My 88 rwd automatic on a hill at low rpm cuts off when I push the gas down past half way. Feels like turning off the key till I back off the gas. New cap and all rotor. At speed it has a hesitation when you stomp it but picks up fine. Has mikuni two barrel.
My 86 Power Ram50 always seems to have some sort of minor miss depending on gear speed throttle position ~ except for replacing the entire distributor the ignition system has gotten all new parts ~ the original Mikuni carb has been completely rebuilt fuel pump replace fuel tank filters replaced etc etc
I can't figure out if its a fuel or ignition problem ~ eventually another Mikuni carb I have will try out ~ bummer, need a real mechanic in order to chase down the problem...
The ignition switch caused engine to stop ' start it was replaced too BUT the little miss persists....
Other members can help & I sincerely hope you find & fix the problem....
P.S. I often wonder if it could just be a loose or worn wire connector wiring electrical stuff ?? The vehicle is not new by any means AGAIN best wishes fixing...
Daily Overhauls Do Get Expensive
Could be a number of things, especially if you have the Mikuni.Originally Posted by Rodehazrd
First: Check and clean the eight-pin harness connector to the carburetor. Poor connections can cause a variety of drivability issues.
Second: With the engine hot, remove the air cleaner top and inspect the choke butterfly. Is it completely open? If not the choke has failed or the shaft is binding.
Third: With the engine running and trans in park or neutral, quickly open the throttle half way or so. Does the engine sputter, cough or stumble? Also, with engine off, remove the air cleaner top and while looking down into the primary barrel, quickly open the throttle. You should see a stream of fuel shoot down onto the primary butterfly. If it sputtered and there's no stream of fuel, the accelerator pump circuit is plugged.
Fourth: With the engine off, remove the "To Carb" hose from the evaporative cannister and gently blow into it. There should be no resistance. Start the engine and again blow into the hose. There should be resistance. If not, the bowl vent valve is toast.
Lastly: Apply a vacuum to the secondary vacuum chamber on the firewall side of the carb. If it doesn't hold a vacuum, it needs replacement.
If any of the above tests indicate a carburetor fault, it may be time to consider a rebuilt Mikuni or, as most have done, a Weber conversion. Also, check the plug wires and plugs. A bad plug wire connection or plug can cause an occasional on/off ignition symptom you described.
Last edited by FMS88; 12-29-2024 at 05:45 PM.
Thanks for your kind attention. I’ll do all those things and report back. I suspected the accelerator pump but I’m confused by the choke and the whole carburetor system. I use it daily hauling wood and stone and need more power on some hills. I replaced the main vacuum line to the computer and made a large improvement when the truck was given to me by a neighbor it barely pulled itself before that. I love the way it takes a ton of rock and still rides fine.
If replacing one hose made a big difference, add an inspection of all vacuum hoses to your list. Also verify their proper routing using the sticker on the underside of the hood or search for hose diagrams on this site. If you remove any hoses, be gentle with the plastic thermo switches on the intake manifold. Their plastic bibs are easy to break off.
Rodehazrd,
Question to my Sony Google TV when verbally asked cause of engine backfire... Answer: per Subaru mechanics, lean fuel mixture, not enuff fuel getting to the engine, rich fuel mixture, bent valve, ignition timing not correct...
Sometimes my truck runs great but sometimes a backfire and annoying little miss or stumble when accelerating in 2nd gear...
Replacing my fuel pump about 9 years ago returned the engine power...
Replacing the in tank fuel filter 6 months ago solved the engine miss (but it's back)
The FSM is complicated about testing the Mikuni carb & fuel system with a DMM
The fuel pump from Amayama might fit my 2.6L engine ? Tempted to buy it...
I need to study find time to test all the fuel system per FSM (hurting my little brain & I have no garage)
Am pretty sure my ignition system is ok studied tested replaced bad parts new coil new NGK plugs new cap & rotor...
The engine vacuum is excellent high & steady, new cylinder head installed abt 2 years ago...
If I get all the above done PLUS adjust the carb AND perform the steps member FMS suggests then ?? FIXED ??
https://www.amayama.com/en/part/mitsubishi/md138586
Daily Overhauls Do Get Expensive
Well I finally got back to the old truck all checks were good. So it's Weber time for me .
I have 88 2.0 automatic the redline kit 614 is on my wish list now.
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