1999 3600 T444e won't rev in first gear

rlg999 · 08-06-2021, 09:15 AM

Got a strange problem with a bus I just bought last week. It drives fine on the road, I drove 60-65mph for 3 hours all the way home with no issues. I noticed on the test drive that it was VERY slow to start out in first gear. It was relatively flat where I test drove it, so I didn't think much about it. Now that I'm home, and my driveway is basically hills either way, the bus won't move out of its own way when you put it in first gear. It will rev up to 1500, then just BARELY begin to move. If you can get up enough speed, say 5mph, it will slowly start to increase rpms and once you get to around 1800 rpms, it will pull fine. 2-4 gears seem to pull fine though. I have to get a run and go to back up over the 3 inch edge of the concrete driveway where it meets the gravel drive. If I try to back straight over it, it just sits there at 1500 rpms and does nothing. It does this when the engine is cold or hot. I read somewhere about a valve post turbo that closes to help warm up the engine, but I don't think I have it. I initially thought the trans was bad, but there is no slippage once you get the rpms up, it just won't rev up high enough to get the 545 to pull. In neutral, it will rev up to 2300 easily, and once you're moving down the road, it will easily pull up to 2500 rpms. I'm thinking there is something with the T444e computer, or a sensor that is not allowing the bus to rev up while starting up. I know nothing about the 7.3s, but am quite familiar with the 545 though. This one does have the electric modulator rather than the cable operated one like on my cummins bus. Any suggestions on what I should check? There are no errors when I push the diagnostic button. I just get a 1-1-1, then another 1-1-1, then the diagnostic gives the end blink. Thanks!

Power Hungry · 08-06-2021, 09:25 AM

There could be a couple things going on here.

1) You could possibly have a split or otherwise leaking intercooler boot somewhere in the system causing a boost loss. The fueling is directly controlled by the boost level seen by the PCM. If it doesn't see much boost, the fueling is held back.

2) The hose going to the MAP sensor is loose or split. Same conditions as above.

3) The MAP sensor itself could be bad and causing a default fueling mode. However, this would normally be associated with a DTC and Warn Engine light.

These are the things I would check first.

Good luck!

rlg999 · 08-09-2021, 07:21 PM

I checked all the hoses and the sensor. I think they were all good and tight. I did try removing the connector for the EBPV and that seems like it may have helped a little. Will update once I get to try it out a little more. Thanks.

Simplicity · 08-09-2021, 09:35 PM

Have you checked your tranny fluid level?

If it's low there may not be enough fluid in your converter. Or, your converter may be showing symptoms of failing.

I too have the electric modulator, yet on a 643, and while it isn't related to this issue, it's a definite problem part. PM me or look at my threads for more info before potential tranny issues.

rlg999 · 08-14-2021, 04:48 PM

I just uploaded a video to Youtube showing my issue. I don't think 1500 rpms is enough to get the Allison's clutches engaged and pulling. Maybe someone on here can look at it and give me some advice. I did add some more fluid after taking the video, because it was at the lower end of the hash mark, but there was no difference in the pulling. No check engine light, or stored diagnostic codes. I'm wondering if the TPS is sending a full throttle signal to the ECM? Anyone have a link to a pinout and diagnostic for the TPS on the Internationals?

The video link is: https://youtu.be/tUS-C5bgJvk

Thanks everyone.

cadillackid · 08-14-2021, 10:35 PM

The allison 545 doesn’t use a TPS or a TCM , there is a mechanical modulator on the side of the trans which when gets 12 volts applied it will put the trans into lockdown / high line pressure mode.

Are you sure you are in first gear? When my 545 in one of the busss began to fail it’s symptoms were that it often didn’t go into first.. sometimes it would later but often never unless I shifted it to 1. At that point I got rid of it for the new trans ..

If it’s not revving then it’s not slipping. And the clutch is engaged. Now the converter might be bad or perhaps your gearing is too tall for good take offs ? Or the engine is super low spec?

rlg999 · 08-15-2021, 05:45 AM

Thanks Cadillac kid for your suggestion. I'll try manually shifting all the way to first to see if that makes a difference. I should have clarified my earlier post. I was referring to the tps for the engine. Maybe it's not sending the correct voltage to the engine ecm at full throttle? Should it be a .5 to 4.5 vdc output? I've got a good 545 sitting on the trailer that I took out of my bluebird when I did the Allison 1000 swap. I could have easily swapped it over to this bus in the time I've spent fiddling with this issue. I need to check the axle ratio. I noticed this bus will run faster than the bluebird did with it's Allison 545. I can hit 65-70 on my GPS with this bus. The bluebird would only do 55-60 with the same size tires. Where is the gear ratio stamped on these axles? Haven't seen a tag or plate with that info. It was clearly stamped on the data plate on the BB. Thanks again.

cadillackid · 08-15-2021, 07:33 AM

for the TPS if you start the 444E and level the throttle in neutral it should run up to 2600 RPM maybe 2700.. the TPS is simply an RPM setpoint so if you can reach these RPMs in neutral then the TPS signal is good.. its not like as gasoline engine where TPS is a percentage of fuel being applied.. on these diesels the TPS sets the desired engine RPM.. almost like an RPM cruise control.. the computer will up the fueling to try and achieve the RPM. there are different throttle maps depending on the year and programming.

now it could be that you have a fueling issue where the engine cant make power.. which would obviously make it sluggish to go

rlg999 · 08-15-2021, 08:53 AM

Ok, so the tps should be fine. Like you said, it will easily go up to 2600 in neutral, and while I'm driving down the road, once it gets up to speed. I'll keep digging. Thanks!

