2000 Chevy 3/4 ton stopped and won't start.

[kcackler]

My friend has a 2000 chevy 3/4 ton with about 130K on it. He was driving to work this morning and it just died on him. No stuttering, just death. He couldn't get it started again. So today while he's working, I'm supposed to be trying to see what's going on.

It turns over strong but just never catches and turns on. He's tight on cash so we're hoping it's something cheap. What should we start looking at first and where should we go from there? I've found lots of info but all it's done is confuse me. In my mind, it seems like we should start with replacing the fuel filter (Never been done on the truck), then the pressure regulator (Though I don't know where it's at on this truck), then the pump, but I don't know enough about his truck to know if it's the right order.

Hoping one of you chevy geniuses can help us out of a tight spot here.

Thanks

[chevysbest92]

well can you here the pump whine when you turn the key to on? check for that, if it is working, change the filter, cheap, easy, and should be done every 10k, so its worth it anyway

[Longhorn321]

Let me start by saying that I know very little about a 2000 3/4 ton truck specifically but I do know a fair amount of general stuff about how an engine/engine electronics system works. Now, with that being said....I don't think a fuel filter or regulator would cause instant death like that. The fuel pump.... maybe but I kinda doubt that too. I'm thinking more like a crankshaft sensor or something like that. Do you have any way of checking to see if it's getting fuel or fire? Are the plugs wet?

[kcackler]

The fuel pump relay was the first thing I listened to and it clicks when we turn the key, so it seems like it's probably working. I can't hear the pump whine, but I don't know if he's ever been able to hear that (He's working so I don't have any way to check).

To longhorn - what's the best way to check for fuel/fire? Tell me how and I'm sure I can manage to check it, but my truck is from before all of these fancy electronics, so I'm completely lost on this engine.

Thanks to both of you for the info.

Also - Would his computer not throw a code if the crankshaft sensor suddenly went out?

[Longhorn321]

Originally Posted by kcackler

To longhorn - what's the best way to check for fuel/fire? Tell me how and I'm sure I can manage to check it, but my truck is from before all of these fancy electronics, so I'm completely lost on this engine.

Well for fuel, you could use a fuel pressure gauge. For fire, it depends on if the coils are right over the plugs or not. If not, you can check it the old fashioned way by putting a plug in the end of the wire and grounding the case of the plug to the engine block and have someone spin the motor over. If you have fire, you will see the spark and or feel it if you are actually holding the plug while touching it to ground. I don't recommend the feel method.

Originally Posted by kcackler

Also - Would his computer not throw a code if the crankshaft sensor suddenly went out?

Yes it would likely throw a code but not a guarantee. Have you checked the codes? I didn't realize that from your original post if you have.

[kcackler]

Not even sure HOW to check the codes on this truck. I drive a 77. All these sensors and fuel injection terms are throwing me off

I can't find the fuel rail on his damn truck either. I've only had one fuel injected vehicle, and it was a 4 cylinder with the rail right on top. I've looked all over his engine and I can't find the rail anywhere. If I could find it, I'd put a gauge on it and see what was going on there. I guess I could also just pull the fuel line that goes IN to the rail and crank the engine and see if I get sprayed, right? If I could find the rail anyway.

[kcackler]

I guess I can remove the fuel line before the filter and have someone crank it and see if we get high pressure fuel coming out. That would help us narrow it down to a fuel problem and not electrical I guess.

[Longhorn321]

Originally Posted by kcackler

I guess I can remove the fuel line before the filter and have someone crank it and see if we get high pressure fuel coming out. That would help us narrow it down to a fuel problem and not electrical I guess.

Yes that would work. It should not be too high of a pressure though. What engine is in this thing by the way? It's not a diesel is it?

[kcackler]

5.7L (I think) gas.

We're headed back up there now to double check the fuse and relay and also check the line pressure.

I just got some useful information. Apparently for the past month, the truck's been getting harder to start. They thought it was just the cold weather, but it sounds more like a pump slowly dying to me.

[Longhorn321]

Does the engine look like this?

If so, #3 is the rail and #8 is the schrader valve where you would put your fuel pressure gauge.

[kcackler]

I don't believe it looks anything like that (Though I haven't had a great look at it yet)

I do have an update though. We disconnected the fuel line going into the filter and cranked it over for 10 seconds or so and not a drop of gas came out. Replaced the relay just as a thought, and the same thing is happening.

So since we know there is no fuel at all going through, do we know it's the pump or is there another cheaper replacement that it might be?

