'74 Argosy 20' Motorhome restoration/rebuild

[martin300662]

Originally Posted by bkahler

I need to ask the tuner if the program uses different averaging periods for different RPM ranges. I wouldn't be surprised if that was the case. Also thinking along those lines I wonder if it's possible the number for the averaging period may have been entered incorrectly or inadvertently altered. I'll query him about this idea. However that idea might not be the answer because I do know we've tried memcals from two different vehicles and both are exhibiting the same exact behavior. The first one we tried was from a very similar engine configuration that is in use and running on the street right now. The second is from a 1994 454 P30 motorhome.

The only thing that is the same is I haven't as yet substituted any of the electronics hardware.



Hmm, define street racing.....

Its interesting because I can imagine the biggest change required in the timing is when the engine is still spinning quite slowly, and so there is less data points on which to make the decision. So any 'invalid' data point (say from debounce) has a more significant impact (so needs a bigger averaging 'number').....the phrase between a rock and a hard place comes to mind, you need more data to make a decision, when you have less data on which to make a decision!

I would check if the averaging is on number of data points vs time as well - number of data points will give you a different averaging period (faster = shorter). But faster may need 'more' data if you see what I mean.

[bkahler]

I think the real problem is the spikes shouldn't be there and the fact they are is causing the averaging routine to produce erroneous data.

Here are three graphs illustrating how fast the spikes are. At sample one everything is fine, sample two the peak is shown and by sample 3 the spike is gone. There are 6 seconds from the first sample to the 3rd sample. So sometime within that 6 second period the spike came and went.



Weather permitting tonight I will replace the Ignition Control Module inside the distributor and see if it makes a difference.

[bkahler]

Originally Posted by martin300662

Its interesting because I can imagine the biggest change required in the timing is when the engine is still spinning quite slowly, and so there is less data points on which to make the decision. So any 'invalid' data point (say from debounce) has a more significant impact (so needs a bigger averaging 'number').....the phrase between a rock and a hard place comes to mind, you need more data to make a decision, when you have less data on which to make a decision!

I would check if the averaging is on number of data points vs time as well - number of data points will give you a different averaging period (faster = shorter). But faster may need 'more' data if you see what I mean.

I'll ask him how many samples get averaged. I'm sure with good data (i.e. no spikes!) the spark advance would remain stable throughout.

[martin300662]

Originally Posted by bkahler

I think the real problem is the spikes shouldn't be there and the fact they are is causing the averaging routine to produce erroneous data.

Here are three graphs illustrating how fast the spikes are. At sample one everything is fine, sample two the peak is shown and by sample 3 the spike is gone. There are 6 seconds from the first sample to the 3rd sample. So sometime within that 6 second period the spike came and went.

Attachment 264941Attachment 264942Attachment 264943

Weather permitting tonight I will replace the Ignition Control Module inside the distributor and see if it makes a difference.

Brad is the rpm value shown in image 2 real or is it simply a case that the data included in that displayed point includes a spike that is making it look high? If it is just the spike maybe the control script can be written to ignore any 'implausible' data point (for example have a threshold that any raw rpm value above 6000rpm is invalid and can't be included?).

There are a lot of similarities between the powder feeder controllers (I use at work) and these set ups, where you have a system trying to maintain set point, but then a system trying to change set point dependent on the change in state of the process, and the biggest 'control' issue is identifying the difference but valid and invalid achieved data (in my case could simply be an operator walking past a powder feeder effecting the powder feeder balance) and using implausibility limits to reject bad data is a good first step.

[bkahler]

Originally Posted by martin300662

Brad is the rpm value shown in image 2 real or is it simply a case that the data included in that displayed point includes a spike that is making it look high? If it is just the spike maybe the control script can be written to ignore any 'implausible' data point (for example have a threshold that any raw rpm value above 6000rpm is invalid and can't be included?).

The peak value of the spike is the reported value from the tach input to the PCM. For a fraction of a second the input reported the RPM was at that value. The next reported sample was back around the average number.

Unfortunately there's not a lot leeway in what can be done within the PCM programming. From what I understand the GM PCMs have been reverse engineered to varying degrees. Tuners know what values can be changed in what areas of memory to affect various operating parameters such as throttle position and length of time to open the fuel injectors.

I would be surprised if the original code by GM has something like value thresholds that can be rejected. However, I will ask about it just in case!

There are a lot of similarities between the powder feeder controllers (I use at work) and these set ups, where you have a system trying to maintain set point, but then a system trying to change set point dependent on the change in state of the process, and the biggest 'control' issue is identifying the difference but valid and invalid achieved data (in my case could simply be an operator walking past a powder feeder effecting the powder feeder balance) and using implausibility limits to reject bad data is a good first step.

We do a lot of close loop control here as well and fortunately we have a lot more control over how the loops operate and could easily tune out something like RPM spikes!

[bkahler]

I just finished reviewing all of the log files for the test runs that I've made. On the first day I made 5 runs where I had the RPMs above idle. The 1st three runs had spikes in the tach readings. The last 2 runs had no spikes and the engine sounded pretty good.

