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240 1988 240 DL lack of power and overheating?

SenseiRice

New member
Joined
Aug 5, 2016
Location
Southern NH
So I've got a 1988 244 DL automatic with about 130k miles on it that I bought as a winter beater, when I got it the car ran and idled like crap which was a leaking intake manifold gasket, I replaced that and the fuel pressure regulator and the car runs very smoothly but had a high idle, I have to turn the idle adjustment screw in all the way just to make it idle at 1000 rpm. Also when it's cold outside the car starts up then immediately dies, I have to give it throttle to get it to start but once it's at idle it's fine. I've also noticed at around 3500-4000 rpm it feels like it starts to loose power. The car still revs but it starts revving slower and it just doesn't pull as hard. Then the past two days have been pretty warm and I noticed my car was overheating. I cranked the heat and started moving and the temp immediately went back down. I got home and my coolant level as right in between the high and low marks on the expansion tanks, I let it idle for about 10 minutes after it got to temp and it started to overheat again, I checked the temp with an infrared hand held thermometer and it said my upper radiator hose was only 180 degrees (F) which doesn't seem that hot to me but I don't know what temp these cars are supposed to run at. I suspected possibly the compensator board so I smacked the dash and the gauge didn't move and I grounded the red and yellow wire that goes to the temp sensor then the gauge went straight to the red so I don't think it's the compensator board. I'm thinking maybe a sticking thermostat? When I have the heat on the temp gauge fluctuates a lot below the middle mark but never really reaches it. Maybe the sticking thermostat is making enough resistance that I feel it at high rpm? Maybe I've got two separate problems I don't know. Any insight on what I should be testing would be greatly appreciated because I'm stumped.
 
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I rented the tester from autozone and it says theres no exhaust gasses getting into the cooling system, I'm going to throw a coil and thermostat in it just to see what happens and as far as I know those parts are 31 years old so it can't hurt.
 
It's straight piped so I'll have to look into doing the fuel filter. I replaced the coil and thermostat and it runs fine, you can still feel it plateau a little but not nearly as much. I let it get to temp and let it idle in my driveway for about 45 minutes with the heat off and it didn't overheat. It was a little warm today and once I got off the highway on my drive to school and the temp immediately started to climb and sat right below the red. Does anyone know what the temperature these cars are supposed to run at is? I'd really like to know if I'm actually overheating or if I have to start looking at issues with the gauge.
 
I would verify timing base setting with a strobe light. It is a '88, so it is quite possible that it is too advanced, which would kind of give answer to high idle, power loss and overheating. I'd also check its vacuum and centrifugal unit (if it has, i never worked on LH2.2 in a 240)

Gauge should just sit at the middle.

How is your clutch fan?
 
The clutch fan is good, with the car at operating temp at idle (just a hair under 1000 rpm) the ignition timing is at 10 degrees on the timing cover.
 
Don't know if this adds any insight but my car chugs gas, I go through about 5-6 gallons after about 100 miles of highway driving.
 
Somebody said earlier compression test, to confirm not only the blown HG possibility but also the health of pistons/rings, valves not burnt, warped head from overheating, the list goes on and on. Compression test results will confirm the primary compression functions are proper, including cam events.

Have you pulled the plugs to inspect for color, with positions noted?
 
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