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Discussion Starter #1
I really need help with a 2001 S10 2-wheel drive with the 4.3L engine. It is the extended cab with the 3 doors. I don't know which model as the doors say extreme and the cab says LS.I have been trying to diagnose the bad issues with it running.

I bought it from a neighbor that apparently had no idea what he was doing to the truck with his "mods". He removed the catalytic converter and both oxy sensors. It runs ruff and when I bought it, he said it needs a tune up. I took it to the parts store and they agreed and said it has a P300 random misfire code and 2 codes for oxy sensors (because they are not there anymore)

It runs very rich. It will back fire and the tailpipe is black. The trailer hitch I installed is coated black from the exhaust. It clearly has a misfire and runs ruff.

It has the symptoms of a bad spider injector or bad fuel pump. I replaced the cap, rotor, coil, spark plugs and wires. It changed nothing at all. It runs the same.

I tried to get a fuel pressure test but the gauge set I bought will not seal enough to get a good reading. The schrader valve test/bleeder port can't get depressed to get a good reading. With the gauge screwed on, the rubber seal on the fitting will not allow the pin to be pushed down so no gas flows into the gauge. With the rubber seal pulled out and removed from the fitting, it will read pressure, but it will leak gas everywhere when running. The highest reading I got was 45psi when running. It then hits 22psi when off. It holds at that pressure. That can't be accurate as it will have a small stream of gas coming out of the fitting when it is running. I also noticed after depressing the pin after shutting off the engine, it only drips fuel out. People say to put a rag when bleeding the pressure. You have to feel with your finger to see if gas came out as you can't see it as it just kind of drips out.

I have had a terrible time the last few weeks of it shutting off while driving. It doesn't matter how high of rpms or speed. It will shut off like the key is turned off. No real warning.

The last few days it will do a "micro" stall. It will drop rpms (about 200-500 from what you are at) and then jump back to the rpm you are at. If it drops more than 500rpm you have to feather the gas to bring the rpms back up.

It is also doing something new now. It will stutter and drop rpms and the gas will not respond at all. Even if I shift into natural at speed, the rpms will drop to an idle, or below, and pushing the gas does nothing. If I stop and put it in park. It well then allow me to rev the engine. It appears the computer is over-riding my throttle input and will not respond to the gas being depressed when this happens. It will also try to idle at around 200 rpm when this happens. That has caused a lot of intake backfires and really ruff stumbling and stalling and smoke out of the air cleaner.

It never used to stall/shut off like this. I have had the truck about 3 months.

The "normal" issues with it are:

Long cranking time (around 5-20sec long cranking)
Ruff idle
misfire while driving (with flashing check engine light)
bad gas mileage (around 6-8MPG)
popping/backfires
dark exhaust when accelerating hard.
strong smell of gas all the time.

It now will take longer when cranking and it will not fire up to 500rpm, it will kind of slowly stumble up the rpms and you have to gently rev it to get it to 500rpm+ to start.

What I have noticed is I have to drive in 3rd gear. If I use over-drive, it will cause the stalling almost immediately. Even on the highway in 3rd gear if I shift into over-drive it will stall out and do the odd stuff of not responding to the gas pedal. Leaving it in 3rd gear can still have it happen, but it is about 90% less likely to do it.

I ordered a new fuel pump and filter and a new spider injector unit. I am assuming I have the factory injector. I bought the "upgrade" injector where the tips have the injectors on them.

Would fuel pressure and/or a leaking/bad spider injector being causing all my running issues?
 

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Mr Goodwrench's Evil Twin
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It's a crude method to test for leaky injectors, but when you depress the schrader valve after shutting the engine off it initially should have a strong spray of fuel. If it is just dribbling out, it's a good sign the spider is failing. And yes, a shot spider is going to have similar symptoms to what you have. It isn't the only issue by any stretch though...

