1995 5.8l efi omc ford, takes a long time to start when hot.

[chico0509]

I have a 95 5.8l EFI ford omc engine that when the engine is warm it will not start right away. When it is cold it turns over about a half a turn and fires right up. When the engine is warm it will turn over for 5 or so seconds. I have changed several things and I am not sure what to try next.

The things I have change are, the coolant temp sensor, intake temp sensor, throttle pos. sensor, ignition control moduel, spark plugs, solenoid, cap and rotor. The fuel pressure is at 36 to 40 psi, when it is not starting.

Also the tack jumps around when crusing. It will read 4000 rpms and then the next time I look at it, it says 3500. Then it goes back to 4000. That does not happen all the time.

There has been a couple of times where it seems like the engine is cutting out, like the key is turned off for a split second.

I have seen other posts with the same and similar problems but I can not find anyone that actually got it fixed. I also have taken it to two marina's and they are not sure what is going on. Please help!!

 

[purcell87]

Re: 1995 5.8l efi omc ford, takes a long time to start when hot.

check to see if the choke is stuck.

 

[Gettinther]

Re: 1995 5.8l efi omc ford, takes a long time to start when hot.

check to see if the choke is stuck.

"1995 5.8l efi" , does this have a choke

What about an IAC thats plugged or partially plugged

 

[chico0509]

Re: 1995 5.8l efi omc ford, takes a long time to start when hot.

"1995 5.8l efi" , does this have a choke

What about an IAC thats plugged or partially plugged

No choke that I know of, It is a Multi port fuel injection. what is the IAC?

 

[chico0509]

Re: 1995 5.8l efi omc ford, takes a long time to start when hot.

No choke that i know of. It is a multi port fuel injection

 

[stackz]

Re: 1995 5.8l efi omc ford, takes a long time to start when hot.

IAC is the idle air control valve. it will be located on the throttle body or immediate area usually opposite to the tps sensor and is held on by two bolts and has about a 2.5" cylinder jutting from it. they tend to clog with carbon and can cause starting issues.

it doesnt perform any function though while you are underway so the stumbling at speed would be something else.

 

[skippy2235]

Re: 1995 5.8l efi omc ford, takes a long time to start when hot.

If you need to replace the IAC GOTO autozone.
ask for 1993 mercery courgar 5.0 liter HO... Most stores have it in stock... $65

 

[chico0509]

Re: 1995 5.8l efi omc ford, takes a long time to start when hot.

Thanks guys, I will give it a try. Any info will help. I have tried everything that I know of.

 

[skippy2235]

Re: 1995 5.8l efi omc ford, takes a long time to start when hot.

Have you checked the temp of the fuel in the reservoir. I know that lake water goes directly into the fuel reservoir to prevent vapor lock. If you have a water constriction you may be getting vapor lock. Also make sure your low preasure pump is filling the reservoir. The low preasure pump is the week link in the fuel system.

 

[chico0509]

Re: 1995 5.8l efi omc ford, takes a long time to start when hot.

Well I tried a IAC and that did not help at all. I really am getting sick of this boat. I just got it this spring and I think I know why they got rid of it.

 

[chico0509]

Re: 1995 5.8l efi omc ford, takes a long time to start when hot.

My question to you is. If there was vapor lock, or a bad low pressure fuel pump, would I get a good reading on the fuel rail. It was 38 to 40 psi. The pressure is at that when you turn the key on, and it drops a little to 35 when the key is off.

 

[skippy2235]

Re: 1995 5.8l efi omc ford, takes a long time to start when hot.

You can have pressure but what about volume.
There are two pumps.
there is a low pressure and a high pressure.
My low pressure just went out showed good high pressure, but very little fuel was in the rail.


Also vapor lock has nothing to do with pressure. Has to do with water cooling. I have never had this, but my guess would be since you say it only happens when motor is hot. meaning it is heat related, and I know that those rails are metal and collect heat.

 

[chico0509]

Re: 1995 5.8l efi omc ford, takes a long time to start when hot.

I checked the low fuel pressure and there was about 3 to 4 psi after the engine was started. That does not seem good to me. I just ordered a pump and was wondering if after you turn the key on and the pump shuts off should it hold the pressure in the fuel resivour. When mine shuts off it dropps to 0. Is that ok or is there something wrong with the float in the resivour?

 

[skippy2235]

Re: 1995 5.8l efi omc ford, takes a long time to start when hot.

I dont know exacly about the the pressure in the resivour. My guess is that zero when the pump is off, would be normal. on the low side I have never had pressure when I disconnect the lines, but then I never thought about it. As long as there is fuel in the resivour that is the issue.
propper pressure for the Low pressure pump is 7 - 10 PSI.

Where did you order it. I tried NAPA about 2 weeks ago and after 3 days learned there was a nation wide back order from carter.
However Sierra has the $225 part instock.
If you are willing to wait, you can get a pump from autozone for about $120 Airmax.
I have all the part # 's for the low and the High.