1999 Chevy Tahoe 4x4 Crank - Will Not Start - SOLVED

[OBSTheBest]

Hey TYF family,

I've got my first thread to post on a problem that I am having with my 1999 Chevy Tahoe 5.7L Vortec 173K miles. No check engine light, no codes, no misfires, and no loss of power.

Recently, (past 6 months) the truck has had a full tune-up, along with a fuel pump and fuel filter replacement. The problem started with a random no start 6 months ago. When I say random, it felt like the truck would give me no problems for 4-5 starts then after that 4th or 5th start it would just crank like there was no fuel. If I would let it sit for a few minutes, it would start hassle free and begin the whole process over again it felt like. I was recommended by a family friend to check the battery terminals (no issues there), replace the fuel pump and give it a tune-up. Did the tune-up first and that worked for a few months. Truck went 4-5 months without any issues, before it started to give me trouble starting again..

So, I moved on to the fuel pump and filter. Did the fuel pump about 3 weeks ago. ACDelco fuel pump and fuel filter done. The truck started for about 2 straight weeks with absolutely no issues again but, last weekend (Saturday) stalled in the driveway after running for about 3 minutes while I was helping my son fill up the tire on his bike. Got back in the truck and it fired right back up and I went about my way and did my errands for the day, no issues. The very next day (Sunday), I took it up to the corner gas station. Was hesitant to shut it off but I did. Came out of the gas station and it fired right up. As I was waiting to pull onto the main road out of the parking lot, the truck stalled again. I panicked, but the truck started right back up and made it back home with no issues.

That night I invested in a fuel pressure gauge (a little late, I know lol) and I was getting 60+ psi to the fuel rail when turning the key and 52-54 psi once it started and idled. All this week it has not stalled, but it has started its 4-5 starts then not want to start again unless you let it sit for a few minutes. I began to notice that when it would not start, I would have 0 psi and it would just crank. If I let it sit and swung the key from off to auxiliary on, the gauge may read 0 psi for a few swings, then would shoot up to 60 psi and I would be able to go full swing and have the truck fire right up!

Last night, the truck wouldn't start. I tried for an hour swinging the key off and on.. Nothing. The entire hour the gas pressure gauge never budged from 0 psi so, it feels like whatever the culprit is finally gave out. Also tried this morning when leaving for work and had the same ongoing issue as last night. It is sort of a sense of relief knowing that whatever this ongoing problem is, could finally show itself.

I am now being advised to look into the spider injection and fuel pressure regulator. Would anyone know how to diagnose the injector? I am so deep into this ongoing issue; I would just hate to replace those, and it be a band-aid fix like the other repairs have felt like.

Any past experience and 2 cents are extremely welcome, please.

I love this truck and just want to put my trust back in it.

 

[exp500]

You are on the right track focusing on fuel, given the symptoms presented. Fuel pressure on these should be 61-62 minimum.
Test your oil pressure sender as it is in the circuit to fuel pump and a normal failure after 100k miles.
A 6 foot hose on fuel pressure guage with hose tucked under wiper allows you to see fuel pressure under real conditions.
A cheap scanner looking at live data is a big help also.
Good luck and report back with your findings.

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[Eman85]

When you don't have fuel pressure check for power AND ground at the fuel pump. If you have power and ground you won the lottery of bad parts, nothing to brag about as it's an easy lottery to win.

 

[OBSTheBest]

When you don't have fuel pressure check for power AND ground at the fuel pump. If you have power and ground you won the lottery of bad parts, nothing to brag about as it's an easy lottery to win.

Do you know where I may locate the power wire on the fuel pump without having to drop the tank?

 

[strutaeng]

Well obviously if the pressure is 0 when checking with a fuel pressure gauge, then that's a problem.

Can you hear the fuel pump prime at all? If not, then possibly something related to power or ground. Charm.li website should have wiring diagram for the fuel pump. You can find the wire (or connector) nearest the pump and use those piercing probes to check for voltage with a DVOM. I think you want to in addition check with an incandescent test light just to make sure the circuit is able to handle some amperage.

