Saturn TDI Conversion

[Frankendiesel]

Starting problem - had similar symptom on my Frankendiesel. Mine was fuel line issues though (it's been a year now, I don't remember exactly what the issue was!) You may want to find out if your fuel pump is posing a restriction to the return line. Are you running the electric in-tank pump all the time? Some of them will restrict the fuel flow if they're not running, so I've heard. I don't run mine all the time either. Otherwise, I agree with the VCDS recommendation. Did you do a timing belt when you had the engine out? I did mine and still need to time it!

Speaking of the electric fuel pump, a friend of mine (we both work for an avionics company) reminded me of a jet airliner that blew up in flight becuase the electric in-tank fuel pump ignited the vapors in the mostly-empty fuel cell. I try not to run my pump at all. It may come down to needing to remove it completely.

Oh - one more thing...did you remove/bypass all the gasoline legacy equipment in the fuel lines, i.e. fuel vapor canister, etc.?

It is a great feeling to drive the conversion for the first time, doesn't it! Allow me to officially welcome you to the club!

TLG

 

[CFM]

Haven't done a timing belt on it, although the car it came from was well cared for and the timing belt doesn't appear to have many miles on it. I know it won't fire up on a restart after it's fully warmed up, so it probably is a timing issue, just haven't been able to get back to it yet...my latest class wraps up this week, so I hope to tinker on it some more this weekend!

I have about three gallons of diesel in the tank, should add some more to it...been running the EFI pump off and on while experimenting with the wiring; it is nice to have for priming the fuel system, though! The return is a seperate line entirely, so there are no restrictions there. Got rid of all the extraneous EFI system stuff, too, so it was just the fuel lines and EFI pump left in the system.

 

[CFM]

Been poking around in the wiring harness, found that the power lead that runs to several things on the engine wasn't connected to the 109 relay; somehow managed to overlook that when I was building and installing the harness. But now it fires up like it is supposed to, and wow, it really runs now! The CEL light sometimes comes on and stays on, other times it goes out like it should...not sure what's going on with that yet. I also wired up the in-tank fuel pump to work with the ignition switch; at the moment it is direct-feed until I can wire a relay in there, but at least it works!

 

[Frankendiesel]

Glad to hear you found the issue! Don't know what to tell you about the CEL except to check it with VCDS (duh). So what's left before you start driving it regularly?

Travis

 

[CFM]

Resolved another minor issue, this one being the oil pressure switch; I got one from a Volvo, so now the oil light in the dash comes on with the key, and goes out as soon as the car starts...with the TDI one, it worked just the opposite; was a bit disconcerting to have the oil light come on after the car started.

Just some little things before I drive it regularly...the big thing is the cracked windshield (took a rock from the snowblower last winter). Since this is just an R&D beater, I'll either try to scam a used windshield, or just keep getting permits to drive it while I get things fully sorted out. It sure does run nice, though!

 

[CFM]

Quick update, as I've been pretty busy with work and school and stuff around the house. I installed an Autometer boost gauge that I bought for this project some months back, and buzzed the neighborhood a few times to try it out...pretty neat to watch it build boost, although I wasn't paying attention to how much, just enough to watch it work. I'll try it out again and watch it closer. I'll try to get a picture posted soon. This thing sure pulls hard!

I also just ordered the tach and speedometer signal converters from Dakota Digital so I can correct the gauge readings, and have some brackets made up to secure the intercooler, just need to find the time to install them. Still need to replace the radiator, too...

 

[Frankendiesel]

What year/model of Volvo did you steal an oil pressure switch? The Chrysler is expected the same inverted signal. I was just going to put a relay in to invert it, but if I can just screw in a different switch, that would be less brain damage.

Hey - let me know how those DD converters go. If my engineering buddies here fail me, I'll be buying a set too.

Sorry to hear you are so busy. When you get the chance, post more pic's of the details.

 

[CFM]

Not sure what year Volvo it was...late '80s or so, didn't really pay attention. I just made sure it matched the thread pitch on the VW one, but I think Bosch is pretty standard with stuff like that.

Dakota Digital shipped my order out yesterday, should be here sometime early next week...I'll definitely post some pics of that as well!

 

[CFM]

Quick picture of the Dakota Digital signal converters for the speedometer and tach...they're really small, so finding a suitable place to mount them shouldn't be a problem.




Autometer boost gauge...I just made a quick panel to mount it in the SL2. This car was previously owned by a kid, so there are a few interior parts missing, plus my son took a few bits (he's really good at taking things apart and not putting them back together again). I have a really nice gauge panel I milled for the SW2 that currently house an oil pressure gauge and vacuum gauge some years back, so the boost gauge will have a much neater installation.

I also picked up a new radiator today, hopefully I will get that installed later this week, and study the Dakota Digital instructions for wiring and settings.

