Rusty 720 diesel

[CRD]

New member. It's forum looks like a great place air out my datsun concerns. I bought an 81 diesel king cab 2wd a while back without checking it out close enough. It had a bad trans which I had swapped with a gasser using the old BH and got it on the road. The engine runs good but the floors are gone. The IP arm is attached to a manual choke cable for a kill switch and the wiring looks fairly molested. I'm on the fence, I'm not sure if I want to fix this thing or not. I've wanted a small diesel for several years but this a basket case. I'll post some pictures soon. I'd appreciate any input the group could offer.

[wayno]

Welcome  B)

 

Good job, most could not figure out how to fix the transmission, nice one as that is exactly what I would have told you to do.

 

Do you have all the components to try and put it back to stock, the DPC module(near the ID tag on the inner pass fender), the engine controller(under the injection pump), and the glow plug timer(near the right knee on the kick panel on the pass. side in the cab)?

If you need more info, feel free to ask, I have had several of these diesel engines/trucks, and drive one daily.

[CRD]

The glow plug system seems to be ok. I replaced the plugs thinking it would help the cold start but no dice. It starts but it smokes on startup and has a solid miss when it's cold. I'll check on the other components tomorrow. I'll get some pics if I can figure out how to put em up also.

[wayno]

The glow plug system seems to be ok. I replaced the plugs thinking it would help the cold start but no dice. It starts but it smokes on startup and has a solid miss when it's cold. I'll check on the other components tomorrow. I'll get some pics if I can figure out how to put em up also.

 

The DPC module is near the fuel filter under the hood just in front of the ID tag, I am assuming that the fuel filter is stock, and located in the stock position, it is a black box with 2 sets of wires coming out of it with 2 plugs.

The engine controller is below the injection pump with one set of wires coming out of it with one plug, and it is supposed to have an arm on it that connects to the arm on the injection pump, it has a mounting plate also.

These two parts are needed to turn the engine on and off with the key, sometimes when one of these components starts acting up, people put choke cables on the injection pump, as these components are hard to find, but ted knows where two diesel trucks are right now in a wrecking yard, he could likely grab the parts you need for you for a fee, I talked to him today at Blue Lake, he said they were there.

 

You might check your valve clearances to see if that helps, and when cold outside, these engines tend to miss and blow white looking smoke till the miss goes away, when warm it should not smoke at all, but sometimes if one overheats the engine, or some other bad thing happens, it can take 5 minutes or more to stop blowing white smoke, it's like it has to warm up before it stops, well this is not good, I am not sure why it runs fine but does this, I have only been playing with these engines for maybe 5 years now. 

 

To post photos on this forum, you need to join a photo hosting site like photobucket, picasa, imageshack, ect.

It used to be easy to post photos, not so easy or fun anymore.

[CRD]

The electronics are there. The actuator under the IP seems to be seized. There is a 720d near me in a wrecking yard I can chech out. Maybe I can get lucky and find the components there. Started it and drove it around the house this morning, it still starts hard but it clears up in a minute or two. I can imagine that it will start well in winter. I'll post what I find at the wrecking yard.

[wayno]

The electronics are there. The actuator under the IP seems to be seized. There is a 720d near me in a wrecking yard I can chech out. Maybe I can get lucky and find the components there. Started it and drove it around the house this morning, it still starts hard but it clears up in a minute or two. I can imagine that it will start well in winter. I'll post what I find at the wrecking yard.

 

You cannot turn the engine controller by hand, it would be broken if you could.

To see if it works, you need to connect everything up electrically, DPC module, and the IP controller, then have someone start it while you are looking at the arm on it, if it spins while turning the engine over, it works, if it doesn't move, then the DPC module or IP controller is bad.

There is a rod that connects to the IP(injection pump) from the IP controller, this rod has very tight tolerances, if it's even off a little, nothing will work properly, the problem is that there are different versions of this rod, and you need the one for your truck.

