460 efi ford motor starting problem

[jimsretirementf]

Hi all, I have a 1989 Itasca Class C motorhome with a 460 EFI motor. The problem I am having is, when the motor is cold it will start without turning over more than two to three times. When warmed up it will turn over for a long time before starting. I have replaced the fuel pump and all filters, replaced the air filter with a K&N air filter, replaced the plugs, wires, rotor and cap. Also had the throttle bod cleaned. Could this be a fuel injector problem?
Thanks for your help.
Jim

[Yankee_Clipper]

When my exhaust manifold warped and spit out the bolt cap, this same thing happened until I replaced the manifold. Might look at the manifold bolts on both sides, but especially the passenger side. HTH.

[RLS7201]

Watch the tail pipe when starting warm. See if it blows black smoke. If so, you may be experiencing a flooding condition. Most likely culprit is the fuel pressure regulator diaphragm. Easy enough to check. Look for fuel in the vacuum hose that attaches to the regulator. Regulator is on the left fuel rail, close to the front. Vapor lock is not an issue with high pressure EFI systems. If you had a bad injector, it would only effect one cylinder and the other 7 would start quickly.
Port for checking fuel pressure is on the right fuel rail.

Richard

[jimsretirementf]

Thank you for the information, looks like I have a lot to check. I know I can get a good fuel regulator from Summit Racing so I can check the pressure. I did pull the gas tank and put a new fuel pump and all gaskets in because it was leaking when it was filled up, no more oder of gas when filled up. I am not sure if the motor is starving after warmed up because I can smell a slight oder of gas after it starts, but the smell goes away right away.
Thank you for all the info.

[JaxDad]

jimsretirementfun wrote:
When warmed up it will turn over for a long time before starting.

When it's warmed up, and parked somewhere quiet, turn the ignition to the run position but don't start it. Then listen to what the fuel pump is doing. You should hear it run for a few seconds then stop. If it continues to run, or cycles on and off you're losing fuel pressure.

A cold engine will get enough fuel to start on the prime circuit even with low pressure, a warm engine is starved for fuel though.

[John_Joey]

jimsretirementfun wrote:
... Could this be a fuel injector problem?
Thanks for your help.
Jim

When I had my 460 MH I never had the problem you're describing, but the injectors did gum up fairly fast.

First trip south with the new rig the engine didn't give me all it had until Mobile, AL. All of a sudden she opened up. After sitting for a couple of months I would notice a lack of power once I got on the road. A few tanks of high detergent gas would solve that problem.

Your problem could be vapor lock. Depending on the coach maker and how well they channeled air to the engine could determine how often you would get that issue on a Class A. That 460 puts out a lot of heat.

[RLS7201]

cmeade wrote:
Have you considered adjusting the fuel pressure regulator? It is near throttle body and brass colored. Cap pops off with small slidehammer and has allen head adjuster. I think auto parts stores still sell pressure gauges that connect to shrader port. Factory setting of 30 psi but had great luck at 36-40 psi back in the day.

Factory fuel pressure regulator on a 460 EFI is not adjustable and is not brass colored. It is factory set at aprox 38-40# with vacuum hose removed.

Richard

[cmeade]

Have you considered adjusting the fuel pressure regulator? It is near throttle body and brass colored. Cap pops off with small slidehammer and has allen head adjuster. I think auto parts stores still sell pressure gauges that connect to shrader port. Factory setting of 30 psi but had great luck at 36-40 psi back in the day.

[midnightsadie]

change the coil ,when cold it doesn,t short out, hot it expanse and shorts, and throw that k,n filter in the trash .

[jimsretirementf]

Thanks for the info, I'll check the relay.

[Home_Skillet]

Those models were bad about the fuel pump relay getting water in it.
I would unplug the relay and look for rust in the relay.
The relay is located between the battery and the fender. Should be green.