 

[Frankendiesel]

Glad to hear you are moving along! I sure like the size of those DD convertors. Space is a premium under my dash now that I have 2 huge fuse panels and the Chysler BCM (Body Control Module). The problem I'm running into with the Chrysler is that the instrument panel talks on the data bus to the tranny controller and the engine controller. I'm guessing your Saturn is analog signals all the way up to the IP, no? My engineer friend says we should be able to talk on the bus to feed it tach and speedo; I need to research that theory...

Nice work on the boost gauge; you don't want to see mine. It's temporary, what can I say.

 

[apaterso]

Resolved another minor issue, this one being the oil pressure switch; I got one from a Volvo, so now the oil light in the dash comes on with the key, and goes out as soon as the car starts...with the TDI one, it worked just the opposite; was a bit disconcerting to have the oil light come on after the car started.

Just some little things before I drive it regularly...the big thing is the cracked windshield (took a rock from the snowblower last winter). Since this is just an R&D beater, I'll either try to scam a used windshield, or just keep getting permits to drive it while I get things fully sorted out. It sure does run nice, though!

Seems like an awful lot of work for "Just an R&D beater". Will you use the same engine and bracket for the "real dea"?

 

[CFM]

Yep, the whole drivetrain is going into my '95 SW2, but I'm doing the conversion in this car first to get the swap fully sorted out before installing it in my daily driver...it makes sense when you consider all the fabrication involved!

I was able to ditch the Saturn ECU entirely and just piggyback the gauge cluster wiring harness to the TDI ECU and sensors, just a matter of wiring up the Dakota Digital converters to calibrate the tach and speedo readings. I also came across a company that specializes in custom gauge faces, so I'm thinking about having a 5000 rpm tach face made and change the fuel gauge to read "Diesel Fuel Only" once I get everything installed in the wagon...a company called Black Cat (found them on the internet) does this. They do a lot of custom stuff, so I would expect that they could easily modify the OEM style.

 

[CFM]

I have the intercooler fully mounted, replaced the radiator, and took it for a quick blast up and down the road...the boost gauge gets to about 17 lbs before the bypass opens. This thing sure pulls!

In the process of making a bracket for the Dakota Digital boxes...I found there is plenty of room for them under the dash cover on the passenger side, and there is already an unused mounting tab with a hole in it to secure it to, so that's one more problem solved.

 

[lupin..the..3rd]

Fired it up again today, had to give it another shot of starting fluid...I don't want to make a habit of that, as I'm sure it's not very good for a diesel.

You really really REALLY shouldn't use starting fluid on a diesel. Use WD-40 spray, it works just as well and is much much safer.

 

[Frankendiesel]

I agree with Lupin; WD40 works just as good. Sounds like you have a fuel supply issue...this is sounding all too familiar. I run my electric pump all the time now. Bypass regulator is on the way. Here's my theory, and it may be happening to you too: The fuel pump acts as a well from which the engine will draw its fuel. If you don't run the electric pump, the 'well' will dry up except for what little fuel gets in through the seems of the housing. I had starting troubles with mine last year. Once started, it will run about 1 mile before stalling/starving. Are these symptoms similar?

 

[CFM]

That was an earlier posting when I first tried to start it...as it turned out, I had overlooked a couple of connections in the harness going to the relay; once I found out what I had done and fixed it, it fired right up like it is supposed to. I just started it the other day after sitting for awhile, just a couple of cranks and it fired up and idled with no problem.

Made up the harness for the Dakota Digital boxes, now I just need the time to install them and tie them into the rest of the harness!

 

[CFM]

I got the Dakota Digital boxes plugged into the harness this afternoon and got to work with them for a bit. The speedometer was fairly easy, I just buzzed around the neighborhood with my GPS and calibrated the speedometer to match. The tachometer box is a little tougher, though; I haven't been able to get it to run the tach, so I'm a bit stumped. I ran out of time, so I'll just sit down with the instructions and read them over again. I think it's just a matter of getting the correct settings, but wasn't able to get them in the short time I had left.

 

[CFM]

I popped the hood this morning to work on the car, and discovered a hole had been chewed in my AEM filter. Some chipmunk is going to pay dearly for this one!

Anyways, I pulled it to make sure that nothing else was in there, then fired it up to experiment with the Dakota Digital signal converter for the tach. The tach works, but it still reads way low, so I'll have to contact them for advice. I'm thinking that I may end up using their Hall sensor to read off the flywheel teeth to get the tach to work properly, but I'll see what they have to say first.

 

[Herm TDI]

Chimpmunk love

I popped the hood this morning to work on the car, and discovered a hole had been chewed in my AEM filter. Some chipmunk is going to pay dearly for this one!

Anyways, I pulled it to make sure that nothing else was in there, then fired it up to experiment with the Dakota Digital signal converter for the tach. The tach works, but it still reads way low, so I'll have to contact them for advice. I'm thinking that I may end up using their Hall sensor to read off the flywheel teeth to get the tach to work properly, but I'll see what they have to say first.