The fact there are no O2 sensors is NOT helping AT ALL. The computer has absolutely NO clue how to control the air fuel mix if there are no O2 sensors. It will run terribly until it has them again. It is in limp mode without those o2 sensors in it and until it has O2 sensors back in it, it will continue to run in limp mode even with a new spider in it. Limp mode essentially translates to... runs like sh*t. The computer operates on a set list of parameters instead of operating on the inputs from all the sensors when in limp mode. If the spider is leaking its just going to make Limp mode all the more worse because even that set list of parameters is thrown off by the extra fuel that the computer has no idea is there. Limp mode is intended to get you safely off the road. Limp mode is not intended to get you from point A to point B.

So it sounds like there is a good chance the spider is shot but you absolutely NEED to get some O2 sensors in the truck so the computer knows how to control the air fuel mix. If the spider is indeed shot, replacing it will help but only so much. Those O2 sensors are 100% needed and it won't run right without them, they are a must have. If there are still driveability issues after that, then go from there.

I'd ask what if those are the only codes for the check engine light but it doesn't really matter until it has O2 sensors in it.... and only use the OE AC Delco O2 sensors.

Welcome to the forum, by the way ;)
 

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What he said.
The truck can't run right without functioning O2 sensors. Get that fixed first. And look for any other sensors disconnected. Some people should be allowed to touch trucks. Your neighbor, for example.
BTW the LS Xtreme thing, it is both. One is an interior trim package, the other exterior.
 

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Discussion Starter #4
Thank you for the replies.

Is there a reason why only AC Delco sensors should be used? The parts store, and Amazon, has sensors that are much cheaper.

I was looking at a universal catalytic converter. (mainly because it is about 1/4 of the cost of an OEM one.) It would be easy to install but I'm not sure if it matters how far back from the headers is should be. I don't know if it has to be a set distance from the headers, or if it can be anywhere before the muffler. I normally had vehicles that are pre-computer and had no emissions or stuff like that on them. This is all new to me.

I tried looking for pics on Google to see where it would be located and where O2 sensors would be installed. I can't find any good pics showing them.

The guy that sold the truck works at tire/repair shop. (Like a Jiffy Lube) He put a straight exhaust pipe on that connects right at the header. He removed the sensors and catalytic converter. It runs straight and has one of these square mufflers that looks like a normal one, but is loud when driving.

I'm not sure if the O2 sensor needs to be in the catalytic converter, or in front of it in the pipe. The parts store said both styles of catalytic converter are showing for the truck.

The only codes on the truck are the P0300 and one for no voltage to a "down stream" O2 and wrong voltage to the "upstream" O2. I will have to check the codes again to get the specific number. I finally got a simple reader and it still only shows those 3 codes every time I clear the codes and test again. I was thinking new codes would show but it hasn't given any yet.

I'm hoping to get the new fuel pump in by tomorrow and I have a new spider injector that will arrive later this week. I was hoping it would smooth out the idling and running, but it sounds like with the O2 sensors missing it might still run the same.

It's good to know what the difference is between the Extreme and LS. I was thinking it would make a difference to mechanical options or something.
 

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Discussion Starter #5
Thank you thebadwrench for the welcome. I'm glad to be here and look through things to learn more about these trucks.
 

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Ok so now the truck is acting weird after replacing the fuel pump.

When I first replaced the pump, the speedometer and gas gauge pegged to max after hooking the battery back up. I tried un-hooking it and hooking it back up about 3 times. It still kept those 2 gauges pegged. I un plugged the connecters at the fuel pump and tried the key and they still were pegged. I figured that would rule out the pump sending a odd signal. I re-connected the plugs on the pump and no difference.

Even with the truck running the gauges stayed like that. When I went to drive the truck the Speedo snapped back to normal as soon as I started moving. The gas gauge was reading all the way around past full pointing straight down (almost back around to the empty mark.)

I went and got gas and the gauge then seems to be reading now.

The truck used to crank about 20-30 sec. It now cranks about 2 secs before firing. I guess I have much better pressure now.

I now no longer get the P0300 random misfire. I get a P0303 cyl 3 misfire. Great. It also seems to be running more ruff with a real stutter to it. It will now stop responding to the throttle.

