kmorvant

I've been having this problem for a while. When the engine is hot (4.2 V6) it takes seven or eight seconds to start. If I hold the throttle half-way to the floor it will start in about half that time. It always throws a puff of black smoke from the tailpipe when it starts. Fuel pressure is good and it holds when stopped. The pump whines when the key is on. I have checked all the sensors except for the Mass airflow and O2. The plugs are new. I'm thinking a leaking injector, but would that cause it not to start for several seconds? I'm at a loss as to where or how to check for other problems.

bigkenni

i would just say to junk the motor and put in a 4.0L V6 from a ranger or something bc those 4.2's are junk...ive had nothin but problems from the ones in my shop

lucky13

sounds like theres carbon build up somewhere but thats about all the help i can offer

Good old Bill

Black smokes indicates to much fuel or not enough spark. How long does the fuel pressure hold when engine is off? Is spark present when first cranking or is it delayed and if so, how much of a delay? Get back to us. One other opinion, I must have the only 4.2 in the world thats any good. 167K, one DPFE sensor, and cold mornings PO171 & PO174. (intake gaskets).

kmorvant

The fuel pressure holds for the amount of time the manual says it should hold. I did a while back so I forget the exact amount of time. However, when it sits for at least 10 hours (overnight) it cranks right up with no problem. How would I check for the spark and if it does not spark right away what could be the cause?

Good old Bill

With the advent of fuel injection an enginered delay (2-3 seconds) was introduced for oil pressure purposes. Or so I was told. We have some very sharp people here, I'm sure they will correct me and maybe help you with this excessive delay in start up time. Good luck!

kickinit

leaky injector or possibly motor is getting old and low compression.