M1028 hard starting

[Drock]

Hi all I'm new to this site and have gotten ah lot of info from here. I'm having the same problem I've reading about with these cucv's. With it being hard to start. So far I've replaced the glow plugs, All rubber fuel lines as well as convert to a Stanadyne fm100 filter ,with fuel heater. The problem persists , Hard to start ,white poof of smoke. I just ordered ah new lift pump I'm hoping this may be the final piece. Other then that all I can think of is replacing the injection pump? But it seems to run fine once started sooo??

 

[Recovry4x4]

Sometimes you can't avoid a pump reman. Hot restart troubles are often pump related issues.

 

[Drock]

I assume you mean the injection pump? What's the preferred course of action? (Rebuild) or (Replace) it?

 

[Recovry4x4]

This can be a debated issue. Replacements are rebuilds 99% of the time. Honestly fresh rebuilds are probably best as the parts are fresh. Many online places offer discounted rebuilding services that are very attractive cost wise. Local rebuilders are almost always more but if you have a warranty issue, you are better off. See? Debatable.

 

[Drock]

Well I installed my new lift pump last night. This morning it started better, but still took the second round of cranking to light it off. Also still getting the poof of white smoke. I just can't see how the injection pump could be bad if it runs so well once started? It's dry as ah bone around it ,you would think at this point even a small leak would have revealed it's self by now. I think I'm guna install an electric fuel pump. I've bin reading that the 6.5's had these. So I assume it should be easy to just by one of those and install it? My question on that is can or should I install it WITH the mechanical pump, Or INPLACE of it?

 

[cpf240]

Leaking fuel lines on these trucks don't always leak full... they generally leak air into the lines. Try replacing the short section of return line on the IP with a clear fuel line. This will show if there is air getting into the lines.

The OP states that the GPs have been replaced, but have they been tested? The GP relay can get carbon buildup on its contacts, and may not be passing current to the GPs. A multimeter can verify the GPs are getting power when the relay cycles. The supply and GP terminals on the GP relay could also be jumped for a few seconds to see if the truck starts easier.

One question: When is it hard to start? When cold? When hot? All the time?

 

[Drock]

I drive the truck every day so it's mostly hard to start in the morning ,but also if it's bin sitting for several hours.

 

[Drock]

I just put the clear line on the IP so I'll see tomorrow what I get..

Leaking fuel lines on these trucks don't always leak full... they generally leak air into the lines. Try replacing the short section of return line on the IP with a clear fuel line. This will show if there is air getting into the lines.

The OP states that the GPs have been replaced, but have they been tested? The GP relay can get carbon buildup on its contacts, and may not be passing current to the GPs. A multimeter can verify the GPs are getting power when the relay cycles. The supply and GP terminals on the GP relay could also be jumped for a few seconds to see if the truck starts easier.

One question: When is it hard to start? When cold? When hot? All the time?

 

[cpf240]

I drive the truck every day so it's mostly hard to start in the morning ,but also if it's bin sitting for several hours.

Could be air getting in the lines, or the GPs aren't heating up enough. Test the output of the GP solenoid when it is energized. They have been known to get carbon buildup on the contacts.

 

[Drock]

Is that the one under the hood on the fire wall, or the one under the dash next to the starter relay??

 

[Drock]

Also I just read online that these trucks should be running 12V glow plugs? Mine has 24V because the first plugs I bought (12V) had too large of ah male plug end and would not plug into the female plugs on my harness. Do they make ah 12V glow plug with the smaller male ends?

 

[cpf240]

The glow plugs are supposed to be 12v in these trucks. Yes, they are connected to the 24v portion of the system, in stock form. However, the big resistor on the firewall and the resistance of all the *working* glow plugs drops the voltage the to correct 12v for the glow plugs.

The original glow plugs had a smaller terminal on them, but the most common replacements have a larger terminal. Most people either replace the connector on the glow plug wire, or trim the connector on the glow plug.

If the glow plugs in that truck *are* 24v, then they are the wrong ones, and could well be the cause of the hard start issues.

Take a look at the glow plug theory of operation thread in the stickies section of the CUCV form. It will explain pretty much all that is needed to know, and then some, with regards to the glow plugs and these trucks.

 

[Drock]

Yeah these are the gp's that are in it (link deleted)

 

[cpf240]

Actually, those look like the stock Wellmans that were the OE glow plugs. It says 24v, but they aren't, they are 12v. If that is the case, then they should be fine, well... until they go bad.

Please check the voltage going into and out of the glow plug relay when the Wait light is on. On the firewall, next to the brake master cylinder and 12v buss, usually a silver can with two big terminals and two small terminals. Take a look at the glow plug sticky in the CUCV stickies section for more details, or, better yet, the glow plug troubleshooting section of the TMs.

 

[Drock]

Thanks for the conformation on the GP's. So I checked my clear return line this morning and all it had was ah bubble the size of a pencil eraser. After starting and running the truck for about ten minutes I shut t off and watched the line. All I gat was some micro bubbles coming back up from the return side. NOT from the pump. Is this all it would take to make it "Hard start"? Or is this normal? As for testing the solenoid I don't have ah tester nor would I know how to use it. It's 30 years old I think I'll just replace the solenoid along with the relay. I also just got ah new "Dog head" relay that I'll also Install. So what you think?

Actually, those look like the stock Wellmans that were the OE glow plugs. It says 24v, but they aren't, they are 12v. If that is the case, then they should be fine, well... until they go bad.

Please check the voltage going into and out of the glow plug relay when the Wait light is on. On the firewall, next to the brake master cylinder and 12v buss, usually a silver can with two big terminals and two small terminals. Take a look at the glow plug sticky in the CUCV stickies section for more details, or, better yet, the glow plug troubleshooting section of the TMs.

 

[cpf240]

I doubt that that amount of air is enough to cause your issues. My bet is on the GPs not functioning correctly. Do you have a friend who might have a meter? Maybe know an electrician that has one? Just a simple voltage reading would help.

As a simple thing to try the next time the truck is cold, like sitting overnight, take a heavy gauge wire and jumper the two large posts on the GP solenoid for 8 to 10 seconds or so. The wire may get warm. Then try to start it. If that works, then either the solenoid is bad, or there is something else in the GP system that is not energizing it.

In the CUCV faq there are recommended part numbers for the GP relay/solenoid, should you chose to replace it. It does need to be an isolated ground solenoid.

 

[Drock]

I couldn't find a part number for the solenoid on the facts page, or in the TM's . I'll see what I can find on the interweb.

 

[cpf240]

Post #4 & 5 here: http://www.steelsoldiers.com/showth...ead-for-CUCV-s&p=211671&viewfull=1#post211671

If your parts house wants to substitute a different solenoid, have them show you with a meter that there is *NO* conductivity between the mounting tabs and any of the terminals.

I couldn't find a part number for the solenoid on the facts page, or in the TM's . I'll see what I can find on the interweb.

 

[Drock]

I found this one and ordered it from Ebay (link deleted)

 

[Drock]

So I did the jumper wire thing you told me about this morning and it started INSANTLY!! So I guess now we know it's something to do with the GP controls. I should get my new solenoid in the mail Wed or Thurs so I'll install it and go from there...If it turns out to be the GP card, where can I get ah new one? They seam to be scarce..