While driving, it will stop responding to the gas. It is like you let off the gas peddle. Pushing the gas pedal or pumping the peddle does nothing. Sometimes if you put it in Neutral it will then respond to the gas pedal. Other times you have to actually stop and put it in park and then it will respond to the gas. Most of the time it will just still shut off like you turned the key.

On my first trip after replacing the fuel pump, it stalled about 7 times in a 4 mile trip. After I had parked and tried to start up, it would not fire. It would only crank. I was stuck for 15 minutes. It would not start at all. It acted like within the 1 sec of cranking it was killing the spark. It would sound like compression for that 1st second, and then just crank for as long as you held the ley. I finally disconnect the battery and then re-connected it. It then fired right up. It still would stall on the way home though.

The only codes now are the P0303 and P0135 heated oxy sensor codes. Nothing else. Would the oxy sensor cause the gas to stop responding and the truck refusing to start?

I think I still have to replace the spider injector as I tried checking the fuel bleeder port. It now doesn't just drip out, it will kind of squirt about 1/2 to 1 inch when I press the valve. If it sits for about 2-3 minutes, it still just drips out.

I now have a new updated spider injector to install, but am worried about the gas not responding when driving and it not restarting unless I disconnect the battery. Could there be some type of VSS or something on the transmission that is making the computer ignore the throttle? I also don't know why it will not let me rev if in Neutral when it happens.
 

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You have got to get those O2 sensors installed before throwing anymore money at this truck. Its like the engine is running, your blindfolded and don't know if the truck is in Drive or Reverse in traffic. The catalytic convertor will be installed under the passenger seat area but you don't need that until you get the engine fixed.
 

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Sounds like you either unplugged the VSS or damaged the wiring to it when you installed the fuel pump and the ground wires on the fuel pump connector are reversed. The pump grounds to the frame. The fuel gauge comes back to the PCM for grounding. If they're reversed the gauge will go to full.
I really wish they could come up with a better way to replace that connector than crimping 4 wires that are exposed to weather. The last one I replaced just had 2 black wires with no indication which was pump and which was ground.
What brand pump did you install?
BTW 3 experienced members have said GET THE O2 SENSORS FIXED. They tell the PCM how much gas to give the engine. If they aren't working the fueling will be FUBAR and the truck won't run right. At least get the two upstream (one on each bank, before the cat) installed and working. The bank 2 #2 is post cat and not as important. Watch that the wiring doesn't come close to or contact the exhaust or it'll melt and short out.
 

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Discussion Starter #9
Thank you for the responses. I am working on getting some oxy sensors. I'm disabled so money is very tight and my sister has been helping get parts. (amazon store card :)) We already had the fuel pump, filter, and spider injector ordered when I had posted originally.

I was told to go with AC Delco and found "ACDelco AFS105" for the oxy sensor. I am assuming there should be 1 in each header. I tried looking around and I think it is showing another one at the Y collector, and then one after a catalytic converter. I didn't see for sure if s10's have it at the Y location or not.

There is no spot for one at the Y collector from what I can see. The straight pipe that was put on is right at the Y part. If it needs one there, I would have to make a connection spot and find if there are wires around there to hook to.

I think we can get 2 sensors, but would have to wait to get anymore. (card almost maxed out).

As for the fuel pump/gauge issue. The gas gauge seems to be working. It will sometimes peg out when reconnecting the battery. It will then come back to normal after driving. I've never had gauges do that before. I also don't have computer vehicles so it is a world of difference for me. Most of my vehicles were mid 1970's.

The fuel pump is an off brand from amazon. It shows DWVO for the brand. It was a pain to install because I did the trick I saw of just tilting the bed up by leaving the rear bed bolts in. I had 2x4's that were angle cut from a past project so I just walked the bed higher and higher until I had room to reach the pump through the wheel well.

The spring compression strength was very strong so that was difficult to install one handed. The old pump looked very similar but was missing one of the metal support rods and had no springs around the rods. It already had the newer plug connector so I didn't have to splice the new connecter in.

