i have a 1990 chevy k-1500 i have no fuel out of the injectors but have lots of fuel pressure. I have already changed the fuel relay and the oil pressure senser since it was firing but wouldn't stay running. I installed a new ecm today and i have no fuel from the injectors. The last two days the truck would start in the morning than die after a few minutes and never start again. have already put in new plugs, wires, cap and rotor. the truck had been sitting a lot over the last year only used about once a month.
Hello, I'm Aran. I will try my best to answer your Chevy question and make this a positive experience. Your COMPLETE satisfaction is my goal.
So when the truck dies or is not starting does it have spark?
How many miles are on the truck?
When the truck dies or is not starting does it still have spark?How many miles on the truck?Do you have a test light?Thanks, Aran
yes i still have spark
it has about 300,000 km
yes i have a test light.
my first thought was the fuel pump but when i turn the key on the pump runs for 3 seconds and i can hear the relay kicking out. i have fuel pressure havn't used a gauge but when i looseing the line at the carb i have lots of pressure. thats why i assumed the ecm. I thought the enginer should fire up and than dye if the pump was bad. but if it sits over night it will start. I'm thinking maybe its a ground keeping a signal to the injectors but i haven't tested to see if the injectors have power.
Hi thanks for the reply.
ok i have done the test and no fuel comes out of the injectors but i can hear the relay clicking
Hi thanks for the reply, if you hear clicking each time you touch the terminal it probably is triggering the injectors. Have someone place their hand on the injectors when you trigger them and see if indeed it is the injectors clicking.
Let me know.
Thanks I have checked and no i get no sound from the injectors when i touch the Purple / white wire from the four pin plug from the distributor with the test light on the postive of the battery all i hear is the fuel relay on the firwall. I do have power at each injector.confirmed with the test ligt.
Relist: Incomplete answer.
Hi thanks for the reply,
First thing, at this point I am trying to get enough information to give you an accurate diagnosis, so be patient with me as I only know about the problem what you have told me and what information we have gathered so far, so resisting the question will more than likely give you a longer wait time as technicians see you have already been helped and will leave the question alone.
The next step is hook the distributor back up and then hook your test light again up to power and then on the wire that does not have power on one of the injectors touch that terminal while cranking it over and see if the test light lights up while cranking it, it should pulse.
If you need clarification or have additional questions just post back here.
If you would rather work with a different tech let me know and I will open the question back up.
If there is NOT a pulse, disconnect the 4 pin distributor connector and use another jumper from battery positive and touch the PURPLE/WHITE WIRE and see if it flashes the test light.
If the test light flashes then, you still need a distributor.
I recommend a whole distributor as even if you replace just the module, the pickup can go bad and also the bushings wear inside, it is just better to replace the whole thing.
Thanks again for your information, help and patience.
Thanks I have done the test and I don't get any light at the injectors I only have power on one wire on each injector
Thanks for the reply, I added another post in between our last conversation, did you try the powered test light on to the non powered wire of the injector, key on and then touch the purple/white wire with another powered test light and see if the test light on the injector flashes with each wire touch.
If the test light flashes then, you still need a distributor. It makes sense the fuel pump relay is triggering with the purple/white wire touching as this is the pulse input to the ecm for engine rpm, so it will turn on the pump once it sees this signal, so I believe we are on the right track, I just want to verify the pulse at the injector.
Do you need any clarification?
Ok I still hAve no power at the injectors just to confirm hot to the white or purle than a test light to the injector wire that doesn't have power sorry was on my blackberry. when i power thwe white or ourple wire or both at the same time i get the fuel relay and the first time i did it i could hear fuel going into the fuel regulator.
I have power on 1 wire at each injector but still can get anything form the other injector wire with the test light with a power jumper on the four pin purple and white wire.
Thanks for the reply let me try this and see if this makes a little more sense.
Power up the test light and place it either on the BLUE or the GREEN wire at one of the injectors, it will NOT LIGHT at this time.
Then take a jumper wire from the POSITIVE at the battery, KEY ON, and disconnect the 4 pin connector at the distributor. Momentarily touch the PURPLE/WHITE wire with the jumper wire, each time you touch the PURPLE/WHITE wire, the test light should light.
Is this clear enough?
Is this the test you did?
Thanks thats clear and yes that's the test I did I wasn't sure I was doing it correct because I figured it had to light so I asked another person to do it as well. And he did the same thing in fact I asked him to start from the at the beginning and he got no light as well.
Wow that is weird, because we know the ECM is getting the signal because it turns the fuel pump relay on as you stated.
So now we have to decide why is the injectors not being fired. There is a tool called a noid light, it may be a better test tool for our injector. They have them at any local parts house, here is a picture of them.
They make specific ones for GM throttle body injections. It is possible that the test light is not being powered on long enough to flash the test light, where as a noid light is very sensitive to electricity.
So as it stands, based on the information we have, we know the ECM is seeing you touch the PURPLE/WHITE wire as the fuel pump relay is triggered. This should also trigger the injector with each tap also. So either the test light is not the right tool to use and we need to try a noid light with the PURPLE/WHITE wire tap or we are going to have to start chasing wiring from the ECM.
Having said that I have never had to find bad wiring from the ECM to the injectors, so my hunch is still the distributor.
Let me know how I can help.
Ok I will change the distributer and let you know
Great, keep me posted.
I know you replaced the cap and rotor, so make sure the new distributor has the module and pickup at least with it.