rlg999 · 08-16-2021, 09:58 AM

I'm beginning to think it MAY be the transmission. I tried pulling up the drive again today in first and it just sat there around 12-1300 rpm. Turned around and backed up the drive at 1300 rpm with no issue. I know the trans ratio is higher in reverse than first, so that might make a difference also. Guess I'll debate over swapping the other 545 for this one now. Unless anyone has any more suggestions.

rlg999 · 08-17-2021, 03:51 PM

OK, so I was browsing over on another bus related site, and found a guy who was having the exact same problem I'm having, except he had a 24v Cummins. After chasing down multiple paths, he found that the engine ECM had a parameter limiting the engine speed to like 1400 rpms until the ECM sensed the road speed was like 4mph or so. Do any of you 444 guys know if there is such a parameter in the T444E ECM? Thanks.

cadillackid · 08-17-2021, 08:15 PM

There’s nothing I know of. I drove my bus Lenny of times after my 1000 swap with road speed data as zero till I fixed my Speedo sensor . There are parameters limiting road speed and limiting peak RPM but none in relation to road speed that I’ve found. I can even rev to 2700 in neutral . Does the engine run smooth? Or is there a possibility you have a dead cylinder? That would make it feel gutless at start and not terrible at speed .

rlg999 · 08-17-2021, 08:31 PM

The engine seems to run smooth. If you watch the video I linked above, you can see the engine rpms just hang out at 1300 when on the hill. But if I'm on flat ground, and it ever gets above 1500, it will rev all the way up to 2600 in first gear. I may try to do another video tomorrow showing it working like it is suppose to on flat ground. Thanks!

rlg999 · 08-19-2021, 01:13 PM

Making Progress!!!!! I disconnected the MAP sensor at the Y going into the intake, and BOOM, I was able to jump over the ledge with no issue. Took off like a banshee up the road compared to what it was doing before. Much more power off the line. Of course I got a 122 error MAP sensor Low. BUT.... now I know it isn't a trans or torque converter issue. SOOOOO.... Do I replace the MAP sensor and hope that fixes it, does this give any insight to anyone else about the problem? Any diagnostics I can do on the MAP to test it? How about the Baro sensor? I haven't located it yet, but it is supposedly up under the dash somewhere. I read somewhere that if a fault is detected with the MAP or the Baro sensors, it defaults to a preprogrammed fueling program. It's definitely fuel related, just have to figure out exactly what. Thanks!

rlg999 · 08-19-2021, 03:07 PM

OK now I'm getting really confused. I was checking the part number I got off the MAP sensor, and it is 1807330. When I look that part number up, it shows as an oil pressure sender??? I don't know what the previous owners have done to this thing. Can anyone verify the proper MAP sensor part number for this engine? I'm thinking 1840078C1 is the correct number, according to what I'm seeing on line. This part number also comes up as an exhaust back pressure sensor. I guess they are both just measuring pressure, but I would think the range of measurement would be important.... Again the bus is a 1999 International 3600 7.3 T444e. Thanks!!

rlg999 · 08-21-2021, 02:57 PM

Well, either I got a bad sensor, or the 1840078C1 isn't the correct sensor. Plugged it in and the bus would barely move at all. Returning it, and currently have the MAP unplugged. Bus is running fine though, other than the Warn light being on. Anyone else have a part number for the MAP sensor that screws into the intake Y on the T444e engine? Thanks.

Power Hungry · 08-23-2021, 12:39 PM

Quote:

Originally Posted by rlg999

Well, either I got a bad sensor, or the 1840078C1 isn't the correct sensor. Plugged it in and the bus would barely move at all. Returning it, and currently have the MAP unplugged. Bus is running fine though, other than the Warn light being on. Anyone else have a part number for the MAP sensor that screws into the intake Y on the T444e engine? Thanks.

It appears that you may have some sort of short in the harness or some other interruption between the sensor and the PCM if replacing the sensor is still causing an issue.

Since leaving it unplugged seems to improve the drivability, that pretty much eliminates the other systems related to fueling and isolates it to the actual boost feedback to the ECM.

It's pretty much going to come down to being able to datalog the boost and see if the sensor is actually providing a valid value to the PCM. Without that information, there's no telling what the PCM is seeing for boost and whether or not it's providing the fueling necessary.

At this point, it's gonna be either leave the sensor unplugged and deal with the WARN ENGINE light, or take it to someone that can scan the PIDs and see what the boost is doing.

Good luck!

rlg999 · 08-23-2021, 01:06 PM

I've got a guy down the road who may be able to hook his scan tool to it. I'm gonna try to get with him this week to look at it. Thanks for all the help!

Power Hungry · 08-23-2021, 03:40 PM

Quote:

Originally Posted by rlg999

I've got a guy down the road who may be able to hook his scan tool to it. I'm gonna try to get with him this week to look at it. Thanks for all the help!

Based on something you said in your message ("disconnected from the tube"), I have some concern that the sensor you're addressing is not the MAP sensor, but may possibly be the EBP sensor.

Can you please provide a pic of the sensor and location you're referring to?

Also, please reference this post.

https://www.skoolie.net/forums/f37/t...ged-22484.html

Thanks.

rlg999 · 08-23-2021, 05:11 PM

I was referring to the vertical pipe that comes from the intercooler, then y's into each side of the head. I have already messed with the EBPV sensor, and have verified that the EBP valve is in the open position. And as soon as I unplug the MAP sensor, I get the warn light. When I do the codes it gives me the Map low signal. Here's the sensor and location:

https://photos.google.com/share/AF1Q...31NEdFwGc0gzTj

Anyone have the correct part number for it? Everything I saw online referred to it as an 1840078 sensor.
Thanks.

You may also like: