Running engine stand: what all needs to be connected

Mountainman · **Posted:** Thu Dec 24, 2015 7:38 pm

I'm looking at setting up a stand that will seat an engine to test it prior to install. I have most all of the parts, so I figured, why not, and If there is a knock, I don't want to find out about it after I worked myself to death installing it...

Anyhow, I wonder what all sensors and other stuff will need to be installed to make it run?

I'm thinking:
ECU, both rail sensors, injectors, Map, Air temp?, cam and crank sensors, alternator, a battery, both starter connections, and under hood fuse block.
Edit: and TPS/go pedal

Somehow wire in the ignition switch, or somehow bypass it (12v jumper to the associated pin at ECU)?

I know it will run with no coolant, so I assume I won't need to connect the coolant level sensor or temp sensor?
Can I get away without any of the TCU or other transmission coms (might have to ask GDE this one)?

Thanks for any advice :JEEPIN:

Am I missing anything else that I would need to make it run?

Mountainman · **Posted:** Thu Dec 24, 2015 8:41 pm

Am I right in guessing that I can skip the turbo entirely? I'd just make a bypass line for the oil, and lightly bolt on the exhaust manifold...

oh, how many seconds can I run it like this with no water? I've ran them for probably 15-20 seconds without water. I just want to be able to listen for knocks real quick, basically testing the bottom end, and maybe the injectors if they run reasonable smooth like this. Maybe I will get a cheap junkyard radiator actually. Then I could run them worry free for a while, and really check them out. It wouldn't be hard to recycle the coolant. I'm liking the sound of this more and more :rockon:

flash7210 · **Posted:** Thu Dec 24, 2015 10:20 pm

An engine test stand.
Thats quite an ambitious project.

When I used to work on armored vehicles, the entire engine-transmission combo (we called them power packs) was designed to be removed from the chassis and ran on the ground for testing and diagnostics.
It came with extension cables so that everthing could be powered and operated from the cab controls.

I have no idea how you would make this work for a CRD motor.
If you could make extension cables for all the necessary sensors, everthing else can stay in the vehicle.
Have a good stable base that wont allow the engine to shake too much and fall over.
I think 30 seconds of running without coolant is safe. With a few minutes of cool down in between tests.

Enjoy the cold weather and have a Merry Christmas

Mountainman · **Posted:** Thu Dec 24, 2015 11:00 pm

flash7210 wrote:

An engine test stand.
Thats quite an ambitious project.

When I used to work on armored vehicles, the entire engine-transmission combo (we called them power packs) was designed to be removed from the chassis and ran on the ground for testing and diagnostics.
It came with extension cables so that everthing could be powered and operated from the cab controls.

I have no idea how you would make this work for a CRD motor.
If you could make extension cables for all the necessary sensors, everthing else can stay in the vehicle.
Have a good stable base that wont allow the engine to shake too much and fall over.
I think 30 seconds of running without coolant is safe. With a few minutes of cool down in between tests.

Enjoy the cold weather and have a Merry Christmas

Thanks Flash. I parted out a CRD a while back, so I have most of the parts I need to make another CRD, electrically anyhow. I sold some of the necessary parts, but then I have been collecting them back again. I don't think I'll need an extension with a complete engine harness, but maybe I'm overlooking some things. I can't remember if the motor mounts mount on the k-frame/engine cradle, but I think they do, and I kept that part, so that makes most of the stand with having to weld anything. I think I'll bold it to a 4x4 sheet of this plywood. Not sure how I'll stabilize the back of the bell housing yet. I wonder if two metal bars bolted to the frame would be too rigid? I mean, when the engine is in a vehicle it has rubber flexing in all axis. I'll probably have to come up with a flexible mount for the bell housing that is as tough as nails...

olypopper · **Posted:** Fri Dec 25, 2015 3:41 pm

The frame will be the easiest part of this project. If you have the harness then you are ahead of the game.

I'd concentrate on any sensors,senders and items that are required for running. They will run without half of what is on the engine.

papaindigo · **Posted:** Fri Dec 25, 2015 3:51 pm

I know it will run with the turbo installed on the exhaust manifold but not plugged in/hooked up. We did so when we installed my GDE Stage II turbo. However it will throw a code. If you plan on trying to run with no turbo on the engine at all better get premium grade ear muffs as the exhaust will do straight to atmosphere.

Mountainman · **Posted:** Fri Dec 25, 2015 4:13 pm

papaindigo wrote:

I know it will run with the turbo installed on the exhaust manifold but not plugged in/hooked up. We did so when we installed my GDE Stage II turbo. However it will throw a code. If you plan on trying to run with no turbo on the engine at all better get premium grade ear muffs as the exhaust will do straight to atmosphere.

Thanks Oly and Papaindigo :BANANA:

I bet you're both right on. I have a junk turbo that I can hook up, and that will solve the problem of oil pressure, and exhaust noise. Wiring this thing up will give me a good education on the wiring diagrams, which I've been lucky enough to avoid almost completely. I do have the background to understand it though, luckily.

geordi · **Posted:** Sat Dec 26, 2015 1:44 pm

I'm definitely interested in how this progresses - I'd love to be able to start up and check an engine before doing all the labor to put it back in, but the interactions between the computers is the tough part for me.

I think you'd need to figure out which wires connect to the throttle and the ignition, and obviously wire up a couple of switches and a push button for the power-on and then starter engage. If you can do that through the computer, so much the better. I know there is an airbag safety mode however, where if the computer thinks the airbags were deployed, then it will refuse to let you have the starter. You might wind up with directly wiring things.

