[s-cars] By-passing the CPS

[Vincent Frégeac]

I’ve read somewhere that the role of the CPS is to tell the ECU the starter
is actually cranking the engine so it’s OK to activate the fuel pump
(something you don’t really need a buried in 8h of work sensor to realize).
Then, the engine speed sensor takes the relay and tells the ECU to keep the
fuel pump running. This brought two questions to my mind:

-          Would a check light on the fuel pump wires be a good way to tell
if the CPS is the problem, at least for the warm-start problem I’m having?
If the fuel pump does not receive the expected ~12V when the starter crank
the hot, not starting engine, but does when the engine is cold, it’s a CPS
problem. If it’s receiving 12V when the engine is hot, look elsewhere.

-          Would a wire from the starter solenoid wire to the fuel pump,
with a diode on the existing fuel pump positive wire to avoid frying the
ECU, be a good way to get rid of the CPS problem until I have time to go
through the timing belt and CPS, which is not exactly the case right now,
except if I start considering sleeping time as optional?

I can’t see any logical reason this wouldn’t work but before I fry the ECU
with my somewhat tired logic, I though pinging the list wisdom would be
safer.

 

-          Optional question: Why in the hell did they use two engine speed
sensors, which means two reason to fail on us, when one would do the job? I
mean, when the ECU would realize that the crankshaft is turning but not the
camshaft because of a broken timing belt, it’s way too late to save the
valves and pistons anyway, and the engine would have probably stopped by
himself by loss of any compression, or intake or exhaust or whatever.

 

TIA for your help on bringing reality check to my poor beaten up logic.

 

 

 

Vincent

’96 S-Bitch keeping me busy and frustrated

’81 Fiat Spider 2000 I would’nt qualify in fear my post would be rated 18+


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