4.3 lacks pickup

I have a 92 T-10 2 dr 4x4, it has a 4.3 Z motor, It runs fine, a vacuum leak in the 4x4 system but thats what a twist lok cable is for. It lacks pickup, Ive done a full tune up, just had a cat back put on not to long ago, it has 147K on it.


Any info on where to look is helpful, ive also cleaned the EGR valve.

Thanks

is your ses light on? if your truck has O2 sensors, how long has it been since they have been replaced? a bad o2 can richen the engine and cause it to stumble. you may need to run a bottle of fuel injector cleaner through the tank if you have not done so in awhile.

is your ses light on? if your truck has O2 sensors, how long has it been since they have been replaced? a bad o2 can richen the engine and cause it to stuble. you may need to run a bottle of fuel injector cleaner through the tank if you have not done so in awhile.


Ive seafoamed it, no lights but ABS for right frnt sensor, O2 I havnt checked but its not stumbling, It drives fine, until I floor it then it takes forever to respond and when it does its very weak. The tranny is not slipping at all either, Im confused, The motor was rebuilt almost 30k ago.

Reset your timing to base zero.

Unconnect the black and tan wire under the passenger front footwell carpet going to the PCM, you will see a connector you can unattached.

Set the timing to zero.

Reconnect the wire.

Also, what did this full tuneup include?

Reset your timing to base zero.

Unconnect the black and tan wire under the passenger front footwell carpet going to the PCM, you will see a connector you can unattached.

Set the timing to zero.

Reconnect the wire.

Also, what did this full tuneup include?

Plugs,wires,cap,rotor,all filters, coolant change, all fluid change, wipers, basically a very expensive tune up. Now setting the timing on these pigs is identical to small block chevy timing adjusting , correct?

Remove the timing wire, set to zero, reconnect wire. Remove negative battery cable to clear the computer and start'r'up.

Remove the timing wire, set to zero, reconnect wire. Remove negative battery cable to clear the computer and start'r'up.

Will do, thanks.

Plz give an update to this thread once you complete the clearing process. I am interested in the results.

Plz give an update to this thread once you complete the clearing process. I am interested in the results.


Im gonna try to do it today but might not happen for a few weekends yet.

I agree with LT check the timing, and adjust if needed. If that doesn't work, disconnect the EGR , and plug the line, and take it for a drive, see what that does.

I agree with LT check the timing, and adjust if needed. If that doesn't work, disconnect the EGR , and plug the line, and take it for a drive, see what that does.
I did the EGR thing, it didnt change anything at all. the idle didnt even stumble when I pulled the line.

have you had the fuel pressure checked, you could have a bad pump....?
my 4.3 was lacking pickup as well changed the pump and module and it runs like a top now....not enough pressure means not enough fuel therefore engine wont run like it should

I did the EGR thing, it didnt change anything at all. the idle didnt even stumble when I pulled the line.

And what about the timing?

And what about the timing?


I didnt get to it that day, the new weekend isnt here yet. I doubt I can do it this weekend either.



the Fuel pressure is fine, the thing moves when you floor it in first but if you are in 3rd or OD and kickdown to 2nd(passing) it doesnt have the pick up it should, Other then that it runs just fine, a little noisy but i get between 13-19 mpg to each tank. I want to know why nothing changed when the EGR was unplugged.

Ive always ditched the smog systems first but this car needs to keep em due to its daily duty.

For starters,if the plug gap is off either way it will affect alot of different things.Wrong plugs,cheap wires or what ever will cause issues as well.The timing can handle more than a 0 base,try it 6,8 maybe even 10.As far as the in tank fuel cleaners,save your money,they only clean the pintle and the pintle alone.A real carbon clean,ie:motovac, will clean all,intake runners,valves etc etc.

I want to know why nothing changed when the EGR was unplugged.

Ive always ditched the smog systems first but this car needs to keep em due to its daily duty.

Because the EGR is closed at idle. It only opens when cruising.

For starters,if the plug gap is off either way it will affect alot of different things.Wrong plugs,cheap wires or what ever will cause issues as well.The timing can handle more than a 0 base,try it 6,8 maybe even 10.As far as the in tank fuel cleaners,save your money,they only clean the pintle and the pintle alone.A real carbon clean,ie:motovac, will clean all,intake runners,valves etc etc.



