Truck doesn't start.

[burtcheca]

My brother's truck is a '94 7.3 with factory turbo.

He's having a hard time to start it lately. When he plugs it for few hours then it will start after some effort. When its running it works fine, no hesitations or problems and behave like it's in the correct timing. He thinks there could be some problems with the advance cold timing.

Glowplugs are new, glowplugs controller system is a new one from Motorcraft, he has fuel in all the lines (he test them loosing up a little the nut at the injectors), injectors are new.

He's afraid to use the truck because after a hard time to started it, it will be almost impossible to started it again when you go someplace and try to comeback home.

Any advice or tests you would recommend?

Thanks,

Burt, the Florida *******.

 

[OLDBULL8]

Battery condition? Gotta spin it to start. GP's suck a lot of amps out, then slow spin.

 

[Diesel JD]

Burt, I'm not 100% sure if you mean that it doesn't want to start cold or it doesn't want to start after he's run it and it sits for awhile. Option 2 sounds like a heat soak problem, option 1 is probably a return side leak which can be really hard to run down as you know. Please clarify. Good to hear from you again.

 

[amishtrucker]

yes, my truck. one battery brand new. starter 1 year old, chino brand, and fuel leaking down on it....but, also have to mention that i have suspected maybe an electrical problem? advice needed on this.

i bypassed fuel line and return lines by putting clear lines from a gas can with diesel direct to an external elec fuel pump then to filter...direct from injection pump return barb back to a bottle. kept both lines filled with diesel. no change.

here are the symptoms: when cold, truck cranks flat, doesn't even TRY to fire. after 4 hrs with the block heater, RATTLES when trying to start. after about the third LONG try, starts rough. acts like GP's, but they are all new.

i wondered about voltage getting to them: meter on the caps while in the run position, oscillates between 10.5 and 11.5V while relay clicks...here is the part I would like advice on, please:

I found that the GPS AND the cold timing advance and high idle solenoids all receive their go ahead from the engine coolant temperature switch . I did test the voltage to those two solenoids. someone on one of the forums said that the cold timing advance did knock the timing forward 2 degrees for starting, then when engine warms up, backs it off to normal. The voltage going to both there and the high idle solenoid (H/I may not be important, can do that manually) oscillated between 10.5 and 11.5 with the glow plugs! I don't know if this IS the problem or not, but it reminds me of when my running lights flashed on and off with the blinkers, bad ground or short somewhere that had to be fixed. Is it possible that the cold advance solenoid is not functioning, and that is why it will only start warm? Or, any other ideas? CAN ANYONE TELL ME HOW TO TEST THE *FUNCTIONING* of the cold advance solenoid? (not the voltage getting to it).

2. If my temp coolant switch (not the dash light sensor) is locked in the off, or an 'almost on' position, that is, not shutting on and off, and frozen where it does not make full contact, but partial.....could that be the cause of the advance not working?

 

[OLDBULL8]

amishtrucker:
Being this is your 1st post, don't hijack this thread, start another thread with your problem. Copy your post, then edit it and delete it. Start new thread. Makes it confusing to answer the original thread. Not flaming you, but that is just how it should be.

 

[amishtrucker]

sorry for the confusion. burt was writing about my truck, so i added more information. any advice is appreciated. thanks

 

[snicklas]

amsihtrucker,

Welcome to the forum. Hopefully with the help of the collective here, and Burt there, you should be able to get your truck going again.

Also, since this is your truck that Burt is asking about, this is not a hijack. Please add anything you feel may help. Let up know everything you and Burt have done... also. Please add your truck info into your signature. At the top, click on UserCP and then Edit Signature. It will help us to know what "we" are working on.

 

[amishtrucker]

Thanks, Burt, for posting, Snicklas, for the welcome. Added my signature. new fuel return lines added, but not new caps (but, i bypassed that with temporary lines, unless someone thinks that wouldn't have been an effective test?)

again, it starts, but rough, when connected to the block heater for 4 hrs, then runs fine. starts not at all when cold, doesn't even rattle. anyone know if the cold timing advance solenoid is that important that it could be the cause? or, how to test the part itself? or, if my oscillating 10.5V to 11.5V going to it could be the problem, or how to diagnose/fix that? or the coolant temp switch playing a part? Thanks in advance (no pun intended).

