How JustAnswer Works:

  • Ask an Expert
    Experts are full of valuable knowledge and are ready to help with any question. Credentials confirmed by a Fortune 500 verification firm.
  • Get a Professional Answer
    Via email, text message, or notification as you wait on our site.
    Ask follow up questions if you need to.
  • 100% Satisfaction Guarantee
    Rate the answer you receive.

Ask Eric Your Own Question

Eric
Eric, Automotive Repair Shop Manager
Category: Chevy
Satisfied Customers: 24030
Experience:  20+ yrs. experience as repair shop manager and technician.
Type Your Chevy Question Here...
Eric is online now
A new question is answered every 9 seconds

I have a 94 chevy k1500 4x4 2door extended cab truck. Im not

Customer Question

I have a 94 chevy k1500 4x4 2door extended cab truck. I'm not getting power to the fuel pump fuse. Replaced the fuel pump relay, checked the fuel pump and fuelpump fuse all are good. When I turn the ing on I get no power to the fuel pump. I can run a hot wire to fuel pump fuse to make it run but still wont squrit fuel through the throttle body injectors. If I pour feul into the throttle body it will start and run till what I poured in gets used up. I got power to all sensors and injectors with ing. on but no power to the fuel pump. all wires are good is there something I'm missing or advice on what to check next. Please help, I want to pull my hair out but I don't have much to spare.

Thanks John is stumped.
Submitted: 5 years ago.
Category: Chevy
Expert:  allchevy replied 5 years ago.
HelloCustomer the issue of no power to the fuel pump fuse concerns me, the fuel pump will only run aprox 2 seconds on key on, did you check for power during that time? In my experience , I have little trouble with the fuses and harness, it is almost impossible to check for power at the pump, please ensure the fuel pump relay is clicking on key on and also check fuel pump fuse for power at this time, you need an assistant as the fuel prime will only last aprox 2 seconds. i hope this helps, Dano
Expert:  allchevy replied 5 years ago.
Hello again, I quite often jump the gun on answering questions, after having read you concern , i feel as the problem mey be ignition problems, please check ignition 0 and ignition 1 fuses for power on key on. I do not want to lead you down the wrong path, please advise, thx dano
Customer: replied 5 years ago.

Yes I have tried the test with a helper as my wife turn the key on and I'm at the fuse with a volt ohmn meter I get no power there. at the connection to the fuel pump by the tank I got power to fuel gauge but not the pump. I've allready droped the tank and checked the pump and wires they are good. I can hot wire the pump via the fuel pump fuse on fire wall and hear the pump running. also loosened the fuel ine at the throttle body and both sides of fuerl filter and will spray gas. I checked al fuses at the fuse block in the dash, and they are all good. I'm so lost as to my when I turn the ign. on I don't get power at the fuel pump fuse. I can hear clicking when I turn on the ign. and the relay is brand new. Is there any thing else to check and locations would be helpful. any other info you might need let me know. by the way where are ign. 0 and ign. 1 located so I can make sure that I checked them.

Thank you so much for your advice.

John

Customer: replied 5 years ago.

Yes I have tried the test with a helper as my wife turn the key on and I'm at the fuse with a volt ohmn meter I get no power there. at the connection to the fuel pump by the tank I got power to fuel gauge but not the pump. I've allready droped the tank and checked the pump and wires they are good. I can hot wire the pump via the fuel pump fuse on fire wall and hear the pump running. also loosened the fuel ine at the throttle body and both sides of fuerl filter and will spray gas. I checked al fuses at the fuse block in the dash, and they are all good. I'm so lost as to my when I turn the ign. on I don't get power at the fuel pump fuse. I can hear clicking when I turn on the ign. and the relay is brand new. Is there any thing else to check and locations would be helpful. any other info you might need let me know. by the way where are ign. 0 and ign. 1 located so I can make sure that I checked them.

Thank you so much for your advice.

John

Expert:  allchevy replied 5 years ago.
HelloCustomer sorry its taken me so long to get back to you, please check INJ fuse and the ECM-INJ fuses located in the fuse block, they should be hot in run or start. Please check the connector at the fuel pump relay for possible burnt and/or corroded connections, repair as necessary. Do you have a wiring diagram if not i can try and send you some , do you have a fax or email that i may send these? please advise, thx dano
Customer: replied 5 years ago.

