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1990 Chevy S10 2WD 2.8 TBI FUEL INJECTION
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slamman8
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Feb 15, 2014, 7:05 AM
Post #1 of 26
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1990 Chevy S10 2WD 2.8 TBI FUEL INJECTION
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I have put in two injectors that I know are good and I put in a new cooling temp sin. It was loading up bad but now it will start and run when it is cold but if you turn it off then try to restart it will not restart . If you don't give it fuel it wont try to fire but if you hold it to the floor
It will fire but not run I put a new fuel pump in and the fuel pressure regulator was working fine on the other truck I took it off of. What could it be. Thanks Stan[:|]
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Discretesignals
Ultimate Carjunky
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Feb 15, 2014, 7:37 AM
Post #2 of 26
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Re: 1990 Chevy S10 2WD 2.8 TBI FUEL INJECTION
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Probably start out by doing a compression test to see what you have to work with. Disable fuel and spark by unplugging the distributor electrical connectors. Make sure the battery is fully charged and hold the throttle wide open while doing the test. Write down the numbers.
Since we volunteer our time and knowledge, we ask for you to please follow up when a problem is resolved.
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slamman8
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Feb 15, 2014, 9:25 AM
Post #3 of 26
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Re: 1990 Chevy S10 2WD 2.8 TBI FUEL INJECTION
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Thanks for your help on this. I rebuilt the TBI on this truck because it was flooding it so bad that it was getting gas in the oil. So I changed the oil&filter put injectors off of my other truck that was running great and put a new cooling temperature sensor on. New plugs & wires & cap & rotor. I have made sure I have no vacuum leaks. It will start right up and run good when you go out to start it the first time but then when you shut it off it won't restart it don't matter if you let it warm up or it is cold you got to hold it to the floor just to get it to try to start. Thanks
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kev2
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Feb 15, 2014, 2:14 PM
Post #4 of 26
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Re: 1990 Chevy S10 2WD 2.8 TBI FUEL INJECTION
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There was an issue where the injector harness as it passes thru the air cleaner assy would ground out causing a full or WOT mixture.. And sometimes removing the air filter to observe this would be enough to remove the 'pinch' and bring all back to normal .. check the injector harness at air filter
with KOEO no inj spray. let us know what you find
FYI - theory- holding throttle WOT when starting is called "clear flood" .. inj don't spray - and will start that flooded engine
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slamman8
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Feb 17, 2014, 9:00 AM
Post #5 of 26
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Re: 1990 Chevy S10 2WD 2.8 TBI FUEL INJECTION
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Thank you for your info on the wires I check the injector wires and replace them and it still loading up. I done a onboard computer check it gave me two codes a 34 and 45 I replaced the MAP sensor I'm going to replace the O2 sensor today it also said to check the evaporative charcoal canister and its componennts for the presence of fuel. Can that cause it to give it to much fuel. I know the O2 sensor dose not start reading until it gets 600 degrees so I don't think it would cause it to do this all the time. Right now when you start the truck it is just giving it to much fuel. If these don't work I'm going to put a new ECM on and then go from there. Thanks
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Hammer Time
Ultimate Carjunky
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Feb 17, 2014, 9:23 AM
Post #6 of 26
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Re: 1990 Chevy S10 2WD 2.8 TBI FUEL INJECTION
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Why would you assume it needs a MAP sensor and an O2 sensor? Having those codes doesn't mean the sensor is the cause.
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We offer help in answering questions, clarifying things or giving advice but we are not a substitute for an on-site inspection by a professional.
(This post was edited by Hammer Time on Feb 17, 2014, 11:05 AM)
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kev2
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Feb 17, 2014, 10:41 AM
Post #7 of 26
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Re: 1990 Chevy S10 2WD 2.8 TBI FUEL INJECTION
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slow down on replacing the ECM.... way down on the list of things to look at
OK - you checked the wiring- with key on eng off KOEO - were the injectors spraying, dripping, dribbling?
let us know there is a step by step process of elimination.
other factors to consider:
The ECT - temp gauge will cause a real rich condition if not operating correctly.
Fuel pressure - the wrong pump will cause overfueling.
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slamman8
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Feb 17, 2014, 3:23 PM
Post #8 of 26
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Re: 1990 Chevy S10 2WD 2.8 TBI FUEL INJECTION
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I know they are not what is causing my problem. The only thing I can do is change the ECM to see if it is telling it to give to much fuel and go from there. I have work on cars and trucks and every thing else for over 35 years and every once and while I get one that stumps me like this. Thank you I will let you know as I start changing thing's
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Hammer Time
Ultimate Carjunky
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Feb 17, 2014, 4:07 PM
Post #9 of 26
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Re: 1990 Chevy S10 2WD 2.8 TBI FUEL INJECTION
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Sounds like you're going to be throwing a lot of money out the window. You need to spend you money on someone knowledgeable enough to diagnose the problem. You are not even close to finding this problem.