After Burt gets here, I'll update on what else we did. If anyone posts suggestions beforehand, he and I can implement them

 

[Diesel JD]

Welcome to the forums Amish. So are you saying the problem is cold starts only? If you were to drive it till it warmed up and then try again it would start normally? Really you are correct in how the cold timing advance works but it should not have much effect on how the glow plugs work. I have an older truck that used to have the 83-86 style system and I tried to hook the controller up so that the glow plugs would only come on with the cold timing advance but it didn't work right that way. As far as I can tell your year truck is supposed to have juice to the controller whenever the key is turned to the "on" position. Can you hear the glow plugs cycle? You'll hear that big relay click on and off, and they should stay on about 8-10 seconds or so, longer in very cold weather. You can't always pay attention to that dash glow plug light, listen for the clicking on and off and the dimming of the dome light and so forth. I hate to even suggest it, but I wonder what would happen if just for trial purposes you guys put 12VDC directly to the controller and let the plugs cycle for no more than 6-8 seconds. If it then fired up, I would guess you're getting no glow plugs and somehow the controller is wired wrong or some other electric problem. You might want to wait and see what the others say because I don't quite know which terminal should get the constant 12V without risking burning something else up, but I do feel like for some reason you may not be getting a normal cycle out of your glow plugs. Also if you have fuel leaking you probably also have air intrusion which will make the engine harder to start. I hope you guys get it fixed.

 

[burtcheca]

Thank y'all for helping my brother. I'm on my way to his place now. I'll post from there what we are finding and doing.

Burt.

 

[amishtrucker]

yes,JD, if i shut down, then start within an hour, no problem starting (maybe a little roughness, but nothing of concern), but cold starts impossible!

when i turn the key, wait to start light on for 10 seconds, then off and the relay starts clicking for, who knows? 40 seconds? I can shut the key off and restart the cycle and the light stays on for only 3 seconds, still clicks afterward.

i would be afraid to directly wire the GPs to 12v, as they are rated for 10.5v, unless 8 seconds wouldn't harm them? i think i can do that if i short the two fat bolts on the contoller? (advice?)

yes, the dash lights dim as it clicks (draw). the radio clock is on and off (electrical problem somewhere in the truck), too. the fuel leak was fixed, but the return line caps never replaced. but, i ran a test making IP overflow directly in to a bottle with clean lines full.

still wondering about the cold timing advance and the coolant temp switch? thanks for all the advice

 

[OLDBULL8]

sorry for the confusion. burt was writing about my truck, so i added more information. any advice is appreciated. thanks

My apologies. Welcome to the OB.

 

[Diesel JD]

OK, well then I'm confident your engine is perfectly healthy. I'm not an expert when it comes to these solid state glow plug systems but there are some good diagrams on here that show how it is to be done. I wouldn't think 6-8 seconds with direct voltage would hurt them because a lot of guys are running 12 volts to the ZD-1As which are only rated for 6V(maybe 10.5 as well now that I think of it??) but it is a risk, even though a slight one. I'd think you'd want to put the 12VDC to the terminal with the red wire on it or maybe the stud where the glow plug harness bolts to the end of the controller. Keep it very brief if you do so. I don't want to give specific advice because my electrical expertise isn't so good and I wouldn't want to lead you astray but there are good diagrams here and some really highly competent people with the 7.3 style system. I do know that if there is not a good ground and there is not key on power to the relay you will get nothing.

 

[icanfixall]

Welcome to the forum. Please teel us what new glow plugs you installed. Your problem is either a glow plug problem or a fuel problem. Either one will cause the sytoms you have posted here.

 

[amishtrucker]

Bosch brand new. I tested the ones I took out. 0.7 ohms, which leads me to believe they were plenty good and the problem is either in the GP circuit, or somewhere entirely different. New controller/solenoid/relay/timer for the GPs was motorcraft, brand new

as for fuel, would my 'test' work to rule out fuel leak, blockage, bad mechanical fuel pump, or leak in return lines? (the clear hose from gas can to elec fuel pump direct to filters, then from IP return barb back to a bottle).

by the way, i have always had an electric fuel pump between the tank selector valve and the mechanical fuel pump, which seems to have good pressue, by eye. The mechanical fuel pump I replaced 3 years ago. Could be bad, but there is more to it, from my 'test'.