I recently got a 96 blazer. It runs fine and everything but it has trouble starting the intake on the throttle body was loose and getting to much air in so I fixed that yesterday and replaced the fuel filter tested the fuel pump when the filter was off worked fine. But it wont start when the engine is cold I spray carb and choke in the throttle body and it starts. I came back out 2 hours later and fired it up without having to put any carb and choke in it. Woke up this morning and was replacing the exhaust because it was rotted out. took the old exhaust off and it wont start. I would think it would start with no exhaust on it its the headers then the cad on it. My question is is there not enough back pressure?

 

Since you had the problem previous to your exhaust change, I don't think that is where you should be looking for a problem. I think your back pressure is fine. A very, very common problem in Blazers is a fuel pressure issue. When you state you checked the pressure with the fuel filter off, did you do that with a gauge following the fuel leakdown test? If not, you need to do a fuel leakdown test before you start throwing parts at the problem. See this link https://blazerforum.com/forum/tech-a...agnosis-23038/ Follow the diagnostic charts.

Just to summarize the first steps, key ON engine OFF, the first two seconds while the fuel pump is running your pressure must be between 60-66 psi, then it must remain above 55 psi for at least 10 minutes. Post your results so people on here can help you out.

 

Yesterday it was starting fine after I fixed the air intake because it was getting to much air. Today I went to start it and it turned over but wouldnt start I put starterf luid in the throttle body and tried starting it and it didnt even sputter. I dont think its the fuel pump because when I put starter fluid in it it dosnt want to start.

 

Do you have any DTC codes? Check for spark on your plugs (should be strong blue spark not orange). When was the last time the rotor, cap, wires and spark plugs were changed? Are they all AC Delco? Blazers are very touchy about the secondary ignition parts and apparently don't work well for long with anything but AC Delco.

 

I have no idea when anything was changed I just baught it I test drove it twice it ran good had allout of pickup but stalled because the air intake would blow off because of the pressure it was missing the bolt. But I let it sit for about 3 or so hours went out there to start it and it sputtered twice on the first key turn so its getting gas I think it might be electical.

 

Since you don't know when anything was changed, in your shoes I would replace rotor, cap, wires and plugs with AC Delco parts. It's piece of mind knowing when tose parts were changed.. However, it is odd that the "air intake would blow off". If anything, it would suck it down under normal circumstances (unless it's backfiring), not blow. Since you're concerned with back pressure, think about trying this, disconnect and separate your exhaust between the down pipe and the catalytic converter and try to start it. it will be noisy, but it definitely not be the first cat converter to be clogged.

 

I dont think its clogged I put seafoam in it yesterday down the throtle body and it smoked good. I went out just a few minutes ago after charging the battery because my battery died from starting it. But I went outside turned the key it sputtered so I put some carb cleaner in the tb and it started. I did a fuel pump check by slamming the pedal and it didnt hesitate one bit. Waited an hour went back outside turned the key again and it sputtered and started. So I have no idea what could be wrong. But what would cause the engine to backfire and blow the cap off I know the guy I baught it from put dry gas in the tank because it was sitting for a year and I put seafoam in the gas also. I never heard it backfire while driving it but could it backfire from to much gas dumping in?

My dad keeps saying it might be the temp sensor because his chevy pickup did the same thing and I remember him replacing the wires rotor cap and all plugs and it still would sputter like mine does then he replaced his temp sensor and it ran like a champ.

 

Which temp sensor? Anyway, you really should go to the auto parts store and get a fuel pressure tester. They have them there as part of their loaner tool program. Do the fuel leakdown test mentioned earlier. Slamming your foot on the pedal doesn't do it. This is a very, very common problem. Read some of the threads. It is discussed in hundreds of posts on this forum. At the very least you will be able to rule any fuel delivery problems out.

 

The temp sensor that tells the computer when its cold or hot and how much fuel to dump depending on the temp.

 

The ECT (Engine Coolant Tempature) sensor. It would throw a code on your DTC (Driver Trouble Code...the "check engine" light) of P0118. I asked before, but I don't think you answered...is your check engine light on? If it is, do you have a scan tool? If you don't, the auto parts store will scan your codes for you. Respond with all codes that come up. I will be unavailable after this message until tomorrow night...but there are experts on here that I am learning from and will help you if you give them all the information. Basically, the same things I told you about. DTC codes & fuel leakdown test results. Look for posts from "Captain Hook", swartlkk, 50lb cat and several others. Here is a link that goes over quite a bit. It has many things on Blazers. The diagrams you see are straight from the dealer shop manuals (most of them). https://blazerforum.com/forum/tech-a...e-first-30093/

P.S. By the way...I wouldn't trust that gas in your tank if it is still the gas you bought it with.