# 92 Stanza KA24 runs rough at all speeds



## DE3fan (Jan 23, 2006)

Got a '92 Stanza with the KA24 engine. I rebuilt it 10,000 miles ago and it has run great until just recently. The car has a total of 92,000 miles on it. It's running rough from idle up until about 2700 to 2900 rpm. Does not matter wether it is cold or hot. I have replaced the injectors, fuel pump and fuel filter because it felt like a fuel delivery problem. No change. I then changed the plugs, although the ones I took out did not look too bad. My vacuum gauge shows 19.5 and it's steady. I can't remember where the compression readings were other than they were all within 5 psi of each other. When I press up on the EGR diaphram, with the engine idling, the idle gets worse. I have run the engine in total darkness and did not see any spark jumping, so I assume the cap and rotor are okay. The timing is exactly at 15 BTDC. I had a spare distributor and swapped it out, again no change. I have brand new plug wires on it, no change. The air cleaner still looks almost new (it was when I rebuilt it). I have not checked the PCV valve but I am having a hard time believing it can cause the sort of problems I am experiencing. I am at my wits end. I am beginning to think "the cure" is a can of gas and a match. Any other ideas out there?


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## DE3fan (Jan 23, 2006)

I have checked the pcv valve, it's okay. I replaced the fuel pressure regulator with another "known good" one. I also removed and completely tested the egr valve and bpt valve, both checked out ok. According to the vacuum diagram under the hood, there is a egr solenoid control valve, under the air filter canister. It sits in a bank of 3 other solenoid valves. I cannot find any reference to this in my chiltons book. So I'm not sure how to test it. I have continued to drive it this week and it seems to be getting worse. Could this be a plugged catalytic converter?


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## isb360 (Apr 6, 2005)

given all the parts you've replaced, this may seem rudimentary, but have you pulled one plug wire at a time to see if you can isolate it to a cylinder?

Does it run rough at first, then get ok when warmed up? Losing any coolant or oil?

Tim


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## DE3fan (Jan 23, 2006)

Yeah, did that last night and guess what?,,,,#3 cylnider is dead. I changed the spark plug this morning before I went to work, no change. I know the plug wire is okay because I get the same color spark from the end as I do the other 3. I'm going to replace the injector tomorrow (I have spares). I have previously removed the valve cover and visually inspected the camshaft and the rocker levers. All appeared to be okay. I'll let you know what the injector replacement does tomorrow. Thanks for the assist.


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## isb360 (Apr 6, 2005)

Glad you were able to isolate it to a single cylinder. I have found on my car that the wiring harness going to the injectors is extremely brittle and even wiggling it around by hand with the car running is enough to drop a couple of injectors. 

I discovered this by accident when I had pulled the valve cover off for some reason. Getting the cover back on requires pushing the injector wiring harness back toward firewall slightly....when I started the car, it wa hobbling along on three cylinders. So I popped the hood and jiggled the harness and suddenly it was back on 4 cylinders again. My guess is that where the pigtails come out of the main harness and take a sharp turn into the connectors for the injectors is a stress point and the connection is weak there now. 16yrs and 215k miles worth of thermal cycles and engine vibration will do that to a harness.

Try wiggling the harness while it's running...before changing injector -- you might find that it restores your #3 dead cylinder.


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## DE3fan (Jan 23, 2006)

I had tried that earlier and it did not make a difference. Today it did. So since I have another vehicle to drive, I'm going to let this sit for a day or so while my frustration level diminishes. I tired finding a set of noid lights today, none found. I wanted to confirm this problem visually. SInce I can't find any locally, I intend to un-wrap the harness and locate the short.


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## izzen (Mar 30, 2005)

Try posting here


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