'93 Saturn SOHC SL-1 TBI (single injector) 5-sp MT 207k miles
When the coolant level on the dash rises above the mid point – engine is hot - and when the car is turned off, and then sits for 22-25 mins, it won't re-start hot. Starts cold every time - though first time cold perhaps with a slight delay followed by a 'let's get this thing going kick.' Runs great (once started)! Starts hot if re-started within 2-5 min.S Starter turns fine (and is new). Solid spark on both coil packs and all 4 wires (all new, including ign mod ground bolts). Fuel pressure is SOLID, UNWAVERING 29.5 PSI at idle (spec is 26-31) - and, again, car runs great! Fuel pressure goes to 28 or 27 as soon as car is turned off. Fuel pressure decays 6 PSI down to 22 or 21 within 5-6 min.S after car is turned off and down to 16 PSI within 15 min.S and down to 14 PSI within 21 min.S BUT, successfully, when putting key into RUN position, the pressure immediately goes back fine to 30 (29.5) for the 3 seconds the Fuel pump runs in RUN. Gas cap new. When hot no-starting, no fuel coming out of the injector. CPS, CTS, IAT, and TPS test fine - cold and hot. Ign switch tests fine (cold) and is new. Fuel pump fuse and fuel pump relay test good - and fuel pump runs each time key put into Run and Start - which also validates ign switch is sending Run and Start signals to ECU and ECU is processing them. No check engine light. No codes - this is the old ALDL connector at the driver's left knee. Check engine light does illuminate during start - which also validates ign switch Start position is getting to the ECU. Ign Mod input V and Bypass mode V (back to ECU) test fine - and ign mod appears to be in Bypass Mode (0 Vs) at start - both cold start and hot start. Ign mod appears to transition to Ign Control Mode (4.81 Vs) once car starts - both cold and hot.
Also, perhaps related, battery V never stays in the 12.6 range once car sits overnight. Solid 14.5x to 14.6x after starting (alternator) and solid 14.10 after trips and charging periods. But, after turned off and sits for several hours and then overnight, battery V falls through 12.7x range, falls through 12.6x range and into 12.5x range and sometimes 12.4x range. Battery, starter, alternator, and alternator-to-starter fusible link cable all new. Checked all fuses electrically for current draw. Found modest draw through chime fuse and radio, but when I disconnected them overnight, the V drop still occurred at the battery. Checked all relays electrically - none stuck on - and none warm to the touch when car off. BUT, I did see a modest 0.06 V on the primary side of the fuel pump relay - on the coil side. When I checked this V through the multi-meter to a ground, the modest V went to 0.00. Fuel pump gives no evidence of running when car is turned off.
Questions - could you please answer each one:
What is 'causing' the hot no-start?
What part(s) need to be replaced - for the hot no-start?
'Why' does car start cold every morning?
What is 'happening' during the 22-25 min.S when the car is turned off hot?
What is happening overnight - that enables the car to start cold the next morning?
Why is the fuel pressure solid at the schrader port right there at the throttle body - just inches from the fuel injector - when back in Run position, but the car then not start?
If it's the fuel pressure regulator leaking, then why does car run great once started? How this can this be? Can you explain this?
How can the injector not be getting or outputting the fuel - it IS clicking -when hot no-start - since the fuel pressure when back in Run position goes right back to 29.5 (spec)?
Could the Fuel filter be the problem by itself - it is 5 years old - but noly 20k miles? If so, can you explain this?
Why is the battery V drop occurring through the 12.6 range into the 12.5 range?
Is the battery V drop related to the hot no-start problem?
Is the modest 0.06 V on the fuel pump relay primary (coil) side a concern - or is this too neglible to affect anything?
have the same problem?
Saturday, October 12th, 2013 AT 7:41 PM