If I were you, I would go to that wrecking yard and buy all the diesel specific components that are there, the alt, DPC module, IP controller, glow plug timer, engine RPM control cable, throttle cable, thermostat cover/neck, starter, fact is I would even by the transmission, or at least the front case and steal bearing cover, as these are hard to find.

For sure go get the electrical components, that way you can figure out which one is bad on your truck, that is if they are bad, sometimes BIO diesel guys start fiddling with the IP timing, and the rod gets out of adjustment and quits working because it jams, it has very little room for adjustment.

[CRD]

Thank you for the advice. I'll head out on Wednesday and scavenge what I can off the scrap truck. I tried hooking everything back up and nothing seemed to work. I'll post what I pick up.

[wayno]

OK, I would grab this stuff for sure, get this arm with all the springs, washers, and pins/clips/keys.

Make sure you get the hardware down here also, and grab this IP controller also, it's hard to get to, but try to find one anywhere else.

This is the DPC module, you definitely want this, they are really hard to find, and expensive, the relay beside it is for the glow plugs, you should maybe grab that also.

This is the glow plug timer, I would grab that also, for what you would pay someone else for one, this will likely be cheap at a wrecking yard.

Photo from bottom up.

Photo from the side, these are hard to get to also, that's the blower on the left.

See the green and black wires with the plugs coming off the battery, they are your fusible links, grab them if they are there.

As I said in an earlier post, the alt. has a vacuum pump on the back of it, if yours were to go bad, good luck finding one, I personally would grab the whole alt, but that is just me, I have rebuilt extras, but they are mine and not for sale, the starter is also hard to find, but they are buy-able,  just super expensive(over $200.00 new).

Grab this engine RPM control cable if you don't have one, it's under the dash on the left, and goes all the way to the pedal.

See the cable going forward from the top of the pedal, that is the other end of that cable.

[w_datsun_a]

Wayno (and so many others), you are one of the reasons why I love this forum.  So quick and willing to share your information (with pictures to boot)!

[CRD]

Thank you for the shopping list, I'll take it with me. Now all I need is a day off!

[CRD]

I've been working tons of OT but it looks like I've got a few days off on the horizon. I changed the rear tranny seal today to stop a leak and noticed the pinion seal has a leak so that'll be tomorrow. The wrecking yard should be open on Tuesday to get after some parts. While I wa under it I noticed that the rust seems to be confined to the foot wells. This cab might still be salvageable.

[wayno]

I've been working tons of OT but it looks like I've got a few days off on the horizon. I changed the rear tranny seal today to stop a leak and noticed the pinion seal has a leak so that'll be tomorrow. The wrecking yard should be open on Tuesday to get after some parts. While I wa under it I noticed that the rust seems to be confined to the foot wells. This cab might still be salvageable.

 

Salvageable is good, after a few hundred thousand miles they sometimes need a few seals, it likely would not hurt to change the tranny and rearend oils also.

[CRD]

I made it to the wrecking yard this morning and bought all I could off the scrap truck. Got the trans, starter, alt, wiper motor and transmission and the fuel shut off (the part that bolts to the block but not the module. It was a factory ac truck but there's not much of the system left and the wiring is too Frankensteined to mess with. All in all a good find. I don't need the trans right now but it seemed a shame to let it get crushed.

[wayno]

I made it to the wrecking yard this morning and bought all I could off the scrap truck. Got the trans, starter, alt, wiper motor and transmission and the fuel shut off (the part that bolts to the block but not the module. It was a factory ac truck but there's not much of the system left and the wiring is too Frankensteined to mess with. All in all a good find. I don't need the trans right now but it seemed a shame to let it get crushed.

 

So the diesel specific electrical parts were gone?

[CRD]

The electronics were picked over and the wiring cut. The injectors and lines were pulled so the motor is full of water. Throttle lock cable was broken and the cluster was mangled. It looked pretty used up and rusted out. I was looking at my pickup and noticed that the fusible links are missing. The last owner bypassed them. I need to get a book with wiring diagrams so I can start trying to put it right again.