I do not have a wiring diagram, That would be helpful. XXXXX@XXXXXX.XXX is my address. No burnt or corroded connections at the fuel pump relay. One thing I did find, that might help, is I have power comming into the relay, but with the ign turned on I cant find any power on the other wires comming out, just that one orange wire is hot with the ign. on or off. The relay is new from NAPA.

INJ fuse and ECM-INJ fuse are they blade fuses? are they located in the fuse block in the dash? I checked all fuses in the fuse block in the dash and all have power.

Customer: replied 5 years ago.
Relist: I still need help.
Customer: replied 5 years ago.
Yes I get power at the INJ fuse and power at the EMC-INJ fuse.
Customer: replied 5 years ago.
Relist: I still need help.
Expert:  Eric replied 5 years ago.

Hi,

 

If you are still in need of help let me know and I will see what I can do to assist you

Customer: replied 5 years ago.
Well I still got the same problem. Some help would be great. PLEASE
Expert:  Eric replied 5 years ago.

Hi,

 

I was looking at the other posts and either dont see it mentioned, or am overlooking it-what size engine? Is it a TBI or CSI engine?

Customer: replied 5 years ago.
350 tbi
Expert:  Eric replied 5 years ago.

Hi,

 

Check for power at the orange wire and at the dark green/white stripe wire that go to the fuel pump relay and let me know if there is power at both wires or not

Customer: replied 5 years ago.

I have power comming into the relay,orange wire, but with the ign turned on I cant find any power on the other wires comming out, just that one orange wire is hot with the ign. on or off. The relay is new from NAPA.

Expert:  Eric replied 5 years ago.

Hi,

 

Ok, the orange wire is battery feed. The dark green wire/white stripe is the fuel pump relay control signal from the ECM. If that wire doesnt have voltage when key is turned over to crank vehicle, the fuel pump relay isnt energizing.

 

You are going to need to check for voltage at the pin itself at the ECM for voltage going out. If none going out, ECM is defective. If voltage present, then there is a short/open in that wire that will need to be traced:

 

graphic

 

graphic

Customer: replied 5 years ago.
I will check that out and let you know.
Expert:  Eric replied 5 years ago.

Hi,

 

Ok- let me know what you find.

 

The ECM is located behind the right side of the dash near the blower motor. Remove the glove box for easier access

Customer: replied 5 years ago.
It's dark and raining here so having trouble finding a good ground and not sure if I found the right wire with a flashlight. I'll check it tommorrow if the snow we are going to get isn't to bad. I found the ecm hard to see all the wires a little tight in their. Thank you so much for the help. I'll be in touch when I find out if there is power there.
Expert:  Eric replied 5 years ago.

Hi,

 

Ok, will be here all day tommorrow

Customer: replied 5 years ago.
Ok I checked the dark green wire with a white stripe at the ECM connection and no power there. Could the ECM be bad? The truck was running fine when I parked it, it sat about 4 weeks and when I went to start it the battery was dead. I tried to jump it but it wouldn't start. So I purchased a new battery and it would turn over but not start. That is when I started to trouble shoot the problem and here we are. Could the jumping of the old battery fried the ECM? I'm at such a loss here. The dark green wire with a white stripe is good from The ECM to the relay. Thanks, John
Expert:  Eric replied 5 years ago.

Hi,

 

Ok, that is what controls and enrgizes the fuel pump relay. No power there means either a fauty ECM or a short/open in ECM. To further test the ECM at this point to verify its bad is going to take a factory level scan tool that can operate the different functions of the ECM for testing purposes, but based upon not having power at that pin, odds are that the ECM is faulty

Customer: replied 5 years ago.
Thank you so much. that was driving me crazy trying to figure it out. what causes that to go bad? is it the age of the ECM or was it the jumping it off?
Expert:  Eric replied 5 years ago.
Hi,

