hey there farm boy... sure glad your video was on youtube... $18 fix with the relay... I just bought the truck , only has 111,000 miles on it and that hard starting issue was the only issue... thanks a bunch...
This video is great! A lot of great info on pulling codes and using wiring diagram to help find the problem. Looks like I have some reading to understand how to read the diagrams better. Thanks for creating this video!
Thanks man. I did some more troubleshooting today. Check out part 3 which should be up soon. I think it's the PCM but it does send almost 12V to relay but no power from relay. I checked the relay and the old one worked fine but the new one didn't.
The code 54 "low voltage" does not mean the overall voltage is low, it means the ECM is not seeing power in the circuit from the relay to the pump. The circuit has a backfeed built into it so the ECM can monitor it. So, obviously the relay is either not being commanded on even though the ECM thinks it is, or the relay is actually commanded on but the power stops somewhere along the way. I would test for ECM commanded-on power at the relay connector, and then relay power in the FP feed.
It could be but I think it would have the same issue whether it was powered from relay or from the oil pressure switch. I did find the new relay wasn't working but the old one was. The old relay may just be sticking or its the PCM. I'll get part 3 up asap.
I don't think that's the problem. I just had the entire distributor rebuilt last year. It'll fire right up when I put the fuel pump fuse directly to battery positive. However, I will check to see if gas is being injected when cranking.
I had code 54, less than 2 volts coming into fuel pump relay, number 2 switch is getting low power. Where does the switched power come from that goes to number 2 wire. I can however jump a wire from the battery to the fuel pump wire and it will start right up, then unhook the wire and it runs fine. Great oil pressure from the new oil pressure sending unit.
I'm wondering if the fuel pump is taking more juice than normal to run. Maybe it's about ready to die. But, if the orange wire (fused from battery) has the same amount of voltage as the battery it shouldn't matter where it gets the power from (relay or oil pressure switch).
I had a 96 Chevy 1500 truck 4x4 5.7 V-8... crank no start it would kind of shudder or slightly start but not run smooth then just crank but would not start. Replaced the cap and rotor along with ignition coil pack and it started right up and runs great now. I didn't just throw parts at it though i did about 2 hours of checking fuel pump, fuel relay, pressure at fuel rail and it all checked out. Next tested spark it was there but faint or weak not much flash in my tool tester. Pulled the cap and rotor and had a burn hole in the rotor so I knew I was on the right track. Replaced ignition coil and cap and rotor and its fixed. Hope this helps someone with my symptoms!!
Also when replacing the coil pack it has two pins pressed in to hold it to the bracket instead of drilling I used two good punches and was able to punch the pins right out in one or two minutes instead of drilling it out. I spray it with PB Blaster or WD-40 and then start the punch and give it another quick spray half way through and the pins will just start to fall apart and it'll come right out of the bracket. I did have a drill ready if I needed it but the punch and a hammer did the trick. Just a tip to anyone looking for ways to get those "rivet pins" out. Good Luck.
Since you get a code 54 that should eliminate some possibilities, because it means at least at the ECM level it is TRYING to run the fuel pump. If you had a bad IGN module it would never run because the ECM would not know the engine was spinning over. Look inside that fuel relay connector carefully. If the fuel pump is pulling a lot of amperage it may be burning the connector up.
seems for me fuel pump is getting to less current whereas voltage is actually there, and when the oil pressure switch bypass this connection enough current can be supplied to the pump...
Hard starting Check the hose clamps on the fuel pump in the tank .When you replaced the pump the clamps that came with the pump are NO good .They come undone Charlie
They will give you a key at autozone for free. Put it on your key chain. Once the key is in, never try to start the vehicle. You may not get a code for this problem. 10 years ago I ran a power lead from my battery to a 30 amp switch. The other lead to the fuel pump power lead. Truck starts right up. Every time. Changed the oil pressure sending unit and relay but no help. The switch did the job.
I had 12.0V on gray wire at the relay. I haven't checked the voltage leaving the PCM to see if its higher. If I put the fuel pump fuse to battery positive, it'll fire right up.
have you measured the voltage on the gray wire? try to jumper the orange and the gray on the oil pressure fuel pump switch and see if its still there have you measured voltage drops on the gray wire?