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We offer help in answering questions, clarifying things or giving advice but we are not a substitute for an on-site inspection by a professional.
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slamman8
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Feb 18, 2014, 10:15 AM
Post #10 of 26
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Re: 1990 Chevy S10 2WD 2.8 TBI FUEL INJECTION
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This truck has a new fuel pump it has a new ECT sensor I put two good fuel injectors that is spraying fuel out in a cone shape but one is spraying out more than the other . They stop and shut off like they should . You said something about the ECT gauge how do I check it. I do have another fuel presure regalator that I can put on it to make sure it is right. The Temp. gauge works fine on this truck .
Thanks Stan
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Hammer Time
Ultimate Carjunky
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Feb 18, 2014, 10:31 AM
Post #11 of 26
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Re: 1990 Chevy S10 2WD 2.8 TBI FUEL INJECTION
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"Swaptronics" isn't going to get this car fixed.
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We offer help in answering questions, clarifying things or giving advice but we are not a substitute for an on-site inspection by a professional.
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slamman8
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Feb 19, 2014, 6:52 AM
Post #12 of 26
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Re: 1990 Chevy S10 2WD 2.8 TBI FUEL INJECTION
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I understand that. I'm going to start all over and recheck all the wiring and vacuum hoses. This truck is just loading up getting to much fuel . I have got a book on it and I've went thru it page by page and checked every thing it said . I'm going to start over and recheck it all before I spend the money out for a ECM. I'm going to do a fuel pressure check and all. Thanks Stan
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Hammer Time
Ultimate Carjunky
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Feb 19, 2014, 7:18 AM
Post #13 of 26
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Re: 1990 Chevy S10 2WD 2.8 TBI FUEL INJECTION
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Why don't you just pay someone that knows what they are doing to diagnose it for you? Someone needs to be able to analyze the sensor data to determine what is happening inside that engine.
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
We offer help in answering questions, clarifying things or giving advice but we are not a substitute for an on-site inspection by a professional.
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kev2
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Feb 19, 2014, 7:45 AM
Post #14 of 26
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Re: 1990 Chevy S10 2WD 2.8 TBI FUEL INJECTION
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TBI is such a simple system ....in post #7, I asked a simple easy question it was a start to a planed diagnosis,?
the ECM follows the computer logic of GIGO - garbage in garbage out, very rarely is it failled it follows a program.
the other factors
ECT how did you check? this is a major input to mixture
Map did you check - what is eng VAC, map signal voltage
TPS did you check - what is signal voltage
(This post was edited by kev2 on Feb 19, 2014, 11:23 AM)
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slamman8
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Feb 19, 2014, 8:07 AM
Post #15 of 26
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Re: 1990 Chevy S10 2WD 2.8 TBI FUEL INJECTION
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I have took it to someone and had it looked at. I'm not just a shade tree . I have work in auto shops and done this kind of work for years just ever now and then I have one that gives me a hard time. Thanks
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slamman8
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Feb 19, 2014, 8:18 AM
Post #16 of 26
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Re: 1990 Chevy S10 2WD 2.8 TBI FUEL INJECTION
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I put a new ECT sensor in and the OBC code only showed the O2 sensor and MAP sensor so I changed them and cleared it and now the OBC shows no codes. It is hard to find a shop around here that will hook to this truck because it is a OB1 they all have the OB2 COMPUTERS THANKS FOR YOUR HELP
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Hammer Time
Ultimate Carjunky
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Feb 19, 2014, 8:19 AM
Post #17 of 26
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Re: 1990 Chevy S10 2WD 2.8 TBI FUEL INJECTION
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Judging by the way you are approaching everything here, you really are not experienced in computer diagnostics.
An entire page of posts and you are yet to identify what is occurring to cause this.
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
We offer help in answering questions, clarifying things or giving advice but we are not a substitute for an on-site inspection by a professional.
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Tom Greenleaf
Ultimate Carjunky
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Feb 19, 2014, 8:43 AM
Post #18 of 26
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Re: 1990 Chevy S10 2WD 2.8 TBI FUEL INJECTION
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Slamman8: Dizzy reading this but as just asked, "how did you check the CTS?" I bet you changed one for a gauge not the one for telling the thing how cold it is and how much fuel to deliver - is that a maybe? Plug alone on those go bad so most come with the pig-tail. But you can check it first as it changes OHMs let thru it by the temp of the engine NOT info for your dashboard,
T
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slamman8
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Feb 19, 2014, 8:43 AM
Post #19 of 26
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Re: 1990 Chevy S10 2WD 2.8 TBI FUEL INJECTION
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No I'm not up to date on all the computer stuff. I'm am limited to places here in my area for shops that have the equipment to work on it. Our GM dealer and shop went out. Most of the shops around here don't have what I need for the older stuff most have 1995 and later.