Several years ago I posted a few photos on this same topic.
Seems that a pair of chimpmunks built 8" nest on top of the cabin filter under the plenum. The photos were lost some time ago when the photo- server crashed.
I smell a nice chimpmunk stew with carrots and green ionions and snow peas with a hint of garlic.

 

[CFM]

The tach works!



After a few emails back and forth to Dakota Digital, I found out where I went wrong with my initial settings for the tachometer signal. I set it up with a 2-cylinder input signal, an 8-cylinder output signal, with the switch settings for the tach as #1 off and #2 on, with #3 on and #4 off for the 8-cylinder output settings. It seemed to read too high, so I changed #3 to off and #4 to on for a 6-cylinder, and it seems to be about right. When I put this thing on the road, I'll do a few calculations to find out what it should read at 65 mph and fine-tune the settings.

In the meantime, I made a mounting bracket and installed them under the dash cover on the passenger side, using an existing mounting tab with a clip nut slipped over it to provide a threaded boss. I have a container full of these from a parts car that I recently got rid off; all those little fittings and hardware sure come in handy for projects like this!

 

[Frankendiesel]

Looking good CFM. Glad you got the DD boxes figured out. My TDI friend recently acquired a neat little gizmo that displays torque & HP. It also reads the RPM's through the noise off the +12V power line. I plan to borrow that whiz-bang box to calibrate my tach...perhaps you know someone with a similar device? Would make a quick and easy tach calibration. It needs to be setup on a similar car/engine first.

 

[CFM]

That sounds like a pretty neat item! I'll have to check into that. I know my GPS came in handy when I was calibrating the speedometer, so at least I got one of them to read correctly!

 

[CFM]

Crazy busy on my end, just finished my last class for the semester, and then winter had the audacity to show up. I took care of a few minor things in the car over the last couple of weeks, but had to do it outside because my kid decided to use my garage to pull the motor out of his car, and hasn't put it back together yet...going to shove it into a snowbank soon if he doesn't!

Aside from needing a new battery (the one I put in the car is kind of old), it starts up without much trouble. I lost boost the last time I ran it...I probably just popped an intercooler coupling loose, just need to check it out. Even so, it still runs well, and I'm anxious to insure and register it so I can drive it for awhile and see what it's like at highway speeds.

 

[VWBeamer]

Interesting. Nice work.

 

[Frankendiesel]

Heh; yeah, winter showed up here with a vengeance. Silly me, I went snowmobiling.

I'm sure you're gonna really like the driving experience. Say, did I ever ask you how much noise the beast makes under the hood? My intake noise is very loud and I'm looking for others who may have helped theirs hush up a bit.

Travis

 

[CFM]

Well, aside from the diesel clatter, it doesn't make much noise. Of course, I haven't had it on the road beyond buzzing the neighborhood and a few clandestine blasts up and down the road, but I hope to in the next couple of weeks. Another factor is that it is bolted up to the OEM Saturn exhaust system. My SW2, on the other hand, runs a 2" T304 system going into a Borla muffler; I'm sure the TDI will make a little more noise and power once it's coupled to that!

 

[CFM]

Well, aside from the diesel clatter, it doesn't make much noise. Of course, I haven't had it on the road beyond buzzing the neighborhood and a few clandestine blasts up and down the road, but I hope to in the next couple of weeks. Another factor is that it is bolted up to the OEM Saturn exhaust system. My SW2, on the other hand, runs a 2" T304 system going into a Borla muffler; I'm sure the TDI will make a little more noise and power once it's coupled to that!

 

[CFM]

On the road!

After two years of plugging away at this project, I finally got it insured and registered yesterday and drove it. I put about fifteen or so miles on it, running errands in town and getting a feel for the car. I got in a quick blast to 70 mph and found the tachometer read about 2300 rpm, which sounds about right for the gearing and the taller 195-60-15 tires it runs; anyone know the ratios for fifth year and the R&P so I can calculate it?

The diesel gear ratios took a bit of getting used to, as I'm accustomed to the twin-cam gearbox in my SW2. But it sure does pull! I still have some minor sorting to do; the glow plug relay quit, so I made a heavy jumper wire to do the job for now, and the fuel gauge also quit working after I fueled up. Got some funny looks when I pulled up to the diesel pump, but nobody said anything to me! It also has a really good heater in it; even with the temps in the low 20's, it didn't take long to warm up, and the temp gauge stayed at about the halfway mark.

 

[Growler]

Congratulations!

Did you swap it over to the wagon as originally planned?

 

[CFM]

Not yet; I'm still sorting it out in the SL2 test mule...that way, I can make sure everything is right so I won't have any unforseen issues when I finally put it in the wagon.