Cat 300 low power

[Hemertwv]

Hello I have a 97 safari savannah cat 300 Allison tranny pusher, recently it has starting going into what I thought was limp mode, I get no turbo pressure at all

It happens after an hour on the road or maybe two, seems to happen after working it a bit

I lose all turbo pressure, and of course down on power

I thought it was going into limp mode so I have had the codes scanned, zero codes

All fluids are good, temps are good engine and tranny oils are good

I thought at first it was a sensor that was coding causing the ECM to put in in limp mode but there are no lights. If I power down and wait even 1 minute it fires right back up and works fine for a while maybe an hour or less till it happens again

So I just changed the air filter and haven't tested it since and the old one was mildly dirty but I can't see how that would be intermittent unless I am missing something

I am suspecting the waste gate is sticking open and the problem is this is very hard to diagnose on the road

I am hoping someone here will have oome suggestions, I have thought about clamping the actuator hose to see if that changes it and driving smart so as to not over boost it

Help?

[JNSNWT]

Sounds like a loss of fuel due to a restriction. Maybe trash in the tank being sucked up against the pick up tube then falling off the tube when shut down.

When was the last time you changed fuel filters?
And did you cut them open to see what was in there?

[JNSNWT]

Can you use compressed air to actuate the waste gate? Is there any way to lube the waste gate mechanism?

[Skip426]

Welcome to iRV2 .

What chassis is your coach on ?

Have you tried changing fuel filters ?

[Hemertwv]

Fuel filters were replaced late last year there is probably 1000 miles on current filter but that is an easy thing to try, thanks

[Hemertwv]

I will try that but I thought you needed vacuum not pressure to operate that and how much pressure.i presume up to 30 lbs

[Hemertwv]

Safari coach not sure on chassis but I will try ffuel filters

[Bigd9]

Originally Posted by Hemertwv

Hello I have a 97 safari savannah cat 300 Allison tranny pusher, recently it has starting going into what I thought was limp mode, I get no turbo pressure at all

It happens after an hour on the road or maybe two, seems to happen after working it a bit

I lose all turbo pressure, and of course down on power

I thought it was going into limp mode so I have had the codes scanned, zero codes

All fluids are good, temps are good engine and tranny oils are good

I thought at first it was a sensor that was coding causing the ECM to put in in limp mode but there are no lights. If I power down and wait even 1 minute it fires right back up and works fine for a while maybe an hour or less till it happens again

So I just changed the air filter and haven't tested it since and the old one was mildly dirty but I can't see how that would be intermittent unless I am missing something

I am suspecting the waste gate is sticking open and the problem is this is very hard to diagnose on the road

I am hoping someone here will have oome suggestions, I have thought about clamping the actuator hose to see if that changes it and driving smart so as to not over boost it

Help?

Originally Posted by JNSNWT

Can you use compressed air to actuate the waste gate? Is there any way to lube the waste gate mechanism?

Yes on both questions concerning the wastegate. . In my coach, I used 30 psi air pressure to see the waste gate valve move . Mind you, look closely because the movement isn't very much, maybe only a 1/4 inch or so.

The waste gate should be lubricated using a high temperature lube like the PacBrake one.

One general comment, when the OP indicated he had the codes scanned and didn't find any. How/where did you get the codes scanned? I had codes scanned at a over the road truck repair place and he didn't find any, but when Caterpillar performed the scan there were hundreds.

OP, how do you know you don't have any "turbo pressure at all"?

There are several sensors that can cause your problem, but start on the easy to fix things like fuel filters. Does you engine have one or two fuel filters? When they were changed, did the shop use the correct ones?

[Hemertwv]

Originally Posted by Bigd9

Yes on both questions concerning the wastegate. . In my coach, I used 30 psi air pressure to see the waste gate valve move . Mind you, look closely because the movement isn't very much, maybe only a 1/4 inch or so.

The waste gate should be lubricated using a high temperature lube like the PacBrake one.

One general comment, when the OP indicated he had the codes scanned and didn't find any. How/where did you get the codes scanned? I had codes scanned at a over the road truck repair place and he didn't find any, but when Caterpillar performed the scan there were hundreds.

OP, how do you know you don't have any "turbo pressure at all"?

There are several sensors that can cause your problem, but start on the easy to fix things like fuel filters. Does you engine have one or two fuel filters? When they were changed, did the shop use the correct ones?

