sooo, i just went and got myself a stock 2.0L plenum with stock throttle body and TPS from EASY.
while i was cleaning the stuff i noticed that the TPS didn't have *any* gunk on it, it fact it looked shiny new. so i pop the plastic cover and low & behold it looks brand spanking new!
no wear on the sliders at all ...

so i'm thinking, can i use the stock 2.0L TPS with my MegaSquirt brain or do i need to go to a aftermarket TPS ???

also, when i took the plastic cover off 2 little rubber spacers (triangle shaped) fell out. i can only see 4 spaces where they might go, but which ones is it?
top or bottom?

Andy

andy there is someone who did the MS on a type 4, well they used a suby tps, i dont know why but i think it has to do with ohms of the stock tps. if you need i can go get a reading from the one in my car ( suby 914 )

You can pretty much use anything under the sun with megasquirt. Guys are using AC delco sensors, bosche sensors, etc...In my research for my MS project, I ran across all kinds of different stuff.

Check this site out:

http://www.dune-buggy.com/turbo/index.htm

and this one:

http://www.megasquirt.info/

This one too:

http://bellsouthpwp2.net/s/_/s_moseley/meg...gasquirt/msgui/

Here is my MS thread:

http://www.914world.com/bbs2/index.php?act=...f=2&t=23859&hl=

Picture is of my setup as it is now. How far along are you?

Corby

Big no on the stock TPS.

The stocker is basically like a switch, where a modern TPS is more of a rheostat.

a new tps uses a variable resistor right? the stock tps is just like a multipoint switch. the new one would be way more accurate. i'm sure someone has something alot more smarter than that to say.

QUOTE (balthazar @ Feb 4 2005, 05:32 PM)

Picture is of my setup as it is now.

wow, nice setup! looks professional. what did you yank the TB off of?

i'd buy that stocker from you. i was gonna buy a new one shortly...it reads coninuity and infinity in ohms, no progressive sweep like a std tps would

Proper term is a potentiometer type TPS

QUOTE (nickg @ Feb 4 2005, 05:44 PM)

i'd buy that stocker from you. i was gonna buy a new one shortly...it reads coninuity and infinity in ohms, no progressive sweep like a std tps would

ok, that makes sense ...

i sell you the TPS, i have no idea what they go for. lemmy look around real quick ...
Andy

PS: thanks for the links and stuff guys ...

QUOTE (balthazar @ Feb 4 2005, 05:32 PM)

How far along are you?

i'm having bigger runners and expanded plenum fabbed as we speak ...

Andy

QUOTE (SirAndy @ Feb 4 2005, 05:52 PM)

lemmy look around real quick ...

$128.75 from pelican parts

i payed $40 for the whole crap-o-la, so you can have the TPS for $20 plus shipping ...
Andy

QUOTE (Mark Henry @ Feb 4 2005, 05:49 PM)

Proper term is a potentiometer type TPS

alright, so mueller says he used a aftermarket TPS on the stock 2.0 throttle body that fit the D-shaped shaft.
but he can't remember what brand it was ...

anybody here know which one he's talking about ???
Andy

QUOTE (mattillac @ Feb 4 2005, 05:40 PM)

QUOTE (balthazar @ Feb 4 2005, 05:32 PM) Picture is of my setup as it is now. wow, nice setup! looks professional. what did you yank the TB off of?

Thanks for the digs! Here are some pix of the progress.

On another note, I have a EET from ITT Tech, and have been working in the electronics fields for 10 yrs now. I would be willing to build these kits for a small fee if anyone is interested. I can even hook it up to my laptop and pre- tune it for stock or?

Butterfly housing...

One more...sory for the hijack... I am

QUOTE (balthazar @ Feb 4 2005, 06:35 PM)

One more...sory for the hijack... I am

answer me!

what TPS did you use ???
Andy

QUOTE (mattillac @ Feb 4 2005, 05:40 PM)

what did you yank the TB off of?

The TB is from a 1.7l. The engine in my car is a 1.7l...I thought I could use the stock TPS, but I guess not...gotta do more research....grrrrr

This is the exaust I will use(pic of one I will copy)...muhahaha

Everyone is up in arms about the sleezy avatars...I tell you, this is straight up PORN to me!!!

alright, i guess i have to do it all by myself ...

here's a link to a older thread about different types of TPSs to use with the MS system ...

http://www.914world.com/bbs2/index.php?act=...2&t=6171&hl=tps

QUOTE (SirAndy @ Feb 4 2005, 10:29 PM)

QUOTE (Mark Henry @ Feb 4 2005, 05:49 PM) Proper term is a potentiometer type TPS  ;) alright, so mueller says he used a aftermarket TPS on the stock 2.0 throttle body that fit the D-shaped shaft. but he can't remember what brand it was ... anybody here know which one he's talking about ??? Andy

You can get one from SDS but they're spendy at $75.

If I remember right the 2.0 TB turns opposite (I think CCW) from most TB's

You can see the "D" shaft on my install thread here...BTW that's a hacked up stock TPS that the new one is mounted on.

ok, found one (thanks benno! ) ...

d-shaped shaft cutout plus right rotation.
http://www.vishay.com/product?docid=57002&query=971

they even have a few dealers in the bay area.
time for a little roadtrip ...
Andy

most gm tps' should work, but try looking at this one...1987 buick grand national, 3.8 turbo injected 6. i had several of them and know that the tps is very similar to the 914 throttle switch, it uses a d shaped shaft and has similar mounting as well...best of all they are like 20 new ac delco....standard ignition should be like 15

QUOTE (balthazar @ Feb 4 2005, 06:44 PM)

This is the exaust I will use(pic of one I will copy)...muhahaha Everyone is up in arms about the sleezy avatars...I tell you, this is straight up PORN to me!!!