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slamman8
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Feb 19, 2014, 9:20 AM
Post #20 of 26
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Re: 1990 Chevy S10 2WD 2.8 TBI FUEL INJECTION
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No I change the one on the intake that tells it the fuel mixture. I have a book on this truck. I have been working on autos for years and when I don't know something I always get a book on it and read to understand what is going on. I just came back from one of the best shops we have here and their computer only reads back to 1996 so we talked shop talk about it and we know I have done every thing other than making sure the EFR valve is not stuck open or the pressure reg. Is putting the right pressure out 9 to 13 psi . I'm also going to check all the wires. With my ohm meter to make sure that ECT sensor is working right. Thanks for all your help everyone. Stan
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Tom Greenleaf
Ultimate Carjunky
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Feb 19, 2014, 9:21 AM
Post #21 of 26
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Re: 1990 Chevy S10 2WD 2.8 TBI FUEL INJECTION
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Is this what you replaced? Has info on how to check it below....
See Figure 1
The Engine Coolant Temperature (ECT) sensor, sometimes referred to as the Coolant Temperature Sensor (CTS), is a thermistor (resistor which changes value based on temperature) mounted in the engine coolant stream. Low coolant temperatures produce a high resistance - 100,000 ohms at -40°F (-40°C), while high temperatures cause low resistance - 70 ohms at 266°F (110°C).
  
Fig. Fig. 1: Coolant temperature sensor and connector
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Comes with pig-tail if you wish or see troubles as said.
No expensive tools for this. Volt Ohm meter, even a less than $10 one would check it!
T
PS: Not up to date on all this computer stuff? This car is at least 24 years old. Not many DeSotos kicking around anymore....
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slamman8
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Feb 19, 2014, 9:32 AM
Post #22 of 26
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Re: 1990 Chevy S10 2WD 2.8 TBI FUEL INJECTION
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Yes I changed the right one
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Tom Greenleaf
Ultimate Carjunky
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Feb 19, 2014, 9:54 AM
Post #23 of 26
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Re: 1990 Chevy S10 2WD 2.8 TBI FUEL INJECTION
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OK - It's old as we know. All those things need to have good connections. Most never need replacing but wiring and plug ins can fail. Lots to check out in general with the age and need to have some basic stuff to check stuff. Not really huge bucks.
Opinion: 2.8s were either gems or junk right out of the gate and since it's still here might be a good one. Flooding out will wear it out with cylinder wash as oil will be diluted, cat/conv will fry so you have to fix this or the thing could out cost you for some stuff,
T
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slamman8
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Feb 19, 2014, 10:47 AM
Post #24 of 26
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Re: 1990 Chevy S10 2WD 2.8 TBI FUEL INJECTION
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You are right and that is my next step I'm going to check all the wire and plugends on it . A few years ago I had a 1990 Pontiac with a 3.1 in it and it started flooding out and then it just stop running all together and I check it all and I end up putting a wiring harness on the motor because I just could not find the wire that was bad on it but that fix it and it ran for another 100,000.00 miles
I end up with 275,000.00 miles on it before I sold it to a friend that drove it for three years before it blew up.
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Tom Greenleaf
Ultimate Carjunky
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Feb 19, 2014, 11:23 AM
Post #25 of 26
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Re: 1990 Chevy S10 2WD 2.8 TBI FUEL INJECTION
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Get yourself a volt/ohm meter. If a few bucks more go for DigitalVoltOhmMeter (DVOM) some "T" pins, regular like shirt pins, some wire and alligator leads but get one in line fuse to make up is safer. Ha - clear nail polish at a dollar store. Works ok to seal any poked wire insulation if testing stuff. Keep that at a minimum and better is liquid electrical tape. You can poke a wire at one end and see if power gets way away at another end where you expect it to. Go easy with that and better to back probe connectors when possible.
Even cheap soldering iron, wire stripper of course, shrink tubing and pre fluxed solder for electrical is fine gauge can come in handy tube and pull out what you need.
Gotta have some basics at the ready and know what item are for in the vehicles. You'll always need help with some things way too expensive to have tools for one time things many times.
Point is the dartboard approach plain costs more unless you have known spares of simple things just hanging around,
T
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