I noticed the strong smell of gas is now gone. Before it was like you had an open gas can all the time. Driving or parked it reeked of gas. I also noticed before when accelerating hard it would leave a cloud of smoke. Now I don't get that cloud. The cloud was probably gas. Your eyes actually burned from the smell. At least that is gone. I don't know why that stopped by just changing the pump.

I am trying to understand the oxy sensors and fuel ratios. I am assuming if I have a bad sensor on one side of the motor that means the opposite side would be getting proper fuel and the bad side would be getting full fuel because the computer doesn't know what to do. That would mean only 1 side is running correct and the other side is running very rich. To me that would be the reason for the stuttering and backfiring. Also with a leaking spider injector, gas would be getting into random cylinders which would add fuel to a cylinder that is already getting gas from the injector tips. If it gets into the side that is running rich already, that just adds more fuel then the cylinder can handle.

I don't know if I am close, or way off on thinking this. I much prefer carbs that I can adjust needle and seats and balance out ratios. Sensors and computer stuff just seems to make things harder. Especially when the previous owner removes parts.

I'm replacing the spider injection today. The previous owner said he replaced it 6 months ago and it was $600 for the part. He also said it is the newer MPFI injector. I will see. Everything he has said so for is full of crap. He works for a tire shop and thinks he is a master mechanic. He removed the oxy sensors and put the straight pipe so that says a lot about his skills right there.
 

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As far as the plug on your pump is concerned...even though it has the new style plug on it, the wires may not be in the correct place for your new plug. My new pump and harness had different wiring instructions depending on the vehicle...your current setup may be wrong. Check the directions that came with your harness.
 

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Discussion Starter #11
My pump didn't come with any instructions. It just had a note saying I can get tech support by phone. The plug looked to have the same color wires as the one on the truck. I'm thinking when the gauge pegs it has something to do with the gauge cluster. When I installed the new pump, I had about 1 gal or less in the tank. After I put about 6 gal in, the gauge reads. Only when I disconnect the battery does it peg, but it then will jump back to normal after I start driving. It will not peg again unless I disconnect the battery. The old pump also had the float not adjusted right. Placing the old pump on a flat surface, the float can still go lower than the surface. It can actually go about 1 inch past level. That would have been making it read like there was still gas when in would have been empty. The guy that had the truck really messed with everything.

I did have all the gauges start flipping back and forth from min to max rapidly on one battery reconnect. I had turned the key and every gauge started flipping back and forth about 5 times. They stopped on the min marks and when the truck started they seemed to respond like normal. It has only done that 1 time with all the gauges flipping like that.

I am in the middle of changing out the spider injector right now. He did put the new style injector in. What I am concerned about now is, each line came out with no problem at all. I have read that it is very difficult to remove the tips after their installed. You could use 1 finger and just lift the tips out. They had about as much resistance/weight as picking up a screw driver.

I'm trying to find pics online to see if they were not seated deep enough. I did see the green tip was still visible on all of them. I want to see if the colored tips should be deep enough that you can't see them and only see the metal color/white color of the lines.

I also am trying to find a pic of the setup for the screws that hold the 2 fuel lines into the injector. I think he stripped out the holes. The driver side screw had almost no resistance and I could spin it out with my fingers (no wrench). When I popped the 2 lines out, I saw 3 small washers that have the gripping pattern on one side. They were sitting in the space just behind the screws. They were just sitting there. I looked in the light and say there are shadow marks of the washers in the plastic where they were sitting so I think they were never used. They would have been under the odd shaped hold done piece that is metal that fits between the lines on the ports. When I went to tighten the 2 screws, they will not tighten, They will keep turning and only have mild resistance. I'm not using a wrench, I'm using my fingers on a socket.

I even found 2 screws that hold down the intake that were not tight. One was on the piece on the left side that pops out and has a line running to the firewall. I don't know the name of the piece. It is like a solenoid shape and has 2 screws and is near the rear left side. The 1 screw was not even seated. It was wobbly when I touched it. The other screw was on the driver's side that is just a normal intake hold down screw.

