in it. He missed the top speed mark by just a hair recently.

 

As far as Jim goes himself, he's a product of Tennessee with the drawl you'd expect. I can't say enough about the guy- he's brilliant and comes across as a dumb hillbilly. He's hilarious as well.

 

Oh, by the way, he sells a great line of reman injectors at a reasonable price with a lifetime warranty.

 

[ETS]

Just for information: The short plastic fuel lines between spider and outside intake are known for splitting inside lower intake. This fills cylinders on left side of engine. Just left GM Dealer, Have seen it several times. Customers replace spiders and still have same symptoms.

[Fredsvt]

Yes, and those lines aren't called lines.

 

GM calls those feed lines a "nut kit" for whatever reason.