454 No Start

[Bret]

So I recently posted this thread: http://www.gmt400.com/threads/7-4-rough-idle-no-codes.42089/ about a slight idling issue my trucks been having. About a week ago, one morning the truck decided to not start. After a lot of cranking, it started. It ran horribly until it warmed up. Afterwards, it ran and started fine for a few day until it started repeating the issue, but would only do it after sitting for a night. Once the truck was warmed up, it ran fine and would the rest of the day. Today after work, the truck just wouldn't start. It did the same starting procedure, but just never got enough oomph to finally start.

While cranking the starter, it will stop every 3 seconds or so with the key still at crank, and then start again. Occasionally the truck will get going a little, but not enough to run. After a lot of cranking I can smell fuel, which leads me to believe the injectors are squirting.

While cranking, in addition to the 3 second on and off thing, the Tach only moves when it almost starts or does start, never while its just cranking.

When it would run after a no start while cold, being hard on the throttle, even at speed, would cause the rpms to very quickly drop, and wouldn't rise back up until I let off the accelerator.

I've replaced within the past 4 months:
IAC, Fuel Pump, Fuel Filter, Fuel Pressure Regulator, Lower and Upper intake manifold, and all Lifters and Pushrods, new distributor, new plugs and wires, and all 8 injectors. I've also tried different Crank Position Sensor, MAF Sensor, and EGR. My Cam Retard Offset is around 0.4 at 1000 RPM (checked when it was running).

At no point has the truck thrown any codes.

I'm starting to get confused at this point, and running out of ideas as to what the issue could be. Tomorrow after work I'll be taking a crack at checking the grounds, but wanted to see if anyone has had similar issues or can think of a reason it might be acting like this.

 

[Schurkey]

the Tach only moves when it almost starts or does start, never while its just cranking.

1. WHAT VEHICLE???

2. Sounds ignition-related to me, although I'm curious about the "cranks for three seconds" thing, too.

 

[Bret]

It's in my signature, 1999 Suburban 454 with floor shift 4x4. Today I checked the grounds, they all seem good. Just put a new top post battery in since yesterday I stripped the side post battery. It cranked the same way as previously, but when it stopped, it killed all the power in the truck. There's no power at crank or at accessory. At this point I'm thinking either ignition switch or starter maybe? But I don't think the starter would cause this to happen.

 

[Bret]

I also forgot to mention, I wasn't able to find any blown fuses.

 

[east302]

It cranked the same way as previously, but when it stopped, it killed all the power in the truck. There's no power at crank or at accessory. At this point I'm thinking either ignition switch or starter maybe? But I don't think the starter would cause this to happen.

Do you have 12V at the fuse block where the battery cable connects?

That no accessories come on would seem to remove the starter from the equation, unless your positive battery cable is damaged where they sandwich together and connect to the battery. A quick check would be to see if you have voltage at both the fuse block and the starter when this happens.



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[Eveready]

Checking a wire at a time off the truck for continuity might tell you something. I'm sure it will be a PITA but it sounds like something barely connects then vibrates loose. A broken wire inside the insulation and not visible would be high on my list of suspects.

 

[Bret]

So update: After a lot of diagnosing and tracing wires, it turned out to be the battery terminals I bought that were the problem, I went out and bought a better set and the power issue is now fixed, but the previous no start is still holding true, although it doesn't seem to stop cranking every couple seconds now. I took out the number one plug to take a look and this what I got:

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I put a plug on it and put the threads on the manifold and had a friend crank it, and I was getting sparks. I also found this under the dash:

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Had a hard time finding anything on that yellow wire, not sure if it would even have anything to do with this issue.

 

[Bret]

Got more to add now, used my fuel pressure gauge from harbor freight to test the fuel pressure coming from the rail.
Key On- 60 PSI while pumps on, down to 49 when it shuts off.
that 49 eases down to 43 after 10 minutes with the key still in accessory.
I'm pulling 57-60 PSI while the starter is cranking.

Here is a video of the truck cranking, just in case some of y'all can pick anything out from the sound.

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[east302]

It wouldn’t hurt to check for spark on the other cylinders, or at least some from the other bank.

Fuel pressure doesn’t look to be an issue.

 

[SirJeffro]

My K2500 Big Block was running iffy a year or so back, then one day just stopped dead in its tracks at a traffic light. It turned out to be a broken pickup in the distributor......I mean the ring was *broken* in *2* places. It had spark and fuel, just not together at the right time. Don't know if a '99 is same/similar or not......

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