Im using the delco plugs it came with(not originals but OEM), as well as delco wires. The gap is .035.

I honestly havnt had the time to mess with the timing. I will try to get to it this weekend.

Because the EGR is closed at idle. It only opens when cruising.
Ahhh, ok. They never made it past the first day of ownership on previous vehicles. always bypassed them.



Now what am I looking or listening or feeling for and does it have to be warm or cold?

Just a stupid question here, but did you change the cap and rotor?

And how many miles on it again?

Just a stupid question here, but did you change the cap and rotor?

And how many miles on it again?
Yeah cap/rotor/plugs/wires/all filters and fluids. It has 147K on it. its a 92 TBI.

I can just cap the "tit" coming out of the round thing with on the passenger side of the manifold/TBI unit that supplys the EGR valve with vacuum, right?

I forgot to mention, I did have the EGR off the vehicle this past late spring, I soaked it for 24 hours in seafoam, it was clean when I reinstalled it, I didnt use a screened gasket and it is tight. It was filthy.

Yeah cap/rotor/plugs/wires/all filters and fluids. It has 147K on it. its a 92 TBI.

You know what made a difference with mine?..... a new O2 sensor. They have to be changed every 100,000 miles at the worst.

It is the most important sensor on that engine seeing it controls so much. Even though you don't have a check engine light doesn't mean it is worn out, they still can be within tolerances and have the engine not running very well.

So, timing and a new O2 sensor....

Oh, how is the fuel filter?

You know what made a difference with mine?..... a new O2 sensor. They have to be changed every 100,000 miles at the worst.

It is the most important sensor on that engine seeing it controls so much. Even though you don't have a check engine light doesn't mean it is worn out, they still can be within tolerances and have the engine not running very well.

So, timing and a new O2 sensor....

Oh, how is the fuel filter?


Just replaced, happen to know the part # for the o2? Id rather order then go to the store and wait for someone that speaks english to help me.


I can tell you right now that my fuel filter was OE, as well as the plugs and wires. Im quite sure its OE as well.

Thanks for more tips, Im sure it needs to be replaced anyways. I know there was alot of carbon in the motor( gone now thanks to elbow grease and wood carver tools) when I got it. Prolly fuggled up like I suspected, All this crap when its cold outside, why cant crap break when its warm?

I am going to be replacing my o2 sensors here this weekend so I will let you guys know if it helps or not. I can't believe there is 4 of them on a 99' Blazer. If am sort of in a similar situation as you.

Just replaced, happen to know the part # for the o2? Id rather order then go to the store and wait for someone that speaks english to help me.


I can tell you right now that my fuel filter was OE, as well as the plugs and wires. Im quite sure its OE as well.

Thanks for more tips, Im sure it needs to be replaced anyways. I know there was alot of carbon in the motor( gone now thanks to elbow grease and wood carver tools) when I got it. Prolly fuggled up like I suspected, All this crap when its cold outside, why cant crap break when its warm?

Oh, so the fuel filter was changed? Ok...

As for the O2 sensor, go with RockAuto and get the parts there, you should be able to get the part number there beofre you buy it.

TIMING, you gotta do the timing as well.

Ok 1996 Chevy S-10 4x4 with a newly remanufactured engine (about 1000 miles on it). Cap & Rotor (NEW) Plugs & Wires (NEW) Fuel Pump (NEW and 66 psi at the rail) fuel Filter (NEW)

My old broke engine was getting me 18 MPG. "New" engine getting me 15 MPG:banghead: .

I know for sure they did not replace the O2 Sensors and my guess is it is the EGR is off my old engine.

1) Obviously the O2 Sensors need to be replaced and EGR soaked or blown out. Understand these two items have a tremendous effect on performance.

2) Checking/Reseting the timing. I have never checked or reset the timing before. I saw BlazerLt's desription on unpluging the ECM connector and reset timing to zero. But how do I put the timing at zero (or 6 or 8 as previously mentioned to improve pick up) or check to make sure it is at zero. By putting it to zero or 6 or 8 do I understand correctly that it will improve pick up in the engine?

