Throttle Position Switch, I'm confused Options

[Rhodes71/914]

Here is some background -

Attempting to get my 71 1.7 D-jet tuned here is what has been done so far

New: plugs, wires, cap, rotor, points, condenser, changed out FI trigger points with clean ones (that made a huge dif)

Valves adj, dwell set, timing set.

Idle is ok, timing set 27 deg BTDC engine revs fine in neutral.


No power when engine is under load.

Went to calibrate TPS per pelican tech article. Problem is that my TPS has only 4 pins and the one in the article has five. Plug matches my TPS

Any ideas?

Would post a pic but I keep getting a timeout error so gave up on that

[Bleyseng]

Are you sure you have the wires hooked up right? Check the firing order..... Check the spark plug wires to make sure one isn't undone.

Geoff

[JeffBowlsby]

my TPS has only 4 pins and the one in the article has five

The early cars only have a 4 pole TPS...the later cars have a 5 pole...but the same four wires. The 5 pole TPS connector has a blank cavity. The four wires are the same and in the same order on both the 4 and 5 pole TPS.

[Rhodes71/914]

Are you sure you have the wires hooked up right? Check the firing order..... Check the spark plug wires to make sure one isn't undone.

Geoff

I have a feeling something is going on with #2 Cyl, it has spark at the plug but when the engine is running and I pull the FI connecter the engine doesnt miss a beat.


It may all be for not, I may just bag the whole thing and work on the 2.0 and get it in the car. Just too tempting to try and get the 1.7 going since it is sitting in the car.

[BPGREER]

I'm new to the board, so maybe I shouldn't go around throwing out my advice...But...Have you checked your fuel pressure? I had a similar problem about a week ago, and realized my fuel pressure was about non-existant. It idled/reved fine, but had no power under load. I've only been an owner for about 2 months now, and just got mine on the road this past week. 2 months of steady work on a car that sat for 17 years, is a descent learning experience to say the least. Good luck, I'm sure you'll figure it out.

Brian

1973 Silver 2.0

[Bruce Allert]

Sean, if you pull #2 injector connector and there's no difference try testing to see if it is getting a signal to fire. Check the continuity between the connection at the ECU and the FI connector with a multimeter set to ohms. Pull the connector off the ECU and count down to #5 terminal. You can check its ground the same way. Here's the link to Brad Anders site where he lists all the pins with their numbers. If you do your whole FI harness that will eliminate the possibility of a shorted or broken harness.

http://members.rennlist.com/pbanders/DJetP...arts.htm#setups

Good luck, the testing of the harness is fun & you learn where everything is (IMG:style_emoticons/default/beer.gif)

.....b

[Cap'n Krusty]

You adjust the valves yet? FIRST thing you do in diagnosing a running problem. After you do that, get it hot and do a compression test .............. The Cap'n

[Joe Ricard]

Yup 4 pins is OK my 70 1.7L has 4 pins. but glad it has been said that the center pin is a blank. (thanks Jeff). I have a dead spot on the 4 pin TPS I also have a 5 pin TPS sitting on the shelf. Now I may have to do some soldering to change out the contacts. HMMMM (IMG:style_emoticons/default/idea.gif)

I think you will be really suprised at the umph and ecomony of the early 1.7L engines. 32 MPG @ 75-80 MPH. Shoot they are rated at 80 HP.

May be as simple as the injector is plugged. Move the injector to a different cyllinder and see if the symptom moves. You may consider pulling all the injectors and doing a spray test into plastic cups. Observe the pattern and volume of fuel.

[Rhodes71/914]

Can somebody tell me if the wire in the middle of the picture should be attached somewhere. It's just kinda hangin out there.

[Bruce Allert]

Just looked at 2 of my TPS's from my old (blown up) 1.7 and neither had any wires in them. It is a 73 & ot a 71. Also it is an 021 TPS. Wonder if these would work on yours?

......b

[Rhodes71/914]

Just looked at 2 of my TPS's from my old (blown up) 1.7 and neither had any wires in them. It is a 73 & ot a 71. Also it is an 021 TPS. Wonder if these would work on yours?

The numbers following the VW symbol 022 906 111 A. On the back of my TPS does this mean 022 would be the corresponding #. Does it have a 4 prong plug?

[JeffBowlsby]

glad it has been said that the center pin is a blank. (thanks Jeff).

Nay nay, nay, I didnt say that. One of the endmost cavities on the 5Pole TPS is blank...NOT the center cavity. I can't tell you which end, because it would depend on how you held the TPS hosuing on the harness.

Now I may have to do some soldering to change out the contacts

No soldering necessary, the 4 pole TPS plug fits perfectly in the 5Pole TPS...you just gotta be sure you miss the correct pin on the 5Pole TPS body. Don't know if the 2.0L TPS is appropriate for a 1.7L car though, I suspect its 'curve' is different so you may not get optimum results.

022 906 111 A

Thats the correct TPS for your 70-71 1.7L 914, it is a 4 prong TPS.