Ok thank you very much i will check those and no the fuel pump is kicking on all if a sudden its not getting fuel again ive got spark, jus not getting fuel I replaced the fuel pump about 4 months ago im only getting that low voltage to fuel pump relay code
Man I love my truck. same year. No smoke lots of power and no leaks. My problem is strange bump feeling after braking coming to stop Then from stop while turning I feel a lift. bumping. hard to describe. If I give too much gas while turning from a stop I feel a strange vibration. U joint ? or more than one issue. ? lol
Mine bumps sometimes too when accelerating or decelerating. I think it's the slip yoke in the transfer case. It could also be a bad CV in the front that could be causing some issues when turning.
+farmboy30117 yeah thanks man. I notice that top Mount on left tire arm that is most visible is worn too. I have the ext cab long bed. She's a boat but I love her. She needs to breath though. gotta get her opened up intake and dual out exhaust.
I have a 1989 Camaro and the same exact problem with it. I ran a 30 amp switched wire to the power lead on the fuel pump. I also have a direct power on a switch which I turn on when it is cold. It starts right up and I turn the switch off.
farmboy30117 That was my first choice. An easy way to check the relay on a Camaro is to swap it out with the fan relay on the other side under the hood. I replaced mine anyway. Not that expensive. Didn't work, put a new oil sending unit on car, that didn't work either. Same with my truck. Sounds like you got lucky.
Hey farmboy, Enjoyed your video. I have a 94 sierra with a no crank issue. I have been fighting it for a while. No crank from key, however fuel pump and everything else comes on when key is in run position. Engine will crank with wire directly to starter solenoid. Key must be in the on position to run. I have changed Starter and solenoid, neutral safety switch,ignition switch, and ignition control module. I have checked all fuses including inline fuse. Worked great one day then the next day it was gone and hasn't functioned intermittently. Just gone, seemed like a blown fuse but I sure haven't found it. Key tumbler still interacts with the rod and new ignition switch. Any help would be greatly appreciated .
Wow, sounds like you've eliminated the usual suspects. I believe your issue is electrical, but the wiring diagrams I've looked at seem a bit confusing. It appears there's a 5A crank fuse on the lower right hand corner of the fuse block on 5.0/5.7 engines. The wiring diagrams doesn't show this for 4.3/7.4 engines. On another diagram, it showed a 3A fusible link on the pink wire from the ignition switch to the ECM. I believe both of these are just for crank indication to the ECM. I'd take a test light and make sure I had power at the purple wire in the ignition switch harness with the key in the crank position. If not, you may have a bad ignition switch. If so, trace it on down to the neutral safety and so forth until you get to the starter solenoid. You may have a broken wire somewhere in the circuit. Good luck!
@ Toney Charles, that sounds like you have a bad distributor pickup coil, if you're running a hot wire to the starter solenoid to get your engine to stay running after starting it.
Hey, my friend, my 93 diesel want start, ( it turns over ) when I look underneath the truck, there is a pile of diesel fuel leaking towards the back of the engine. I need the truck to haul my horses. Any idea what the problem might be ??? Please help with a suggestion.
I'd check the fuel line running from the filter to the injection pump first. If you have a leak in the supply line, the pump will draw in air and won't pump.
Im not sure whats going on, my 93 idles kinda right, then not like a slight miss. Once its in gear slight hesitation sometimes then catches up, dont notice it at all after that or down the road. Today just started shifting hard from 1-2. Just put in a new TPS and spark plugs. Not sure whats going on or what to try next.
I have 1996 GMC Sierra 5.7 v8 I change spark plugs and wires, cap and rotor, fuel pump and the truck still take to long to start and when the truck start the engine shake a lot and i don’t have powe and also have a ugly gas smell... I need help what I can do... 🤷♂️🤷♂️🤷♂️🤷♂️🤷♂️🤷♂️🤷♂️🤷♂️
Hey farmboy i have a 92 chevy Cheyenne c3500 5.7l i have been getting the same code for low voltage to fuel pump relay i replaced the relay and fuse thought i fixed it but its doing the same thing running out of ideas
Electrical issues can be a real pain to sort out. You might want to check for a voltage drop between the battery positive post and the relay. Also between the battery ground post and the relay (ground) - this will only be active for a few seconds when the key is turned on. Bad grounds can cause all sorts of issues. I assume you're only getting the code but not an issue with the fuel pump.
