Need a Machanics Advice!

[old digger]

I am working on a 2000 GMC 1500 pickup, with a5.3 v-8 engine. I was sure that the reason that it just quit was because the fuel pump quit working. The reason was that the gas gauge on the dash would show empty whenever the tank reached half empty. Anyways, I replaced the fuel pump (which entailed lifting and removing the bed) and also replaced the fuel filter. Then I proceeded to start the vehicle, but luck. I borrowed a electronic analyzer from the local parts supplier and it read that my crankshaft position sensor needed replacing. So with much difficulty I changed that sensor, but the vehicle still won't start. I finally checked to see if I was getting any spark, and guess what, I am not getting any spark. So, my question is; what should be looking for to be the problem? I appreciate any suggestions. Thank You.

 

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[Red James Cash]

Does the engine have a seperate coil for each spark plug?

 

[old digger]

I am not sure. Please forgive my ignorance, I'm not savvy with these newer electronics.

 

[fyrffytr1]

It's possible that you got a bad crank sensor.

 

[smokeythecat]

Possibilities are a bad crankcase sensor, or a bad coil or bad coil pack. Those GM coil packs are not too expensive, but sometimes hard to get to. I had a '96 that would run then stop. The coil pack got hot and would quit on me. Trouble is, knowing which one. What we did was replace one and try it. Then if it didn't work, move to the next. Yours has eight. I think it takes a 10 mm socket to get off. GM loves the 10 mm size. The only three things I could think otherwise would be the main computer, the wiring harness itself or one of those big relays. Go buy an ODB II sensor reader and try it first. It may tell you as it will tell (more than likely) where the trouble lies. Last possible thing is the timing chain. When I lost by beloved '96 Pontiac Transport it just stalled out and would not start. No warning. It had slipped the timing chain and destroyed its engine. There are quite a few possibilities. That's why I now go to a local guy with a BIG computer.

(Bet you didn't know the ol' cat knew cars!)

 

[old digger]

It's possible that you got a bad crank sensor.

I replaced it.

 

[old digger]

I did a little looking on youtube and I believe I need to do a little more testing. First I'll check the or those coils, and then If I'm not getting a proper spark, then I need to check the EMC1 fuse. And if that is not functioning right, then it is most likely the ignition switch. I think this is the route I should take. Wish me luck!

 

[Nitric]

All I know for sure? Is that you do not want shocked by that coil pack!!! I'm no help with any of the rest. I usually just have to try to search out the problem on my own. Past experience...Check the signal going to coil pack/s (if you can), check ignition switch(some vehicles are known for this issue, I'm not sure about GMC), You can also check your sensors, there are pages online that explain how and what readings they should give. And last maybe a bad computer,connector/s, wire etc.... But all of this is hard to guess at or to tell someone how to do(for me). I just dive in and start guessing and tracing things out randomly until I find the problem. I know the instrument clusters are also a problem in some of those year trucks, I've rebuilt those before, the little motors go bad. Cheap fix if your good with a soldering iron, but I've never heard of one causing a no start. The Ignition switch thing threw me one time. I worked on the truck, did everything I knew and couldn't figure it out. It cranked, turned on, but for some reason the switch wasn't allowing spark. That is probably a rare case, but something to check too. I forget what truck that was.

Ohhh! Another thought...Not sure if this is any help or not, but we have had anti-theft or alarm systems go haywire and not allow spark. But my memory sucks and couldn't tell you what vehicles those were.

 

[old digger]

Does the engine have a separate coil for each spark plug?

Yes, you are right it does. Thank You!

 

[old digger]

I hope it's not the ignition switch.

 

[Nitric]

I hope it's not the ignition switch.

I would have never found that problem if it wasn't for a friend that wandered into the shop that day and ask.."did you check the ignition switch?"

If you don't have an dvom(I think that's the right letters) A meter..... You need one and a very basic idea of how to read it for working on this stuff. I taught myself so I have no clue what the correct terminology or how to walk someone through it. You just have to be able to read voltages, ohms, and continuity to check sensors and wires. The small scanners are helpful, but they just give you a starting point, sometimes the problem is further up the line than the code that they are giving.

