Hi guys-
My 71 was recently converted back to FI (had a single carb). It starts up great and runs fine until it gets warmed up. After about 10 minutes of driving the motor seems to lose power while accelerating. Especially if I'm going up a hill or even a slight incline. If I let off the gas a little the motor seems to pull a little better, but still less than I need. So the more gas I give it, the more sluggish it gets.
Also, this may be a separate issue, but sometimes when warm and at idle it stalls and needs to cool off for several minutes before it'll start back up. I more interested in solving the lack of power issue as I've gotten accustomed to feathering the gas at stops. Or maybe they're related.
By the way I've moved the dial on the FI computer around and there's really no noticeable difference in the hot/sluggish issue.
Thanks all-
Bill in Atlanta
Full Version: 71 914 1.7 Engine boggs when warm
My first suggestion is to check your timing to make sure it's right. Too retarded timing can cause what you're describing.
Have your valve clearances been checked? That'd be my next suggestion.
Have your valve clearances been checked? That'd be my next suggestion.
Remove, clean, and replace your advance timing plates in the distributor.
QUOTE(dlee6204 @ Sep 22 2017, 04:53 AM) 
My first suggestion is to check your timing to make sure it's right. Too retarded timing can cause what you're describing.
Have your valve clearances been checked? That'd be my next suggestion.
The timing and valves were adjusted by a mechanic that works on 914s a lot, but I'll double check. Thanks
QUOTE(r_towle @ Sep 22 2017, 05:10 AM)
Remove, clean, and replace your advance timing plates in the distributor.
I'll do this. Thanks
The suggestions provided are all good and valid, but I'd also suggest that this could be classic case of running too rich. That would explain both symptoms (sluggish and low idle when warm). Running too rich can be caused by one or more of the following factors:
1. MPS that doesn't want to hold a vacuum anymore
2. CHT failing
3. Fuel Pressure too high
4. Leaking Cold Start Valve or other injector(s)
5. Worn/dirty trigger points
6. Disconnected / faulty T1 sensor (ambient air temp)
Feathering the throttle introduces more air that can help lean out the mixture a bit. That dial on the ECU is supposed to only be applicable to idle mixture. When the TPS "enters" the idle circuit the ECU controls mixture based on that knob. CCW will lean the idle mixture, CW will enrichen it. Try turning it iteratively CCW and see if it makes any difference at all while idling (when it's already warm). That's not a solution, but it may be additional info pointing to an overly-rich condition.
1. MPS that doesn't want to hold a vacuum anymore
2. CHT failing
3. Fuel Pressure too high
4. Leaking Cold Start Valve or other injector(s)
5. Worn/dirty trigger points
6. Disconnected / faulty T1 sensor (ambient air temp)
Feathering the throttle introduces more air that can help lean out the mixture a bit. That dial on the ECU is supposed to only be applicable to idle mixture. When the TPS "enters" the idle circuit the ECU controls mixture based on that knob. CCW will lean the idle mixture, CW will enrichen it. Try turning it iteratively CCW and see if it makes any difference at all while idling (when it's already warm). That's not a solution, but it may be additional info pointing to an overly-rich condition.
Exact problem on my '72 and turned out to be a bad mps.
Easy to check.
Good luck!
Easy to check.
Good luck!
Thanks all. Will work on her next weekend and post what I'm able to figure out.
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