Indications of no turbo pressure are from No turbo pressure on guage falls right to zero, and some black smoke out tailpipe, there is one fuel filter and yes correct unit was replaced

Scanned at a dealership using cat tools

I will lube the actuator and waste gate control and will try 20 to 30 psi to validate movement

I have a spare filter so will take the old one out and cut it in two to see if anything is in it then replace with new one this week then test it this weekend

Thanks again

[Bigd9]

First off, your engine and mine are 7+ years apart in design age so Im being cautious here.

Are you sure about only having one filter? My 2006 Cat/Freightliner has two fuel filters. One in the water/fuel separator mounted on the rear Freightliner chassis, and there is another smaller one Cat 1R0751 mounted high up on the engine. But not all coaches came out with two. If you only have one fuel filter, it is different from those of us with two filters.

Also, there could be a third filter! On some Freightliner chassis, there was a inline filter installed. I do not know what years these inline filters were used. Here is a picture.


I find it odd the turbo suddenly shows no boost, but you are not getting any ck engine lights. There is a "Boost Pressor Sensor" It could be bad but I would think it would throw a code.

[Hemertwv]

Originally Posted by Bigd9

First off, your engine and mine are 7+ years apart in design age so Im being cautious here.

Are you sure about only having one filter? My 2006 Cat/Freightliner has two fuel filters. One in the water/fuel separator mounted on the rear Freightliner chassis, and there is another smaller one Cat 1R0751 mounted high up on the engine. But not all coaches came out with two. If you only have one fuel filter, it is different from those of us with two filters.

Also, there could be a third filter! On some Freightliner chassis, there was a inline filter installed. I do not know what years these inline filters were used. Here is a picture.


I find it odd the turbo suddenly shows no boost, but you are not getting any ck engine lights. There is a "Boost Pressor Sensor" It could be bad but I would think it would throw a code.

Sorry I should have been more clear one fuel filter, one water separation filter so yes two in that sense, I am changing both I have both I keep spares in the RV

I went under the chassis and searched for a third filter there isn't one that I can fine, nothing accesible anyways I followed the line from the tank bank

Yes it is odd that turbo pressure falls off like that, there is definitely no turbo pressure, loss of power and some black smoke is a trigger to that. The cause is yet to be determined I am going to put a small camera if I can by the wastegate actuator and have someone watch it and drive this weekend to see if the problem comes back after fuel and air filter change and lube of actuator to see if it is getting stuck open no way to watch it while driving otherwise.

it does happen while working the motor which is why I tied it to the wastegate it seems to happen after working it hard going up a hill so I was suspecting that it was getting stuck open but as soon as we stop it clears up.

Thanks for all the input, I will keep updating probably after the weekend when we can test it for a few hours

[Bigd9]

When I had a engine problem where the engine when under load would suddenly just for a second loose power, dashboard lights would indicated Check engine, STOP engine, loud noise, then all clear within 3 seconds. I replaced several sensors and thought I fixed it, but the problem persisted. After checking the wastegate and knew it was moving, I narrowed the problem down to the waste gate activation solenoid. Sure enough, that was the problem. The solenoid gets a signal from the engine module of a turbo over boost and it then opens and sends a shot of compressed air to the wastegate. That air opens the gate and bleads off some turbo pressure. On my engine the solenoid is located on the passenger side on the engine toward the transmission end.

Does your coach have a exhaust brake? Could it be sticking?

[Hemertwv]

Originally Posted by Bigd9

When I had a engine problem where the engine when under load would suddenly just for a second loose power, dashboard lights would indicated Check engine, STOP engine, loud noise, then all clear within 3 seconds. I replaced several sensors and thought I fixed it, but the problem persisted. After checking the wastegate and knew it was moving, I narrowed the problem down to the waste gate activation solenoid. Sure enough, that was the problem. The solenoid gets a signal from the engine module of a turbo over boost and it then opens and sends a shot of compressed air to the wastegate. That air opens the gate and bleads off some turbo pressure. On my engine the solenoid is located on the passenger side on the engine toward the transmission end.

Does your coach have a exhaust brake? Could it be sticking?

it does have a PAC Brake, it is turned off most of the time but I will look at it.

[grldst]

Originally Posted by Hemertwv

Safari coach not sure on chassis but I will try ffuel filters

Back in that era Safari was built on their own chassis, Magnum.