I have seen on rare occasions where jumping a car can fry a computer, but usually it just due to the age. Wires, solder connections, etc., just start to break down over time.
Eric, Automotive Repair Shop Manager
Category: Chevy
Satisfied Customers: 24030
Experience: 20+ yrs. experience as repair shop manager and technician.
Eric and 7 other Chevy Specialists are ready to help you
Customer: replied 5 years ago.
Thank you! I'm going to replace it and hopefully that will fix the issue. If not I'll be back to ask some more. Thank you again.
Customer: replied 5 years ago.
Well, I replaced the ECM and still wont start. I can run it if I pour fuel in the TB but still no power to the fuel pump. 120.00 for ECM and still at a loss, any ideas????
Expert:  Eric replied 5 years ago.

Hi,

 

Let me put the brain cap on and see what I can come up with...this one is a bit strange

Customer: replied 5 years ago.
got me stumped also. thank you for helping.
Expert:  Eric replied 5 years ago.

Hi,

 

You havent mentioned anything about the oil pressure gauge not working, so I have assumed that it does. Does the oil pressure gauge work?

Customer: replied 5 years ago.

as far as I know. I havent had it running long enough to see what it is, as the fuel I pour in the TB gets used up rather quickly.

 

Expert:  Eric replied 5 years ago.

Hi,

 

Anyway you can get some one to feed TB while you crank it and see if oil pressure gauge is functioning and let me know? There is a reason for this- the oil pressure switch acts as a secondary fuel pump relay.

Customer: replied 5 years ago.
Let me check that I'll get back to you shortly.
Expert:  Eric replied 5 years ago.

Hi,

 

Ok, in the meantime, I will keep checking into this

Customer: replied 5 years ago.
Ok, I got it running and I get over 40 psi on the oil pressure gauge.
Expert:  Eric replied 5 years ago.

Hi,

 

Ok, that eliminates the oil pressure sending unit/secondary fuel pump relay.

 

I am going to call a buddy and run this by him and see if he has a clue, as I am stumped right now. I will get back to you - probably be an hour or so

Customer: replied 5 years ago.
ok, thanks again for your time. John
Customer: replied 5 years ago.
Relist: I still need help.
Expert:  Eric replied 5 years ago.

Hi,

 

I wasnt able to get a hold of my buddy until today. He was going to check some things and call back. Justing waiting to here back. I emailed him a copy of our posts, and he had the same thought as me- bad ECM. He was initially stumped as well- he is leaning towards a short/open but wanted to review the schematics and see if he could narrow it down.

 

I havent forgotten about you.

Customer: replied 5 years ago.
ok thanks. hope we can whip this. I think we will both learn something from it.
Expert:  Eric replied 5 years ago.

Hi,

 

Have you checked for power at the injector harness connector? Does it have 12v at one or both terminals?

Customer: replied 5 years ago.
is this where the wires hook to the injuctors? if so I got power there.
Expert:  Eric replied 5 years ago.

Hi,

 

correct.

 

Have you tried applying 12v to the fuel pump test connector(located at firewall behind brake booster)? If you have, did the fuel pump run?

 

graphic

Customer: replied 5 years ago.
I tried at the fuel pump fuse and it runs but haven't tried at the test connector. I'll try it tommorrow and let you know. is that under the dash or at firewall under hood? and do I just run voltage to it or check it for voltage?
Expert:  Eric replied 5 years ago.

Hi,

 

Ok, try that and let me know. That will help narrow down area and potential wiring to test

Customer: replied 5 years ago.

sorry reread your question and see that I need to apply power to it. still want to know if it's under the hood or under the dash?

Thanks

 

Expert:  Eric replied 5 years ago.

Hi,

 

Sorry, gave you wrong diagram.

 

You want to apply 12v(can use a jumper wire from battery) to terminal G in the DLC(data link connector), located under left side of dash, just to the left of steering column:

 

graphic

 

 

Customer: replied 5 years ago.
ok, I'll hit it tommorrow afternoon and reply as soon as I find out . thanks for you time on this.
Customer: replied 5 years ago.
ok I ran a jumper to test terminal G and the fuel pump runs.
Expert:  Eric replied 5 years ago.

Hi,

 

Ok, there is an open in fuel pump relay drive or power circuit, or faulty relay. You have replace relay, so you will need to test wiring between ECM and relay.