Sorry for the silly question(s) I am new to the 4.3 Vortec and want to make sure I do the necessary maintenance to keep it in shape and get the absolute best performance (power/fuel) I can.

Ok 1996 Chevy S-10 4x4 with a newly remanufactured engine (about 1000 miles on it). Cap & Rotor (NEW) Plugs & Wires (NEW) Fuel Pump (NEW and 66 psi at the rail) fuel Filter (NEW)

My old broke engine was getting me 18 MPG. "New" engine getting me 15 MPG:banghead: .

I know for sure they did not replace the O2 Sensors and my guess is it is the EGR is off my old engine.

1) Obviously the O2 Sensors need to be replaced and EGR soaked or blown out. Understand these two items have a tremendous effect on performance.

2) Checking/Reseting the timing. I have never checked or reset the timing before. I saw BlazerLt's desription on unpluging the ECM connector and reset timing to zero. But how do I put the timing at zero (or 6 or 8 as previously mentioned to improve pick up) or check to make sure it is at zero. By putting it to zero or 6 or 8 do I understand correctly that it will improve pick up in the engine?

Sorry for the silly question(s) I am new to the 4.3 Vortec and want to make sure I do the necessary maintenance to keep it in shape and get the absolute best performance (power/fuel) I can.

It is considered rude to ask for help in someone elses thread.

Start your own thread and I will help you there.

Don't whore this guy's thread, I am only out to help him here.

I will help you in your own.

I think you misunderstood me here BlazerLT. You are helping this guy and I am asking for confirmation of what is being said.

1) Obviously the O2 Sensors need to be replaced and EGR soaked or blown out. Understand these two items have a tremendous effect on performance.

This was more again, confirming what I am reading with your advice.

) Checking/Reseting the timing. I have never checked or reset the timing before. I saw BlazerLt's desription on unpluging the ECM connector and reset timing to zero. But how do I put the timing at zero (or 6 or 8 as previously mentioned to improve pick up) or check to make sure it is at zero. By putting it to zero or 6 or 8 do I understand correctly that it will improve pick up in the engine?


Again, just asking someone to confirm what I am reading so I know that i am getting right.

If it is "rude" for me to make sure that I am understanding what is being written then I'll know next time, that by your standards, I need to just start a new post, refer back to this post, and ask you to re-confirm what i am reading.

On a 1996 you don't touch the timing at all.

I dont mind, if it pertains to this why not add to it?



Anyways, i pulled and capped the vacuum supply TO the EGR, drove it around, not sure if i noticed it, I will be driving it today to check it out. Timing wont be this weekend, I got to get my new house ready to move into in 3 weeks.

What does a bad converter sound like, not the cat the torque converter. I got a Hissing when I accelerate and it sounds like a coffee can full of rocks, but its not coming from the crankcase.

I am buying a new timing gun too, my old one is well, 20 years old.

Ok here's the deal as short as I can get it.Stock timing is 0,the pcm controls the spark curve and advance.IE,base at 0,total full in timg under load at lets say 3000 rpm,maybe,30 degrees.Base timing set at 8 degrees,total full in timing,38 degrees.Just because the decal says 0 and the trusty old "do not adjust" line, doesn't mean you cant.Every and I mean every engine is different.The knock sensor will pull back the timing if it's to much,you will hear a slight knock or ping when under load just before pcm pulls back timing,if you hear that take some out of your base timing.There is alot more involved here than just base timing,injector pulse is affected,02 response and I wont go on.Been a tech for 23 years,drag raced for 10,bench raced for 25.I have picked up a few things along the way.Does anyone know why the timing is 0?I'll give you a hint,cleaner emmisions at perfect tdc.Less waste gases to come out the tail pipe.