Also, swap a FP relay just to make sure you don't have an intermittently failing one.

Finally, I don't know if your truck has this blue wire hanging out near the fuseblock. I believe most GMs of these years had that, and it's to manually prime the fuel pump. I've never had to do that, just know that's what it's for. I can't remember if you ground it or apply a 12+ to it. I'm sure you can Google it.

Start with the easiest diagnostics and the system of elimination to start ruling things out.

I hope this helps.

 

[OBSTheBest]

Well obviously if the pressure is 0 when checking with a fuel pressure gauge, then that's a problem.

Can you hear the fuel pump prime at all? If not, then possibly something related to power or ground. Charm.li website should have wiring diagram for the fuel pump. You can find the wire (or connector) nearest the pump and use those piercing probes to check for voltage with a DVOM. I think you want to in addition check with an incandescent test light just to make sure the circuit is able to handle some amperage.

Also, swap a FP relay just to make sure you don't have an intermittently failing one.

Finally, I don't know if your truck has this blue wire hanging out near the fuseblock. I believe most GMs of these years had that, and it's to manually prime the fuel pump. I've never had to do that, just know that's what it's for. I can't remember if you ground it or apply a 12+ to it. I'm sure you can Google it.

Start with the easiest diagnostics and the system of elimination to start ruling things out.

I hope this helps.

Thank you for the feedback.

Before the fuel pump was changed, I used to hear the whine of the fuel pump for 1-2 seconds when turning the key to auxiliary. That eventually would not happen on times that it would not start. Leading to believe it needed to be replaced. Strangely on this new fuel pump, I have not heard any whine at all since the day it was put in. I've replaced the fuel pump relay before the new pump was put in, but it did not make a difference. I will need to check for the blue wire. I do not recall seeing anything like that.

 

[east302]

On my 98, the pump test wire is red with a white connector on the end. Just put battery voltage to it and see what happens. It’s at the driver side firewall.

Here’s the wiring diagram. With a meter, check for voltage at the relay terminal coming from the fuse (87) and also the VCM relay control (85). Check using the relay’s ground (86) and if you get no voltage use the chassis for ground.

Grounds G103 and G104 are at the thermostat neck bolt and at the back of the right cylinder head. See how those look. The pump ground (G404) is somewhere by the tank on the top of the frame rail.

 

[exp500]

A few more 98 pages that may help-

 

[east302]

A few more 98 pages that may help-

Hey,

What page was that diagram with the oil pressure switch? I looked all over my manual (1998 2nd edition) and couldn’t find it but knew that I’d seen it somewhere before.

 

[exp500]

Hey,

What page was that diagram with the oil pressure switch? I looked all over my manual (1998 2nd edition) and couldn’t find it but knew that I’d seen it somewhere before.

page 6-1677 vol3 . It really depends where your manual is from.... Some pages are left out or not considered in that type. Only difference I noticed between trucks & Suv fuel was dual tanks or 6.5 Diesel. Hope this helps.

 

[east302]

Thanks, that helps. I see it now in the 1st edition C/K book but they deleted it in the 2nd. But mine still has the blurb about the oil pressure switch powering the pump. I guess the revision made sense to someone at the time, lol.

 

[Coveman]

My 99 burb needed 3 new fuel pumps before I got one to work properly. When it didn’t start up before the new pumps I’d give it a whack on the fuel tank with a 2x4 and the pump would start right up. I had a shop do the pumps and we found that redline pumps made the gas gauge wildly inaccurate and the delphi worked out of the box.

 

[waveryd]

My 99 burb needed 3 new fuel pumps before I got one to work properly. When it didn’t start up before the new pumps I’d give it a whack on the fuel tank with a 2x4 and the pump would start right up. I had a shop do the pumps and we found that redline pumps made the gas gauge wildly inaccurate and the delphi worked out of the box.

Agreed that the brand of pump matters. I had similar issues on my '96 Suburban. OEM GM or Delphi is what I would try to get. There may be other good ones out there also. Unfortunately, AC Delco doesn't mean much these days. Might be good or not.

