87 s10 blazer problem

[my70chevelless]

Good Morning,
Last Nov. I bought a s10 blazer 4x4 which has the 2.8L in her. The guy I bought it off of told me he put a diffrent cam in it headers & a holley tbi. I had to adjust the tvs cable as she was shifting to high in the rpms. I bought the truck for a winter vehicle & daily driver. I have had to put a new radiator in her as she was running around 230 deg. now she runs at 210 which is better. Since I know very little about the 2.8 I'm having some running problems with her!. She does not like to go up up hills she seems to hit third and bogs down? She also stumbles every now & then as if she is starving for fuel. The holley that he put on her has red throttle plates. Could anyone tell me what this engine had as an original tbi. As it feels to me as she is getting to much fuel. I also replaced the o2 sensor as I was getting a check engine light & checked the code. but it still comes on every now & then with the same code & I cleared the memorie. Any help on these or this problem would be a great help! Thank you for your time.

[Tink]

Sounds like you are on track on thinking she is getting too much fuel... she maybe bogging and stumbling because of too much fuel, ie. the mixture is wrong. (I had a carb that was too big for my 350 that caused boggin and stumbling).

Also what code did you get for the O2 sensor? 13, 44 or 45? I'm guessing 45, which would be rich... meaning the O2 sensor itself isn't bad but that the the O2 sensor is showing a persistently low exhaust oxygen content (rich), despite the efforts of the ECM to decrease injector on-time (thus decreasing fuel delivered).

The conditions for setting this code are:

no Code 34 or Code 35 (MAF error) present, and
the O2 sensor voltage remains above 752 mV, and
the ECM is in Closed Loop control, and
throttle position is < 2 percent or > 20 percent, and
the above conditions exist for more than 20 seconds.Typical causes for this code include:
1) O2 sensor defective or contaminated (if incorrect RTV sealant or too much RTV is used, this may happen)
2) Leaking fuel injectors
3) Fuel pressure too high
4) Evaporative Emission system defect
5) TPS and/or EGR problem

I'm not sure what the cfm of the stock 2.8L TB is... if I had to wager a guess, I'd say 400-500.... I'm sure someone here knows.

Oh, and welcome to the planet!

[Mikz86TA]

Welcome to The PLANET!!!! How exactly did you adjust the TV cable....there is only one correct way and it is NOT to be used to fine tune shifting with. Improper adjusting will cause tranny failure. Got a pic of the bracket for it too?

[my70chevelless]

Thank you for the welcome!
The code I got or keep getting is 12 this is what I can't figure out!. Going up hills as we have a lot of them when she hits 30mph she just wants to slow right down to nothing I mean crawl. I can put my foot right down to the floor & she does not respond. The 02 sensor is in the header. Like I said I replaced the 02 sensor plugs wires cap rotor checked the coil. Another thing is it seems as if the light only comes on when the temp. reaches 210 deg.
As far as the bracket goes for the tvs cable I will take some pics. & post them latter maybe that will show something as a friend of mine adjusted that when I first bought her he is a mechanic but he just put some slack in the cable nothing technical!. Thank's for the help & I will post pics. if I can figure out how latter.

[Mikz86TA]

There is only 1 proper way to 'set' the TV cable. You might need to drop the pan to veryfy it. Also the TV valve in the trans could be sticking. Have you serviced it lately? If the TV valve was sticking, there are correction kits for it. Get back with pics. ON the other thread there is a link for you to read.

[my70chevelless]

Here are the pictures of the cable the bracket & the holley carb. I hope they help. Also I want to thank you for the link I will read it latter. I tried to push that button in but it was frozen so I have put some liquid wrench on it!. Also about the tranny I have changed the fluid before & filter in another car but since I owen manuel vehicles I never played with this valve before is this something I can do? Thank's again for all your help Will,3322

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[Mikz86TA]

Thats a OEM replacement style TB unit and its using the stock brackets. To properly set the TV cable, push in on the D-shaped button, feed the plastic sleeving that the center cable comes out of back toward the bracket and release the D-button. Have someone else push the accelerator to the floor and hold it. At some point in the throttle rotation the TV cable you just pushed back toward the bracket is going to 'ratchet' out some. Maybe less than it is now...seems to be out more that it should to me. Whole they are holding the throttle down, try to manualy rotate it open more. If you cant...Good If you can...then your accelerator cable is not allowing WOT to your TBI unit. Address that fix 1st. If your TV cable DID NOT ratchet out any, you will need to drop the pan and check whats going on in there. If it DID ratchet out, you really dont need to drop the pan at this time. By it NOT ratcheting out, means that the TV valve isnt being actuated fully at WOT and therefore will cause line pressure issues inside the trans. Effects downshift, WOT shift timing, part-throttle shift timing and fluid pressures that control shifting firmness/etc. But DO NOT try to 'play' with it to get shifts different. Just because it effects it, doesnt mean its to adjust it. Reading the link will open your eyes alot about this. Thr ratcheting is caused by the valve bottoming out WideOpen and the excess slack is being self-adjusted. For now thats about as far as we go. Get back on what you find out concerning these 2 things ( Throttle Opening and TV Setting)

[Mikz86TA]

Pics are always best. 1st shows probably what you already know. This is the way to reset it and then WOT the accelerator pedal. 2nd shows to also chacl for slack once the throttle is wide open. Tug at the metal cable to verify its taught...and no slack. No need to yank it, just press it while keeping throttle wide open. Should be no slack which indicates the TV plunger is fully depressed in the trans and seating the TV valve as it should.