My 1992 chevy Cheyenne 4x4 just took a crap on me at work. Not sure what to throw at it first, but I'll deffienitly try the paper clip method first! And I'll be playing the lotto with all those codes numbers! 35 57 32 12 lol
Haha, good luck with it! If there are no codes, check for fuel when cranking and then spark. Most of the time, as far as I've seen, it's either the fuel pump relay or a bad distributor.
have a 93 myself having issues if i undo the brown wire for timing it will start and run a bit rough but plug it in it will only start with gas pedal floored and only run if foot is on the gas some plus when it is running my gas hand bounces everywhere temp only goes up to bout 110 then stop (have 185 thermo) new egr valve brand new distributor shaft and sensors rotor plugs wires also temp sensor is new as well any idea
Could be the fuel pump, but first, unplug the brown wire and make sure the timing is set to factory spec. Should be on the emissions label on the radiator core support.
WARNING, you need at least 60psi - 65psi fuel pressure on the rail when CRANKING. If your fuel pressure gauge indicates less that while CRANKING, you will have trouble cold starting even if your vehicle is properly tuned up. if replacing your fuel filter doesn't fix it, you may need a new fuel pump.
Ben-David Armstrong Sounds like a bad starter solenoid. The solenoid pushes the drive gear out to engage the ring. You can verify by viewing the end of the starter while someone tries to crank it (or film it with a camera). If it doesn't come out, it's easier to just replace the starter since it has to be removed anyway to fix. Hope this helps.
I have a good many on my other channel Farmboy's Garage. If you go to my channel page and view all videos, I believe you can search my videos with keywords like 1993 or Silverado.
I've got a 92 Chevy Blazer and I'm having starting troubles too. I have to push the gas just to get it to start up. Not sure what the problem is but when it gets started it'll idle extremely rough and about 2 minutes later it runs like there was never an issue. Any ideas? I've got a New fuel pump, fuel filter, distributor cap, rotor button, plugs and wires.
@@denisemoseley9662 These OBD1 vehicles usually only set a code if it was related to emissions or a sensor. Need to see if it's a firing or fuel issue.
I added a ground wire from lock ring on fuel tank to the frame and it fixed my problem. I drilled a 1/16 hole in the ear on the lock ring, then ran a small metal screw into hole in the lock ring ear and attached the wire with a crimp-on eye. Also, a faulty oil pressure sending unit behing the intake manifold will cause low voltage and or no voltage.
hey there farm boy... sure glad your video was on youtube... $18 fix with the relay... I just bought the truck , only has 111,000 miles on it and that hard starting issue was the only issue... thanks a bunch...
Awesome!
Thank you for showing how to read the codes, very helpful
This video is great! A lot of great info on pulling codes and using wiring diagram to help find the problem. Looks like I have some reading to understand how to read the diagrams better. Thanks for creating this video!
You're welcome! Glad it helps.
Thanks for your video on fuel pump relay. Fixed my problem
Glad it helped Robert!
Thanks man. I did some more troubleshooting today. Check out part 3 which should be up soon. I think it's the PCM but it does send almost 12V to relay but no power from relay. I checked the relay and the old one worked fine but the new one didn't.
The code 54 "low voltage" does not mean the overall voltage is low, it means the ECM is not seeing power in the circuit from the relay to the pump. The circuit has a backfeed built into it so the ECM can monitor it.
So, obviously the relay is either not being commanded on even though the ECM thinks it is, or the relay is actually commanded on but the power stops somewhere along the way.
I would test for ECM commanded-on power at the relay connector, and then relay power in the FP feed.
It could be but I think it would have the same issue whether it was powered from relay or from the oil pressure switch. I did find the new relay wasn't working but the old one was. The old relay may just be sticking or its the PCM. I'll get part 3 up asap.
farmboy30117 ;7
I don't think that's the problem. I just had the entire distributor rebuilt last year. It'll fire right up when I put the fuel pump fuse directly to battery positive. However, I will check to see if gas is being injected when cranking.
I had code 54, less than 2 volts coming into fuel pump relay, number 2 switch is getting low power. Where does the switched power come from that goes to number 2 wire. I can however jump a wire from the battery to the fuel pump wire and it will start right up, then unhook the wire and it runs fine. Great oil pressure from the new oil pressure sending unit.
