1995 Chevy 454 intermitant hard to start

[BluegrassBill]

I have owned my 1995 Itasca 29 since 2002. It has 73,000 miles on it now. The engine has always been easy to start. Now It randomly is hard to start. Cranks strong but nothing, After cranking and cranking it will fire up and die unless you can catch it by pumping the throttle rapidly. Once running after a few seconds it runs normally. Goes down the road with plenty of power. I changed out the Engine Coolant Sensor, No change. I then checked the MAP sensor with a vacuum gauge and volt meter, It is within specs. The sparks plugs are new as are all wires ,coil and Distributor cap with MSD parts. The TBI is spraying fuel onto the throttle plates as it is cranking. Friends I am stumped. Any ideas. Many Thanks, Bill

[enblethen]

Thanks for the update!

[BluegrassBill]

Finally problem found and fixed. Pos Battery cable bolt at a connection, Bolt was cross Threaded at chevy or Winnebago 20 years ago creating a sometimes loose sometimes OK connection. Amazing it went so long with no problems until this past year.
I want to thank everyone for their responses, There is truly a wealth of information on this forum and people like you willing to share.

[Bill_Diana]

I had a similar problem with my Georgie Boy 1996 454 TBI. Click here to read that thread.

[Bill_Diana]

Click on this link for some info about fuel pump relay.

Be sure to scroll down the page for a rather good sketch.

Hope this helps.

[BluegrassBill]

Thanks all, The search goes on.

[Born_To_Travel]

A fusible link is like an inline fuse built into the wire.. If you follow the main power leads from the battery to the firewall you may see something on the wire that is round and about an inch long and about the diameter of a pencil.. Take your test light and pierce the wire before and aft and see if power is going through.. If not new ones can be bought at the auto parts store...

[fischer]

if you had chattering it means you have a bad connection for your starting battery. remember you must have battery and ground for the starter to work , check both.

[BluegrassBill]

I wouldn't know a fusible link if it jumped up and bit me, Sorry, electrical is one of my many weak points. Seems strange that every thing works when using the MOM switch. Chassis battery seems to be out of the loop. Could be a fusible link to that circuit. Thanks.

[Born_To_Travel]

Did you check the fusible links to see if power was getting thru them?...

[BluegrassBill]

The relay I found was the heater blower. So continuing search under dog house I found another relay but it turned out to be the A/C relay. I checked out under the steering column, didn't find anything. Went back to the oil pressure switch and unplugged and cleaned. (forgot it was unplugged) Went try to start, Got chattering but no start, Now it gets weird, Plugged oil switch back in, From that point on key switch is dead. Now the only way to start is to use the MOM switch ! When running everything works normally. Turn the key switch off engine dies and nothing works again no head lights dash lights turn signals or Kwicki step. Hit MOM switch (don't have to hold ) everything live except key switch have to hold MOM then key switch works. I am up a tree, Checked every fuse I could find and all good. With engine started Chassis Battery 13.3 V Coach Battery charging at 14.4 V. Chassis Battery is brand new Les Schwab 84 mo. does not appear to be getting charge from alternator.
Regarding oil pressure switch, The engines starts shows oil pressure at gauge. No leaks around it. Hopefully someone here has some ideas where or what to check. Other wise I'm off to a mechanic tomorrow.

[cross_country]

jwoods61us x2

[BluegrassBill]

I think what I found was the relay to the heater blower, Rats. I going out now and do a test on the relay by jumping pin 87 to 30, That will run the fuel pump or the heater motor. Will report on findings, Thanks

PS Yesterday I did a test start. The engine fired right up, Go figure.

[enblethen]

The orange wire provides power to the fuel pump and the fuel pump relay. The burnt wire could be the problem or part of it.

[BluegrassBill]

I finally found a relay under the front hood passenger side on fire wall. 2 orange, 1 Blue, 1 black and 1 white wire, prongs were slightly corroded. I also went under the coach and disconnected the Oil Pressure sending plug. The orange wire in the connector looked Like it had been burnt. Cleaned and reassembled. Engine started right up. I'll wait a few days and try it again. These parts are 20 yrs old , Hate to change functioning parts though. Thanks for all the Ideas, Only time will tell on this starting problem. Bill