Tighten Fuel Cap + No Codes + Random Starting Issues = Fuel System?

[nick0789]

2005 Z71 Tahoe (non-flex)

Within the past month I have had the following happen, which suggests to me that they are all related:

- "Tighten Fuel Cap" message on dash
- no codes stored
- random starting issues; sometimes the starter will crank 2-3 times as normal and it the engine will fire right up, sometimes I get a half-crank out of the starter and it turns over, sometimes it's a half crank and the engine dies out, once (so far) I had a 6-7 second crank until the engine started.

Troubleshooting / repairs so far:

- new purge valve (last year)
- new purge solenoid (last year; on top of engine)
- new gas cap (last week)

At first I thought I was having an issue with the starter solenoid until I got the "tighten fuel cap" message to come back this week. Now I am wondering if I am having a fuel system issue somewhere and/or vacuum leak. When I turn the key to the ON position I can hear the fuel pump getting power no problem but I do not know of a way to test anything out with the fuel system.
Are there easy things to check myself before taking it to the shop?

 

[ivin74]

Have some one pressure test the fuel system, that would rule out the fuel pump. Did you get the purge valve and solenoid after market? You need to buy oem parts, aftermarket are junk. I'm willing to beat one of those items is bad.

 

[Doubeleive]

fuel pressure test, evap test

 

[nick0789]

Thanks for the replies, Wes and Ivan.

Update:

Stopped by the parts store on the way home from work and tested the fuel pressure in the parking lot and got the following results:

Static pressure (key in ON position, engine off): 45 psi
Engine running pressure: 56-58 psi (ie bouncing +/- 1 psi off 57 psi)

While I was there I had them test the starting and charging system and all that came back normal.
The purge solenoid was an aftermarket replacement when it was replaced about a year ago. I currently have an AC Delco (214-1105) on the way and will just replace it tomorrow when it arrives.

If that doesn't fix my issue will I be looking at a smoke test at that point?

 

[Erickk120]

Thanks for the replies, Wes and Ivan.

Update:

Stopped by the parts store on the way home from work and tested the fuel pressure in the parking lot and got the following results:

Static pressure (key in ON position, engine off): 45 psi
Engine running pressure: 56-58 psi (ie bouncing +/- 1 psi off 57 psi)

While I was there I had them test the starting and charging system and all that came back normal.
The purge solenoid was an aftermarket replacement when it was replaced about a year ago. I currently have an AC Delco (214-1105) on the way and will just replace it tomorrow when it arrives.

If that doesn't fix my issue will I be looking at a smoke test at that point?

Most of us go through this, and the consensus is that if it isn't leaking its one of 3 things most of the time, Purge/vent solenoids or charcoal canister. Mine went as follows, tighten fuel cap changed to oem cap the message came back, changed purge and vent solenoid and it came back later, then I decided to do the charcoal canister and it fixed the message, as far as symptoms, gas tank held pressure and when I opened the gas cap it would vent a lot of air through it but that was a year after putting up with "tighten gas cap" message. After a while I got the codes of a large leak and what not but it started with a simple tighten gas cap message or at least that's how it went for me.

The taking several cranks to start might be a different issue.

 

[Fless]

Update:

Stopped by the parts store on the way home from work and tested the fuel pressure in the parking lot and got the following results:

Static pressure (key in ON position, engine off): 45 psi
Engine running pressure: 56-58 psi (ie bouncing +/- 1 psi off 57 psi)

The Haynes manual lists the key ON, engine OFF pressure spec for non-Flex at 55-62 psi. Low pressure may be contributing to long cranking times.

 

[nick0789]

Most of us go through this, and the consensus is that if it isn't leaking its one of 3 things most of the time, Purge/vent solenoids or charcoal canister. Mine went as follows, tighten fuel cap changed to oem cap the message came back, changed purge and vent solenoid and it came back later, then I decided to do the charcoal canister and it fixed the message, as far as symptoms, gas tank held pressure and when I opened the gas cap it would vent a lot of air through it but that was a year after putting up with "tighten gas cap" message. After a while I got the codes of a large leak and what not but it started with a simple tighten gas cap message or at least that's how it went for me.

The taking several cranks to start might be a different issue.

When I had the codes stored last year I had large and small leak codes. I replaced both the purge valve and vent solenoid and no issue up until a couple weeks ago when I got the gas cap message. It was about that time when I also had the random cranking time issue so I figured it was related (or I am just unlucky sometimes haha).
OEM gas cap installed and the message went away for the next week. This week it came back.

The longer cranking times I’ve recently had have been after driving around town and starting it back up after 20-30 minutes, so I figured maybe I was having a heat soak issue since it’s been warm here.

I’ve noticed that first thing in the morning when I go to start the vehicle it starts after 2-3 cranks like always. This week in particular, every day when leaving work I go turn the key to the ON position to allow the fuel pump to get going and then I turn the key and the engine turns over after half a crank. It just comes off as odd to me that they happened the same time together but it’s not out of the question that I have two potential, unrelated issues going on.
Thanks again for the replies!

 

[ivin74]

When I had the codes stored last year I had large and small leak codes. I replaced both the purge valve and vent solenoid and no issue up until a couple weeks ago when I got the gas cap message. It was about that time when I also had the random cranking time issue so I figured it was related (or I am just unlucky sometimes haha).
OEM gas cap installed and the message went away for the next week. This week it came back.

The longer cranking times I’ve recently had have been after driving around town and starting it back up after 20-30 minutes, so I figured maybe I was having a heat soak issue since it’s been warm here.

I’ve noticed that first thing in the morning when I go to start the vehicle it starts after 2-3 cranks like always. This week in particular, every day when leaving work I go turn the key to the ON position to allow the fuel pump to get going and then I turn the key and the engine turns over after half a crank. It just comes off as odd to me that they happened the same time together but it’s not out of the question that I have two potential, unrelated issues going on.
Thanks again for the replies!

The long crank its caused by the fuel pump loosin pressure, I had the same issue 3yrs ago. I replaced the fp with an autozone pump and it lasted about 16 months then it started to do the same shit again. The second time I bought the AC Delco pump and the truck has been running like a champ. Let us know what happpens after you install the new purge solenoid. Have you changed out the vent valve above the rear differencial? Thats another sensor that is know to go out specially if you top off your gas tank. How many miles are on your truck?

 

[nick0789]

I changed the vent valve out at the same time as the solenoid last year with an AC Delco vent valve. The original one I took off didn’t really even have any of the foam mesh inside of the cylindrical part.

I’ve got ~162k on the clock right now. I don’t top off when filling up and I don’t have a problem with filling in general either, so I wouldn’t imagine I have something going on with the canister unless it’s starting to crack somewhere.

 

[ivin74]

I changed the vent valve out at the same time as the solenoid last year with an AC Delco vent valve. The original one I took off didn’t really even have any of the foam mesh inside of the cylindrical part.

I’ve got ~162k on the clock right now. I don’t top off when filling up and I don’t have a problem with filling in general either, so I wouldn’t imagine I have something going on with the canister unless it’s starting to crack somewhere.

Another sensor to look at is the fuel tank pressure sensor is located next to the fuel pump, if you replace the FP that sensor comes with the new pump.