[Longhorn321]

Next step I would take is to check for power and ground at the pump. Sounds like its FUBAR though.

[kcackler]

But to do that, we've got to pull the bed, right? So pull the bed, check the connections, and if they're good, replace the pump? Not what I was wanting to hear

[Longhorn321]

I couldn't say if the bed has to be removed or where the best place to check for power and ground is. Right at the pump would be my preference but as I said, I don't know how easy or hard that would be. Maybe someone with more specific knowledge on that particular truck will chime in. My guess though is that the tank could be dropped rather than the bed removed.

[kcackler]

He's got a full tank of gas and no easy way to drain and drop the tank. We've got air tools and a front loader to take off the bed though, so it's probably quicker to do that.

I guess that's what we'll be doing tonight. Thanks for your help. Hopefully it's the pump because I'm tired of messing with it

[Longhorn321]

I hope you find a solution too. Especially if you are going to do all that work. Let us know.

[kcackler]

Will do. I'm going to go pull the bed bolts now and when he's off we'll take off the bed and see what's going on.

Thanks again. Very appreciated.

[kcackler]

Thought I'd update this since you helped me out so much today. Buddy got off work tonight and we went up to where his truck was at and it started right up (I was kind of upset when that happened). We messed with the relay to try and get it to screw up again and it wouldn't. Then tried to start the truck later and it wouldn't start again. Jiggled the +12 wire at the pump and it primed. Jiggled it again and it wouldn't prime. So tomorrow I'm taking the bed off and I'll see if it's just a loose wire or what's going on there.

Thanks again for your help.

[Longhorn321]

Sounds like you are getting closer.

[bwood]

2000 3/4 will be the 88-98 body with the Gen I Small Block Vortec. The fuel pumps are a weakpoint with these trucks. Try taking a rubber mallet and smacking the bottom of the tank and then seeing if it tries to prime when the key is on. Pulling the bed is the common way to change the pump. While the pump is out/you are looking at connections, inspect the connector to the pump, they are known to have burned/bad connections. The fuel pressure test port is located on the driver side of the intake on top of the larger steel line feeding into the injector assembly. These trucks don't have a fuel rail like your used to, the feed fuel into a common injector assembly that contains a electric solenoid valve for each cylinder and a line from each solenoid to a poppet valve that contains a spring loaded check valve that opened with pressure to create the spray. If I remember correctly, it was called Central Sequential Fuel Injection (CSFI). You should be able to turn the key on and hear the pump run for about 2-5 seconds. This also would not set any codes. The fuel pressure spec should be around 63psi running.

[kcackler]

WOW. Thank you for all of the information. I'm bookmarking this for future reference.

[Longhorn321]

Originally Posted by bwood

2000 3/4 will be the 88-98 body with the Gen I Small Block Vortec. The fuel pumps are a weakpoint with these trucks. Try taking a rubber mallet and smacking the bottom of the tank and then seeing if it tries to prime when the key is on. Pulling the bed is the common way to change the pump. While the pump is out/you are looking at connections, inspect the connector to the pump, they are known to have burned/bad connections. The fuel pressure test port is located on the driver side of the intake on top of the larger steel line feeding into the injector assembly. These trucks don't have a fuel rail like your used to, the feed fuel into a common injector assembly that contains a electric solenoid valve for each cylinder and a line from each solenoid to a poppet valve that contains a spring loaded check valve that opened with pressure to create the spray. If I remember correctly, it was called Central Sequential Fuel Injection (CSFI). You should be able to turn the key on and hear the pump run for about 2-5 seconds. This also would not set any codes. The fuel pressure spec should be around 63psi running.

I figured someone with some specific knowledge would speak up. Thanks bwood for some interesting information. I looked that CSFI stuff up. That is some weird chit to me.

[kcackler]

Yeah, I started reading about it too. Makes me feel a little bit better for not seeing the fuel rail. I was really starting to think I was an idiot there until I read about it.

[kcackler]

Hi guys - Quick question: We don't have the bed off of the truck yet (Work delays) and we haven't bought the new pump yet. My question is this: How can we know which pump to buy? There are 2 styles available for this truck, and we aren't sure which one we need without taking the old one out and comparing it with the pictures of the 2 available units. Is there a sticker somewhere on the truck that might lend some light to this?

[clinebarger]

If you go to a dealership parts deparment with the VIN they will give you the correct part. Chevy having two different body styles in 2000 is probably the confusion