 

[OBSTheBest]

Just wanted to provide an update.

The truck has started and ran since my original post. It does seem that the problem is getting much worse though. I only got it to start 3 times before it did not start for 12 hours+. Again, the truck used to give me 5-6 starts before it would just sit and crank. I could swing the key back and forth for 5-10 minutes before I would hear the fuel pump prime, and it would fire up and repeat the whole process over. Not the case anymore.

Went ahead and just purchased a GM Genuine (ACDelco) oil pressure switch and put it in on Sunday. Did not seem to fix the problem. It did seem to normalize my oil pressure gauge a bit. Before it was a little jumpy/glitchy. Could be a placebo effect, but hey I'll take it. Lol

Got the truck to start up yesterday morning, so I went ahead and drove it straight down to a family friend who knows vehicles and owns his own shop. He is going to look into the electrical aspect of the fuel pump. He was also suspecting the spider injector. If the fuel pump electrically checks out. He said he will be removing the intake today to determine if the spider needs replaced.

I noticed this time driving it, upon acceleration it had the slightest hesitation when keeping a steady throttle. I was going down the highway around 45-50 MPH, and the truck felt like it had the slightest bit of bog in it. I could even see my RPM's ever so slightly bogging down when I would feel it.

I will keep this thread updated as the information comes. Hopefully we can finally put this problem to rest. I love this truck and just want to trust it again.

 

[Eman85]

If the pump isn't running the spider injector has nothing to do with it. The oil pressure switch doesn't come into play when you turn the key to prime the system, at least it helped your gauge. I guess you never monitored voltage at the pump or ground. Did you try activating the pump at the test lead shown in the wiring diagram?

 

[OBSTheBest]

If the pump isn't running the spider injector has nothing to do with it. The oil pressure switch doesn't come into play when you turn the key to prime the system, at least it helped your gauge. I guess you never monitored voltage at the pump or ground. Did you try activating the pump at the test lead shown in the wiring diagram?

I did not. I shared all the wiring diagram information with the mechanic, and he was going to look into it. Been waiting since yesterday to hear back.

Once I get any information, I will update this thread.

 

[exp500]

I did not. I shared all the wiring diagram information with the mechanic, and he was going to look into it. Been waiting since yesterday to hear back.

Once I get any information, I will update this thread.

Fuel pressure is low when running. Your mechanic should be able to decide whether that is a burned connector/wiring, bad ground or bad pump. A look at the computer connector for relay to check for corrosion/water/green stuff in there a possibility also.

 

[OBSTheBest]

Fuel pressure is low when running. Your mechanic should be able to decide whether that is a burned connector/wiring, bad ground or bad pump. A look at the computer connector for relay to check for corrosion/water/green stuff in there a possibility also.

Thank you for this! I am going to suggest this to him, even if he should already know. I still have not got any word from him today, so I may give him a shout on my way home from work. Thanks again!

 

[OBSTheBest]

SOLVED - Turns out the Spider Injector was bad.

Purchased the GM Genuine MPFI Spider for $480 on CarID with GM Genuine gaskets, and the old man charged me $250 to put it all in. Took about a week to arrive from UPS and the old family friend had the truck done and back to me the next day.

Have been driving it since Thursday without any issues. Fuel pump primes at the first turn of the key, and the truck starts with every swing of the key, instantaneous!

Boy, it feels good to finally have the truck in good running shape again!

Thank y'all again for all your knowledgeable feedback on this forum!

 

[exp500]

SOLVED - Turns out the Spider Injector was bad.

Purchased the GM Genuine MPFI Spider for $480 on CarID with GM Genuine gaskets, and the old man charged me $250 to put it all in. Took about a week to arrive from UPS and the old family friend had the truck done and back to me the next day.

Have been driving it since Thursday without any issues. Fuel pump primes at the first turn of the key, and the truck starts with every swing of the key, instantaneous!

Boy, it feels good to finally have the truck in good running shape again!

Thank y'all again for all your knowledgeable feedback on this forum!

Glad you got it fixed!
Please EDIT title page, add "SOLVED". Thanks