1999 Chevy Trailblazer Engine turns, but will not start

TIMMYHBASS

MEMBER
1999 CHEVROLET TRAILBLAZER
6 CYL
4WD
AUTOMATIC
135,000 MILES

As you can see, I have a 1999 Chevy Trailblazer. I drove it to work 3 weeks ago today and when I left from my job, I drove about two blocks and it died in the middle of a major road. Since then I have spent many hours trying to decipher what was wrong with it. It was low on oil at the time (I have since added two quarts of oil to refill it). I know it's a fuel issue, whether it be a bad fuel pump or not, I'm not sure. The engine is definitely not receiving fuel to make it run though. I have heard that there is a failsafe with this model of blazer that causes the computer to send a message to the fuel pump to shut off if it sees the engine is running too low on oil. I have also heard that there is a reset switch to correct this issue somewhere in the vehicle. The automotive manual for blazers from this year shows something c alled the "FUEL PUMP OIL PRESSURE SWITCH" within the wiring diagram, and it leads me to believe that this is the switch I'm looking for. I have checked all of the fuses that have to deal with the fuel system. There is one fuse on the engine underhood fuse block that, when taken out and reconnected, sounds like it is trying to make the fuel pump cut on, as a single click happens, followed by several clicks from the fuel injectors attempting to put fuel into the Throttle Body Injector (It has a TBI system, but I forgot to mention that earlier). This makes me believe that the fuel pump is getting a message not to operate rather than being bad all together. Basically I need to know where the reset switch to correct this malfunction is so I can rule this out prior to replacing the entire fuel pump. Also if you think it could be something else, I would like to know. Any information you can offer me would be greatly appreciated.

5 Replies

RACEFAN966

MECHANIC
5,029 POSTS

Ok first off there is no sensor to reset and second no trailblazer built in 99 is this an S-10 Blazer with a V-6? The oil pressure sensor which is also a fuel pump shut off is under the distributor on the left or drivers side of it. It has a 3 wire plug in on it. Now are you sure it is a fuel problem. Have you checked fuel pressure? It takes 65 psi to start this injection system and it needs 55 to run. Have you check the cap and rotor as they corrode badly? Let me know what you can and we will take it from there.

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Monday, December 22nd, 2008 AT 12:27 PM

TIMMYHBASS

MEMBER
3 POSTS

With all due respect (and I mean that sincerely as you obviously know alot more about this type thing than I do), the Trailblazer was released in a limited series in 1999 as a high-end model of the blazer s-10. It is not a trailblazer as the model was released in 2002, but nonetheless it has the name. That being said, I have noticed some differences betwen this model and others, such as the fact that, after I looked for well over an hour trying to find it, I do not see the "fuel pump oil pressure switch" anywhere near the distributor. That is not to say that it does not exist, just that I can not seem to locate it. I have looked on all sides as well as below the distributor for it. As far as the fuel pressure goes, that was checked by an ASE certified mechanic friend of mine while he was down visiting a couple weeks back and he said it was absolutely fine, along with the fuses. His belief is that it's either the switch or the fuel pump has gone bad. Which cap and rotor are you talking about so I can check those out? I'm not sure if that would cause the fuel pump to not turn on like it is, but I definitely want to check it if you would think it would help. I really do appreciate anything you can offer.

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Monday, December 22nd, 2008 AT 5:41 PM

TIMMYHBASS

MEMBER
3 POSTS

As an extra side note, I was working on the car a few minutes ago and I noticed that the oil pressure would jump to about 40 while I was trying to crank the car. Could that be an indicator of a bad sensor not telling the fuel pump that there is sufficient pressure to run the engine, or does that rule out the possibility of that being the problem alltogether, thus further staking a claim that the fuel pump itself is bad?

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Monday, December 22nd, 2008 AT 6:37 PM

RACEFAN966

MECHANIC
5,029 POSTS

Ok I must assume that this has the 4.3 ltr V6? Now if the fuel pressure is good then the fuel pump is working a little confused here. Your friend said the fuel pressure was good so that would indicate the fuel pump is working and you do not have spark this why you should check the dist cap and rotor. Like I have said it takes 65 psi of fuel pressure to start and needs 55 psi to run so maybe you can ask him what the pressure was. Here is some pics one of the distributor cap and rotor and one of the oil pressure switch. The oil pressure switch that you are looking for is a three term type not a single ok. Let me know what you find. The 1st pic is the cap the 2nd is the rotor under the cap and the 3rd is the oil pressure sensor.

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Monday, December 22nd, 2008 AT 7:01 PM

ARHOLDEN

MEMBER
1 POST

I had to replace the fuel pump in my '99 Trailblazer two months ago. Now I am having a problem with, when the fuel gets down to half a tank, it dies like there is no gas in it. It has done this a couple of times now, so I make sure to fill back up before I get under half a tank. I have been very curious as to why there would be fuel in the tank but the truck not recognize it. I have put off taking it back in to the shop because I have spent so much money on repairs in the last 3 months.