Tyler01

I just bought a 89 Cherokee about a 2 weeks ago and the guy said he put 4 hole injectors aka bigger but it smells like it runs real rich and has a slit back fire when to the floor to the release.

Trumpster

If anything the 4 hole injectors would help reduce running rich and backfiring because it helps the fuel burn better in the combustion chamber.

I'd start with a full tune up on it (plugs, wires, distributor cap/rotor, air filter, etc) and see if that helps out at all. It's also possible that you could have an o2 sensor that is on its way out and not reading A/F ratios right, but start with the basics first before you throw money at things you don't need to.

NorCalJeep

For backfiring, it could be spark plugs(check those first), timing issue, or the distributor. The 4 hole injector upgrade improves throttle response and makes the engine run at a stable rate.

cruiser54

Basics, Tyler. As stated already. I am doubting it's the injectors. could be as simple as a cracked vacuum line from the throttle body to the MAP sensor. And that probably happened during the injector install...

Tyler01

Well it already has new plugs but what type of gas mileage are yall getting because I went threw a quarter and probably drove 30 miles but I'm not used to a jeep I guess

cruiser54

Stay on track and fix the initial issue.

Tyler01

Well im asking this because you can smell the unburned gas. I seems like fuel is just running out but ill check for spark friday and let yall know. Thanks for the replys though

cruiser54

Every 30,000 miles, they get new plugs, wires, cap and rotor.

freegdr

What injectors were installed by PO ?

cruiser54

Yeah. Get the number off them.

Have you checked that vacuum line yet?

Tyler01

Tomorrow after school ill take pics and let yall determine what you think.

cruiser54

Pics of what?

Just get the number off the injectors and check out the vacuum line with your own eyes.

Tyler01

Well after driving it today it seem like it runs pretty smooth just still sucks gas (usuall) ..... Went played in mud a little and front end got swallowed but came out. Only thing I need to fix is my driver door and figure out why it wont run warmer than it does cuz temp gauge runs around 120 and while I have heat on it barely gets warm.

cruiser54

Go buy a 83501426 thermostat from the dealer.

Tyler01

Bought a 160' degree temp thermostat and it got the heat inside the cab to feel hotter and temp gauge runs one mark past the 100 degrees. (idk if that good...never owned a jeep)