I tried to see if the old injector leaked by putting the lines back on and turning the key. I didn't see any fuel leak. I know I lose fuel pressure after just a min or so by checking the bleeder port. Within about 2-3 min it will just make a single drip after the truck is off. If I try it right after turning the key, it will squirt about 1 inch up into the air.

I did see the inside of the lower intake is clean around the rear, and heavy carbon in the front. I would think the entire inside would be fouled. I'm wondering if the fuel regulator on the back of the injector leaked and gas caused the clean area. I'll try to attach a pic to show what I mean. It just seems odd to me that it looks like that.

335700
 

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So I got the intake back together. It runs smoother now so the spider was really a big issue.

Now it has a hard time starting. The 1st time starting after installing the parts it started fast. Now it struggles and doesn't want to start unless I hold the gas pedal to the floor. It will then start.

It now idles lower than before. It actually idles at different RPMs now. All the gauges were acting messed up and pegging and resetting. They seem to work now, except for the temp. I might not have gotten the plug into the temp sensor all the way as it is almost impossible to reach.

It wants to idle at about 1,200 rpm. (it was cold, about 30 degs out )When driving, it can change and stay at a good 500 or 600 rpm at a stop light. It will also drop to around 300 rpm when sitting.

It is not shaking like before and the RPM needle is ridged and not bouncing like before. Before it would cover about a 400 rpm spread as it would be changing/bouncing all the time. Now it acts like a normal gauge as the motor is running smoother.

It will now be very hard to start. It is like it is getting flooded with gas. When I tried starting it and it took 3 tries, it then reeked of gas. I found if I just hold the throttle it will start. It will then act like it is searching for what RPM to idle at. I have had it as high as 1,400rpm and as low as 300 rpm. It will then stumble and try and die at that low of speed.

It has not stalled out at all yet. Even on the highway in overdrive it runs like normal. Before it would stop responding and stall out.

I cannot get it to give me an error code for the oxy sensors. I have gotten a MAF error (p0102) that I cleared and it hasn't come back. I got a P0303 code only when testing it on the 1st drive where I floored it and shifted through the gears at full throttle. It blinked the check engine and then went away. After clearing the p0303 code it has not come back. The ONLY code that returns is the coolant sensor p0118.

I have cleared the codes about 5 times now and have driving it each time. The only code is the p0118 coolant error. I have absolutely no idea why the oxy codes are gone and why the cyl 3 code is gone.

I am worried that the random idle speed might be due to an air leak. I had a difficult time getting the intake to pop over the injector gasket. I am wondering if I have an air leak and it is changing the idle speed based on the fuel mixture. Or could it be changing the RPM because of the coolant sensor error?

I'm glad it is no longer stalling every 100 feet. I am concerned that it is hard to start now. After the fuel pump change it started in 1-2 sec. Now if it takes longer than that, it will not start unless I hold the gas pedal down.

Any ideas as to what I should be looking for? Should I be looking for air leaks, or coolant sensor, or fuel issues?
 

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Probably not going g to like this...it's really easy to get the drivers side injectors in the wrong place...not to mention the ignition wires.
 

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The plug wires should be fine as I only took off 2 of them and marked them with tape before removing them. I also had put a new set on about 2 months ago so they're fresh.

I did watch videos about the injector and saw the #3 and #5 lines have to be manipulated. I was very careful and slow when doing it. The old injector tips just sort of fell out when removing. These tip didn't make a click, but the seated firmly and even trying to pull on them, they would not move after sliding them into the ports.

The motor runs much smoother and has more power. It will actually spin the tires if I slam the gas. Before it would just sort of stutter and get up to speed (and randomly stall all the time)

In the straight road where I'm at (that is hardly used and has no side streets) I tested the acceleration. Before I would be about 40-45mph in a certain distance. Now when I accelerated in the same distance I am hitting 70-75mph.

