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fuel pump engine rotate sensor

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Hi, my Legacy won't start, has spark, turns over, sounds like it's gonna start (for a second or two) then just cranks like out of fuel or spark, but as I said I have spark although plugs have not been checked. I disconnected the fuel line and turned the key on, I get about a second or two of fuel flow then it stops, I know the ECU and fuel pump at some point needs verification the engine is spinning from a rotation sensor (located at the driver side intake cam?). Any help appreciated....thanks

some legacies and outbacks have a problem with a cap and swollen o-ring on the fuel pump.

 

um, what year and model car do you have? what is its history, mileage and general condition?

Year?

The ECU controls ground for the fuel pump relay and primes the system for about two seconds when the key is turned to ON. Once the prime is done the fuel pump turns off.

You may still have low fuel pressure though.

Or you could be flooding because the ECU thinks the engine is too cold. Or it could be too lean because the ECU thinks the engine is hot.

 

Have you tried starting fluid? Don't need much just a quick shot or two should do it of you do indeed have spark.

  • Author

yes, check engine lite disclosed fault with crank position sensor, I swapped it cause I had another, no better, same deal, my question is now this, can the engine "jump" timing by a tooth or two on the belt, I know being a 2.5 dohc it's an interference engine and will lock up if timing jumps enough, could this have jumped just enough to inhibit starting? I will add there is a faint to distinct "popping or backfire" in the intake at times when it turns over, as I said fuel and spark are present, still don't know if fuel pressure is up to spec, starting fluid couldn't make it run either.

yes, check engine lite disclosed fault with crank position sensor, I swapped it cause I had another, no better, same deal, my question is now this, can the engine "jump" timing by a tooth or two on the belt, I know being a 2.5 dohc it's an interference engine and will lock up if timing jumps enough, could this have jumped just enough to inhibit starting? I will add there is a faint to distinct "popping or backfire" in the intake at times when it turns over, as I said fuel and spark are present, still don't know if fuel pressure is up to spec, starting fluid couldn't make it run either.

It sounds like you still have the CPS failure code?

 

yes, you need to confirm timing. If the CPS disagrees with the cam position sensor, the ECU won't start the car.

If timing jumped 1-2 teeth the engine will not lock up. More than that and it would just bend the valves and keep cranking.

Definitely need to check timing at this point.

  • Author

turning it over with the coil pack voltage unplugged to stop plugs from firing (to get a sense of the turn over rhythm) the engine has a definite "skip" and is not uniform but erratic, probably salvage parts off it for my 98 Forester and get $100 for scrap at this point, besides the engine the rust has done quite a number

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