1986 2.3 FEI 5 speed trans.

[86RangerMan]

Hello, i have a question for you all.. as you can see by the title i have a 2.3 EFI engine.. I have noticed that when I first start it up it revs high, then drops down after a few minutes. thats ok, the thing i don't understand is, when I go to take off, it hesitates a little and backfires.. once it warms up it don't do that anymore.. I have replaced the plugs, wires, dist. cap rotor button, and the AIC on the breather box...is there something that i might be missing that you may have thought about????? all help will be greatly appreciated

 

[shadetree]

Is it hard to start, or starts then dies when cold??

If it cranks longer than normal, and a little harder to keep running when cold, then runs fine as it warms up, the engine coolant temperature sensor, or it's circuit could be the problem. The ECT is the engines automatic choke.

If it starts and dies, or you have to keep it revved slightly to keep it running, until the engine is warm, plus a faster idle, it could be vacuum leaks. Check all the hoses, including those in loom.

Either of the above problems can cause the hesitation and back fire due to lean fuel conditions.

Also, check your camshaft timing. The timing belt could be off a tooth.

A bad throttle position sensor will also cause stumbling and backfire like problems, and is due to a worn spot on the sensor, but this problem is constant, and doesn't clear up when the engine warms up. It can also cause hard starting.shady

 

[feellnfroggy]

Backfire like that is timing. You can run with 1-2 degrees off, but when its at open circuit like warmup 1-2 degrees is actually a whole lot more. Check your cam timing.