I am wondering if not having a signal from the coolant sensor makes the idle change up or down. I should have plenty of fuel pressure now. I can't get my new tester gauge to work as the fitting will not depress the valve to test properly. I do know that before when pushing the bleeder port that fuel would just make a single drip out. Now it will spray against the firewall with force.

I'm thinking of getting a can of starter spray and making small sprays around the intake to see if it revs up from having any leaks. I put new throttle plate and upper intake gaskets on. I didn't have any new gaskets for the EGR or brake vacuum ports.

The starting and sometimes low idle is what has me puzzled. It is running smoother and has more power, but will idle at low speeds sometimes and is hard to start.
 

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If the coolant sensor or wiring are not working or completing the circuit the truck will think it is -40°F and run way rich.
Take your "new" fuel tester back and get one that works.
 

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I'm going to try and find a fitting for the tester. I got the kit from Amazon. I used the 90deg adapter in the kit (as the other pieces are for other fittings )and with the rubber seal in the piece, it will not depress the pin far enough in the valve/bleeder port to allow any gas to flow to the tester.

If I take the rubber seal out of the adapter, it will depress the pin but not make a tight enough seals so it will leak gas when the motor is running.

I can't send the kit back because of using it so I am going to try and find an adapter locally. It has to be about 1mm or 2mm from depressing the pin when it is screwed all the way down. The gauge/hose itself doesn't depress the pin far enough either. I can only get a reading if I take the rubber seal out, but then it leaks all over.

I'm going to see if the connector on the coolant sensor is on backwards, or not seated enough. There is no tab to lock to on the sensor. The ear tab is on the wire harness, but the sensors tab it locks to is not there. It must have been broken off from the previous owner. I wasn't sure if I got it pushed on all the way as I can't hardly reach it as my hands are too big to fit in that area.
 

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The engine coolant temperature sensor is a two-wire thermistor immersed in coolant and measures its temperature. The computer uses the signal of ECT as the main correction factor when calculating the ignition advance and the injection duration.
Since it is simply a temperature sensitive resistor it's doubtful that reversing the connector would make much if any difference. Most resistors aren't current flow direction sensitive. If it were a diode, then it would be critical that it be connected in the correct direction since diodes (LEDs for example) only allow current through them in one direction, but that's another subject.
You can test the sender with a ohm meter. At ambient temp it should be in the 2000-3000 ohm range. When hot it'll be in the hundreds. When -40°F it'll be in the 100,000+ range. Usually when they fail it's off the scale high. (open)
 

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Thank you very much for the info. I'm going to write down those values for future reference.

I am used to simple vehicles where you have a temp sensor to show how hot the coolant is. Stuff from the 1960's-70's. I guess this new stuff has to use input from all sensors to make the air/fuel ratio correct.

I got a flashlight and saw the coolant connector was actually falling off the sensor. I can't really get my hand in there so I used a wooden rod to gently push the connector on. It seems to have worked. I ran the truck for a few minutes and the temp gauge started to move.

The idle was then slowly dropping back from about 900 to 600rpm after a few minutes. I hooked up my code tester and cleared the code. It didn't come back yet. I did get a MAF error and saw an IAT reading was showing -38F when in live mode.

I shut off the truck and then realized those are on the air cleaner assembly. I put it back on and then the IAT showed +58F. It was hard to start again, but I figured it was because those 2 codes were in memory and not hooked up. I let it run a few minutes and it seems to idle smooth and the IAT temp would slowly rise. I checked for codes (after clearing them again) and nothing showed up.

I also saw the abbreviations for the oxy sensors (B1S1 B2S1) had values that were changing. I had set the live view to show all and the sensor values were something like 0.488 and having small changes. There are a lot of abbreviations in the live view and the manual doesn't say what they represent. I didn't realize the B1S1 B2S1 were oxygen sensors until I saw it online. I wonder why I had a hard error code for an O2 sensor if they are reading.

As of right now, I don't have any codes showing on the tester. I plan on taking the truck for a drive later and will see what happens.
 
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