Customer: replied 5 years ago.
would that be the dark green wire with a white stripe? or is there other wires as well. do I check for continuity in the wire?
Customer: replied 5 years ago.

Hello,

I unhooked the ECM and the fuel pump relay, I attached a hot wire to the dark green wire with a white stripe and checked the same wire at the relay connector and it is passing power. that wire is good. scratching your head yet?

Expert:  Eric replied 5 years ago.

Hi,

 

Yeah, just deleted a post on reading this. I was going to get you to run a wire overlay for the fuel pump relay to pin #F6 at the ECM

Expert:  Eric replied 5 years ago.
With ECM plugged up, do you have power at the orange wire and the dark green/white wire? or is power still missing at the dark green/white wire at fuel pump relay connection?
Customer: replied 5 years ago.

Ok, there is not power at the darkgreen/white wire. there is power at the orange wire

John

Expert:  Eric replied 5 years ago.

Hi,

 

Ok, lets do a wire overlay. Run a new wire from the ECM pin #F6 to where the dark green/white wire goes into the fuel pump relay. For now, just run it as temporary wire the easiest way possible. If fuel pump energizes, then we know the open is in the dark green/white wire.

Customer: replied 5 years ago.
I checked that wire while it was unhooked. then hooked up the ECM turned the key and no power at the green wire at the relay connector. if power is not comming from the ECM to the relay how would a jumper from there to relay have power. or do I not understand what you telling me.
Customer: replied 5 years ago.
I checked that wire while it was unhooked. then hooked up the ECM turned the key and no power at the green wire at the relay connector. if power is not comming from the ECM to the relay how would a jumper from there to relay have power. or do I not understand what you telling me.
Expert:  Eric replied 5 years ago.

Hi,

 

if there is an open in dark green wire between the ECM and relay, then although there will be power at the ecm, there is none at the relay. So by running another wire between the 2, we are giving new route for power. At this wire, you will only have power for 2 seconds when turning the key to the on position.

 

Check for power at pin #F6 at the ecm. With connector connected, backprobe that pin for 12v during first 2 seconds when ignition turned on. That confirms ECM is sending power to the relay. Now, check for 12 during first 2 seconds when ignition turned on at the green wire at relay- no power confirms that voltage is lost between the two, so we know there is an open in that wire.

 

We run a new wire, theoritically we should have power during first 2 seconds ignition is turned on to the relay.

Customer: replied 5 years ago.
ok I didn't check to see if power from the ECM was there. I assumed that it should be if it is new. When I checked the green wire at the relay after I hooked up the ECM, I was by myself, so I'm sure that it took more than two seconds. I'll double check the ECM for power by back probbing and if power there I run a jumperwire. either way I'll be back when I find out what I got.
Customer: replied 5 years ago.
ok back to square one I got no power from the ECM at #F6. Yell
Expert:  Eric replied 5 years ago.

Hi,

 

Hmmm...

 

possible bad ground to ECM or a power supply issue to ECM, but then it wouldnt run when you pour fuel into it...

 

My buddy's thoughts have been the same as mine.

 

Let me beat my head against a different wall and see if any new thoughts pop out...

Customer: replied 5 years ago.
Thanks, XXXXX XXXXX be such a pain in the butt.
Expert:  Eric replied 5 years ago.

You're not... we always come across the vehicle that seems outsmart us...just takes time- especially on electrical problems...

Customer: replied 5 years ago.
Relist: I still need help.
Customer: replied 5 years ago.
Hello Eric, I was wondering if there might be something that is not telling the EMC to send power to the fuel pump relay. Have you found out anything yet?
Expert:  Eric replied 5 years ago.

