Hello everyone I have a problem I am trying to figure out why my blazer will not start unless I give it starting fluid then it will set there and and idle untill it runs out of starting fluid. If I squirt starting fluid in the intake and then start it and then give it some gas or push down the throttle pedal it will run but jump up-and-down at higher rpm's around 3000 to 3500 and if I back off and not pump the pedal it will die again. When it started acting up about a month or two ago it would run fine when I started it up but as it got warmer it started to buck on low RPMs and chug but if I gave it some fuel it would run ok Just as long as I kept it in acceleration mode. Well it got worse to where it won't even start now without starting fluid. I have checked the fuel pressure which is fine, holds pressure isnt leaking down I know what the specs are on that. I replaced the fuel filter. Fuel pump relay is fine. I know it's starving for fuel which is why it won't start. So I'm trying to figure out why it is not getting fuel at idle but it will run but jump up-and-down if I keep pumping on the pedal at higher rpm after getting it to initially start with some starting fluid. It's obviously so lean if it is getting any fuel at all that it won't even start without help from starting fluid. Ignition checks out fine. So what does it sound like that I've got, clogged up injector or possibly throttle position switch or even a coolant temperature sensor? I've switch those out with known good ones even a map sensor. One problem I have is I'm not able to read codes because it's got that rotten intermediate year computer. And my OBD two scanner won't work on it neither does any paperclip.

 

It will not stay running I forgot to mention that unless I keep pumping on the throttle pedal and once I let off of pumping on it it will die

 

I'm sorry I'm new at this it is a 1995 S10 Blazer with the 4.3 Vortech with the CPI.

 

Well all you need is fuel and spark to run so thats strange. Where did you do your pressure testing at? You should probably check the injectors to see if theyre leaking but even if they were you would see a drop in pressure. Sounds to me like a computer issue, possibly a cam position sensor. Your really would need to go to a shop equipped with a decent scanner. Is the service engine light on? Maybe bad gas or water if its been sitting.

 

Another thought would be maybe to check the throttle body and make sure its functioning correctly. Pull your spark plugs too and see if theyre black indicating a rich air/fuel mixture

 

I have a fuel pressure gauge and I went through the procedure to check it gets 60 pounds never drops below around 58. And it stays pressurized for at least 10 to 20 minutes I stopped even checking after that. It is not running rich I know that the injector spider or the fuel pressure regulator isn't leaking. I guess the cam position sensor would play a part in pulse widths? and if it was off it wouldn't do so until it had higher rpm's? That's the one thing I have not checked I'm assuming it's on the distributor in the back? I checked the fuel no water it's fresh fuel. I mean the only thing I can come up with is that the injector isn't firing until it gets higher RPM's.

 

Is it true that if the cam shaft position sensor is bad that it can lead to a no start condition? I always thought that it would still run but just maybe run roughly.

 

Camshaft position sensor will not cause a no-start condition, it has nothing to do with spark.

Have you checked the connector at the injector? It requires removing the plenum. There are two wires in the connector and the connector has been known to fail. It can be replaced seperately.

It would be best to check pressure and leakdown at the fuel filter outlet with all pressure and flow ending at the tester. When you check pressure at the service port, it shows the LOWER of fuel pump maximum output and regulated pressure. It's possible the pump can only build 60psi and that's not nearly enough. Fuel pump volume could be too low to keep the engine running.

 

Thanks a lot for all the advice and guidance everyone. I finally figured out what was wrong with it. Even though I tested the fuel pump multiple times over several days and it showed a reading of 60 pounds and when I revved it up it would move up in pressure, today it ended up checking out at 40 pounds so something was really going on with the fuel pump. As you mentioned it probably was due to volume. I just replaced it with a brand-new Delphi and it runs fine for now. Merry Christmas everyone and happy holidays!

 

Well once again I should've kept my mouth shut. That's why added at the end it runs fine FOR NOW. Apparently after it warmed up this last time I took it down the road and was coming back It started bucking and then losing power unless i would accelerate and then finally it died when I let off the gas. I am beginning to think that the connector at the injector is not making good contact. Is it possible to access that by pulling off the tuning valve at the top of the intake?