2000 Tradewinds Diesel won't start no wait light

[cliffjl]

I replaced my main engine batteries this winter, but didn't try to start it after replacing them. Now it's spring and I go to start it and just turns over and over. I did notice the typical "WAIT" light that comes on while the glow plugs warm up doesn't come on (other than when turning the key on and all the lights come up). That leads me to believe the glow plugs are engaging. I've checked fuses and my battery connections, but am at a loss. I can't seem to find a relay for the glow plugs on my electrical sheet. Need help.

[Skip426]

Your coach's engine , be it Cat or Cummins , doesn't have glow plugs , it has a grid heater in the inlet of the intake manifold , and is ambient temperature controlled . Above 55 F , the heater won't cycle on.

The grid heater and it's relays are part of the chassis wiring and vary by engine as does no start diagnostics ; so I have to ask ; what chassis is your coach built on ,and what engine does it have.

[mrk]

Originally Posted by cliffjl

I replaced my main engine batteries this winter, but didn't try to start it after replacing them. Now it's spring and I go to start it and just turns over and over. I did notice the typical "WAIT" light that comes on while the glow plugs warm up doesn't come on (other than when turning the key on and all the lights come up). That leads me to believe the glow plugs are engaging. I've checked fuses and my battery connections, but am at a loss. I can't seem to find a relay for the glow plugs on my electrical sheet. Need help.

If it's been a while since you started the engine, I assume that you've primed the engine with the priming pump (under the bed).

Barring an un-reconnected wire, it sounds like the new batteries are connected properly.

I had a similar problem with my '99 TW: it would crank but not start. To make a long story short, it had a bad oil pressure switch, and after it was replaced, all was well.

It's easy to test--just disconnect the wiring to the switch, and turn the key to see if the engine fires. If it does, it's a bad switch. If not, you're problem is something else.

I wish I had known about this test BEFORE I dropped the TW off at Freightliner. They ran diagnostics, replaced the switch, took it for a test drive, and charged me $175 for the switch and about $475 for labor. I'm confident that I could have saved the labor by doing the replacement myself.

Where's the switch? Since I didn't do the replacement, I don't know, but I recall reading something about this, probably in the CAT forum. I think it was on the passenger side of the engine, about 1/3 of the way toward the "front" of the engine. Since the engine faces to the rear, I'd probably look closer to the fan rather than the tranny.

Good luck.

[Skip426]

Originally Posted by mrk

Barring an un-reconnected wire, it sounds like the new batteries are connected properly.

I had a similar problem with my '99 TW: it would crank but not start. To make a long story short, it had a bad oil pressure switch, and after it was replaced, all was well.

It's easy to test--just disconnect the wiring to the switch, and turn the key to see if the engine fires. If it does, it's a bad switch. If not, you're problem is something else.

OK , I'll assume that like Dale's National , your coach is on a Freightliner chassis with a Caterpillar engine.

Go back to the batteries and look for a small wire left off the positive terminal or connected to the negative terminal terminal by mistake .

In the case of a Cat engine the wire has a single 20 amp inline fuse that is the battery power for the ECM , if your engine is Cummins the wire feeds five inline fuses for various ECM circuits. All inline fuses must be located and tested.

Here's info on the Cat no start diagnostics , that includes the sensor disconnect that Dale mentioned.

Post if your engine is Cummins. there's different diagnostic procedures.

[cliffjl]

Thank you for the replies. I truly appreciate the help. It is a cat engine 3126B. I'll try your suggestions and report back here in about 24 hours.

[cliffjl]

I found the wires that I think you’re referring to that power the ECU. I checked the online fuse and also verified there is power there with my meter. Those wires are red. There is also a black wire there too which goes no where. I did try hooking that to ground but it didn’t make a difference. I’ll look at your other suggestions on Saturday morning.

[cliffjl]

Originally Posted by mrk

If it's been a while since you started the engine, I assume that you've primed the engine with the priming pump (under the bed).

Barring an un-reconnected wire, it sounds like the new batteries are connected properly.

I had a similar problem with my '99 TW: it would crank but not start. To make a long story short, it had a bad oil pressure switch, and after it was replaced, all was well.

It's easy to test--just disconnect the wiring to the switch, and turn the key to see if the engine fires. If it does, it's a bad switch. If not, you're problem is something else.

I wish I had known about this test BEFORE I dropped the TW off at Freightliner. They ran diagnostics, replaced the switch, took it for a test drive, and charged me $175 for the switch and about $475 for labor. I'm confident that I could have saved the labor by doing the replacement myself.

Where's the switch? Since I didn't do the replacement, I don't know, but I recall reading something about this, probably in the CAT forum. I think it was on the passenger side of the engine, about 1/3 of the way toward the "front" of the engine. Since the engine faces to the rear, I'd probably look closer to the fan rather than the tranny.

Good luck.

I had last drove it in March and then tried to start it in late May. That doesn’t seem so long as to need priming. However I did pump the priming pump a few times just to be sure. Do I need to pump it a lot?

Also I found the oil pressure sending unit (photo attached). I don’t know how to get the wires off it. I don’t want to break it. Suggestions for that is appreciated.

[Skip426]

You should pump the primer pump until it gets very difficult to push in ; indicating 65 psi of fuel pressure in the system.

I believe the " oil pressure sending unit " being referred to is actually the IAP sensor , detailed in the ; 3126 no start pdf .

The IAP sensor has wiring attached and a disconnect about 6" away from the sensor it's self .

[cliffjl]

Originally Posted by Skip426

You should pump the primer pump until it gets very difficult to push in ; indicating 65 psi of fuel pressure in the system.

I believe the " oil pressure sending unit " being referred to is actually the IAP sensor , detailed in the ; 3126 no start pdf .

The IAP sensor has wiring attached and a disconnect about 6" away from the sensor it's self .

That helped a lot. I did the priming task until it was really hard to push the plunger down, and also disconnected that IAP sensor. Still just turns over and over. Not sure what the next obvious thing to try is.

[Skip426]

Originally Posted by cliffjl

I found the wires that I think you’re referring to that power the ECU. I checked the online fuse and also verified there is power there with my meter. Those wires are red. There is also a black wire there too which goes no where. I did try hooking that to ground but it didn’t make a difference. I’ll look at your other suggestions on Saturday morning.

From the wiring diagrams that black wire may be the Cat ECM ground , did you connect it to the chassis battery ground ?

[cliffjl]

Originally Posted by Skip426

From the wiring diagrams that black wire may be the Cat ECM ground , did you connect it to the chassis battery ground ?

That wired is “wrapped up” at the end, but I did peel a bit of the metal out and ran an alligator clip wire to ground and it didn’t make any difference. I may have been a bit sloppy with that test though. I should try it again.

[cliffjl]

I’m wondering if anyone who really knows this rig pretty well would be interested in going over this with me in a video call. I’m happy to pay for your time. I really need to get this running.

[Skip426]

Originally Posted by cliffjl

That wired is “wrapped up” at the end, but I did peel a bit of the metal out and ran an alligator clip wire to ground and it didn’t make any difference. I may have been a bit sloppy with that test though. I should try it again.

Because the wire shared a run of plastic conduit with the fuse wire , I'll have to assume it's the wire I've highlighted in this diagram and needs to be properly connected to the negative terminal of the chassis battery .

I see my highlighting didn't come through , I'll try again .

EDIT: Should be ok this time .

[skyexplorer]

Go to the Cat deisl form . This engine is in a Lot of coaches and you find the mechanics that knows it there.