[wayno]

The electronics were picked over and the wiring cut. The injectors and lines were pulled so the motor is full of water. Throttle lock cable was broken and the cluster was mangled. It looked pretty used up and rusted out. I was looking at my pickup and noticed that the fusible links are missing. The last owner bypassed them. I need to get a book with wiring diagrams so I can start trying to put it right again.

There are 4 big wires, two white ones, one red one, and one white/black one, one of the white ones goes to the alt/fuse block(B)/DPC module, the other white one goes to the glow relay, the red one goes to the light switch, and the white/black one goes to the ignition switch, each one of these has it's own fusible link, both white wires have a black fusible link, and the two others have a green fusible link, I do not know if there is a difference in the colors, my wiring diagram doesn't specify that or amperage. 

[CRD]

I was thinking of putting in an auxiliary fuse block to replace the links. It would be a bit more modern. I'm going to work on it a bit tomorrow. I replaced the pinion seal the other day and haven't test drove it yet. Hoping I stopped the last gear oil leak. I'll post more tomorrow.

[wayno]

I was thinking of putting in an auxiliary fuse block to replace the links. It would be a bit more modern. I'm going to work on it a bit tomorrow. I replaced the pinion seal the other day and haven't test drove it yet. Hoping I stopped the last gear oil leak. I'll post more tomorrow.

 

I don't know it being more modern, as brand new aftermarket wiring harnesses have fusible links, but it is a little more user friendly to be able to see if a fuse is blown.

I have no idea the amperage at the fusible links, so I suppose you will have to guess what fuse to use.

I hope all your leaks are fixed, I myself don't like leaky trucks, it drives me crazy till I get it fixed. 

[CRD]

My fixes on the gear oil leaks are holding so far. I started looking at the engine kill setup and found the dpc to be bad. The dpc circuit board is burned all the way thru so no fixing it. That was one of the parts missing from the wrecking yard truck. I've got some time off for the holiday and might be able to get some work done on it.

[wayno]

Perhaps till you find another DPC module, you could set up some kind of solenoid that pulls the IP arm towards the off position when the key is on, don't know what to do while the key is in the start position.

Otherwise just use a choke cable, and pulled out shuts it off.

You need to find another DPC module, try asking Ted if he can find one, here is a link to him, PM him and ask.

http://community.ratsun.net/user/37-tdaaj/

[Cahoon520]

I have a extra dpc...if your interested.

[CRD]

I'd like it to work off the key so I think a working dpc will be worth chasing down. I'd thought about using a power trunk release on a button to kill it. The resting position for the pump arm is the run position so if you rigged a trunk release or a remote door opener like you would use with shaved door handles would work. The problem with old rare parts is that they're old! Are the dpc modules available new anywhere? What is a fair price on a used one?

[CRD]

I got lucky and found an 84 720d with a SD25 at an auburn wrecking yard. I got the electronics for mine and a few other needed pieces. Now it starts and stops off the key, the wiper transmission is tightened up and I also put in some new ball joints to tighten the front end up a bit. Still looks terrible but it drives much better now. Thank you all for the help and advice getting it this far.

[wayno]

I got lucky and found an 84 720d with a SD25 at an auburn wrecking yard. I got the electronics for mine and a few other needed pieces. Now it starts and stops off the key, the wiper transmission is tightened up and I also put in some new ball joints to tighten the front end up a bit. Still looks terrible but it drives much better now. Thank you all for the help and advice getting it this far.

 

Was it at a "u pull it" wrecking yard?

I have been wanting to find a good SD25 head, was it still there?

 

Good for you finding the parts you needed to make it work like it is supposed to.  :thumbup:

[CRD]

I pulled the parts I took. It's at budget truck wrecking in auburn. They told me they didn't have any diesels but its out there. 84 white kc. Engine was still whole as of Saturday.