I need y'all to give me some advice on this: When I turn the key, the engine will crank up nicely, normal sounding ignition. But it won't turn over for a good 2-5 minutes or so, and I stop every 30 seconds or so to heat the glow plugs (its jerry rigged and I have to press and hold a button under the steering column to heat the plugs)

My friends tell me the glow plugs are going and I need to replace them. Do you agree? Also, how would I go about fixing the problem with the glow plugs and remove the necessity of the button?

And just recently my friend mentioned to me that GM still makes 5.7 and 6.5 litre engines. If I decided to buy one of those while I fix up my current engine, would they fit?

Thanks

 

You need to wire your glow plugs to a 12V ignition source. There should be a 12V ignition source on your fuse panel.

 

and that would fix it? or just the button issue

 

Are they connected through a relay or directly to the button?
I don't know much about diesels, or how this is rigged, but do make sure that button / relay can handle the current of all plugs heating. I bet the plugs draw a significant amount of power.
A volt meter probed across the button (or relay contacts) should not measure much voltage when the contacts are closed.

Or for simplicity, just verify that 12V are at the plugs.

 

I'm not sure. I looked, and it has two blue wires feeding into the button. One from the fuse box and the other from what i assume to be the engine. I'll try to get pics up within the hour

 

Well here it is. The two blue wires feed from the button to the fuse panel and to the engine bay.
EDIT: Seems to be a problem with uploading them right now. I'll try again later

 

Sorry I didn't elaborate.

From my understanding the glow plugs in a diesel engine are supposed to warm up when you turn the key to the run position. Then you wait a few moments and turn the key to the start position to start the car. On most modern diesel trucks I've seen there is an indicator on the dash for the glow plugs that remains lit for about 45 seconds when the key is in the run position. This allows time for the glow plugs to warm up before starting the engine.

I figure the glow plugs would need a 12V ignition source. Rob has a good point though. Make sure however you wire them that the switch/relay they are wired through can handle the current they are rated at.

 

The 80's Cutlasses have an orange "WAIT" light that was used when a diesel was installed...

 

Hmm... the plot thickens. I wonder if this light is working on his car.

 

Being its rigged, the whole circuit may be dead (that is if the 70's cars had the light.)

 

Sorry for not being clear myself. It has both a wait and a start light. The wait light works only when it wants to. I'm going to try to get pictures of where the wires go in the engine bay and I'll get pictures of the lights too.

 

Ok I posted the pictures up on flikr because for some reasons the forums don't like my computer. Here is a link:
http://www.flickr.com/photos/49951388@N06/#photo4583759931'


Oh, and the brake light is on right now because I wanted to see if the parking brake still worked once. It didn't. I know I can take it off but I don't want to because I want to fix the e brake. The other lights are always on right when I start the car. They usually turn off after a while.

 

So what do ya think?

 

Okay, I looked at the pictures.
The "blocks" are relays, high current switches that are electrically controlled by a low current switch (your dash button).

Those current relays look aftermarket and should switch 12V from main harness to the glow plugs.
Sounds like your dash button works fine, despite the kludge.

The original relays look to be the bigger ones to the side with cut wires.

The "thingie" over the master cylinder would be the power booster for the brakes, since diesels do not make enough engine vacuum to run a vacuum booster.
Do you have a wiring diagram? I might have one at home - I will look. Not sure if it has the diesel part though.

You need to measure voltage from the glow plug (while someone holds the button) to ground and make sure you get 12V. If much less, then the relays or wiring / connectors are failing or insufficient. Not sure what 12V source the newer relays are hooked to.

The wait and start lights ~might~ be controlled by a simple power thermistor (a resistor that changes resistance as it selfheats from its own current flow). The factory relays might have been controlled by that circuit. My Ford seat belt light is wired through a power thermistor and it takes longer to go out in colder weather.
A wiring diag would be needed to be sure.

The parking brake switch on the pedal might be stuck - find the only wire to connect to it and exercise the switch some. I cannot read what the other lights are that are on.

 

Thanks.
Top left is GEN(erator) top right is OIL middle left is HOT (Radiator? engine?) There are more lights on the other side of the head unit that I didn't take a picture of. I've always assumed that since they go off after a few minutes its like modern cars, the way everything lights up when you start em.

Aftermarket relays. Gotcha. I know the dash button works fine, but I want it back to how it used to be. The previous owner had that button installed due to the fact the glow plugs weren't warming automatically anymore. If possible, I would like to get it back to no-button pressing.

Power booster, behind master cylinder. Makes sense. I have a Chassis Service Manual and a Ficsher Body Service Manual for 1978. One or both of which have wiring diagrams. Since I have no background in electronics, I have no idea what it means.



Don't have anything to measure voltage. How would I find out what source the relays are hooked to?


Thanks again,
Krich

 

Follow the wires to their source...
If you know a local buddy who is good with electrical stuff, coax him over with a BBQ and case o' beer.

If you can take some high quality photos (macro setting) of the glow plug wiring from the manual and email them to me I might be able to help more. I am curious to know how the plugs worked, too.
I looked in my manuals at home and nothing about the diesel was in there.

Not being there as well as a previous hack job makes this difficult.

 

lmao. Which wires?

OK I'll see if I can find the diagrams. The one of the car should have the glow plugs one in it, right? Or should I look for specifically glow plugs?

 

The wires coming off the added-in relays.
Some go to the glow pluggs, one goes to the button, and another goes to 12V ) that is the one we want to follow...

Look for a diagram for the glow plug circuit as well as the wait and start lights on the dash.

 

OK will do. Thanks

 

Well I found one big one for the 88 and 98 models. The only thing I could find told me something like circuit number 6 is not used on diesel cars. I gotta get batteries for my camera but I will get pictures hopefully by tomorrow.

 

OK the wiring diagram should be up and in my photo stream now.

 

Thats what i am looking for - now I need a big readable copy.
Please email it to me directly at ry_ry75081@yahoo

 

Email sent

 

I have not received it yet, not even in the junk folder.
I assume you added the .com to the end of it...
Please resend.

 

I did... I'll try again.


EDIT:

Sent

 

Okay, so I looked at the circuit diagram; pretty straightforward...

Time to get a voltmeter or a test light and start chasing electrons!
But first, you need to clean up the wiring going to the two old relays so we can see their colors. I see the light green one, which the module should ground when the 'wait' light is on. The pink wire should always have 12V to it when ignition switch is ON (RUN position.) Check the pink and let me know what you get.
Both the pink and light green should branch and feed to both relays.

Where does the thick light blue wires go that come from the two aftermarket relays? To the battery? These do not look original - the originals should have been black with fusable links in them.

I know the small darker blue wires go to the dash button and the orange ones go to the glow plugs.

Let me know what you find out and we will go from there!

 

Well I looked at the black wires and they go under the engine block--and then I lose sight of them. I don't have time to get under the car because I leave tomorrow. I'll try to do it sometime around the 4th. Thanks, and I'll get back in touch then.

 

Sorry its been awhile, real busy with school. Right now I gotta replace the power steering pump befoer anything and I have little money to do it with. I'll try to get on here more often