Phelan

I just recently bought a 97 jeep Cherokee 4.0 and the previous owner said all it needed to get back on the road was fuel pump, so I replaced the fuel pump and now it starts and idles but when I open the throttle at all it stalls and backfires into the intake tube, of I keep the throttle open for more than a second or two it dies. I have also replaced the fuel pressure relay switch in the fuse panel and part of the fuel line along with a brand new battery.

BlueRidgeMark

Hmmm. Interesting. Just as a wild stab, I suggest you get out your trusty multimeter and check the TPS (Throttle Position Sensor).

Here's a good video on it. Notice he's using an analog meter. That's really much better than a digital meter for this test. Even a Cheapo from Harbor Freight will do the job for you.

Phelan

Ok I will try that as soon as I can get ahold of one.

Phelan

I tested it and the voltage read good. I have a video if I can figure out how to post it.

freegdr

Scan for codes ...

Phelan

Not sure if it makes a difference but there is no check engine light. At least there wasn't before. Just ordered a new set of injectors to try that and was going to blow some air from my air hose through the fuel line to be sure it's not clogged at all what do you guys think is that a bad idea?

fb97xj1

The CEL might not come on when there is a problem but codes can still be stored, so checking for codes is always a good idea. Check the fuel pressure, too. It also wouldnt hurt to check for vacuum leaks and clean the throttle body and IAC. When was its last tuneup? If nobody knows, give it one. Thats how it went with my 97. It wasnt cutting out or backfiring, but it did run better. Every little bit helps.

XJeepCheep

Check the fuel pressure, sounds like a bad pump or bad gas.

Turbo X_J

Rule #1
Promptly forget about everything the "PO" said to you concerning this vehicle. They couldn't fix it and if you only follow their advise you won't either...lol
Rule #2
Takes 3 things to make an internal combustion engine function:
Air
Fuel
Spark

Is the bulb present or burned out? Lamp should illuminate as soon as the ignition key is turned to "ON".

Fuel pressure gauge used to obtain an actual reading would be better.

BlueRidgeMark

It's always a bad idea to throw parts at a problem.

Test. Diagnose. THEN replace or adjust as needed.

Phelan

The bulb works with key in acc but goes black when it starts up. I will rent a fuel pressure gauge from AutoZone today and after I will see about renting an obd scanner unless there is another way to test it for codes?

Phelan

Ok quick update, I just rented a fuel pressure tester and it reads 0 at the fuel rail with the car running.

Rogue4x4

Car's running and you get no reading at all?

Something isn't hooked up right. If it's running you should have SOME kind of reading at least. Double check your setup.

Did you get any pressure at the rail without the vehicle running, key on?

Phelan

I did not check that don't you just screw the gauge into the fuel rail as far as it goes? Lol never used one before I'm still a bigenner with mechanics. And no I didn't get a test with car off I tested it right after taking off fuel injectors and cleaning them with some throttle body cleaner and reinstalled.

Rogue4x4

Here's a link to a basic procedure, should be close

https://www.2carpros.com/articles/ho...-and-regulator