 

[old digger]

Thanks Nitric! I appreciate your input.

 

[randywa]

I know it's a real pain, but check all the frame to body, frame to engine, and frame to component grounds. My '93 was shutting off when it wanted to, but only when weather was hot. Until it got worse. A new fuel pump relay helped. Then when I changed the fuel pump I found the pump to frame ground at the pump connector had 4 or 5 strands of wire left. After I fixed that one I found something similar at the taillights. In all I found and fixed 10 or 12 bad ground wires or connections. It even made my check engine light stop coming on as much. Still chasing the EGR code though.

 

[huntsman53]

First, I would recommend checking all of the fuses as these are quite often the culprits and the easiest first check. Check all the ECM Fuses and Fuel Pump Fuses. My daughter's Hyundai Santa Fe died on the highway about 10 miles from the house. At first I thought it was out of gas, so I put some gas in it but it would not hit a lick. Towed it to the house and destroyed the rear bumper on my' Ford Ranger because my daughter kept letting slack get in between my' truck and her' car. After switching out relays of which I keep extras and no luck, I changed out the PCM (ECM) since I had a good spare but again no luck. I went back and checked the fuses again and found that I had missed a little 10 amp Fuse for the ECM which I found was blown. Replaced the Fuse and Voilà (whallah) the car cranked right up. If you find that the Fuses are good, then go with the other recommendations. Normally, I would say to check the Relays but without the proper equipment and knowledge of how to check them, it is sometimes a useless endeavor unless you keep spares. I keep a lot of spare parts, Fuses and Relays and pick these up when I visit Pull-A-Part to find other parts I need.

 

[Kray Gelder]

Distributor shaft may have broken. Pull your distributor cap and while someone is cranking the motor, you watch to see if the rotor is spinning. If not, you've found the problem. If it is spinning, good luck locating the issue.

 

[Nitric]

Distributor shaft may have broken. Pull your distributor cap and while someone is cranking the motor, you watch to see if the rotor is spinning. If not, you've found the problem. If it is spinning, good luck locating the issue.

I may be completely wrong...But I don't believe his truck has a distributor or cap. On the same Idea, it does have trigger(don't know the actual name) wires from the computer and a sensor to tell it to "trigger", on the Cam, crank or maybe even both(not sure without looking into it). Same idea though, they just took some of the mechanical stuff out for electronics.

Here's a funny one for ya...I bought a 98 diesel truck. dodge with a 12 valve cummins. I've never owned one and I'm still learning more about diesels. I had a friend with me. We got in, I turned the key to wait, my friend asked"what are you doing?" I said, waiting for the glow plugs to heat up.". He said, "This truck doesn't have glow plugs!" while he laughs at me. "Oh, ....ok!" I was use to all the trucks at where I worked, you had to turn the key and wait for the glow plugs to heat up before starting the motors.

 

[IDXMonster]

Well,being an ASE certified Master Automobile Technician(cough cough...a-HEM!) I kinda have to jump in here. It’s an unfortunate part of today’s world, but it is COMPLETELY possible to get a “bad” or non-functional brand new part. It doesn’t happen every day but it happens more than you’d think.
FIRSTLY...GM trucks of this vintage are notorious for fuel pumps croaking. You have to check for fuel pressure to make sure it is sufficient. IF you had to re-wire the connector at the pump, which is very common, you have to double check and make sure it works correctly by running the fuel pressure test. Report back when this is done with the result.

 

[flyadive]

Also check the neutral safety switch. How about try starting in neutral?

 

[IDXMonster]

Keep in mind the OP said “it just quit”. When diagnosing anything,”when” or “under what condition” the problem happened must be determined. “It just quit” says to me that the truck was already running....taking any “crank to start” issue of any kind off the table.

 

[Kray Gelder]

The only reason I suggested the distributor, is my Jeep just quit running while driving home from work one day. No stutter, no warning, just died. It was a broken distributor shaft. I looked to see if this model has a distributor before posting the suggestion. It doesn't look like the "old" distributors, but apparently has one with rotor. Shade tree mechanic here. A lot of good suggestions. Good luck.