I have a question concerning an "apparent" ip problem ('94 F250, 7.3L non-turbo) and would sure appreciate an expert opinion on this. Here is the story:

105K, excellent cold start, hard hot start. Dealer said IP pump was suspect and it was replaced. Their diagnosis is consistent with opinions that I found here. Starting improved but was never the same as it was originally.

120k (13 months later) same problem; hot start was slowly getting worse over last few months. Cold start is excellent, hot start immediately after shut off is excellent, after 15 minutes of sitting, very hard start. Dealer warranty ended at 12 mo.

Absolutely no water in fuel system; maintenance by far exceeds OEM recommendations. Glow plugs, batteries, starter all 100%. This truck is babied.

I am not convinced that the ip is at fault; it sounds to me like a vapour lock since it goes away when the engine cools down. I do not like the idea of spending another $1800 to shotgun the problem or to have it only work for a year; if it is the ip why is Stanadyne so unreliable?

Please share your experience or opinions on the following questions:
1. Any other possible cause other than the IP?
2. Is there a source of parts to service the IP? (I am aware of what is involved and I am prepared to handle this)
3. Can you recommend a good rebuilder who can tell me exactly what is wrong with it (rather than just exchange it)?

My first post here but I read a lot.

Thank for any advice,
Mike.

 

You have not mentioned whether you use a good Diesel Lubrication Additive but seeing how dilligent you are about everything else you are probably right on top of that.

Make sure you do a pressure check on the fuel lift pump next time the truck is hot and won't start. Check for fuel pressure at the schraeder valve as you start cranking.

Are you blowing any kind of smoke (white or black) while hot cranking? If not, check and make sure you have 12V power to the fuel shut-off valve on the IP (front electrical connector on the drivers side of the IP) If you don't get smoke during cranking the IP is not sending fuel to the injectors.

Have you tried pouring cold water over the IP prior to a hot start to see if the truck will start? If so this is a standard way of confirming that your IP is no good anymore.

Personally I am not in favour of rebuilt IP's due to all the variability you could run into in regards to the rebuilt job you are going to get. I guess what I am saying is do you feel lucky? New pumps are very affordable if you really consider what you get. (And yes there is still a small chance of getting a faulty one)

Air intrusion is not likely to be the cause of the hot starting issues seeing that you don't have cold starting problems. Your hot starting problems are most likely IP related.

Lastly, a longshot you could try (assuming you get smoke during hot cranking) is to permanently disconnect the cold idle advance solenoid wire (the one next to the fuel shutoff wire on the driver side of the IP). I did this on my aging 93' factory IP with 212k on it and it has both improved the cold and hot starting.

Best of luck,

Seb....

 

which wire is which?
which wire is the fuel shut-off valve on the IP?
which wire is the cold idle advance solenoid wire?
im just trying to figure out which are which on mine yellow and red.

 

The wire terminal closer to the radiator is the fuel shut-off, the wire terminal closer toward the firewall is the cold idle advance.

The fuel shut-off should always have 12V on it if the ignition is ON.

The Cold Idle advance solenoid should only have 12V on it while the engine is warming up and should shut off once the engine reaches 135 deg. F. It uses a signal from the temperature switch that is located on the drivers side cylinder head (front).

The above is a longshot, most of what you described point to more serious IP problems.

Seb....

 

Actually, pour ROOM TEMPERATURE water on it. Cold water is too much, you can kill an IP doing that, and if that's not your problem then it will be after trying that. Pouring water on it at all is considered to be the last attempt at diagnosing a bad IP.
Wow $1800 for an installed IP. You can get a rebuilt pump from a variety of reputable sources for between $300-$450, and if you can't install it yourself, surely you can find a fuel injection shop or even a local diesel mechanic to install it.

 

If your having hot starting problems, I would look into air getting into your system, ie fuel filter, or the injection system it self...next time if it doesn't start when it's hot, push in the shrader valve above the fuel filter, if air hisses out, you have air in your system. lol

 

i have a 94 f-350, i have had for two weeks, but had the same problem,so i am no expert but i found that by appling 12vdc to the cold sol. the one aft(toward the fire wall)and my problem with hot starting stopped i now have a toggle switch on the dash to apply power during starting i know thats sounds about oppisite of what you have heard on here but it works 100% time for me i dont even try cranking after it has ran with out the switch on just shut it off after it starts or you will run about 950 rpm at idle.simple test tho, when it wont start after running put a jumper on the cold sol from the positve side of battery and see if it starts.hope it helps.

 

I have thought about a toggle on the cold advance solenoid on my 93 but decided against it as the solenoid itself is not designed for continues duty and probably will burn out in time if used continuously.

All I can say is that my cold and hot starting on my 93 has improved ever since I disconnected the cold advance solenoid.

What can I say, do whatever works for your truck.


Seb....

 

i agree the thing isnt set up for long trem duty, but mine is only turned on for a minute or less. i flick it on start, flick it off ...now if i forget at some point i may kill it but that would be me being stupid lol