Hi,

 

I am still looking into it. Havent given up yet. I have ordered a different set of schematics to see if mine are missing something. Should be in Mon

 

 

Customer: replied 5 years ago.
ok thanks!
Customer: replied 5 years ago.
Relist: I still need help.
Expert:  Daves71 replied 5 years ago.
Hi,I hope I can help you.I read the posts and from what I can make out,if you run a 12v jumper to the fuel pump FUSE the pump&truck will run.The fuel pump fuse is normally 12v all the time and is fed by the battery to the underhood maxi fuse center then to the dash fuses.When you turn the key to the on position does the service engine soon light on the dash come on?
Customer: replied 5 years ago.
The truck won't run when you jumper the fuel pump fuse. It will only run when I pour fuel into the throttle body. When I turn on the key there is no service engine soon light.
Expert:  Daves71 replied 5 years ago.
Ok,here is a step by step upload to start withgraphic
Customer: replied 5 years ago.
Relist: I still need help.
Customer: replied 5 years ago.

Ok I tested the 740 orn- wire got .5 volts, and 639 pnk/blk- wire and got 12 volts, with IGN on per instructions you sent. Not sure of the voltages are what should be there, but it states that it could be faulty ECM or ECM ground. The ECM is brand new from advance auto parts, with the original PROM installed. They don't give a new PROM with a ECM purchase. If the voltages are ok then what is the next step in trying to fix this issue? Also I don't have the service engine soon light, but there is a check gauges light that stays on. Don't know if that helps any.

Thanks

John

Customer: replied 5 years ago.
Relist: I still need help.
Expert:  Howard Duncan replied 5 years ago.
Hello, forgive me, but I don't think I seen anything telling you to replace pickup in the distributor. I don't think your ecm is sensing rotation of the engine therefore, not powering the fuel pump relay or giving injector pulse.
Customer: replied 5 years ago.

+

Is this what is called a crank sensor? or do I just ask for pickup that goes in the distributor. Thank you

John

Expert:  Howard Duncan replied 5 years ago.

Hello,

You should ask for the pickup that goes in the distributor; this will be cheaper than replacing your distributor and hopefully this will fix your problem :) If not, let me know if I can be of further assistance to you; I will be happy to try and help. Regards, Howard

Customer: replied 5 years ago.
Ok, I've replaced the pickup and when I turned the key on I heard the fuel pump run but it still would not start. after about 2 to 3 seconds of trying to start the fuel pump stoped and would turn on again when I cycled the IGN. I poured gas into the throttle body and it fire up and died as soon as it used up the gas I poured in. Man this has got me confused. I'm about ready to stick a stick of dynamite under it. Ok lets try something else, so what is the next step?
Expert:  Howard Duncan replied 5 years ago.
Well that's more than what it did. I want you to do one more thing put in a new ignition module in the distributor and let me know what happens. I know it's another thing, but I really want to help you. Trust me I've had some real winners to work on that have driven me insane! Thanks
Customer: replied 5 years ago.
The fuel pump would not turn on again.. sorry for the miss type. Also I guess what I replaced was the control module. 2 screws hold it down and 3 wire hook ups on it. I'm not sure what the pick up would be.
Expert:  Howard Duncan replied 5 years ago.

Okay, what you replaced was not the pickup. I have researched it to be able to give you a visual of the part. Go to e-Bay and either search by auction # XXXXX or type in under search "ignition pickup chevrolet c1500". This way you can even print it out so you make sure you get the right part. Advance has this part online in stock (I already searched it); you can go to www.advance.com and it is part # XXXXX I know trying to do this online is rough :) P.S. Don't buy the dynamite!! LOL!! Let me know how THIS goes; I'm here.......

Customer: replied 5 years ago.

ok. I replaced the distributor, it had everything new with it. still the same problem.I've spent 28 for a fuel pump relay, 120 for an ECM, 30 for a control module, and now 130 for a distributor,cap rotor button. so at a complete loss. and besides that I think I got the distributor one tooth off. do you know where I can find some cheap dynamite? LOL

I don't know what else to do.

Expert:  Daves71 replied 5 years ago.
Hi T9,please go back to the chart for the service engine soon light.orange wire(#740)should be 12v at connector c16 and b1 at the ecm connector(unplugged from the ecm) with key on.a6(pnk&blk)should be 12v wth key on.Ground a5 with key on and see if the service enine soon light comes on.

