Why is my 1975 jeep cj5 fuel running very rich even though I replaced the carburetor, fuel pump, wires, spark plugs, cap and rotor? someone told me that aftermarket fuel pumps are defective is that true?
I have a 1974 CJ5 with a 258 I have replaced the carb,pump,plugs,wires,cap,button,coil filter and the jeep will idle fine but when you try to drive it or give it alot of fuel the jeep back fires and its like someone turned the fuel off. what could the problem be.
Carter YF carb? (1bbl) You don't say which engine/carb, so I am guessing I-6 with a 1bbl. It was most common engine in the mid-70's.
Most commonly a slobbering-rich running YF (we are thinking so slobbering rich it barely idles at all-black exhaust, but will run with throttle open, still rich) is usually a stuck float. The second most common will be a result of a hole in the accelerator pump diaphragm. In either case removing the air cleaner, and looking into carb while engine is running you will see fuel rapidly dripping from venturi. (ok, just in case you forgot, wear safety glasses for that part, don't get too close, a backfire is going to cause a face-flaming !) Some of the cheapo carb kits are not all that compatible with ethanol, and the diaphram will get soft and start to break down in very short order.
If the carb is not assembeled correctly, and the power-valve needle isn't installed correctly it will cause a rich off-idle condition.
Provided the engine is not missfiring, the problem has to be carb related. The only time I can think of ever seeing a fuel pump cause a rich condition it was a result of a performance fuel pump designed to produce 20+ psi overcoming the float valve.
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Re: troubleshooting fuel system for 1975 jeep cj5
Fuel pumps just supply fuel to the carb. Either they work or don't
work. I would make sure that the mixture screws on the carb are set
properly. Turn the screws in to lean out the mixture, do one at a time.
You want to turn the screws in to the point where the jeep will start
to idle rough and then back out a 1/2 turn. Check your timing also. If
the jeep has alot of miles on it, the timing chain will stretch and
it's possible that you cannot get the correct timing.
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If you ran out of gas there is a very good chance that the fuel pump relay has blown a fuse or requires a reset. Fuses and relays are in the main fuse box behind battery. When you turn your ignition on to the one setting before the starter engages you should be able to hear the fuel pump running. If it does not then check those fuses. If it does run then there is a good chance that the crank shaft positioning sensor needs replacement.
fuel filter or a fuel pump could also be plugs, wires, cap and rotor I would try fuel filter first then take a plug off a cylinder and hold it close to screw driver or something(dont hold unless have rubber to grip to please dont get shocked) if it doesnt spark your not getting spark and try plugs wires cap and rotor if it does spark then open gas lid have someone turn ignition switch on and listen if you here the fuel pump is still good if not replace it. It does sound like a fuel pump
Hello! Even though you have replaced coil, cap, rotor, plugs and wires; I need to know that you have a strong blue spark at a plug...Have you checked a plug for spark? I don't want you to misunderstand why I'm asking you that question; Certainly not to insult your knowledge but I need to know for sure that there is a strong spark...Guru..............Saailer
You've already eliminated the spark plug & wireset, distributor cap & rotor. Sounds like your car needs a tune-up, specifically, the PCV (positive crankcase ventilation) valve, and/of the EGR (Exhaust Gas Recirculation) valve.
Components checked/replaced during a tune-up are: air filter motor oil motor oil filter breather filter fuel filter(s) fuel strainer PCV valve EGR valve spark plugs spark plug wires ECM or distributor cap & rotor cabin air filter transmission oil filter transmission oil engine coolant check all vacuum hoses and lines
Troubleshooting the no-start condition - from the 1990 Mitsu Mighty Max Repair Manual:
Priority Action Part Type -- Cause 1 Inspect Battery -- Battery Discharged or Faulty. 2 Inspect Battery Cable -- Corroded, Broken, Shorted or Poorly Connected Battery Cable. 3 Inspect Distributor Cap -- Distributor Cap Cracked or Burned. 3 Inspect Fuel Filter -- Clogged or Dirty Fuel Filter. 5 Inspect Ignition Coil -- Faulty Ignition Coil. 6 Inspect Wireset -- Worn, Damaged or Faulty Spark Plug Wire(s). 7 Inspect Spark Plug -- Incorrectly Gapped or Fouled Spark Plug(s). 8 Inspect Starter -- Starter Motor Faulty. 9 Inspect Fuel Pump -- Low Fuel Pressure. 10 Inspect Solenoid Switch -- Faulty Starter Solenoid Switch. 11 Inspect Fuel Pump Relay -- Faulty Fuel Pump Relay. 12 Inspect Fuel Injector Pressure Regulator -- Faulty Fuel Injector Pressure Regulator. 13 Inspect Ignition Switch -- Improperly Connected or Faulty Ignition Switch. 14 Inspect Starter Drive -- Faulty Starter Drive. 15 Inspect Fuel Injector -- Dirty or Worn Fuel Injectors. 16 Inspect Fuel Pump Strainer -- Clogged or Dirty Fuel Pump Strainerat. 17 Inspect Engine Control Computer -- Incorrect Operating Information Being Delivered and Sent From The EEC. 18 Inspect Fuel Tank -- Fuel Tank Empty. 19 Inspect Carburetor -- Carburetor Flooded or Faulty Choke. 20 Inspect Distributor -- Worn, Loose, or Incorrectly Installed Distributor.
Carburated vehicles ether have an automatic choke, or the very old ones, a hand choke. Yours has an automatic choke. The starting problem likely is a problem with the choke. The problem is almost certainly not the fuel pump.To set the automatic choke, push the accelerator to the floor, and RELEASE. Then start the engine just like you would a fuel injected vehicle. If this doesn't solve the problem, then the automatic choke needs to be repaired.
Coil may be producing low voltage (KVs) to where it makes enough energy to snap out of the coil tower but then supressed as it travels down the high tension leads finally to the plug. Incidentally spark plug leads should have about 10k ohms of resistance per foot.I good coil will jump spark at least a half inch if you pull the wire off the cap and produce this much air gap