One last thought I had, you mentioned spark but no fuel, so after it dies if you pour a little fuel in will it run for a bit?Also do you need any pointers on changing the distributor?I basically pick a point on the firewall and mark where one of the ignition module connectors were and then eyeball something in line with the rotor on the motor and that is usually close enough to be able to time it.The timing connector comes out of the distributor harness and is a TAN/BLACK wire and it has to be disconnected to set the timing. The spec is 0.Thanks, Aran
Wow this thing is kickin my butt. Ok so i just installed a new distributor and everything is the same. By the way the old one looked to be in sad shape needed to be changed anyway by the amount of rust. so my thoughts are the fuel pressure is to low. when i loosing the the lines at the throttle body i have fuel pressure but maybe not enough.
however i did the following
I unplugged the injectors
turned on the key
put a hot jumper and a ground on the injector terminals
injector clicks but no fuel
I just hit the accept button by mistake no big deal I have to pay anyway. however i still need your help in trouble shooting
Hi there thanks for the reply, when we initially spoke you mentioned there being plenty of fuel at the throttle body so that is why I went the direction of the distributor.So at this point we need to determine what we are missing, either injector pulse from the ECM at the injectors or no fuel delivered from the fuel pump.
Ok, I hope you are sitting down. We are starting over from square one. So, this morning I put in a new distributor, as you suggested. When i pour fuel down the throttle body the truck fires. I went back to the parts store, picked up my old ECM, installed it and the truck started. However, it only ran for 5-6 minutes and then died and it will not restart. Which was the problem I had in the very beginning. So what are the odds of me getting
a bad ECM?
So after the truck died I checked for fuel and yes, the injectors are spraying fuel. So then I used a test light and checked for spark and yes, I have spark. but the truck will not start. Which is where I originally started on Saturday.
Hi Doug, thanks for the reply.I just want to make sure I am completely accurate on what information you have just given me.When the truck is NOT starting, the injectors ARE spraying fuel?When the truck is NOT starting, the truck has spark both at the coil and at least one plug?If you pour gas down the throttle body when it is NOT starting, it will start?Thanks for staying with me, I am sure we can figure this out.Thanks, Aran
thank you for still working on this
yes when the truck is not starting the injectors are now spaying fuel ( didn't with the New ecm)
I do have spark at the 1 plug
I didn't checked the coil do i test it the same as a spark plug?
I didn't pour gas down the throttle body since the injector seem to be putting enough fuel out.
I'm laying odds the truck will start in the morning or late tonight after sitting and will run for 5 minutes
I will let you know.
Hi Doug, thanks for the additional input.So I assume these tests were done when the truck was not starting is that correct?If you had spark at #1 then we know the coil is putting out so that is ok.So to recap, basically if I understand you correctly, when the truck is NOT running you still have spark and fuel is this correct?I thought before when it was not running we had NO fuel coming out of injectors?When the truck does run does it run good?Does the check engine light ever come on when its running?I will let another tech look this post over tomorrow to see if he has any ideas and then just post back what you find in the morning.Thanks, Aran40851.0500540509
Correct the test were done when the truck won't run.Correct in the past I had no fuel but once I installed the old ECM I now have fuel at the injectors and they seem to be working correctlyI still have spark after the engine diesThe engine light never goes out when it is running.When it runs it run fair for the first few minutes than it starts running rough and dies after 5 minutes of running if I leave it for 3 or more hours it will start again and run for 3 to 5 minutes before dies
Thanks for the reply, lets see what the computer is seeing, if the check engine light is on, that means there is a code stored.CLICK HERE for the procedure to extract codes, I usually use a small paper clip broken in half.Let me know.Thanks, Aran
Hi Aran, should I start by clearing all codes and than run the engine?
Yes on those just disconnect the battery and that will clear the codes and then after it stalls just leave the on and then jump the terminals and the ses light will flash the codes.Thanks, Aran
HI Aron,I cleared the code started the truck it ran for about 5 minutes it died and the code is one long and 5 short
Hi Doug, that code is for the engine coolant temperature sensor. It is over by the thermostat housing. I usually tug on the wires coming directly out of the connector to see if any feel like an elastic, if it does the wire is broken inside of the insulation.Also disconnect the connector and make sure the terminals in the connector are not spread open so as to not contact the male pins in the sensor itself.If all that looks ok, it probably is a bad sensor.Also There should be some grounds on the thermostat housing if I am correct, test all the black wires there and make sure the bolt and nut are tight.After it died and did not restart did it still have spark and fuel coming out of the injectors when you cranked it over, or what did you find?I am still just trying to get enough definitive information to give me an accurate direction to go with this.Thanks, Aran
Ok I give up!!! I changed the coolant temp. sensor and now it won't start. It fires but thats it and it has lots of fuel.. I think it's time to haul it into a shop and let the professionals such as yourself handle it. thanks for your help this was the first time i used a service like this and I found it awesome to use i will defiantly recommend this and use you again. Thanks for all the help Aran
Wow this has been quite the issue. The only thing that comes to mind is that from all of the cranking the spark plugs could be wet with gasoline and will not fire. You can pull a couple of plugs and see how wet they are, and if they are dripping you need to burn them off with a lighter and then try and start it again.I apologize that this has been such a pain, usually it is not this bad.If you do end up taking it to a shop, I would be VERY interested as to what they find.Thanks for your time and help.Aran
Hi Aron, ok i finally got it running. when I had put in the new distributor i didn't have it right so the engine was getting was to much gas and flooding out. it was so bad i had to change the oil it was full of gas.
The main problem from the begining was the distributor but when i put in the new ecm it was bad which caused the no fuel probelm from the injectors. I should of started whith you instead of on my own. thanks again you were a great help
Glad to hear you got it running, I guess I should have had you verify the install of the new distributor, so for that I guess I too live and learn.Thanks for being patient.Aran