Forgot to re-stress the carbon deal.Coking and carbon build up just kills the combustion in an engine,quick at home fix.ACDelco has a product called Cleens,areosol can, I find the easiest way to get it in the engine is through the brake booster vac line.Get the engine good and warm,start spying into line,going into intake of course,keep the idle just enought to keep it running,use the whole can if you can and don't park it near the house or you nieghbours either,let it sit all nite and in the morn take it out for a real hard drive.You WILL notice the difference.Don't underestimate the amount of crap thats going to come out the tail pipe and it really stinks( unless you have a vendetda against your nieghbour) dont do it near the house.

Ok here's the deal as short as I can get it.Stock timing is 0,the pcm controls the spark curve and advance.IE,base at 0,total full in timg under load at lets say 3000 rpm,maybe,30 degrees.Base timing set at 8 degrees,total full in timing,38 degrees.Just because the decal says 0 and the trusty old "do not adjust" line, doesn't mean you cant.Every and I mean every engine is different.The knock sensor will pull back the timing if it's to much,you will hear a slight knock or ping when under load just before pcm pulls back timing,if you hear that take some out of your base timing.There is alot more involved here than just base timing,injector pulse is affected,02 response and I wont go on.Been a tech for 23 years,drag raced for 10,bench raced for 25.I have picked up a few things along the way.Does anyone know why the timing is 0?I'll give you a hint,cleaner emmisions at perfect tdc.Less waste gases to come out the tail pipe.


Same place im coming from, I had modest mighty mouses for years, now its a v6 with alot of electronic crap. If i adjust the timing, it will just go back to where the ECU wants it, id need to alter the ECU to accomidate the change.

I got 147K and pass smog with ease, I really dont want to change that. I have the EGR unplugged and capped, it didnt notice anything last night but again I dont know what im supposed to look for or pay special attention to.


I am going to change the o2 if for anything just peace of mind, its OE for all I know.

Good man, the O2 sensor is the king of the emission control and it being even weak can cause some definite performance loss.

Same place im coming from, I had modest mighty mouses for years, now its a v6 with alot of electronic crap. If i adjust the timing, it will just go back to where the ECU wants it, id need to alter the ECU to accomidate the change.

I got 147K and pass smog with ease, I really dont want to change that. I have the EGR unplugged and capped, it didnt notice anything last night but again I dont know what im supposed to look for or pay special attention to.


I am going to change the o2 if for anything just peace of mind, its OE for all I know.
Dude,re read it.If you have the tools to adjust the timing up you must have the tools to adjust it back.As for the 02,in my opinion use delco.

Delco's are overpriced and seeing Bosch designed GM's O2 sensor system, I think it is safe to say their sensors are just as good for the cheaper price.

Delco's are overpriced and seeing Bosch designed GM's O2 sensor system, I think it is safe to say their sensors are just as good for the cheaper price.
Yep,your right.I quit.BlazerLT you are the man,the Genie,Mr FixIt and the Grand Master know all.I have been at this site for just a few days and you AND you alone drove me away.Nice job.If your goal was to undermind every comment, well you did well.Great job.All and ALL questions need to go to Mr.BlazerLT.He has all the answers!

PS.Delco's are cheaper than Bosch & NTK.I have to ask.............Bosch designed the GM 02,so with that said they are the same?Is that right?You have no idea and have never seen one in action have you.!Once again,BlazerLT,you win,Weekend Warrior at best.Want a pissing contest with BlazerLT?Nope!No thanx.He rules!

OMG...just.....*sigh*...WOW!

Anyone have a soother for this overreactive baby taking a hissy fit over nothing?

Yep,your right.I quit.BlazerLT you are the man,the Genie,Mr FixIt and the Grand Master know all.I have been at this site for just a few days and you AND you alone drove me away.Nice job.If your goal was to undermind every comment, well you did well.Great job.All and ALL questions need to go to Mr.BlazerLT.He has all the answers!

PS.Delco's are cheaper than Bosch & NTK.I have to ask.............Bosch designed the GM 02,so with that said they are the same?Is that right?You have no idea and have never seen one in action have you.!Once again,BlazerLT,you win,Weekend Warrior at best.Want a pissing contest with BlazerLT?Nope!No thanx.He rules!
dude LT was just stating his opinion and trying to save you (or someone else) money by purchasing a bosch sensor instead of an ac delco. personal attacks are not nessesary and will not be tollerated :nono: .