JustAnswer in the News:

 
 
 
Ask-a-doc Web sites: If you've got a quick question, you can try to get an answer from sites that say they have various specialists on hand to give quick answers... Justanswer.com.
JustAnswer.com...has seen a spike since October in legal questions from readers about layoffs, unemployment and severance.
Web sites like justanswer.com/legal
...leave nothing to chance.
Traffic on JustAnswer rose 14 percent...and had nearly 400,000 page views in 30 days...inquiries related to stress, high blood pressure, drinking and heart pain jumped 33 percent.
Tory Johnson, GMA Workplace Contributor, discusses work-from-home jobs, such as JustAnswer in which verified Experts answer people’s questions.
I will tell you that...the things you have to go through to be an Expert are quite rigorous.
 
 
 

What Customers are Saying:

 
 
 
  • I was having a terrible problem with the wheel bearings on my 98 Chevy Cavalier and I suspect that using this website saved me plenty of time and money. Todd L Rochester NY
< Last | Next >
  • I was having a terrible problem with the wheel bearings on my 98 Chevy Cavalier and I suspect that using this website saved me plenty of time and money. Todd L Rochester NY
  • Wonderful service, prompt, efficient, and accurate. Couldn't have asked for more. I cannot thank you enough for your help. Mary C. Freshfield, Liverpool, UK
  • This expert is wonderful. They truly know what they are talking about, and they actually care about you. They really helped put my nerves at ease. Thank you so much!!!! Alex Los Angeles, CA
  • Thank you for all your help. It is nice to know that this service is here for people like myself, who need answers fast and are not sure who to consult. GP Hesperia, CA
  • I couldn't be more satisfied! This is the site I will always come to when I need a second opinion. Justin Kernersville, NC
  • Just let me say that this encounter has been entirely professional and most helpful. I liked that I could ask additional questions and get answered in a very short turn around. Esther Woodstock, NY
  • Thank you so much for taking your time and knowledge to support my concerns. Not only did you answer my questions, you even took it a step further with replying with more pertinent information I needed to know. Robin Elkton, Maryland
 
 
 

Meet The Experts:

 
 
 
  • Tim's Auto Repair

    mechanic

    Satisfied Customers:

    7641
    Have owned a repair shop for 25 yrs.
< Last | Next >
  • http://ww2.justanswer.com/uploads/TI/tim37857/2011-10-28_23053_S6301814.64x64.JPG Tim's Auto Repair's Avatar

    Tim's Auto Repair

    mechanic

    Satisfied Customers:

    7641
    Have owned a repair shop for 25 yrs.
  • http://ww2.justanswer.com/uploads/DT/dt69nova/2012-6-15_234154_pic1.64x64.jpg Dave Nova's Avatar

    Dave Nova

    Chevrolet Technician

    Satisfied Customers:

    6870
    ASE Master Certification. GM World Class Certification
  • http://ww2.justanswer.com/uploads/ggrote1/2009-06-27_031011_me.jpg Gary's Avatar

    Gary

    Chevy Technician

    Satisfied Customers:

    5404
    15 years GM master tech
  • http://ww2.justanswer.com/uploads/testedtuff/2009-09-26_170108_pictures.jpg John's Avatar

    John

    Master A.S.E Automotive technician

    Satisfied Customers:

    4071
    A.S.E MasterTechnician A1-A8 w/L1,38 years experience General Motors Master Technician
  • http://ww2.justanswer.com/uploads/RO/rodcuda/2011-7-25_224114_Donhoff1.64x64.JPG Neal's Avatar

    Neal

    Chevy Mechanic

    Satisfied Customers:

    2306
    Shop Owner and Mechanic on multiple makes.
  • http://ww2.justanswer.com/uploads/goodwrench9124/2008-11-09_220838_dscf0007.jpg goodwrench9124's Avatar

    goodwrench9124

    ASE Certified Technician

    Satisfied Customers:

    2041
    Ase Master Certified, GM Master Certified Tech. Awarded GM Top performer, Hybrid certified
  • http://ww2.justanswer.com/uploads/DR/drivefast1971/2012-1-12_172422_0009051tQKh.64x64.jpg Ron Z.'s Avatar

    Ron Z.

    - Chevy Tech -

    Satisfied Customers:

    1912
    18+yrs experience. State Inspector and Chevy Diagnostics