1993 s-10

[2001300exguy]

alright i posted here a few weeks ago and it was the fuel pump that was wrong with it but now its doing something weird again, actually the same thing, after it gets arm or is running for a few minutes. it will start to bog down after about one quarter throttle. it wont die but will lurch real bad when letting the clutch out. it was doin thid before the fuel pump whent out and now its doing the same thing after i put a brand new fuel pump in it. i checked the timing, replaced the plugs and wires and now im just out of ideas. Do you guys have any ideas of what i might have overlooked or anyother ideas.
Thanks

[2001300exguy]

bump

[2001300exguy]

i just replaced the fuel pump which was suggested by a member at 60degreev6.com and it is still doing the same think. any other ideas are appreciated

[CDCHONDAS]

you replace the fuel filter? is this one a vortec or not, I know some of the CPI units got leaks in them that you had to fix, yours should be TBI or CPI as far as fuel injection. I used to know all the years and what was what but i have forgotten most of it...:rolleyes:

[2001300exguy]

i have a 2.8 v6 with TBI

[CDCHONDAS]

the tbi was pretty good normally, the 2.8 wasnt though, if you havent replaced the fuel filter do that, and look around the throttle body at the vaccum hoses, they can get brittle and crack

[Heybo]

When you replaced the fuel pump, did you install the new little rubber hose that came with it or did you use the old one? That little piece of hose needs to be replaced whenever you change the pump. It smooths out the pulsation effect caused by the pump so that you have smooth fuel flow and can cause you to have a low pressure problem if it has a split in it.

[2001300exguy]

yea i just replaced the fuel filter today, i checked all the hoses to see if the were cut or ripprf but not to check for dry rot ill have to do that tomorow

[Joe250x]

your problem sounds computer related or at least sensor related.
when you start your truck up from cold it will use pre determined settings stored in your computer also called "open loop" but after a cetrian time it will go to closed loop mode which will use the computers sensors to determine the correct air fuel ratio depending on the temperature sensor, MAP sensor, Oxygen sensor and so forth. your 2.8 should have something called ane ESC sensor on it "electronic spark sensor". I have had problems with them before myself it is located on the middle left side of the firewall with about 4-8 wires going in to it. i am not saying that is wrong with your truck but i think it is computer related. You can read your engine codes "DTC's" from a plug on your dashboard called an ALDL. all you need is a paperclip insert it into terminals A & B the two top right holes while the key is off then put the key into the on position "don't start it" and watch your service engine soon light it will blink numerical codes at you. it will blink 1 time, then a pause then twice. that is code 12. 12 will blink 3 times and if there are any codes stored in your computer you will see them after 12 and they will repeat 3 times also. it will end with code 12 also. when you get the codes try a google search with DTC and the numbers, if there is alot refine your search with the year and make. and if you can't find anything with google i will help you out more. if any part of this confuses you let me know :)

[Joe250x]

I have had problems with them before myself it is located on the middle left side of the firewall with about 4-8 wires going in to it.

EDIT middle right side. left while looking under the hood

[Camaroguy87132]

do you want some slotted tail light covers for $20 shipped? I bought them by an accident thinking they were for my truck.

[2001300exguy]

alright i tried the papeclip idea and the code came up 121212343434 and then it repeated itself

[2001300exguy]

im not sure if this matters but when the truck is on the check engine light is not on, i know this matters on 96 and newer but i didnt know if mine was like that