Each day since then all runs that were above idle have experienced spikes. However the one thing different is on the first day I did not disconnect the battery once I started testing. On all subsequent test runs I have disconnected the battery for some reason or other after a run or two.

I'm not sure there is a correlation here but I find it interesting that I was able to achieve to runs with no spikes. I think before swapping any parts or disconnecting the battery I'm going to do a bunch of test runs to see if the spikes go away after a while.

Stay tuned....

[bkahler]

Originally Posted by bkahler

The peak value of the spike is the reported value from the tach input to the PCM. For a fraction of a second the input reported the RPM was at that value. The next reported sample was back around the average number.

I neglected to mention each sample is approximately 300 milliseconds long.

[bkahler]

The local fab shop finally finished fabricating my new custom 50 gallon fuel tank!

Rough dimensions are 45-3/4" wide, 21-3/4" deep and 12-1/2" tall. Calculates out to 51 gallons if filled to the top.


The sides and bottom are made from 14 gauge steel and the top is made from 12 gauge.


There are 3 baffles installed. Two that divide the tank into thirds and one that goes from front to back in the center section to help keep the sloshing down so the sending unit can work better.


There are ports for the suction and return from the engine and a port for the generator. There is aslo a 3/8" npt bung welded near the filler neck for a vent line that will go up near where the filler neck is. Also there is a 5/8" vent pipe that will up to the filler neck to allow the tank to breath while the tank is being filled.


The cutout is to fit around the rear leaf spring hanger that intrudes into the fuel tank space. Could have added a couple of extra gallons if I didn't have to add the cutout.



Now my hope is I got my measurements right and the tank actually fits!

[bkahler]

I'm happy to say the problem with the tachometer signal spiking has been fixed. It was a bad ignition control module (ICM) inside the distributor. I replaced it today with a new unit and there was an immediate difference in how the engine runs and sounds, and best of all NO spikes!

It's running well enough now that I've declared victory and will start dismantling the test stand and prep the engine to be hoisted into the chassis. I don't know if I'll be able to meet my target of having it installed by the end of the 4th of July weekend but I'll sure try

One other minor task completed today was I drilled the hole for the steering damper and installed it as well. Mike's (Mayco) dimensions definitely helped, thanks!



Brad

[bkahler]

Below is pretty much the entire list of components I had to source both new and used for installation of the TBI system. The Wide Band O2 sensor, Maxtow fuel pressure gauge and some of the programming hardware wasn't totally necessary but made tuning and troubleshooting a lot easier. I chose to use external fuel pumps instead of adding an intank pump mainly because dropping the fuel tank on one of these motorhomes is a royal pain. Me being the lazy type that I am I opted for easy access for future replacement while sitting on the side of the road


Electronic components:
PCM 16197427 (used)
Memcal 16248378 BYYC (for 1994 P30 7.4L with 4L80e)
DRAC/VSSB module (used)
Spark controlled distributor (AM-11978505)
Coil (ACDelco Ignition Coil D535 1115315)
Coil bracket (used)
Programming & Tuning support fee (performed by Old School EFI)


Sensors and ancillary components:
O2 sensor weld in bungs (2)
O2 sensor, narrow band (AFS74 O2 narrow band sensor)
O2 sensor, Wide Band (AEM 30-4110 Wideband O2 UEGO Controller Gauge)
Coolant sensor (Standard Products TX3)
MAP sensor (Standard Products AS5)
Map sensor mounting clip (used)
Oil pressure sending unit (ACDelco 19244500)
Fuel pressure gauge & transducer (MaxTow 100 PSI MT-DV11)


Programming & Logging components (supplied by Moates.net):
ODB to ALDL cable / USB
G1 Memory Adapter: TPI ETC.
BURN2 Chip Programmer'
S4 Aries 28-pin Low-Profile ZIF
C2 SST 27SF512 Chip
HDR1 Memcal Header
License fee for TunerPro RT programming/logging software


Wiring components:
TBI Harness (Fuel Injection Connection TBI/4L80e harness - 2433-3042-N, additional length in main bundle)
Coil to distributor cable
Red dash light for engine warning indicator


Fuel Feed System components:
2" GM throttle body (rebuilt)
Aluminum flat bar 3/4" x 8" x 8" - alloy 6061-T6 (used for TBI adapter plate)
Low pressure fuel filter (AC Delco - cartridge type - GF62P)
Low pressure fuel pump (Carter P4070)
High pressure fuel filter (WIX 33033)
High pressure fuel pump (Airtex E2000 fuel pump)
E2000 fuel pump mounting clamp
Surge tank
Surge tank fittings
Fuel pump block off plate
Fuel injection hose clamps 5/16" & 3/8"
Fuel pump relay (for low pressure pump)
Misc hose and tubing fittings


I purchased the TBI harness from Fuel Injection Connection because they apparently are the only supplier of an aftermarket harness that has the cabling & connectors built in to control the 4L80e transmission.

