Please Help!!

Delorean14 · 12-02-2007, 07:30 AM

I've had it with local mechanics. I should have gotten on something like this in the first place. Now I've spent almost a thousand dollars and still have the same problem. Anyway, now that I've vented...

Here's my problem. I have a '94 Silverado 7.4l K2500. When it gets below somewhere around 30 degrees, the fuel stops flowing through the injectors. It'll crank all day but no fuel. After about 10 mins in a shop at 50 degrees she'll fire right up. If I take her outside WHILE RUNNING she'll die after about 5-10 mins of running with the same problem. A mechanic has already replaced the computer and distributor as well as some other things. She ran fine for a little bit but now it's the same problem. I also have a nasty electrical problem that if I leave my truck sit for three or so days the battery is dead. ANY INFO IS APPRECIATED!!! If you think you can help but need more info, don't hesitate to ask me. I'll try to be on here every couple days or so. THANK YOU!

-Robb-

75K30 · 12-02-2007, 10:11 AM

Welcome to the site:
Too bad about the troubles the old 454 is giving you. I have a theory or two, but would like to know what the mechanic has done already?
The mechanic thinks it is electrical related, and has changed the computer already.
Am wondering if they got ahywhere into the fuel system???

crabtruck · 12-02-2007, 05:57 PM

Welcome to the forum Delorean14. An electronic student, cool.

Only so many times you can have a dead battery before you must replace it. Problem may have been caused by something else originally but once the battery is damaged from repeat discharges it will be tougher to find and you will continue to have a dead battery. Charge the battery (in or out of truck) and then take it inside with you for 24 hours or more. Measure the voltage when you take it in, should be high, like 13.25-14.6v depending on method of charge. After it sits inside for more than a day it should still read over 12.6v. If not replace. If so watch for another day that it doesn't drop. If good, don't reconnect to truck until your ready to trouble shoot. .

Which brings up another point that should have been covered earlier: what is the voltage with engine running ? Cold also makes damage in wire more apparent as the wire shrinks away from the gap. Have you checked that the voltage remains good to the fuel pump since much of that system is very exposed to outside temps?

What exactly has the mechanic replaced ? If the engine runs fine indoors and is at operating temp, then dies out in the cold quickly, you are looking at parts not being readily heat by the engine. That's too big to get that cold so fast.

Check the battery connections are good, clean and tight at all ends since voltage fluctuations can cause other random results, like your IAC misbehaving. When you go out in the cold with the engine warm and running and it dies, is this at idle ? Does it happen when you keep it around 1500-2000rpm while parked ?

Have you checked for fuel contamination, including alchohol depending on where you by gas ? Replaced filter ? checked fuel pressure ?

What can you tell us about how the problem started showing up in the first place ? Do you have any after market gear on the truck that is elcetrical, fuel or intake related ? Do you have trailer brakes on this truck ?

Just my guesses....

tjzz4 · 12-02-2007, 10:06 PM

As far as your battery drain... take a cable off from the battery and connect a test light between the battery post and the cable. If the light comes on you have a draw. you can remove fuses until the light goes out to locate the circuit... be sure your door jam switch is bypassed when you check fuses though because when you open the door it completes a circuit.
On the newer cars there is some parasitic draw from the different modules but that can be eliminated by using a digital meter and after the cable is disconected.. make contact to the battery again and remove while the meter is still completing the path. the max you should see on the milliamp scale is 40-50
On your starting issue... sounds fuel related... Pump??? what has your guy done?

Delorean14 · 12-03-2007, 09:54 PM

I'm going to have to search to find the receipt, as this problem started last Feb and everything was fine until now (once it got cold again.) I did some work the other morning. I removed the battery and alternator. I've heard that a bad something or other in the alternator can cause an electrical short/drain. I found that the ground terminal on the alternator and the ground terminal on the battery was pretty nastily corroded. I cleaned them up very well using my dremel and am planning to take the battery and alternator to Auto Zone tomorrow morning. I will post more then. I REALLY appreciate all your guys' help. I should have done something like this in the first place.

I know the mechanic replaced the distributor entirely. He also replaced the computer. I had a hypertech chip in it but now it is stock. As far as aftermarket stuff, I had the same aftermarket stereo and subs for the last four years. It has never given me a problem. I used to have MSD but have since unhooked it. I used to have a Flamethrower kit and have also unhooked it. I do still have KC lights in my brushguard that are hooked up. Those, however have never given me a problem either. Like I said I'll post some more tomorrow morning and maybe a pic of her. I must be off to work! Thanks again guys!

