Check Engine Light Problem

[barbar0ssa]

That was a very interesting conversation.

Updates:

Jumping the pins on the pigtail worked for the coolant sensor. It looks like it is the sensor and not necessarily the wiring harness. I have a trip coming up in two weeks so I'm probably going to swap the jumper for a resistor and run that way for this trip. I'll be checking the coolant level every time I start rolling and of course the temp gauge will tell me if I have any problems. Not sure if I am underestimating any risks...

My insurance is through progressive and they just dropped me (and then sent me a customer satisfaction survey - not a great plan!) but I read the document and they are giving me a month's notice so I will be legal for this trip that I've been planning for a year!

Yesterday I was pretty sure it that the trip wasn't going to happen but it looks like we just might squeak it in.

[cadillackid]

Originally Posted by barbar0ssa

That was a very interesting conversation.

Updates:

Jumping the pins on the pigtail worked for the coolant sensor. It looks like it is the sensor and not necessarily the wiring harness. I have a trip coming up in two weeks so I'm probably going to swap the jumper for a resistor and run that way for this trip. I'll be checking the coolant level every time I start rolling and of course the temp gauge will tell me if I have any problems. Not sure if I am underestimating any risks...

My insurance is through progressive and they just dropped me (and then sent me a customer satisfaction survey - not a great plan!) but I read the document and they are giving me a month's notice so I will be legal for this trip that I've been planning for a year!

Yesterday I was pretty sure it that the trip wasn't going to happen but it looks like we just might squeak it in.

you were on a commercial policy and they dropped you? or an RV policy?

im glad jumping the sensor worked.. it very well may be that sensor is simply a switch and not a resistance sensor.. if it was a resistance sensor i wouldve thought it throws a short-code and not work.. since you didnt get a short code you may be fine to just leave it as is jumpered..

[barbar0ssa]

I was on an rv policy. Their cancellation note actually says to contact them about a commercial policy.

I am just very relieved that they are covering me through this trip.

[cadillackid]

Originally Posted by barbar0ssa

I was on an rv policy. Their cancellation note actually says to contact them about a commercial policy.

I am just very relieved that they are covering me through this trip.

I have a commercial policy and was afraid id lose that... of course it can happen.. I got a quote of just over $500 / year for Full coverage...

[Booyah45828]

It's just a switch, and I'd recommend replacing it. Main reason is that if you blow a hose, you probably won't notice that on a temp gauge.

[cadillackid]

Originally Posted by Booyah45828

It's just a switch, and I'd recommend replacing it. Main reason is that if you blow a hose, you probably won't notice that on a temp gauge.

true enough.. ive always replaced them on the cars that had them.. (cadillascs with aluminum engines)..

on a diesel getting hot is FAR WORSE than running a standard gas motor hot... and they can get hot QUICK if you are pulling hard and lose coolant...

im building an alarm system for mine to notify me quickly of coolant level,temp, oil press, oil temp, trans temp.. the cooling systems on some of these busses seem so small anyway...

-Christopher

[barbar0ssa]

Ok, I jumped the sensor and the check engine light turned off. But then when I drive, the RPMs still seem limited to 2000 but the check engine light is off and there seems to be a lot more power. Is there any chance that this is normal? I can drive it a lot faster but it still wouldn't be fun on the highway.

I was literally on my way to my first highway run and didn't feel comfortable getting on the on ramp. I know I'm crazy but I'm supposed to start my trip tomorrow.

When I run the idle diagnostics, I get a constant flash instead of any particular flash code. Again, there is no check engine light. Any ideas?

Getting a little desperate.

[cadillackid]

Originally Posted by barbar0ssa

Ok, I jumped the sensor and the check engine light turned off. But then when I drive, the RPMs still seem limited to 2000 but the check engine light is off and there seems to be a lot more power. Is there any chance that this is normal? I can drive it a lot faster but it still wouldn't be fun on the highway.

I was literally on my way to my first highway run and didn't feel comfortable getting on the on ramp. I know I'm crazy but I'm supposed to start my trip tomorrow.

When I run the idle diagnostics, I get a constant flash instead of any particular flash code. Again, there is no check engine light. Any ideas?

Getting a little desperate.

have you tried battery resetting the Computer since you jumped the switch? it IS possible that it was limited to 2000 RPM but sounds awfully low for that engine even with an overdrive automatic.. have you actually tried to run the bus up to 55 yet? say on a 2 lane country state route where you domt have an entrance ramp and large amounts of traffic to contend with?

