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88PowerRam50
05-10-2011, 11:34 AM
Okay Ya’ll, my 88 Ram 50 2.6L (G54B) 5spd MT 4wd w/Mikuni-Solex carb, pings and or bogs down SOMETIMES. Usually when in higher gears and going up a hill or simply hitting the accelerator past the 1/4 way of pedal travel. Sometimes it’ll start pinging 1st, then loose power, sometimes just looses power. It also SOMETIMES cuts out in lower gears at high rpms (3-4k). Here is what we’ve tried so far. New: fuel filter, spark plugs, plug wires, dist cap and rotor, throttle position sensor, O2 sensor, 2 thermo valves that control vacuum in carb system, reman Cardone ECU. Rebuilt carb with new needle, accel pump, aux accel pump, enrichment pump, secondary throttle vacuum/depression chamber, feedback sol valve, gaskets of course. Cleaned EGR valve. Rebuilt distributor. Checked engine temp sensor resistance from 68 to 180 deg F. Resistance drops consistently as temp increases. Replaced ign coil. Checked exhaust pressure before converter. Temporarily boosted fuel pressure w/electric pump. Checked ign coil ground to ECU harness. I don’t have access to a Miller ECI checker (MD 998451) with “E” harness (MD998456) which would allow me to check the Feedback Carburetor System components while driving. My limited understanding of the ECU is that it has ROM and RAM. If it has RAM does this mean it has the ability to “learn” and perform differently under certain feedback conditions? I welcome any and all thoughts and suggestions on how to troubleshoot this. Randall in Nashville TN.

pennyman1
05-11-2011, 06:45 PM
Check the hoses going into the box on the left fenderwell -; there are sensors in the box that feed info into the ecu and adjust the carb. If the hoses split or get chewed on by critters, the vacuum leak it causes will cause issues just like what you are having. I had an 88 Dodge Ram 50 sport cab with the 2.6 that did exactly what yours is doing and it was the main hose from the carb to the box had a 1/4 " hole in it and it was inside the box where you couldn't see it.

88PowerRam50
05-12-2011, 01:59 PM
I think your talking about the vacuum control box where the vacuum switch is that tells the ECU if the throttle is near or at idle. I checked the switch for continuity earlier using a hand pump and ohm meter, but I never checked the actual supply hose. There's also a Vacuum Regulator Valve in there that talks to the EGR valve. I'll check hoses, thanks for the suggestion. Randall in Nashville TN.