No Wait to Start Lite, GPR Test & GP Ohm Test

[Kelster]

Hey Guys,
97 7.3L Powerstroke will not start at -22C.

Block heater is working, batteries are charged & terminals cleaned. Turns over well.

Get 12.5V at GPR with key Off. With key On, GP side of relay shows 10.5V, so relay needs to be replaced.

No 'Wait to Start' indicator light. How should I troubleshoot this one?

Found the 4 large pins in connector plug at the injector cover. How do I run an Ohm Test for each GP?

how many ohms am I looking for each Glow Plug ?

Who makes the best (highest amp output), Glow Plug Relay and Glow Plugs?

Thanks,
Kelly

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[79jasper]

Motorcraft glowplugs.
Replace relay.

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The outer pins on each plug are for the glowplugs.

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[Kelster]

Motorcraft glowplugs.
Replace relay.

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The outer pins on each plug are for the glowplugs.

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Thanks Jasper,
I have the dual pigtails going through the injector cover gaskets and I busted one of the clips today, so I guess if I'm going dive into changing glow plugs, I might want to replace the gaskets also?

Kelly

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[79jasper]

You Probably Should. Motorcraft only on those.
Honestly, every clip on mine is broken. Lol luckily I haven't had them come unplugged.

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[madpogue]

You need to measure voltage at each GP relay large terminal with key ON. The drop in voltage you see could indicate weak batteries or bad connections, not just a bad relay. If difference between voltages of the two terminals WITH KEY ON is more than 0.3 V, THEN you know GPR is bad.

It's interesting that the GPR is energizing at all, with no WTS light. No WTS light typically (of course there are exceptions) means no power to the PCM. Just as a test (don't try to actually start it), try disconnecting one of the GPR trigger wires and then turn the key to RUN. See if that causes the WTS to go on. If so, you have some sort of main power issue. In any event, check main PCM connection.

Best GP relay choices are Stancor 586-902 and Western Plow 56131K. WP relay is physically smaller, more similar to the OEM relay.

ONLY GP choice is Motorcraft/Beru ZD-11.

 

[79jasper]

Depends.
If the relay is energizing or not.
I had a run with the light not coming on, but the glowplugs were working fine.
I had to take the little light cluster out and clean the connections.

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[Kelster]

You need to measure voltage at each GP relay large terminal with key ON. The drop in voltage you see could indicate weak batteries or bad connections, not just a bad relay. If difference between voltages of the two terminals WITH KEY ON is more than 0.3 V, THEN you know GPR is bad.

It's interesting that the GPR is energizing at all, with no WTS light. No WTS light typically (of course there are exceptions) means no power to the PCM. Just as a test (don't try to actually start it), try disconnecting one of the GPR trigger wires and then turn the key to RUN. See if that causes the WTS to go on. If so, you have some sort of main power issue. In any event, check main PCM connection.

Best GP relay choices are Stancor 586-902 and Western Plow 56131K. WP relay is physically smaller, more similar to the OEM relay.

ONLY GP choice is Motorcraft/Beru ZD-11.

There's a drop of over 2 volts between the two high voltage terminals and the batteries may be weak as well.

The truck was running when it was warmer out (it's around -20C today), so I expect the PCM may be operational but I'd like to test that. Will an OBD reader work for that?

 

[greenskeeper]

No 'Wait to Start' indicator light. How should I troubleshoot this one?

No WTS light indicates the PCM isn't getting power. Most likely the fuel bowl heater has shorted and taken out the large maxi fuse under the hood that powers the fuel heater element, and conveniently also the PCM.

Disconnect the fuel bowl heater harness before replacing the blown fuse. IMO the fuel bowl heater element isn't necessary so on both my trucks I have left it disconnected with no trouble starting at -20F with properly treated fuel.

glow plugs should be less than 2 ohms, however the only "true" way to test effectiveness is to pull each plug and manually hook to 12v to see how well they glow. I've seen "good" plugs test out below 2 ohms but only glow very little. Good glow plugs should look like a lightsaber from star wars within 20 seconds.

https://www.buyautoparts.com/images/what-is-a-glow-plug-1.jpg

Motorcraft glow plugs only !

