Can't start in the cold

[harbison]

1998 Tahoe 2 Dr 4WD 5.7 Auto 150,000 miles
My son has driven this vehicle for 2 1/2 years, 35K miles.
This week he has had trouble starting it when it's cold (20 degrees Fahrenheit). He's had to spray starter fluid. Even if it sits 3-4 hours he has the same problem. Once he gets it running it's all good. This morning (in the teens) he couldn't get it to start even with starter fluid.
We recently replaced the fuel pump with a Delphi and changed the fuel filter. It has run really well since we changed the fuel pump until this week when colder weather hit.

Any ideas?

 

[harbison]

So this afternoon (50 degrees) Tahoe started fine. Fuel pressure at 50 psi.

 

[east302]

If it starts with fluid and continues to run without issue, that's "usually" indicative of a weak or dying fuel pump.


A few questions:

When he couldn't get it to start with starting fluid, do you mean that it cranked and wouldn't start at all (no spark and/or air) or did it start, run for a moment and then die (has spark and air but no fuel).

When was the 50-psi pressure obtained? Key on, engine off, spec is 60-66 psi.

Is the "security" light on the cluster staying on or flashing? It should come on when first started and go off after a few seconds.

 

[harbison]

So I don't have all the answers, but here's what I do know. He couldn't get it started at all this morning. He tried leaving the key on for several minutes to see if it would build pressure. 50 psi was with key turned and then also when it started this afternoon. He didn't measure it this morning (he was in a suit).

 

[east302]

50-psi is on the low side. Ask him to try it with key on/engine off, cycling it a few times to see how high it will go.

Then turn it off and watch the gauge. It should hold for a while. It may drop a few pounds over several minutes (say five or so) but if it drops to zero after maybe ten seconds then it's probably a regulator issue.

That he could start it with starting fluid, that it continued to run and that he is getting 50-psi sounds like a weak fuel pump.

But, you'd think that it would at least fire off and then die once the ether was used up. Was he reinstalling the air intake? If not, try it with it back on in case the MAF sensor needs to be in place to start. I vaguely remember hearing that somewhere.

 

[harbison]

Mystery solved. It ended up being a bad battery. The low voltage caused low pressure. We were testing fuel pressure by engaging the fuel pump at the relay and it seemed to keep going lower and lower. We checked the voltage on the battery and it was down to 9. Boosted the battery and the fuel pressure was up in the normal range.

 

[harbison]

UPDATE: Mystery NOT SOLVED. Replaced battery last night. Went out this morning and it wouldn't start. Put the charger on the battery, took it to get gas and run a couple of errands. Came home, 1 1/2 later would barely start. Had to put e-brake on to turn headlights off, then it would start. Drove it 45 miles, ate dinner ( 1-1.5 hours) and it would barely start. We've owned it 2.5 years and replaced the fuel pump 3 times.

 

[RED TAHOE LS]

Richard, I know where you at, so confusing. When or has the Alternator been replaced ? I just went thru the same with my Honda. I don't drive it much and I was going to store and it wouldn't start. I went to put the charger cables on and the + cable was loose and I said there's my problem. After charging it fired right off as usual and the volt meter in the lighter plug 13.2v and I thought is was fine. Off to town and had AC on because it was warm then. Went inside store and came out and it would not start. Now I'm p_____ed, so my battery was over 5 yrs old so I got a new battery, got home and installed the new battery. Fired right up and like you I thought I had it fixed for 2nd time, wrong, next day would not start. PROBLEM, alternator was not charging under load. New alt, all is well, it had never been changed with 207k miles. I didn't mean for this lengthy post, but hopefully it will help you figure it out, know where your head is. Good luck and let us know when you find it.
David g...........

 

[harbison]

The alternator has not been replaced to my knowledge. I checked battery while it was running and voltage was over 14 but I investigate further.

 

[PG01]

The alternator has not been replaced to my knowledge. I checked battery while it was running and voltage was over 14 but I investigate further.

13.8-14.2 should go up a little when you rev it up and down a little when you put accessories on. Hows all your grounds? Maybe something is shorting/some how damaging the fuel pump if you went through 3 of them isnt there a ground for pump by the tank?......my.02...