One thing to keep in mind is I have only run this engine on a test stand so for obvious reasons I can't say just how well it will perform until I'm able to drive it. I will say however that engine response on the test stand has been great. It starts right up at the turn of the key, idles at about 700 rpm and runs cool. In fact it runs so cool I've been having problems in testing the cooling fan controls that were added to the code. When I had it running with the Edelbrock carburetor it ran hotter so I was somewhat surprised that it ran cooler with the TBI installed. I'm not complaining, just surprised!

Brad

[bkahler]

Here's a video of the last test stand run of the engine. I've already started dismantling the test stand so this is the last run until I've finished installing the drive train and a bunch of wiring!

https://www.youtube.com/watch?v=3kJl...ature=youtu.be

[PeterH-350LE]

Originally Posted by bkahler

....and runs cool. In fact it runs so cool I've been having problems in testing the cooling fan controls that were added to the code. When I had it running with the Edelbrock carburetor it ran hotter so I was somewhat surprised that it ran cooler with the TBI installed. I'm not complaining, just surprised!

Brad

My current 310 with an aftermarket TBI is the coolest running 454 I have owned (190-200), even in 100 degree summer temps. This apparently shows us that fuel delivery/efficiency AND computerized timing adjustments need to be considered when trying to troubleshoot and resolve high engine temperatures.

[bkahler]

Originally Posted by PeterH-Airstreamer

My current 310 with an aftermarket TBI is the coolest running 454 I have owned (190-200), even in 100 degree summer temps. This apparently shows us that fuel delivery/efficiency AND computerized timing adjustments need to be considered when trying to troubleshoot and resolve high engine temperatures.

Peter, I've been doing some research on this and definitely agree that the use of computerized control for timing based on the various input parameters is what is making the difference in why it runs so cool.

One question the Tuner asked me was what temperature do I want it to run. Right now I'm inclined to say 180 degrees but I think these engines are actually supposed to run hotter than that. Fortunately it's an easy parameter to change so it's not something I need to worry to much about.

I can't wait to get the Argosy on the road to see how responsive it is while driving

If that doesn't happen this year I'll be real disappointed....

[bkahler]

On Thursday I did a trial fit of the new 50 gallon gas tank. I'm happy to say it slid into place just like I hoped it would


I've already got the saddle arms bent to shape I just need to figure out how to attach them to the frame.

I'll have to enlarge the opening in the floor slightly to accommodate the new filler neck. The opening in the floor will be inside a closet so it shouldn't be noticeable once the interior is finished.



On Friday I started dismantling the engine test stand with the idea of installing the engine in the chassis on Saturday. The first thing I had to do was get the transmission located between the chassis frame rails so it would be ready to go once the engine was installed. By tilting the lift I was just able to slide the transmission and lift under the frame rails.

[bkahler]

I started out Saturday morning by getting the engine fastened onto the engine hoist and ready to go.


Once it was lifted high enough to clear the bumper another problem presented itself. The firewall panel that I fabricated as part of the doghouse cover installation was interfering with the engine hoist arm.


As I was fabricating the panel I thought it might be an issue so I made it removable just in case With the panel removed there was more room to move the engine farther into the chassis.



The next issue was the hoist arm itself interfering with the front of the shell opening. When I started the installation I wasn't sure if this was going to be a problem or not. The solution was to raise the front of the motorhome up about 3". That provided enough clearance above to allow the installation to continue.



The engine is now far enough into the chassis that I can lower it onto the engine mounts.



This is where I ran into the final installation problem. The drivers side mount slid right into place, unfortunately the passenger side was a different story. No matter what I tried it didn't want to slide down far enough to line up with the hole in the mount on the frame.


I was tired and frustrated and needed a break so I decided to call it quits for the day and finish the installation on Sunday.

[bkahler]

Sunday morning started out by me having to chase down the donkey who had escaped overnight. Once I got him back into the pasture I was able to tackle the stuck motor mount!

I spent about an hour under the motorhome poking and prying at the stuck mount and finally managed to get it aligned well enough to get the mounting bolt installed!



The 454 is now installed and the back end is held in place by a 1"x2" piece of tubing and a strap.


It's really weird to see a motor sitting in the chassis! It's been 8-1/2 years sine I removed the 350 that was installed by the PO. There were times when I never thought I would ever get to this point. Just goes to show that if you wait long enough it can get done

Next up is mating the 4L80e to the back of the 454 and relocating the rear transmission mount to work with the 4L80e. But first I'm going to have to spend the next week cleaning up the mess I made in the shop!


Brad

[martin300662]

This is great progress Brad, congratulations!

[bkahler]

Originally Posted by martin300662

This is great progress Brad, congratulations!

Thanks!

Let's hope it's not another 8-1/2 years before I can drive it

[bkahler]

What the heck, while I was hot and sweaty I decided to go ahead and lift the transmission into place


Still need to drill 8 new mounting holes for the cross member and torque a few bolts here and there but at least the hardest part is over.

[PeterH-350LE]

just impressive..., Brad!! Without the pictures, I would not believe that you did all of this in a day and some. And i am talking about chasing the donkey down