White-Rodgers ( Stancor ) 596-902 Glow Plug Relay is a great upgrade since your replacing it anyways

http://www.dieselorings.com/16-009-white-rodgers-stancor-586-902-monster-glow-plug-relay.html

 

[Kelster]

No WTS light indicates the PCM isn't getting power. Most likely the fuel bowl heater has shorted and taken out the large maxi fuse under the hood that powers the fuel heater element, and conveniently also the PCM.

Disconnect the fuel bowl heater harness before replacing the blown fuse. IMO the fuel bowl heater element isn't necessary so on both my trucks I have left it disconnected with no trouble starting at -20F with properly treated fuel.

glow plugs should be less than 2 ohms, however the only "true" way to test effectiveness is to pull each plug and manually hook to 12v to see how well they glow. I've seen "good" plugs test out below 2 ohms but only glow very little. Good glow plugs should look like a lightsaber from star wars within 20 seconds.

https://www.buyautoparts.com/images/what-is-a-glow-plug-1.jpg

Motorcraft glow plugs only !

White-Rodgers ( Stancor ) 596-902 Glow Plug Relay is a great upgrade since your replacing it anyways

http://www.dieselorings.com/16-009-white-rodgers-stancor-586-902-monster-glow-plug-relay.html

Thanks for that.

Replaced a 10A fuse and got my gauges and WTS light back.

I was driving up a long hill and was losing power then started to miss. Check Engine light came on as well as Fuel Filter indicator.

Limped home and changed fuel filter and managed to get it started OK and drove about 1/2 km and died.

No fuel coming into bowl so I'm pretty sure the fuel pump is gone.

Kelly

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[compressionignitionrules]

gelling fuel won't pump electric or mechanical.
I had my van start gelling just below -20C last week and not wanting to start but a small amount of 911 in the tank cleared that up. now I'm running a conditioner every tank as we are getting down to -20 again next week. my block heater hasn't worked in the 6.5yrs I've owned it and I've never had a problem until last week.

get some conditioner in there before it leaves you sitting waiting for a warm shop to thaw out in

 

[Kelster]

gelling fuel won't pump electric or mechanical.
I had my van start gelling just below -20C last week and not wanting to start but a small amount of 911 in the tank cleared that up. now I'm running a conditioner every tank as we are getting down to -20 again next week. my block heater hasn't worked in the 6.5yrs I've owned it and I've never had a problem until last week.

get some conditioner in there before it leaves you sitting waiting for a warm shop to thaw out in

Thanks. I have a couple liters of Stanadyne in there so I doubt it's gelled fuel.

There's no fuel moving and the new filter is dry. Unfortunately there's only the mechanical pump and no electric fuel pump.

I looked at several electric pump filter packages and I just can't afford the $1000+ for the parts.



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[compressionignitionrules]

well its a lot easier to change the mechanical pump in your truck than an electric one in the tank.............. not much snow in the valley less $$$ too.

 

[79jasper]

No in-tank pumps with most diesels.....

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[compressionignitionrules]

IIRC all Fseries after 97 , all Eseries were the same . can't say for the two others from the dark side.

 

[greenskeeper]

Thanks. I have a couple liters of Stanadyne in there so I doubt it's gelled fuel.

There's no fuel moving and the new filter is dry. Unfortunately there's only the mechanical pump and no electric fuel pump.

I looked at several electric pump filter packages and I just can't afford the $1000+ for the parts.



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How full is the tank? It's common for the foot to come loose and run out of fuel before hitting empty on the gauge.

Mechanical pump is pretty easy to replace. Get new fuel lines for the valley while your at it.