-Robb-

12-02-2007, 07:30 AM	#1
Delorean14 Junior Member Join Date: Dec 2007 Location: Bradley, IL Posts: 2	Please Help!! I've had it with local mechanics. I should have gotten on something like this in the first place. Now I've spent almost a thousand dollars and still have the same problem. Anyway, now that I've vented... Here's my problem. I have a '94 Silverado 7.4l K2500. When it gets below somewhere around 30 degrees, the fuel stops flowing through the injectors. It'll crank all day but no fuel. After about 10 mins in a shop at 50 degrees she'll fire right up. If I take her outside WHILE RUNNING she'll die after about 5-10 mins of running with the same problem. A mechanic has already replaced the computer and distributor as well as some other things. She ran fine for a little bit but now it's the same problem. I also have a nasty electrical problem that if I leave my truck sit for three or so days the battery is dead. ANY INFO IS APPRECIATED!!! If you think you can help but need more info, don't hesitate to ask me. I'll try to be on here every couple days or so. THANK YOU! -Robb-

12-02-2007, 05:57 PM	#3
crabtruck Senior Member Join Date: Jul 2007 Location: on your 9 Posts: 3,364	Welcome to the forum Delorean14. An electronic student, cool. Only so many times you can have a dead battery before you must replace it. Problem may have been caused by something else originally but once the battery is damaged from repeat discharges it will be tougher to find and you will continue to have a dead battery. Charge the battery (in or out of truck) and then take it inside with you for 24 hours or more. Measure the voltage when you take it in, should be high, like 13.25-14.6v depending on method of charge. After it sits inside for more than a day it should still read over 12.6v. If not replace. If so watch for another day that it doesn't drop. If good, don't reconnect to truck until your ready to trouble shoot. . Which brings up another point that should have been covered earlier: what is the voltage with engine running ? Cold also makes damage in wire more apparent as the wire shrinks away from the gap. Have you checked that the voltage remains good to the fuel pump since much of that system is very exposed to outside temps? What exactly has the mechanic replaced ? If the engine runs fine indoors and is at operating temp, then dies out in the cold quickly, you are looking at parts not being readily heat by the engine. That's too big to get that cold so fast. Check the battery connections are good, clean and tight at all ends since voltage fluctuations can cause other random results, like your IAC misbehaving. When you go out in the cold with the engine warm and running and it dies, is this at idle ? Does it happen when you keep it around 1500-2000rpm while parked ? Have you checked for fuel contamination, including alchohol depending on where you by gas ? Replaced filter ? checked fuel pressure ? What can you tell us about how the problem started showing up in the first place ? Do you have any after market gear on the truck that is elcetrical, fuel or intake related ? Do you have trailer brakes on this truck ? Just my guesses.... Last edited by crabtruck; 12-03-2007 at 02:01 AM.

12-03-2007, 09:54 PM	#5
Delorean14 Junior Member Join Date: Dec 2007 Location: Bradley, IL Posts: 2	Follow up #1 I'm going to have to search to find the receipt, as this problem started last Feb and everything was fine until now (once it got cold again.) I did some work the other morning. I removed the battery and alternator. I've heard that a bad something or other in the alternator can cause an electrical short/drain. I found that the ground terminal on the alternator and the ground terminal on the battery was pretty nastily corroded. I cleaned them up very well using my dremel and am planning to take the battery and alternator to Auto Zone tomorrow morning. I will post more then. I REALLY appreciate all your guys' help. I should have done something like this in the first place. I know the mechanic replaced the distributor entirely. He also replaced the computer. I had a hypertech chip in it but now it is stock. As far as aftermarket stuff, I had the same aftermarket stereo and subs for the last four years. It has never given me a problem. I used to have MSD but have since unhooked it. I used to have a Flamethrower kit and have also unhooked it. I do still have KC lights in my brushguard that are hooked up. Those, however have never given me a problem either. Like I said I'll post some more tomorrow morning and maybe a pic of her. I must be off to work! Thanks again guys! -Robb-

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12-02-2007, 10:11 AM	#2
75K30 Senior Member Join Date: Jul 2006 Posts: 2,992	Welcome to the site: Too bad about the troubles the old 454 is giving you. I have a theory or two, but would like to know what the mechanic has done already? The mechanic thinks it is electrical related, and has changed the computer already. Am wondering if they got ahywhere into the fuel system???

12-02-2007, 10:06 PM	#4
tjzz4 Senior Member Join Date: Oct 2007 Posts: 277	As far as your battery drain... take a cable off from the battery and connect a test light between the battery post and the cable. If the light comes on you have a draw. you can remove fuses until the light goes out to locate the circuit... be sure your door jam switch is bypassed when you check fuses though because when you open the door it completes a circuit. On the newer cars there is some parasitic draw from the different modules but that can be eliminated by using a digital meter and after the cable is disconected.. make contact to the battery again and remove while the meter is still completing the path. the max you should see on the milliamp scale is 40-50 On your starting issue... sounds fuel related... Pump??? what has your guy done?