Glad you like it. It makes a cool whistling noise right before all the other cars dissapear.

-Ben M.

The TPS I used on MS install is a Wabash...

with the group buy it was like $40 or so, I think a tad higher....

if those TPS units from the Buick GN have the D-shaft and only cost that much that would be great......

the Mikuni throttle bodies I picked up have a TPS already on them, I'll test it to make sure it'll work with the 5vdc the MS gives it.....

Guys

I used a TPS off of a Subi Impreza. $5! It was the right size shaft but rotated the wrong way so I turned it over and drilled a hole in the back and mounted it backwards (turns the right way like that). I mounted it to the back plate of an old stock TPS.

The voltage to the TPS is reference by MS (MS supplies 5 volts) and the TPS returns a 0 to 5 volt signal. There is a calibration program in Megatune. MS uses the rate of change and the amount of change of the TPS to calculate acceleration enrichment. MS runs quite well without a TPS. In fact when doing the early tuning you want set up acceleration enrichment so it is off.

The only issue is make sure that when the TPS is mounted it doesn't interfere with the butterfly closing.

Just go get a TPS with the right shaft and you can make it work. Always grab the connector from the harness.

Dave

I used a TPS from a subaru. You can have it if you come and get it. I also have an adaptor plate for a d-jet throttle body.

Email me if you want to pick it up today.

Fiid.

Oh yeah - I have no idea WTF Bosch was thinking with the stock TPS - it seems to have a signal for WOT and some other signals it outputs on throttle variance, but it's not clear what it's for - and I don't think it's any use with a megasquirt.

The MS can use any TPS that is potentiometer based.

Fiid.

BTW - Happy to help with the tuning and setup if that's a help.

QUOTE (fiid @ Feb 5 2005, 09:00 AM)

Oh yeah - I have no idea WTF Bosch was thinking with the stock TPS - it seems to have a signal for WOT and some other signals it outputs on throttle variance, but it's not clear what it's for - and I don't think it's any use with a megasquirt. The MS can use any TPS that is potentiometer based. Fiid.

Bosch went through a few variations on TPS sensing. Early systems only used a WOT sensor so they could add extra enrichment. A bit later, many systems got a closed throttle sensor so it could go into "idle mode". Still later, they added a few more contacts for intermediate throttle settings. None of these systems had any "accelerator pump" systems, except for things like air flapper overswing for K and L Jet. Some appeared to use MAP variation to judge this, too.

There was a LOT of experimentation going on in the early days. The D-Jet system on the '69 VW I just picked up has no throttle sensor at all, but uses instead a second pressure sensor (in addition to the MPS), which is set up to only switch on near 100kPa MAP for WOT enrichment. They discarded this in '70 for an idle/WOT throttle switch, then in '72, they went to a multiple-contact throttle sensor much like the one in the 914.

The earliest K-Jet systems (circa 1973) on the 911 had a 914-like throttle switch, which was dropped almost immediately for a MAP sensor (basically the opposite of what happened with D-Jet on the VW).

I'm beginning to think that one could build a perfectly acceptable EFI system that has ONLY a modern solid-state MAP sensor (fast reacting) and a engine-speed input. A change in MAP could be used for acceleration enrichment. No TPS at all. You could probably even combine the air intake and engine temp sensors into one "engine bay ambient temp" sensor.

Andy,

I did some looking, and the answer to your TPS question is: "Don't bother, you don't need one." Go to the msefi.com board, and hunt for the "MAPdot" code, which I believe is rolled into the latest "-extra" code (aka MSnS-E, which has its own forum on that board). The MAPdot stuff relies on the fact that current MAP sensors and the MS hardware are fast enough to sense throttle transitions w/o a TPS, giving you the accelerator pump function. I don't believe MS has ever use the TPS for anything else, since MAP will also tell you when you're at WOT (added enrichment), and RPM will tell you when you're at idle (need to operate the idle controller, if present).

Install the MSnS-E code, and you'll get this, plus higher resolution tables (12x12 instead of 8x8) for VE, plus a handful of other handy things, such as the ability to control a few ignition systems with a couple of minor hardware mods (like move this resistor, insert this diode, etc).

You should be able to use the other D-Jet sensors as they are.

there are a few people running the earlier MS and code without a TPS, I forgot all about that until James brought it up.......of course I'd like to sell mine so I say you must have one

Hello Mike,
Why do you want to sell your MS?

Thanks,
Walter

I picked up a Volvo 240 TB. It has the Bosch TPS (3 wire, so it should be variable) and is 58mm in dia. Plus, there is an idle air bypass screw so you can jerk with the idle speed easily.





Later,
Tom

QUOTE (Walter @ Feb 7 2005, 03:02 AM)

Hello Mike, Why do you want to sell your MS? Thanks, Walter

I have an extra Mikuni brand TPS one which came on the throttle bodies I am using



Tom,

that throttle body looks like it'll work great for your application...I wonder if that's the same TB that a fellow 914'r is running on his 2.4 D-jet 914??? He told me Volvo, and I want to say he said 240 as well....

QUOTE (Mueller @ Feb 7 2005, 08:33 AM)

Tom, that throttle body looks like it'll work great for your application...I wonder if that's the same TB that a fellow 914'r is running on his 2.4 D-jet 914??? He told me Volvo, and I want to say he said 240 as well....

I'm not sure... But I figured the Volvo is a 2.3L four and it redlines at 6500RPM. It's gotta be close. Plus, I like the fact that it's compact and has the idle adjuster on it.

You can barely see the Ford 4.6L 65mm TB in the background. I thought that might be a little big for my 'lil old 2.3L

Later,
Tom