I'd contact Keith too and ask him, I think he might have an engine stand or at least an idea of what is *absolutely* needed on the engine side to get this running. Hopefully it is just the engine side of the firewall harness, and 3 other things: Power, starter, and throttle that would need to be connected.

Mountainman · **Posted:** Sat Dec 26, 2015 9:09 pm

hmm, hopefully the wiring diagrams are comprehensive enough to figure this out. I have a transmission to swap on one soon, so I'll see if it will start with all of that stuff removed. It would be really sweet if I can just ignore the transmission entirely.
As long as I can find the signals needed (analogue range, or digital), I should be able to lie to the computer with a cheap power supply, but I don't think I'll have to.

Geordi, I hope you are right about the cab side of the firewall. I can't see it being all that involved to get this project running. But, the airbag stuff might be a pain. Then again, there's probably just a 12v signal to the ECU that gives the ok. If it's some fancy hex signal or something, then I'll just have to include the airbag controller box I guess, and that might be complex. For $50 I can get the ECU (which is from a different CRD than the Airbag module) programmed to the same VIN as the airbag module, and then they should talk.

I sure how all of the voltages are easy to find... Worst case I'll have to check a running CRD.

geordi · **Posted:** Sat Dec 26, 2015 9:35 pm

Well, here is my thought about the airbag module and the computer - The BCM controls the locks and the windows and AC and other things that are not engine specific. The SKIM nonsense is (IIRC) built into the BCM, because that is why you need the ECM programmed to match the vin... Obviously the ECM doesn't care, but there must be a shutdown command issued (probably through the ASD relay) when the BCM isn't happy with the mismatch.

But on the engine side of the firewall... The ECU is looking at the engine sensors, the trans is looking at the trans sensors (but shouldn't care or issue any e-stop codes if the trans isn't there) and AFAIK there aren't any signals to kill the engine other than de-energizing the ASD... But admittedly, I am trying to brain my way through this without any direct knowledge. The basis for my thought process is this: Car manufacturers are lazy and cheap. Anytime they are going to engineer a design that will have multiple engines, it is to their benefit (saving money) to duplicate as many parts as possible.

With that in mind, I am confident that the cab side of the vehicle will be the same / compatible / sending as few signals as possible through the firewall, and those signals should be the same between gasser and diesel. The easiest way to send a kill signal (for whatever reason) is the ASD relay, which can be wired with the engine harness to whatever method is most effective to kill the different engines. Gasser, just kill the power to the distributor system - no spark, engine stops. Diesel, cut power to the fuel pump, same result. So if you intercept that signal or just wire your own kill switch across the relay, when the switch is on (armed) the engine is enabled... Off, it isn't. That solves one problem.

If you are only concerned with idling the engine, skipping the throttle entirely may be a good plan - this is the only signal I can think of that wouldn't be a binary on/off or battery voltage in the analog world. This one may be the tricky one to try and duplicate.

As it is currently, the ignition switch is not an analog signal to close a relay and power the starter - Instead, it goes to the BCM and SKIM and runs the computer through a process that checks the airbags and validates the key and then closes the relay itself. Since we are trying to avoid all that... It may actually work to just separate ourselves mentally from everything on the cab side of the wall... The ONLY signal that we care about is the starter, which we can obviously trigger manually by just energizing the solenoid on the starter itself. Here is my thought though: On a manual transmission engine, you can push-start it by having the computer on (key on) and then dumping the clutch while you are moving. You force the engine to rotate and the computer takes over.

Could it be as simple as powering the ECU with the 12v supply wires, and then manually triggering the starter? The computer will already be in "running" mode, waiting for analog signals from the cam, crank, MAF, MAP, and fuel rail... And waiting to deliver the analog pulses to the injectors and MPROP. The only thing it should be waiting on is a spinning engine.

The only other thought I have is that this is an industrial motor too, as well as being used in functionally the same configuration around the world... Maybe we can get a harness and computer from a simpler design (london taxi? boat? generator?) that will only have or need analog signalling to trigger it?

Mountainman · **Posted:** Sat Dec 26, 2015 9:49 pm

Very good points. I hope you are right, and that it will be easy to manually jump the starter along with a good 12v on the ignition wire, or ASD wire, or whatever, for the ECU. That will be extra nice if ECU doesn't care about the throttle signal, which I imagine is an analogue value. I only care to hear it idle. With the way the motor mounts on these are, it will be really nice set it on the stand, quickly bolt the exhaust on it, plug in the engine connectors, and apply 12v via a switch, and touch a lead to the starter.
Then if it all sounds good, add some coolant for a long run.

About how long is safe to run without coolant. Does anyone know if we have a wet sleeve engine? I think no, but never looked it up...

geordi · **Posted:** Sat Dec 26, 2015 11:06 pm

Yes this is a wet sleeve engine, and to answer your question about running it without coolant... I wouldn't run it longer than 30 seconds at idle. That is the limit I put on myself when working on these or the TDI too.

Mountainman · **Posted:** Sat Dec 26, 2015 11:48 pm

ah, ok, thanks :JEEPIN:

I guess I would have found out when I finally pull a sleeve. I often wonder how long it will take me to get my head around every aspect of this vehicle :dizzy:

geordi · **Posted:** Sun Dec 27, 2015 1:20 am

Couldn't tell you... I'm still learning things about them.

Running engine stand: what all needs to be connected

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