940 stumbles while cruising
#1
940 stumbles while cruising
Hi, I have a 94 940, non turbo wagon(175K). It runs well, except recently it started to stumble while at highway speeds. I will be driving at 70-75 and it will suddenly stumble like the fuel is being cut off, then continue driving fine. This has gotten worse and yesterday I drove home on city streets and parked it. Around town it drives fine, idles fine, runs cool and no CEL lights. Any thoughts? Thanks.
#2
Hi, I have a 94 940, non turbo wagon(175K). It runs well, except recently it started to stumble while at highway speeds. I will be driving at 70-75 and it will suddenly stumble like the fuel is being cut off, then continue driving fine. This has gotten worse and yesterday I drove home on city streets and parked it. Around town it drives fine, idles fine, runs cool and no CEL lights. Any thoughts? Thanks.
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The pump I replaced was very quiet. The new pump was noisy immediately after install.
#12
well, replaced the in tank pump too-pump under car is still noisy and the car still stumbles and nearly cuts out at highway speeds. Could the fuel pump relay cause this? Are there separate relays for each pump? Is there a fuse for in tank pump-if so, where is it? Thanks, very frustrating as I love the car.
#13
There is only a single relay for the pumps. Usually the relay failures occur when the solder joints crack on the little circuit board. If it were me, I'd remove the relay and resolder all the joints to eliminate that possibility.
If the engine is totally cutting out on the highway, I would check the crank position sensor. There really is not test for it but you can inspect it for cracks or flaking insulation. They tend to fail intermittently - usually when the engine is hot.
If the engine is totally cutting out on the highway, I would check the crank position sensor. There really is not test for it but you can inspect it for cracks or flaking insulation. They tend to fail intermittently - usually when the engine is hot.
#14
There is only a single relay for the pumps. Usually the relay failures occur when the solder joints crack on the little circuit board. If it were me, I'd remove the relay and resolder all the joints to eliminate that possibility.
If the engine is totally cutting out on the highway, I would check the crank position sensor. There really is not test for it but you can inspect it for cracks or flaking insulation. They tend to fail intermittently - usually when the engine is hot.
If the engine is totally cutting out on the highway, I would check the crank position sensor. There really is not test for it but you can inspect it for cracks or flaking insulation. They tend to fail intermittently - usually when the engine is hot.
So, not the relay, possibly the solder joints. I changed the CPS and it seems like it may be a little better. Really only happens at speed on the highway. Around town it runs great. Still will run perfect, then stutter for an instant at freeway speeds, then continue as if nothing happened. Sometimes worse than others.
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This site should tell you how to retrieve codes:
https://www.brickboard.com/FAQ/700-9...agnosticCodesi
https://www.brickboard.com/FAQ/700-9...agnosticCodesi
Still dealing with this. What is the diagnostic connector and wire? I have an OBD fault reader but that doesn't apply to my 940. The car runs great and does it primarily when I'm cruising at freeway speeds (70-75) and ease off the throttle. Having the AC on seems to make it worse as well as do hotter days. It doesn't do it at all for the first 5-10 minutes of driving. The car always starts easily(hot or cold), will smoothly accelerate without issue and otherwise runs fine. It does "hiccup" when stopped at a light, again worse with AC on.
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stumbling problems at mild throttle settings, like steady cruise speed are most often ignition related. cap, rotor, wires, spark plugs all should be in good condition, if they are, the problem could be your coil is breaking down, or the power module, or you have some flakey wiring.
I have not replaced the coil though.