Mechanics

PRE IGNITION, DETONATION, PING

1994 Ford Ranger • 4 cylinder 2WD Manual • 300,000 miles

I have a 1994 Ford Ranger XL 2.3l 4 cylinder 5 speed manual trans 2 wheel drive standard cab. High milage 300,000+ uses no oil. I am experiencing an engine ping or rattle while trying to maintain speed up a long incline, 50+mph. If I do not let off the throttle and try to push harder on the trottle to maintain speed the engine loses power pings more and seems to start missing. Engine runs pretty well around town and idle is good.
I have checked engine compression #1 145 #2 145 #3 170 #4 170. I have not done a cylinder leak down test yet. I did try some seafome in the combustian chambers only and water injecting through a vacume port to lesson carbon deposits hopefully. I replaced Spark plugs, spark plugs wires, Mass air sensor, Egr presure sensor, egr vacume regulator, egr valve, and fuel pump. There are no codes on a scan tool I've done 2 tests koeo and koer (key on eng off and key on eng on ) I've also checked ingnition timing 10 degree's initial at idel and between 30-40 eng revved in netral. Fuel presure is 30psi and 40 psi with presure regulator vacume hose disconnected.
I'm not quite sure what part to throw at it next. I do have a NEW set of fuel injectors I will install but I do not think that will cure the problem.
Ignition coils, ignition control module, power train control module, speed sensor, throttle position sensor?
Any help would be great
Thank you
Jim Geddes
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Jimgeddes
February 21, 2011.



This truck should have two removable shunts in the wiring. One of them is the SPOUT connector for setting the timing but the other one is an Octane Adjustment switch that when removed, lowers the ignition timing by 3 degrees to help a problem like this. You also want to make sure the EGR passage is not restricted with carbon and the system is working properly.

Wrenchtech
Feb 21, 2011.
Thank you for your answer. I'm looking into the octane switch. I guess I do not under stand why after so many miles the octane switch would now make a difference. I use chevron fuel 85% of the time and have tired a few different grades and brands since the probl, em showed up maybe 600 miles ago. We have had 10% alcohol in the fuel here in portland for sometime now. The pinging started suddenly. Then there is the power loss associated with the ping, not really a knock sound or a tap, and the enging runs rough after 20 seconds or so after the ping starts.
Thanks again for the prompt answer
Jim Geddes

Tiny
Jimgeddes
Feb 22, 2011.
I'd concentrate on looking for a lean mixture or inoperative EGR.

Wrenchtech
Feb 22, 2011.