2000 GMC C1500 Repair Question
Sierra won't start on first try
The radio is stock or an add on? I would be curious where the radio is getting its power.
Has anyone considered the possibility of it being an ignition switch problem? I would have looked at an injector problem until you mentioned that no matter what the second time it fires.
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It is a stock radio, but I guess it's not the original one, the previous owner replaced it when the turn signal problem started, with no luck. He did wire it directly to the interior fuse panel, but I undid that, it is now wired as it came from the factory. I have not done anything to check the ignition, because honestly, I had no idea where to start on a problem like this.
Still no suggestions? I spent last weekend looking for any wiring issues, didn't find anything. I did remove the car starter module, and the problem didn't go away, so I guess that really isn't related to the starting problem.
A couple of suggestions.
Check for spark when you crank for the first time.
Wen you start (or attempt to start) do you go from the off position immediately to start or do you go from off to run (for a second or two) then to start?
You might have a bad relay somewhere that is not allowing the computer to initialize properly.
Try looking at the connections entering the fuse holders (large one under the hood and the small one inside). Poor connections could cause a multitude of problems.
When you removed the starter module, did you remove the wires as well or just unplug the module?
In General is sounds like one or more bad connections somewhere.
When I start the car, if I go directly from off to start, the engine will not start without cranking for an excessively long time, but if I give up before cranking for too long and try again, it will start right away. I have found that if I turn the key to the run position, wait for the second seatbelt warning chime, then turn the key to start, it will start right away about 80% of the time. That leads me to believe it is an electrical problem with the computer of some sort, perhaps a relay like you mentioned. I already checked all the fuses and connections, and found nothing wrong.
When I removed the starter module, I didn't remove the wiring. I have no reason to believe that the previous owner lied about when the problem originated, so I believe he is correct that the issue is unrelated to the remote starter.
I have discovered that the problem with the radio seems to be thermal. It hadn't done it, and doesn't do it until the mercury hits about 90 degrees. It is also not entirely caused by using the turn signal. I have since had it shut off while just driving, but it seems to be an electrical issue as well. I notice it happens mostly when I use some additional electrical power, such as the turn signal, or to put the windows up or down. It has shut off while just driving only a few times. When the problem does show up, I have a hard time making it happen again to try to diagnose the problem. It seems to have a mind of it's own, and it only shuts off when it wants, and comes back on a few seconds later.
Again, I have no idea if the radio problem is related to the starting problem. They both seem like electrical issues, but only the radio problem is temperature specific. I have the starting problem all the time.
It sounds like you have a bad radio and it doesn't seem to be related to the starting problem.
It appears that the computer is being held in boot-up too long.
I would try to reset the computer and clean the connectors into the unit.
Easiest way, remove the battery connections and wait about 20 minutes (the computers have large capacitors for filtering). Remove the connectors and spray them down with some contact cleaner (Radio Shack). You can use a brush (non metallic) to help clean the contacts.
Other than that, I can only suggest to check the wiring/connectors to the ignition switch and the through the firewall (usually not the case but you never know).
One additional question. When the vehicle idles, is it smooth or rough (thinking throttle position sensor not working properly)?
I don't believe the radio is faulty, since it has been replaced, and the exact same problem persisted.
I will try resetting the computer. I will also try cleaning the connections, but can you tell me where the computer is located? I have a repair manual, but it doesn't mention the location anywhere in it.
When the truck starts, it runs like there is absolutely nothing wrong with it. The idle and acceleration are both very smooth.
I am not exactly sure where the computer is on a 2000.
Most of the models I have seen, the computer was mounted on the driver side fender above the anti-lock brake pump. Mine (1997) is about 12x6.
You should see a large heat sink (fins) with at least 2 multi-wire connectors plugged into it. It needs the large heat sinks because it is directly firing the injectors which could draw up to 20 amps at high revs.
After you remove the battery connection, pull the fuses labels ECM (electronic control module) probably 2 of them and check for corrosion or possibly bad (weak) fuses. You might even try just changing them. Your repair manual should tell you what fuses are for what.
After you reset the computer you might notice that the tranny will shift different for a while because it will be reset as well.
This is a definitely a strange problem!
I recently bought a 2000 GMC Sierra Z71 5.3L with 154,000 miles and the exact same problem. Two words, fuel pump!!! Truck starts first try every time. I have to replace the control module now, but that's another story. I hope this solves your problem.
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In January, the truck wouldn't run at all one day. It would fire and immediately die. I crawled underneath and when I had someone turn the key, I could hear what sounded like an air leak on the left side of the tank (there are no hoses there). Finally, it started after trying for half an hour. Then it didn't do it again until this week, a full three months later(the usual starting problem still existed, but this was only the second time it left me stranded). Today, I was determined to find the source of the air leak, so I tried removing the pressure sensor from the tank, and I could still hear the air noise. Finally, I pulled the pump out of the tank (Tip: Remove you truck box instead of dropping the tank to get to the fuel pump, it's much easier - eight bolts, two electrical connectors for the taillights and the fuel filler neck) and turned the key on. A jet of fuel shot 20 feet out the side of the fuel hose on the fuel pump. It was the fuel hitting the side of the tank at high pressure making a sound like leaking air. When the pump was assembled, they had the hose turned so it was touching one of the metal rods the pump floats on. After 130 some thousand miles, it wore a pinhole in the hose. I'm going to try to find a replacement hose instead of replacing the whole pump - $3 versus $300. I am confident that this will solve the starting problem. Thank you RobsZ71 for the tip, for some reason I didn't get an e-mail when you posted to this message, or your suggestion might have saved me 8 months of frustration. Now for the radio problem...