I'm wondering if the fuel pump is taking more juice than normal to run. Maybe it's about ready to die. But, if the orange wire (fused from battery) has the same amount of voltage as the battery it shouldn't matter where it gets the power from (relay or oil pressure switch).
Could you hear your pump running with the key forward before you changed the relay
I had a 96 Chevy 1500 truck 4x4 5.7 V-8... crank no start it would kind of shudder or slightly start but not run smooth then just crank but would not start. Replaced the cap and rotor along with ignition coil pack and it started right up and runs great now. I didn't just throw parts at it though i did about 2 hours of checking fuel pump, fuel relay, pressure at fuel rail and it all checked out. Next tested spark it was there but faint or weak not much flash in my tool tester. Pulled the cap and rotor and had a burn hole in the rotor so I knew I was on the right track. Replaced ignition coil and cap and rotor and its fixed. Hope this helps someone with my symptoms!!
Nice!
The connector looks good. I'm going to get a new relay and try that.
Did that work? The new relay?
Also when replacing the coil pack it has two pins pressed in to hold it to the bracket instead of drilling I used two good punches and was able to punch the pins right out in one or two minutes instead of drilling it out. I spray it with PB Blaster or WD-40 and then start the punch and give it another quick spray half way through and the pins will just start to fall apart and it'll come right out of the bracket. I did have a drill ready if I needed it but the punch and a hammer did the trick. Just a tip to anyone looking for ways to get those "rivet pins" out. Good Luck.
Yeah, I wondered if that was a typo. I think 1996 was when they went to OBDII.
Since you get a code 54 that should eliminate some possibilities, because it means at least at the ECM level it is TRYING to run the fuel pump. If you had a bad IGN module it would never run because the ECM would not know the engine was spinning over.
Look inside that fuel relay connector carefully. If the fuel pump is pulling a lot of amperage it may be burning the connector up.
Thanks Ryan. I'm still troubleshooting. Check out part 3 which should be up soon.
seems for me fuel pump is getting to less current whereas voltage is actually there, and when the oil pressure switch bypass this connection enough current can be supplied to the pump...
Hard starting Check the hose clamps on the fuel pump in the tank .When you replaced the pump the clamps that came with the pump are NO good .They come undone Charlie
Check the block to make sure all those nuts are tight and not arcing
They will give you a key at autozone for free. Put it on your key chain. Once the key is in, never try to start the vehicle. You may not get a code for this problem. 10 years ago I ran a power lead from my battery to a 30 amp switch. The other lead to the fuel pump power lead. Truck starts right up. Every time. Changed the oil pressure sending unit and relay but no help. The switch did the job.
What key?
I had 12.0V on gray wire at the relay. I haven't checked the voltage leaving the PCM to see if its higher. If I put the fuel pump fuse to battery positive, it'll fire right up.
ima try this!thanks for the video
have you measured the voltage on the gray wire?
try to jumper the orange and the gray on the oil pressure fuel pump switch and see if its still there
have you measured voltage drops on the gray wire?
Ok thank you very much i will check those and no the fuel pump is kicking on all if a sudden its not getting fuel again ive got spark, jus not getting fuel I replaced the fuel pump about 4 months ago im only getting that low voltage to fuel pump relay code
Yes, 96 was the year that they changed it..good luck on finding the power failure on your truck..
96 chevy 1500 done motor swap ran good for 5-6 yrs now cold start it has to crank several times before it will start problem? 305 motor
Man I love my truck. same year. No smoke lots of power and no leaks. My problem is strange bump feeling after braking coming to stop Then from stop while turning I feel a lift. bumping. hard to describe. If I give too much gas while turning from a stop I feel a strange vibration. U joint ? or more than one issue. ? lol
Mine bumps sometimes too when accelerating or decelerating. I think it's the slip yoke in the transfer case. It could also be a bad CV in the front that could be causing some issues when turning.
+farmboy30117 yeah thanks man. I notice that top Mount on left tire arm that is most visible is worn too. I have the ext cab long bed. She's a boat but I love her. She needs to breath though. gotta get her opened up intake and dual out exhaust.
