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Discussion Starter · #1 ·
'99 9-3se 5 gear won't start. never has an issue up untill this point. cold when it first happened, hasn't started since.

first of all, yes i have searched a bunch regarding fuel pump and cps issues. my question is this:

will a bad CPS cause the fuel pump to not prime? i have seen many people say both yes and no. i wouldn't seem to think so. i have no power at the pump at any time. not when first keyed up, not when cranking. no power at the fuse. ECU is not grounding the fuel pump relay to turn the pump on.

when i crank it the tach DOES jump initially, but i do not get a consistant rpm reading. im not sure what is normal for the tach to display when cranking on these cars.
 

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Discussion Starter · #2 ·
nobody? is the pump supposed to prime every key cycle? since there is no FRP sensor i would think so?
 

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As posted a few hundred times before, spray some starting fluid into the throttle body and crank it over. If it starts for a few seconds. you have a fuel problem. If it doesn't start, you have a spark problem.

The best test for a failing fuel pump is to have someone crank the engine while you hit the bottom of the plastic fuel tank with a soft mallet. This may cause the pump to start, but won't guarantee that it will run too long... Ron
 

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Discussion Starter · #4 ·
...

ok look. im not trying to be rude but im way past that point.

i am, by trade, a technician. i work on ford products, not saabs. however, there are certain basic principals that apply to anything with an internal combustion engine. these i am very familiar with.

there is no fuel. i took the line off. none. there is no power to the fuel pump. there is no ECU supplied ground to the relay. not just when cranking, like a bad CPS, but not when first keyed up either. CPS resistance checks out fine, however i also know that does not neccisarily mean it is NOT bad.

i don't know if a bad CPS will cause the pump to not prime. THAT is what i am asking.

i dont know if a cps code will cause the ecu to not prime the pump. i dont know if repeated attempts to get the pump to prime by cycling the key will cause the ecu to NOT ground the FP relay. thats what i dont know.
 

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When you checked the voltage did you check between a good known ground and the +ve feed to the pump or just across the two terminals at the pump connector. Also have you tried running +12V and ground directly to the pump.
 

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Discussion Starter · #6 ·
checked the ground separately. it is good. pump runs when i jump it at the harness connector. it is not a pump problem.
 

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Have you check continuity from the fuse to the pump connector, fuse to relay and relay to ECU. The pump wont always prime every time in my experience. Have you tried just replacing the CPS, it's cheap enough and considered a wear item anyway. Unless you know it was replaced within the last 50K miles I would view it as a suspect.
 

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Discussion Starter · #9 ·
checked continuity everywhere except ECU to pump relay. hadn't gotten there yet. working crazy hours and haven't had time to dig into it more. at work now actually, no internet at home.

just ordered a CPS, will try that and see what happens. don't usually break out the parts cannon, but driving an f250 an hour to work is getting old.

Did the engine start when you jumped the pump? If not, you have another problem: no spark... Ron
thank you, i never would have guessed. which would imply a common problem such as a CPS, which is the entire basis of my original question.
 

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To the best of my knowledge, the pump will prime during the start process, it must...; here, for a second, the CPS plays no role...
Also, one check on the CPS is to assure that the vehicle cannot start and then watch the tach , if the CPS is OK, it should register the starting (spin over) RPM - 200 or so....I think.
 

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Discussion Starter · #12 ·
To the best of my knowledge, the pump will prime during the start process, it must...; here, for a second, the CPS plays no role...
Also, one check on the CPS is to assure that the vehicle cannot start and then watch the tach , if the CPS is OK, it should register the starting (spin over) RPM - 200 or so....I think.
thats what i would assume. but not all vehicles prime, not all prime all the time. i just didnt want to chase a problem that doesn't exist by thinking it should have power for a second every time the key is turned.

tach does not register a consistant cranking rpm. it jumps, then returns to zero. i am replacing the CPS anyways. see what happens.
 

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Before throwing a CPS at it, you might take five minutes and do a resistance test on it. IIRC, it should read 580 ohms +/- 50 ohms for a turbo engine. The test procedure is in the WIS which I don't have loaded on this laptop... Ron
 
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