Single Status Update
Good morning Mike. I've been searching in the forum about rich cold start. I have a 1993 Cadillac deville 4.9 v8. I've done maintenance. full tune up. Plugs, wires, cap and rotor. New EGR, and new PCV valve. Throttle body cleaned and air intakes (those were bad) checked the timing yesterday (at 24 degrees) don't know why but I'll bring it down. Cold start rough... too much fuel. Runs perfect after warm. Any suggestions about the rich cold start? Any info it would be much appreciated. thank you.
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I am sorry, I just saw your message here today, are you still experiencing problems? Mike
I will send a DM
I am. Narrow it down to a bad fuel check valve. On the run position pressure goes to 40 psi. Quick drops to 20 to 25 and slowly works its way down to 10 to 15 psi (2min about) fuel pressure regulator no leaks. Checked vacuum and its good. At times runs fine, but looses pressure under load. On idle as well. Vehicle wants to compensate by accelaring on it's own, and starts causing misfires. lean code. Where is the check valve? At the pump or sending unit? So I know what part to get. If you can let me know please much appreciated. thank you.
Check valve?, you mean fuel pressure regulator from your description above. Yes, those fuel pressures sound problematic, the regulator's diaphragm is no doubt leaking.
Did you get this fixed? The regulator is attached to the fuel rail. I can post photos if you need. Sorry again for my delayed reply, I have been away from the board with much more pressing issues. Mike