1998 Tahoe 5.7 Usually wont start, but sometimes does

[Tagahoe]

My 1998 Tahoe 5.7 2dr. 4x4 wont start. It turnsover, but wont start. Sometimes it will start fine and run fine with no problems. My fuel pump is new, fuel filter about 4 months old, new fuel pressure regulator, and tune-up. Where is the problem? Right now it hasnt started in three days, maybe tomorrow it will.

[oldyeller]

does it crank over? try pressing the accelorator a little and see what happens.. have yo checked for spark and fuel???

[Tagahoe]

It cranks over, but doesnt start. I have tried pumping it, I have tried holding it down, and nothing ever happens. Today it started up again, but after 3 days of not starting. Im fixing to go to the store to get that tool to check for spark. Im pretty sure it is getting fuel, but how can I check just to be sure? fyi: I do hear the fuel pump turning on.

[PEDALDORK]

I've got a 97 and frequently had the same problem. after 3 fuel pumps i was finally told that at least with the 97 there was a problem with the pigtail coming off of the fuel pump. It was apparently shorting out. I replaced with an ACDelco replacement pigtail, and haven't had a problem since.

[oldyeller]

a easy way to check for gas is to try to start it and if it doesn't remove a spark plug and see if its wet with gas.

[srgreene]

A common problem is corrosion in the vehicle electrical connector that connects to the fuel pump. You could be a victum of a mechanic that didn't bother to inspect the connector when replacing the fuel pump. Test fuel pump operation by putting an ammeter between the positive side of the battery and the fuel pump test port near the relay box in the engine compartment. You should get at least 6.5 amp reading on a good pump. Connect a fuel pressure guage to the fuel line port (on top of the fuel line near where it enters the fuel pressure regulator. You should have 60 plus PSI when testing with the engine stopped. You won't start if it is 50 PSI. You can usually get a vehicle with low fuel pressure started using ether based starting fluid.

[jptahoe97]

I'm having the same problem with mine it quit 5 days ago going down the road. Hasn't ran since. It's getting gas up to the motor it just isn't injecting it. Can't figure out whats wrong.

[jptahoe97]

I can pour gas straight into the intake and it will crank, but i can't figure out why it isn't injecting gas. If anyone has any suggestions let me know.

[Acclude91]

I have a 98 Tahoe in my shop now with similar issues. The entire fuel system is new and has all new wires for the pump, sending unit, and pressure sensor. It has just under 60 PSI at the fuel rail and my scan tool says everything is working fine. The only reason it won't start is because of the security feature prohibiting it (VTD). The injectors are getting the +12V they need, but the ECU just won't pulse the ground needed to operate them. I've been trying to find info on this security feature and how to "reset" it. GM says to put the key in the ignition and turn it on and let it sit for 10 minutes. That didn't work. I re-programmed the keyless entry remote and that didn't work either. Another GM dealership said that there is no way to reset it and that there is probably something wrong with the Passlock security feature. You guys might be having a different issue because fuel issues are common on Suburbans/Yukons/Tahoes, but the 98 Tahoe in my shop won't start because of the security feature. If anyone has any info or diagrams of the VTD system please PM or email me with the info. Thanks in advance for any help.

[Tagahoe]

well my problem ended up being an evil possessed fuel pump. it seems that everytime I checked the fuel pump, it would work and start. then I would move on, and the little humming pump wouldnt pump anymore, UNTIL i checked it again. had to replace it again, good thing for warranties.

[ZR800]

Replaced the fuel pump in my cousin's 97 for the third time this weekend. Although a bad pump was not the cause of the pump not pumping. He does have a problem with the wiring, although its not corrosion. Still have to figure it out, but on his '97, he can reach in through the drivers side rear wheel well and grab the wires on top of the tank. He is able to get the pump to run if he messes with the wires.

[V8inVA]

I have replaced the fuel pump twice in my '97. Second time I found the connector was bad. What it seemed to me was the connector gets hot. It was slightly melted and one of the pins on the new pump burned. A new connector and a second pump fixed the problem. GM refused to warrenty the pump because I put it in.

[txgearhead]

Originally Posted by Acclude91

I have a 98 Tahoe in my shop now with similar issues. The entire fuel system is new and has all new wires for the pump, sending unit, and pressure sensor. It has just under 60 PSI at the fuel rail and my scan tool says everything is working fine. The only reason it won't start is because of the security feature prohibiting it (VTD). The injectors are getting the +12V they need, but the ECU just won't pulse the ground needed to operate them. I've been trying to find info on this security feature and how to "reset" it. GM says to put the key in the ignition and turn it on and let it sit for 10 minutes. That didn't work. I re-programmed the keyless entry remote and that didn't work either. Another GM dealership said that there is no way to reset it and that there is probably something wrong with the Passlock security feature. You guys might be having a different issue because fuel issues are common on Suburbans/Yukons/Tahoes, but the 98 Tahoe in my shop won't start because of the security feature. If anyone has any info or diagrams of the VTD system please PM or email me with the info. Thanks in advance for any help.

Your issue defintely sounds like the Passlock has gone bad, which they have been known to do. I've got a 98 and I have been lucky that the Passlock system has only shut the fuel pump off about 5 times and I know what not to do....tu8rn the ignition so ast it dioesn't have time to recognize the key!

This post is old and you may have already fixed the issue, if not reply I've got schems, etc.

[clearman]

Probably the idle air control. They just redesigned the whole throttle body for Tahoes and I know you can retrofit this new design onto at least '02 so I assume earlier.

[Tagahoe]

happend again. i now know its electrical. my pump sometimes doesnt get power. im going to be going over the electrical stuff tmrw. im tired of this sh*t! i want to fix it once and for all. i almost got the dealership to do it, but damn, they are crazy as joe rogan.