Hi Guy's, I ope I have posted this in the right forum. I am having a hard time figuring out why my 454 is hard to start all of a suddon. It use to fire within a couple of cranks. Once warm it seems to start fine. Yesterday, I went to start it and after several cranks, it startrd but back fired three of four times. It has always been rather cold blooded. You probably want to know more, so you can help me diagnose it. It's a 454, Edlebrock performer RPM heads, Performer RPM intake, Holley 950HP, Isky Solid Roller Cam
rr-620, MSG-6AL. As I stated, since I don't have a choke on the HP950, it has always been cold blooded, but why all of a suddon does it back fire upon starting, then settle down once it reaches 150F. Power seems fine. I used a squirt bottle of water and sprayed it on each header tube, as I was wondering if I might have a dead cylinder. All tubes were hot. I have checked my timing, and have set it at 10'initial. This is where is seems to be happy when I shut it off so it doesn't keep running if you know what I mean.
Any more advance and it diesels when I shut it off. My next steps are to run a compression check on all cylinders, check and adjust valve lash if need be, but I am at a loss as to what is going on. Sorry to be long winded, but I wanted to try and give you as much info as I can.

Your thoughts are greatly appreciated as always.

Thanks, Garry

Garry,

What's the ambient temperature when you are trying to start your car?

I'm running a similar setup as yours and when it gets cold outside (30's or lower) and has been sitting for a while (4 or 5 days) it is a BEAR to start. I love the HP950, but it is very cold natured (even to start) let alone to keep running.

During the winter months I try and start it once every week but I usually have to up the idle on the carb and squirt a little starting fluid to get it to start and run until warm.
:mad:
I've run other Holley's in the past and have not had this much of a problem before. :confused:

Originally posted by 71454Chevelle:
Garry,

What's the ambient temperature when you are trying to start your car?

I'm running a similar setup as yours and when it gets cold outside (30's or lower) and has been sitting for a while (4 or 5 days) it is a BEAR to start. I love the HP950, but it is very cold natured (even to start) let alone to keep running.

During the winter months I try and start it once every week but I usually have to up the idle on the carb and squirt a little starting fluid to get it to start and run until warm.
:mad:
I've run other Holley's in the past and have not had this much of a problem before. :confused: Darren,
It was about 60' here on Friday. I know what you mean about the 950HP, I have never been able to leave the throttle alone until it reaches 150' F
then it will idle. It has always initally fired right up though :confused: And the back fire on initail start has me confused at the moment too.
Thanks

Other thoughts folks ?

Gaz