[my70chevelless]

Thank you Mikz86TA
See even after I read that which was about 3 times I still was going to do it wrong!. I thought that when you push that button in the cable it self goes in not the plastic!. Now I understand & will have someone get in the truck to see if the throttle opens fully since I believe this is an aftermarket tbi. I was going to order a new tv cable as this one is a bisket to push in. I also sent them an email about a new spring as I read those get worn & didn't see them on there web page. Lord knows I went over that page if I get this set up DO YOU THINK I SHOULD PRESSURE TEST IT AS THEY SAY?. Well I have all day today & will try this now that you cleared it up I will let you know what happens wish me luck I need it. I'll take my 4 & 5 speeds anyday automatics scare me. Once again THANK YOU for all your help! Will,

[Mikz86TA]

If you have a pressure gague, yes definately do a pressure test. As you might have read, the starting position of the valve could be off inside the tranny...even if the cable is correctly set. It happens sometimes due to wear. That could easily caus issues to. In fact the only real way to determine its operating correctly is by checking with the gague. I have the spec ranges for each gear when you get to that point. Assistance is needed, truck running, applied brakes, put in each gear selection includinng neutral and park, and reading with TV at reas as well as pulling out on the center cable. It took me a while nack when to figure out how it worked too. Its kinda confusing to be honest without a visual or seeing it properly done forst hand. By pushing the sleeving back in, you are effectively shortening the draw stroke of the center cable. Lemme know how it goes. I hope this clears up your issue. Youve spent time on it and it would suck if it didnt. But at least not this part will be right and youll know how it operates =)

[my70chevelless]

Well it took a pair of vise grips to push that button in. Then I couldn't get the plastic sleeve to lock so I took the cable out of the bracket & finally got it to lock. I then put it back in the bracket & put the end back on the carb. I had a friend push the pedal all the way to the floor it ratcheted the plastic. I checked to see if the throttles opened fully which they did. I still don't trust that cable as I think it is worn as it doesn't seem to lock!. Anyway here are the new pictures after this was done. DO YOU THINK I SHOULD ORDER A NEW CABLE FROM THAT WEB SITE?. As it looks as if the the adjustment is the same as before!. I have not took her out since this was done. Could the cable be stretched I'm lost here any sugjestions would be a great help!. Thank you Will,

[my70chevelless]

Good Morning,
Well I just got back from driving her & she is doing the same thing plus now when I'm driving at a steady 40-45mph she was stumbling as if she wasn't getting gas at least that's the way it felt & going up hills 1st to 2nd fine 3rd she drops right down to 20mph & that's with my foot all the way to the floor. Sometimes I have to shift her into 2nd just to make the hill. One thing I noticed was that when I first took her out cold she was shifting fine but as soon as the temp went to 210deg. is when the problems start. I'm not sure if that tells anything but I have put a tranny cooler on her about two months ago when I changed the radiator. So now I'm really lost as to what could be going on! and really embarising. Well if anyone reads this & can give me a clue would be a BIG help. Thank you for your time. Will,

[T Man]

Pull a spark plug and see if it is sooty. I have the exact same combo as you do, and had a leaky injector o ring do the same thing to me. Thought it was the tv cable as well

[Slacker1357]

If I could guess at another thing it would be the TPS (throttle position sensor) about $50

[my70chevelless]

I just changed all the plugs wires cap & rotor. The old ones were fine they were not sooty I thought the same thing I also checked the coil it was firing good as well & at the wires. The tps I checked last night and found when I pulled the connector off I found one of the black plastic pieces that cover the wire was gone. So I ordered a new connector & am going to pick up a tps sensor. I also ordered a tv cable as mine will not hold the cable in position right now I have a wire tie holding it & on we go. My biggest problem is the lack of power especially when she shifts into 3rd & going up hills. Today I had it to the floor & she hardly made it up at 20mph!. Also the hesitation at a standing stop to get her going & on the highway but this only happens when she hits 210deg. I am running out of things to look for & money

[Slacker1357]

not burning oil are you? thats sounds alot like when my jimmy died. burned the oil and now it sounds like a diesel. low high speed raising temp. sounds alot like my truck.

[my70chevelless]

No burning of oil or anti-freeze. I put a new TV cable on her a universal one since I was not going to pay the price that GM wanted & adjusted it just like they said. I'm still having that problem 3rd is where she drops in the rpm's then when she hits 4th she picks right up. I'm waiting for that connector for the TPS then I will replace the Tps also. But it does run worse when she gets hot. Someone told me to replace the valve body but when I seen the price of that I passed out. This is more or less just my winter plus everyday driver.
I was thinking since I don't use the AC to remove the condenser to see if this is blocking the air flow. I checked the oil and it isn't milky or low I'm woundering if the hesitation is due to vapor lock but the shifting I have no clue!