-Christopher

[barbar0ssa]

I am on a bunch of nice straight country roads. I have gotten it to 65 but never over 2000 rpm. I pulled the cable from the battery and put it back in the engine diagnostics is still just flashing and beeping. Is this normal when the check engine light is off?

I haven't tried driving it again yet.

[barbar0ssa]

Am I correct in assuming that if the check engine light is not on, then the ECM should not be limiting the RPMs unless it was programmed with a limit?

[barbar0ssa]

The bus is now back at the dealers to see if they can find the problem. It has officially missed its maiden voyage and we are looking for hotels now.

Thanks, everyone. It was a good effort.

[Robin97396]

Out of curiosity, has your mechanic tried turning up your injector pump?

[barbar0ssa]

I am repeating what I heard, not implying that I know what I'm talking about.

So the current story from the dealer: The tachometer is broken. It maxes out at 2000 RPM but the engine is spinning faster. The top end speed problem is a combination between the "front brake slack adjusters" (Never heard of it) and the top end limit of 68mph. They adjusted the slack and drove 15 minutes out. It performed just as they expected it to on the way out but got more and more sluggish on the way back. Apparently there is a rachetting mechanism in the slack adjusters that is not holding. When you apply the brakes, they don't disengage all the way. So the bus was working pretty hard to overcome the fact that I was effectively constantly riding the brakes.

$300 will replace both slack adjusters and that should give me normal performance except for the top speed limit at 68mph. They can't reprogram the limit but have referred me to someone who might be able to.

[Tango]

Dragging brakes start a lot of fires on 18 wheelers. Nothing to take lightly.

[EastCoastCB]

Originally Posted by barbar0ssa

I am repeating what I heard, not implying that I know what I'm talking about.

So the current story from the dealer: The tachometer is broken. It maxes out at 2000 RPM but the engine is spinning faster. The top end speed problem is a combination between the "front brake slack adjusters" (Never heard of it) and the top end limit of 68mph. They adjusted the slack and drove 15 minutes out. It performed just as they expected it to on the way out but got more and more sluggish on the way back. Apparently there is a rachetting mechanism in the slack adjusters that is not holding. When you apply the brakes, they don't disengage all the way. So the bus was working pretty hard to overcome the fact that I was effectively constantly riding the brakes.

$300 will replace both slack adjusters and that should give me normal performance except for the top speed limit at 68mph. They can't reprogram the limit but have referred me to someone who might be able to.

68 is pretty fast. I'd be happy with that, personally.
Are your adjusters manual or auto?

[barbar0ssa]

I have no idea if they are manual or automatic. I am kindof assuming manual, but that is just a vague guess based on the type of words they used to describe them.

[Booyah45828]

They're likely automatics. Because manuals wouldn't adjust tighter going down the road.

What's it tach out to in neutral? That should tell you if the tach is broken. All the bad tachs that I've seen, they either worked or didn't. Never seen one that stopped at a certain rpm.

As far as reprogramming, you might be limited by gear also. So reprogramming isn't a sure bet. Plus 68 mph is pretty fast, and as long as your engine isn't redlined at that speed, perfectly fine for a bus.

[Docsgsxr]

Originally Posted by Booyah45828

Plus 68 mph is pretty fast, and as long as your engine isn't redlined at that speed, perfectly fine for a bus.

Agreed. If you're in a hurry, buy a jet. Skoolies aren't for drag racing, they're for enjoying the view.....

[opus]

Originally Posted by Tango

Dragging brakes start a lot of fires on 18 wheelers. Nothing to take lightly.

And a lot more fires on Entertainer coaches!

[cadillackid]

Originally Posted by Booyah45828

They're likely automatics. Because manuals wouldn't adjust tighter going down the road.

What's it tach out to in neutral? That should tell you if the tach is broken. All the bad tachs that I've seen, they either worked or didn't. Never seen one that stopped at a certain rpm.

As far as reprogramming, you might be limited by gear also. So reprogramming isn't a sure bet. Plus 68 mph is pretty fast, and as long as your engine isn't redlined at that speed, perfectly fine for a bus.

not necessarily.. if his dashboard was ever replaced the taachometer may have been set up for a different sending unit or different number of pulses per second.. some clusters use dip switches to set this.. others its a computer programmable item.

68 MPH is fast for a school bus.. I sure dont like the feel of them at that speed... 65 tops for me..

there are "audio tachometers" apps you can download on your phone that try to pick up the rhythm in your engine.. you can download one of these and play with it while the bus is stopped and in neutral.. gives you an idea what your tach might be doing..

-Christopher