I have a 1989 Camaro and the same exact problem with it. I ran a 30 amp switched wire to the power lead on the fuel pump. I also have a direct power on a switch which I turn on when it is cold. It starts right up and I turn the switch off.
It turned out to be the fuel pump relay. I got a bad one from autozone.
farmboy30117 That was my first choice. An easy way to check the relay on a Camaro is to swap it out with the fan relay on the other side under the hood. I replaced mine anyway. Not that expensive. Didn't work, put a new oil sending unit on car, that didn't work either. Same with my truck. Sounds like you got lucky.
Were can I download this manual book you have
Hey farmboy,
Enjoyed your video. I have a 94 sierra with a no crank issue. I have been fighting it for a while. No crank from key, however fuel pump and everything else comes on when key is in run position. Engine will crank with wire directly to starter solenoid. Key must be in the on position to run. I have changed Starter and solenoid, neutral safety switch,ignition switch, and ignition control module. I have checked all fuses including inline fuse. Worked great one day then the next day it was gone and hasn't functioned intermittently. Just gone, seemed like a blown fuse but I sure haven't found it. Key tumbler still interacts with the rod and new ignition switch. Any help would be greatly appreciated .
Wow, sounds like you've eliminated the usual suspects. I believe your issue is electrical, but the wiring diagrams I've looked at seem a bit confusing. It appears there's a 5A crank fuse on the lower right hand corner of the fuse block on 5.0/5.7 engines. The wiring diagrams doesn't show this for 4.3/7.4 engines. On another diagram, it showed a 3A fusible link on the pink wire from the ignition switch to the ECM. I believe both of these are just for crank indication to the ECM. I'd take a test light and make sure I had power at the purple wire in the ignition switch harness with the key in the crank position. If not, you may have a bad ignition switch. If so, trace it on down to the neutral safety and so forth until you get to the starter solenoid. You may have a broken wire somewhere in the circuit. Good luck!
Toney Charles check the fuse block on firewall.
@ Toney Charles, that sounds like you have a bad distributor pickup coil, if you're running a hot wire to the starter solenoid to get your engine to stay running after starting it.
Hey, my friend, my 93 diesel want start, ( it turns over ) when I look underneath the truck, there is a pile of diesel fuel leaking towards the back of the engine. I need the truck to haul my horses. Any idea what the problem might be ??? Please help with a suggestion.
I'd check the fuel line running from the filter to the injection pump first. If you have a leak in the supply line, the pump will draw in air and won't pump.
So it's either the PCM or the old relay is sticking and I need to get another new one and try it.
Im not sure whats going on, my 93 idles kinda right, then not like a slight miss. Once its in gear slight hesitation sometimes then catches up, dont notice it at all after that or down the road. Today just started shifting hard from 1-2. Just put in a new TPS and spark plugs. Not sure whats going on or what to try next.
Could be the throttle body needs cleaning. My trans shifts hard from 1-2 sometimes too. I'm not sure why but it seems to be ok otherwise.
I have 1996 GMC Sierra 5.7 v8
I change spark plugs and wires, cap and rotor, fuel pump and the truck still take to long to start and when the truck start the engine shake a lot and i don’t have powe and also have a ugly gas smell... I need help what I can do... 🤷♂️🤷♂️🤷♂️🤷♂️🤷♂️🤷♂️🤷♂️🤷♂️
Saul, my best guess would be a vacuum leak.
Can u help me how to fix the vacuum leak
@@sauljuarez3941 Take it to a reputable shop
Hey farmboy i have a 92 chevy Cheyenne c3500 5.7l i have been getting the same code for low voltage to fuel pump relay i replaced the relay and fuse thought i fixed it but its doing the same thing running out of ideas
Electrical issues can be a real pain to sort out. You might want to check for a voltage drop between the battery positive post and the relay. Also between the battery ground post and the relay (ground) - this will only be active for a few seconds when the key is turned on. Bad grounds can cause all sorts of issues. I assume you're only getting the code but not an issue with the fuel pump.
