chevy gear heads

[booty51]

I have a 1996 p -30 chases with a 454 J code engine. It will start up and run fine (engine cold). After the engine warms up engine will crank but makes no attempt to fire. I drove rv from storage to the house (about 20 miles) backed into the drive. Tried to start rv later and it just turned over never firing. I let it sit over night and it started right up. I turned the engine off and restarted a couple of times sitting in the drive Idling again engine cold. I warmed up engine. I was showing engine temp. and shut engine off. Tried to restart and all it does is crank,never attempting to fire. Is it a coil issue? Also Is this coil external ?

[Kayteg1]

Good to hear it is working again.
For future -You can easy troubleshoot fuel from ignition problem by using some starting fluid.
Hot engine not restarting is also symptom of leaking injector.

[booty51]

Replaced relay solved intermittent starting problem. Starts every time now.

[lonfu]

Follow this order:

check for spark at the spark plug, look at your dist cap and rotor. make sure the cap is tight, but don't break the plastic distributor base if it has one. If no spark then look at ign module, cam sensor, coil in that order.

If spark then it is fuel. Check your fuel pressure, check your fuel filter, take it off see if there is anything in it. If it is clear, then reinstall and listen for fuel pump sound when assistant turns on key. No sound then fuel pump. test fuel pump in tank with 12v.

[booty51]

Ok had faith enough to take mo ho out for a few days. No more intermittent starting problems. Relay solved issue thanks for the help.

[jalabuff1]

Check the ground to the fuel pump, if necessary run a temporary wire to the fuel pump to make sure it is grounded.

[booty51]

Continued to have problems. same thing turns over will not start. then on another day Turns over and starts. Then try it later will not start. I have replaced Ignition module, cap and rotor. It was in need of a new cap and rotor. So the problem is intermittent . Talked with a guy who is a chevy gearhead thru and thru and also an electrician . He suggests that the Relay is bad. Finally found the relays on a forward chevy chassis they are not in a box under the hood like most vehicles. Changed out Relay and away we go. It starts. I cycle the ignition multiple times and started every time. Will try it again later to see if problem is resolved. Thanks for all the help.

[booty51]

I forgot to adding my last post that I did replace the cap and rotor starts and runs fine.. Also may replace ignition module not ecm if I continue to have problems. I will bang on the tank first!
Thanks for the help!

[fourmat]

booty51 wrote:
The saga continues, Had wife turn on ignition while I was under RV near gas tank, The fuel pump ran and primed the line on it own. I didn't have to hit tank on the bottom to help it out. The engine has started every time I have tried it today and ran smooth. Yesterday all it did was turn over and not fire. I did take the distributor cap off yesterday and looked at it and put it back on. It looked well used inside and corroded , tip of the rotor looked burned, which I think is normal for the miles on rv (83000) . I am sure that it is original . I think I am the second owner . If I still have problems I will replace the ecm . It looks like Casper has left the rv for now. will keep all posted. Thanks for the advice and help

Replace cap and rotor now

[booty51]

The saga continues, Had wife turn on ignition while I was under RV near gas tank, The fuel pump ran and primed the line on it own. I didn't have to hit tank on the bottom to help it out. The engine has started every time I have tried it today and ran smooth. Yesterday all it did was turn over and not fire. I did take the distributor cap off yesterday and looked at it and put it back on. It looked well used inside and corroded , tip of the rotor looked burned, which I think is normal for the miles on rv (83000) . I am sure that it is original . I think I am the second owner . If I still have problems I will replace the ecm . It looks like Casper has left the rv for now. will keep all posted. Thanks for the advice and help

[Jayco23FB]

booty51 wrote:
Checked for spark , spark coming off coil wire, then checked spark plug wire, pulled spark plug wire off at distributor spark came out of distributor cap to spark plug wire. So appears to be getting spark. Next, I took off fuel filter under vehicle, turned over engine didn't appear to be pumping fuel out of open line. Fun filter was changed last season didn't appear to be clogged up and I could blow thru it freely, reinstalled filter.When engine start it runs good, you just do not know if it is going to start or not. Today I started it up ,it fired right off and ran. after about a minute I turned engine off tried to restart and all it did was turn over, have tried it several times today it will l not start. By the way Coil is external.

Sounds like a bad fuel pump. When we had trucks come in on the wrecker we would go out with a rubber mallet and thump the tank a good one on the bottom of the tank at the center position. 9 times out 10 they would start and we could drive them in and replace the pump. I forget what the minimum pressure is, around 45 psi if I remember correctly. If it was under by just a pound or two it will not start. Another thing to check is the tank baffle. There is a plastic tank baffle that the pump sits in, inside the fuel tank. It is held in place by two little metal push on keepers. If these keepers fail the baffle can move freely inside the tank and either knock the pump off the sending unit or bump it enough to create an internal pressure leak causing low fuel pressure.

[Jayco23FB]

eHoefler wrote:
A bad ignition module can have spark and have a weak to no signal to send to the ecm to indicate it is cranking, thus not turning on the fuel pump.

The ECM turns on and primes the fuel pump for about 4 seconds then shuts off until the ignition is cycled again. It then relies on the oil pressure sending unit to complete the electrical circuit to keep the fuel pump running. Once the engine is running and has oil pressure. This is so the fuel pump shuts off with the engine in case of an accident so fuel does not continue to flow. It also shuts the engine down when you have n oil pressure (usually too late).

[allbrandauto]

go under rv have somebody turn on ign. can you here fuel pump running if not take a rubber mallet and pound on bottom of tank while somebody is cranking over rv if it starts its the fuel pump the brushes in the pump wear out and don't make contact with armature by banging it seats the brushes when ever a car gets toed in my shop and I don't here fuel pump that's the first thing I do

[booty51]

Checked for spark , spark coming off coil wire, then checked spark plug wire, pulled spark plug wire off at distributor spark came out of distributor cap to spark plug wire. So appears to be getting spark. Next, I took off fuel filter under vehicle, turned over engine didn't appear to be pumping fuel out of open line. Fuel filter was changed last season didn't appear to be clogged up and I could blow thru it freely, reinstalled filter.When engine start it runs good, you just do not know if it is going to start or not. Today I started it up ,it fired right off and ran. after about a minute I turned engine off tried to restart and all it did was turn over, have tried it several times today it will l not start. By the way Coil is external.

[FunTwoDrv]

"Ignition module in the distributor." If you don't have any spark, and the pump doesn't run...

GL
Gary