Glow plugs replaced and now hard to start?

[gishooter]

I bought a MEP-003A with 969 original hours on it from the local surplus auction. Replaced all fluids and filters and it ran fine during the summer. When I turned the start knob to pre-heat I would hear the "clicks". But I ordered brand new glow plugs and two new manifold heater plugs from Green Mountain. I wanted to ensure easy coldweather starting with the new plugs. Switched them out and now I do not hear any "clicks" and the generator is harder to start. I looked at the wiring to the glow plugs and all seems to be connected properly. What do you guys think is wrong?
Chris

 

[cuad4u]

A "good" glow plug will read around 4-5 ohms from tab to ground. I would test the new ones and the old ones. You can test them in the generator by removing the wire and checking ohms from tab to ground. I would use sandpaper to clean the tab. Most are rusty. The "click" you hear is the glow plug relay closing. It does not make any sense that it closed with the old glow plugs and does not close with the new glow plugs unless you accidentally pulled a wire loose going to or from the relay or the switch that energizes the relay.

 

[gishooter]

A "good" glow plug will read around 4-5 ohms from tab to ground. I would test the new ones and the old ones. You can test them in the generator by removing the wire and checking ohms from tab to ground. I would use sandpaper to clean the tab. Most are rusty. The "click" you hear is the glow plug relay closing. It does not make any sense that it closed with the old glow plugs and does not close with the new glow plugs unless you accidentally pulled a wire loose going to or from the relay or the switch that energizes the relay.

Hmm, I'm not a electrician. I don't even have a multi-meter. I'll ask a friend who has one to come over and check as you suggested. Will post the results.

Thanks,
Chris

 

[Rapracing]

Is it possible the clicks he was hearing was the pump priming and not the glow plug relay? You would only hear one click for the relay wouldn't you?

Maybe a fuel pump issue?

ETA: Or a combination of the two? It would have started with out the glow plugs working when warm weather. Maybe they were not working before?

 

[rustystud]

Is it possible the clicks he was hearing was the pump priming and not the glow plug relay? You would only hear one click for the relay wouldn't you?

Maybe a fuel pump issue?

ETA: Or a combination of the two? It would have started with out the glow plugs working when warm weather. Maybe they were not working before?

The fuel pumps are not working when the switch is in the glow plug position.

 

[hurst01]

What happened to this thread? Seems every time I get reading one it just stops with no resolution.

 

[rustystud]

What happened to this thread? Seems every time I get reading one it just stops with no resolution.

A lot of times the original poster will fix the problem and not report back to let everyone else know what they did to fix it. Happens all the time.

 

[hurst01]

Hi rusty,

I know, but it doesn't help others that might have the same problem. If I have a problem and get it fixed I am going to post it no matter how silly it sounds. Never know, it might help someone like me, LOL.

 

[gishooter]

I didn't mean to leave anyone wondering. I'm still working on it. We actually got a warm front that came thru just before Thanksgiving. Got up to the high 40's for part of one day. I thought I'd try turning it over and it started! It was noticably hard to start compared to before the glow plug replacement. The generator ran fine with a load on it. Ran it for 15 minutes before shutting it down. I'm convinced there is something wrong with the glow plugs themselves or the glow plug controller. The temperature drpped the next day to below freezing and has stayed that way. So I'm not even going to try to start it again until I check. I'm waiting to hear from my buddy who has the electrical test equipment. His wife just had a baby and I'm not going to pester him.
I will post the results when I check the glow plugs.

Chris

 

[hurst01]

No worries Chris, there are a lot of people that might be having the same issues and might be following. I know when I first started following forums and they just dropped off it was discouraging. I like to know how things turn out. Out of curiosity, how long are you keeping the glow plugs energized when trying to start?

 

[Triple Jim]

Also, what brand and part number are the plugs?

 

[rustystud]

No worries Chris, there are a lot of people that might be having the same issues and might be following. I know when I first started following forums and they just dropped off it was discouraging. I like to know how things turn out. Out of curiosity, how long are you keeping the glow plugs energized when trying to start?

Yes, you need to keep the glow plugs on for at least 60 seconds. Longer if it's really cold like in the low teen's .

 

[cuad4u]

1. Remove the wires from the glow plug tabs. Check the resistance of each glow plug from tab to ground. The reading should be around 4-5 ohms. If resistance is higher or infinity, the glow plug is bad.

2. With the panel switch in the preheat position and with the wires attached to the glow plug tabs measure the voltage from each glow plug tab to ground. Reading should be 24VDC.

If both #1 and #2 check out everything is working and you are not holding the switch in the preheat position long enough. It is that simple.

 

[hurst01]

1. Remove the wires from the glow plug tabs. Check the resistance of each glow plug from tab to ground. The reading should be around 4-5 ohms. If resistance is higher or infinity, the glow plug is bad.

2. With the panel switch in the preheat position and with the wires attached to the glow plug tabs measure the voltage from each glow plug tab to ground. Reading should be 24VDC.

If both #1 and #2 check out everything is working and you are not holding the switch in the preheat position long enough. It is that simple.

cuad4u, Glad to see you chimed in on this. Everything still ticking?

 

[gishooter]

Update for fall 2015: I was able to run to start and run the generator in warm weather without any problems this year. Finally was able to get my buddy (National Guard mechanic) out to see it when he was doing his training this summer. He looked it over and put a meter on the glow plugs and intake manifold heater plugs. They were getting power but three of the glow plugs were blown. He said a couple of wires (don't remember which) was not connected properly. This overloaded the glow plugs. With cold weather coming I brought the generator to the local Onan shop and they quickly diagnosed the faulty wiring set up. Should be done in a few days. I'm waiting on replacement glow plugs from GMG.

 

[gimpyrobb]

Just so you have options, ziggy has the correct glow plugs for a good price.

 

[hurst01]

I still have a bunch of the CH42 glow plugs.

 

[gishooter]

Hi,
I would be interested in a few glow plugs as long as they are new. Ziggy or hurst01 send me a personal message with the details please.

 

[gishooter]

A big "Thank you" to ziggy. Got the NOS plugs from him and they are installed. Starts like a champ now. I am now waiting on the electrician to come do the hook up to the house panel.

 

[gishooter]

Just got back into town from visiting the extended family for Christmas. We've got a winter storm going. Thermometer reading 25 plus the windchill. Lots of snow. Covered wit a heavy duty tarp and cinched tight at the base. The generator started and ran fine with a load. I modified the starting procedure on the recommendation of the generator shop. They suggested I turn and hold at prime for a few seconds before turning to the preheat setting and holding for a 30 second count (longer in cold weather) then immediately to start. Their reasoning is the glow plugs start cooling off immediately while waiting to prime the engine. So why not immediately start after the glow plugs are at their warmest. This evening I held at the prime setting for about 5 seconds then to preheat for a 30 count then immediately to run. She started just fine. The electrician had to cancel at the last minute when they found they were missing something for the install. They never said exactly what. But they said they would come out when they had all the supplies on hand. Spoke wit them this morning and everything is a go for the wiring. Will take a few pictures and post them when I get a chance.