Also i mine does not fire when i get oil pressure and did not start when i jumped the fuel pump not sure why it didnt start
it can be the sensor or just get the oil pump checked
My 1992 chevy Cheyenne 4x4 just took a crap on me at work. Not sure what to throw at it first, but I'll deffienitly try the paper clip method first! And I'll be playing the lotto with all those codes numbers! 35 57 32 12 lol
Haha, good luck with it! If there are no codes, check for fuel when cranking and then spark. Most of the time, as far as I've seen, it's either the fuel pump relay or a bad distributor.
have a 93 myself having issues if i undo the brown wire for timing it will start and run a bit rough but plug it in it will only start with gas pedal floored and only run if foot is on the gas some plus when it is running my gas hand bounces everywhere temp only goes up to bout 110 then stop (have 185 thermo) new egr valve brand new distributor shaft and sensors rotor plugs wires also temp sensor is new as well any idea
Could be the fuel pump, but first, unplug the brown wire and make sure the timing is set to factory spec. Should be on the emissions label on the radiator core support.
dont know if it matters either im getting no cel light
The CEL on these old trucks usually means something on the emissions side has failed, so I wouldn't expect it if its timing, spark or fuel related.
figured as much but im a jeep guy dabling with a chevy truck and its giving me fits
WARNING, you need at least 60psi - 65psi fuel pressure on the rail when CRANKING. If your fuel pressure gauge indicates less that while CRANKING, you will have trouble cold starting even if your vehicle is properly tuned up. if replacing your fuel filter doesn't fix it, you may need a new fuel pump.
not on tbi engines you dont need 60psi need roughly 7psi
Check your ground back at the tank also have seen fuel t
What if you don't hear crank but just the starter. Then a few cranks , it turns over? Anything will help
Ben-David Armstrong Sounds like a bad starter solenoid. The solenoid pushes the drive gear out to engage the ring. You can verify by viewing the end of the starter while someone tries to crank it (or film it with a camera). If it doesn't come out, it's easier to just replace the starter since it has to be removed anyway to fix. Hope this helps.
thank you i think thats what did the trick!
That's great!
Water temp sensor, right on the front of the intake
I'm having problems finding where all your 93 videos are located on your channel
I have a good many on my other channel Farmboy's Garage. If you go to my channel page and view all videos, I believe you can search my videos with keywords like 1993 or Silverado.
I've got a 92 Chevy Blazer and I'm having starting troubles too. I have to push the gas just to get it to start up. Not sure what the problem is but when it gets started it'll idle extremely rough and about 2 minutes later it runs like there was never an issue. Any ideas? I've got a New fuel pump, fuel filter, distributor cap, rotor button, plugs and wires.
Sounds like the Idle Air Control is not working properly. Here's a good place to start: www.wikihow.com/Check-an-Idle-Air-Control-Valve
The only number that appears is 12. Is there a code for 12? What is 12?
12 is normal. It means there are no trouble codes.
@@farmboy30117 Man. Well that takes me back to the start cause my truck is not starting. Did the whole paperclip and its what it gave me :/
@@denisemoseley9662 These OBD1 vehicles usually only set a code if it was related to emissions or a sensor. Need to see if it's a firing or fuel issue.
Same problem , just I change the fuel pump run but when try to do again nothing happen
Thanks, same problem
Can you jump the 92's the same way?
Yes, it should be the exact same way
+farmboy30117 that was a very informative video, thanks a lot!
Thanks, you're welcome!
check ground off fuel pump to frame
I added a ground wire from lock ring on fuel tank to the frame and it fixed my problem. I drilled a 1/16 hole in the ear on the lock ring, then ran a small metal screw into hole in the lock ring ear and attached the wire with a crimp-on eye. Also, a faulty oil pressure sending unit behing the intake manifold will cause low voltage and or no voltage.
Mine only flashes 12. whats wrong?
It means there are no codes set
with the paper clip
ever get it fix?
+david wilkins Yes, it was a faulty "new" fuel pump relay.
will this work on a 94 5.7 350
Yes, it should work up to '95 models with OBD1.
It only Chevy
Change your filter and check your fuel pump ground
It was a faulty fuel pump relay. Bought a bad one from the auto parts store. Go figure!
Do this work on a 95
I'm sure you have a fuel pump relay somewhere, just not sure if it's in the same spot.
You didn't check the fuse
Take off the distibutor cap and change the ignition module..
I fixed mine by replacing the ignition control module on the alternator.
92,93 and 94 models are just about the same...
ok having the same problem
Pump wiring at sender connector be burned.
No it went up becuase thr truck started 😂