[Joe250x]

code 34 is the MAP sensor circuit voltage to low high vacuum
cose 43 is the ESC electronic spark control circuit

now by getting these codes it dosen't mean that the parts are faulty. i would troubleshoot the code 43 first because that problem might have caused the cose 34 to enter.
autozone has a whole lot fo free information on the net.
go to autozone.com then enter your vehicle. go to repair info and look around. in the DTC's ares they have flow charts. they can get technical but try your best at following them. i know that you don't have a scan tool "Tech1" but try the other stuff they suggest. it's the best free car repair info that i found on the net



is that your number in your sig? i can call you to talk more if needed

[Joe250x]

at autozone after you entered your vehicle info go to
repair info
vehicle repair guide
emission controls
diagnostic trouble codes and charts
figure 127 is for code 34
figure 130 is for code 43

i cant find info on code 31 but maybe i misunderstood that one

[2001300exguy]

yea sorry the 31 was a mis type

[Joe250x]

thats fine i do that too. s-10's and gmc s-15's are my thing. i have owned 5 of them, my mom had 3 of them my dad had 2 of them my sister boyfriend has1 and my sister has one. i know that body style good i have replaced over 10 front ends. 7 on a single truck of my friends LOL. i am the oddball in my house now because i drive an astro van for work. i would have an s-10 but there isn't enough room and soon i will need a fullsize. if you need parts let me know because i have 4 parts trucks right now and the code enforcer is on my butt about getting rid of them. what a pain

[2001300exguy]

well sorry if it seemslike i am asking alot of questions but do you have any idea on how i would go about fixing this, like what do i need to buy

[Joe250x]

i'll answer you tomorrow. it's late here and i will pull out some books about it and post back tomorrow night :)

[Joe250x]

Ok, i did some research and i found this.
First inspect all the vacuum lines in and around the engine bay for deterioration and worn parts.
next step would be to check electrical connections mainly the ones dealing with the map sensor, ESC module, but check all that you can find.

I don't reccomend changing components untill you change the one that is bad. but that will probably be the case here. The good news is that your problem is down to a few components. I would change the ESC first and try that. what the esc does is try to control knock "ping". it can retard timing up to 20 degrees. i think this is your problem. especially if the truck is 4x4. going through puddles/water will get the part wet and can cause problems. the other part i would suggest is the est chip "the one that is under the distributer cap and rotor. they have 1 or 2 plugs on it and is allmost C shaped but usually when this part goes it is a "cranks but will not start situation". go to your autoparts store and pick one up a ESC module for around $35 bucks and see if that fixes it.

any questions let me know :)

[2001300exguy]

alright thanks, in what general area would the ESC be located? near the throttle body?

[Joe250x]

on your firewall when looking under the hood it's on the left side. between the heater blower motor and the center if your vehicle up high. you shouldn't need to pull anything off except maybe the air filter housing.

it will look like this: (http://www.slantsix.org/articles/dibiase_efi/electronic-spark-control.jpg)

[2001300exguy]

alright i know where that is thanks alot man your a life saver

[Joe250x]

No Problem :)

[2001300exguy]

so i replaced the ESC module and it is still doing it, would you say i should replace the Map sensor and put thoriginal ESC back in

[Joe250x]

there are a few things i would try. first either take out both fuses that say ecm or just disconnect the battery for a minimum of 10 seconds. doing this will clear your computer of all latched codes and other non volitile (sp?) memory. then drive it around for about 10 minutes similar to breaking in an engine so the computer adjusts some parameters. dome idleing, some acceleration vary it up.

from there check the codes again and see what you have.
another thing to try would be to tap on the relays located on the left fender with the engine on. mine has 3, yours might have less one of those is a varibale relay thing.

how bad does it run? does it seem rich or lean? does it hesitate?


let me know what happens.

[2001300exguy]

it idles fine before i go and drive it then it doesnt want to go under any gas, it is running perfect A/F wise the plug is a light brown, the battery is disconnected right now and i im going t takle the fuses out too.

