Testing leftover components in the air suspension system (1 Viewer)

[GX470andCJ7]

New member here. I have read a little on hear as the result of google searches but just registered.

The previous owner of my 470 had already converted to coils when I bought this vehicle. I am at the point where I either want a higher spring rate, helper airbags or completely switch back to bags. I have had a look underneath and I see that the compressor/pump is still there and at least one ride-height sensor is present and connected (electrically and mechanically).

Can I simply replace the fuses that I assume have been removed and see if the pump runs? I am thinking that the pump would run for a while and then I'd see some error if the ride height doesn't change. Does the system need to see some pressure at all times or is it completely dependent on the ride-height sensors? I am hoping to jack it up while its pumping and see if the system is satisfied.

If the pump and the sensors work then maybe those assist airbags inside the coils will do the job. My problem is that it doesn't take much added weight to cause the rear suspension to bottom. I have trimmed the bump stops which helped. With either my boat in tow or a near-full load of people it bottoms over moderate dips in the road. I don't know the tongue weight of the boat but I can lift it without too much struggle. I would guess 125-150lbs.

Current springs with helper bags controlled automatically seems like the best scenario if I can make it work.

I'm not against a lift but I don't intend to off-road much but I would consider a mild lift as long as my front CV shaft lives aren't shortened dramatically.

 

[rommelrommel]

I think it's dependant on the ride height sensors. You may have to manually move at least one to where it thinks the truck is too low to see if the pump will click on. AFAIK there's no error, it will just try and pump forever to raise the truck.

Any idea where the coils are from? If someone put in some weak coils that won't be helping things.

I kept my bags and frankly I like them. If the arnott replacement bags last it will have been more economical too.

 

[GX470andCJ7]

They are Arnott coils. I don't remember the model number but when I searched it, a while back, I only found one model that was intended for this vehicle.

I can't say with any confidence how many miles or months/years are on these springs. But, If my plan can work then I think maybe a soft spring and with a bag may be better than a firm spring.

I guess my journey starts with fuse replacement to see how it reacts.

 

[GX470andCJ7]

So far, so good! I moved some fuses around and confirmed that I have a working pump and I have air moving to at least the passenger side air line. The routing of the drivers side air-line looked more difficult to deal with.

The pumps runs with the ride height is set to middle and high but stops running when its set to low. But the low light doesn't stop blinking, so I guess that means that these springs aren't soft enough to drop that low without some adjustments to the linkage of the sensors.

Anybody know the max pressure of this OEM pump? There was no load on the line but I was a little surprise at the volume of air coming from the line.

 

[rommelrommel]

I don’t know the specs but it would be considered a high pressure low volume pump. People have tried to repurpose it to inflate tires and while it might eventually do one, it’s way too slow.

 

[GX470andCJ7]

Today I installed the firestone air assist bags but I can't get my on-board air suspension system to reset this time. Last time I connected terminal 4 on the top side and pin 5 on the bottom side of the OBD port, it went into diag mode and I pressed the brake pedal over and over until it beeped. Turned the key off, pulled my jumper then fired it up to find the pump running and the height switchable. The pump would run while in the middle and high setting then stop when I went to low. I assumed that the springs were holding it to high to reach the low setting but it wasn't quite satisfied that it was in the middle and of course it couldn't reach the high with no bags.

Now, with bags installed and lines connected, I do the same process as before but I get no pump running, the position is stuck in N and off continues to flash. When I go through the ECU reset, I get a long beep but I can't remember what I got last time. I think I may have tried to reset it with the compressor power disconnected.

I have temporarily routed my bags to the included Schrader valves mounted to my hitch and I am happy with the results. I would like to have the on-board system working even if I can't reach the low setting (I can't see the benefit anyway other than maybe .5mpg).

Also, I can see how a low volume pump can easily handle this job. I blindly put air in the bags to test, went for a drive and it was too stiff. My tire gauge showed nearly 50PSI and I didn't have to let much out to drop to 30 where it will be for my next test drive.

 

[aztoytec]

I run mine around 5 psi empty and 25/30 towing the car trailer loaded (about 4500lbs). Anymore than that and it rides really stiff.

 

[GX470andCJ7]

What I thought was a failure to reset my ECU turned out to be an ID-10-T issue. I failed to remember that when I did my initial test I didn't insert a new 10a fuse under the hood. I borrowed the horn fuse and replaced it after the test. I didn't realize this until I went to pull all the fuses and start from where I was when I bought it.

So, now I have it working as I had hoped would. I don't think its going to reach the low setting as it is currenlty but it might when its loaded with people, a boat trailer or a motorcycle carrier. I might tweak my sensor linkages but I think it may be OK as is. The last 1/2 inch or so of movement from high to mid seems to take a long time. Over all its faster moving up than down.

 

[GX470andCJ7]

I realize that this is not likely, but have any of you attempted to use a higher volume aftermarket compressor along with the stock tank and solenoids for the airbags? I assume that most who install a compressor are running coils, lifts and have no use for the stock system.

Not that lifting speed is a big deal to me but this thing seems to take a long time to raise and lower. More volume can't help the lowering speed but, at least in theory, it should cause it to raise faster.

Raising speed alone isn't enough motivation to spend the $$ on a compressor but it would push me a little closer to one.

It seems strange but I think it may be as slow when lowering as it is raising. By slow, I mean it takes and estimated 2 minutes to move between levels.