[2001300exguy]

alright i just got done drivint it and it is doing the exact same thing, it will idle fine but as soon i let out the clutch and try to go it will get real jerky and jump forward then bog down real bad no matter how much gas i give it or how slow i let out the clutch

[Joe250x]

check to see if the knock sensor is still connected it is located low on the block with 1 wire connected to it. probablly a white or gray in color, they can fall off. i can't remember which side it is located on but i believe it's on the right side. left while looking under the hood about starter level more torwards the center of the block.here is a picture of the sensor (http://www.cis.udel.edu/~davis/z28/ecm_swap_730/photos/map_and_knkplug1.jpg)

check the codes again also probablly just the 34 in there though.
did you check timing advancement with the timing light also?
when your are at cruising speed like 50-60mpg do you feel a jerking coming from the drivetrain? if so it's a spark problem of some kind. and if it is dark outside start it up and look for arching coming from the plug wires, you might want a spray bottle with water to get them wet. did you change the cap and rotor? it could be a deadspot on either of them. i am going to do some more research but i am real curious about the knock sensor and the jerking.

[Out_Sider]

sounds like normal bullchit problems from the lousy 2.8 :(

[Joe250x]

Ever drive one with MPFI multi port fuel injection?
I don't think you would call them lousy anymore. A 2.8 in a truck is a bad example of a 2.8 but drive a camaro and they can fly. they have a much better cam in them and they rev like a mofo. It was a bad idea for GM to put a high revving engine in a truck with a cam designed for more torque

[2001300exguy]

alright ill have to check the sensor tomrow and i have checked the timing and the cap and rotor are not that old at all there is barely any where on it.

[2001300exguy]

well my sensor was black but it loked exactly like the one pictured, it was a little loose but was on there so i took it off and put it back on anyway. checked the timing once again and it is fine. Although while it was sitting there idling it would die after a few minutes and i could see the timing change while it was doing it, it would idle up real high then come back down and die. i also wen tto give it gas with the throttle body and it backfired pretty bad, i dont know if that means anything but i figured if mentiong it.

[Joe250x]

Ok, sorry for the late reply but i was looking for a book that my uncle is borrowing and he won't be back until tomorrow. I am leaning more torwards a map sensor or the coolent temperature sensor. I can tell you it is either an electrical problem or a fuel delivery problem, But as long as you installed the fuel pump and filter good I don't see a problem with that because the injectors have a fairly low failure rate. Both the MAP and coolent temperature sensors effect the spark control and also the Ignition control module. The MAP sensor plays two rools when talking about ignition timing, it senses barometric pressure and intake manifold pressure. If you want i can box up a used coolent temperature sensor, map sensor and Ignition control module and send them to you for $10+shipping and see which one is causeing the problem, or try a map sensor next which costs around $35. I am running out of ideas and don't want you to buy unnessecery electronical components that are non refundable.
Let me know

[2001300exguy]

well getting the parts is no problem i would rather just go to a junkyard and get them rather than weight for them to ship but thanks for the offer, and i was able to pass the ESC as not bing used so i got all of my money back on that, are the map sensore that hard to get out cause the junkyard i go to has several trucks witht hte same engine as mine so the parts arent that hard to find

[Joe250x]

A MAP sensor is easy to change. Should take less than 5 minutes. take the air filter cover off, in the air filter housing there is a clip that holds the map sensor on to it, take that off then there is an electrical connection and a vacuum connection. thats it.

here is a map sensor (http://www.acuautoparts.com/images/domestic_images/images/delphi/MAP_Sensor.jpg)

[2001300exguy]

alright ya i know where that is ill have to c if i can get one, its supposed to be raining all day so i doubt ill get one today

[2001300exguy]

quick question if i were to unplug the map sensor would that be an affective way to see if it were bad. This was suggested by a member of another forum. i tried it and it still did the same thing

[Joe250x]

yes it can be. i don't know if unplugging it will make the vehicle think your engine has too high or too low vacuum but that is good advice. Last time i had a bad map sensor the vehicle was hard to start and when it did it wasn't possible to drive it because it would stall out. I thought of something else that would do the same thing while sleeping last night. I changed the sparkplug wires on a 2.8 s-10 once and i crossed 2 plug wires so look into that also.

[2001300exguy]

alright ill try the wires but i replaced the map sensor and it didnt do anything either

[2001300exguy]

alright well now erer trying the o2 sensor, it seems liek its getting worse it does it almost as soona s i start the truck now. Do you think there is any way that my fuel pump was bad?