I need help.
I am at the end of my ability to get this running right.
I cant hear any clicking when adjusting the the tps.
I am not even 100% positive that is what it is.
Someone here in this community has to have the ability and knowledge to help me.
PLEASE!
Thanks guys

Start here: http://members.rennlist.com/pbanders/djetparts.htm
http://www.rennlist.com/techarticles/djetronicfuel.htm

I am not sure what your specific probelm is, but the 914 FI is fairly simple so hang in there!

Get your OHM meter out and go to work. One way to check to all of the components is to do it through the FI wiring harness (this also helps weed out a bad harness) . Remove it from the CPU (lack of a better term), but NEVER ohm out the CPU only the components from the harness that attaches to the CPU. Some where on the web there is a table that list all of the resistances for the FI components. Here it is: http://www.914club.com/bbs2/index.php?auto...amp;showfile=25
you need to down load it.
Go slow and stay calm you can do it!

oh, the ignition needs to be on to hear the clicks, but why not let the OHM meter do the work.

what is the problem? how is it running/idleing ect?? more details..


just went through everything on my '74 2.0 adjusting the tps was part of it.. you should not hear clicking when adjusting the tps or at least i never noticed it, if you take off the throttle w/ tps it is much easier and you can see what the adjustment is doing, you do not need an ohm meter after seeing what the ohm meter is telling you about the toggler switch inside
the tps toggles from idle contact to the other contact, don't look at the circuit board.. look at the switch..

First change your avitar it is getting your car mad

Mainly it is bucking under acceleration.
Is there a place anyone knows of in the Central Florida Area?
Like within a 100mile radius of 34741.
Or know anyone?

that is a curve problem, could be who knows, ecu issue? weird mps issue? bucking under constant speed would be tps.. but purely on acceleration? sorry could not help further..

The first thing I would try would be to unplug the TPS and see if it runs any different. I don't have mine hooked up currently and have a stock 74 2.0 FI. The only thing you could notice is a sluggish throttle response when starting out, but it is extremely minimal. The "experts" have said you can unplug the TPS with little to no effect; that is where I got the idea from. I had weird bucking at different RMP's with mine plugged in. I cleaned my wiring harness and checked the connections. When doing this I unhooked the wiring harness plastic plug in that, went to the TPS, and marked the wires (which are all white) the markings rubbed off and I didn't know the order. Haven't wanted to do anything with it sense. Honestly I haven't noticed any difference since I unplugged it.

Try this first and then post your results. If you prefer phone advice PM me and I will give you my number.

Steve, two things point to the TPS:
1. You can't hear the injectors click when you open the throttle.
2. Your car bucks under acceleration.

These two symptoms can both be explained by a faulty TPS or by faulty wiring to the TPS.

I think you can work your way through it. Seriously, remove the cpu from its bracket and remove the wire harness.
follow this with your ohm meter; use your battery ground:
Terminal(s) Component Expected value
1 and 13 TS1 - air temp sensor 300 ohms @ 68 deg. F
3 and ground Fuel injector - cylinder 1 < 3.0 ohms
4 and ground Fuel injector - cylinder 4 < 3.0 ohms
5 and ground Fuel injector - cylinder 2 < 3.0 ohms
6 and ground Fuel injector - cylinder 3 < 3.0 ohms

7 and 15 MPS primary coil 90 ohms
(check each lead and make sure there is no continuity to the MPS case)

8 and 10 MPS secondary coil 350 ohms
(check each lead and make sure there is no continuity to the MPS case)

9 and ground Accelerator Pump Contact Track #1 10 indications of continuity from fully closed to fully open throttle

20 and ground Accelerator Pump Contact Track #2 10 indications of continuity from fully closed to fully open throttle

11 and ground ECU ground circuit Less than 0.5 ohms
12 and 21 Trigger contact switch #1 Alternating continuity as the engine is cranked
12 and 22 Trigger contact switch #2 Alternating continuity as the engine is cranked
16, 24 and ground ECU power source from main power relay on regulator plate Turn key to the "on" position, read voltage, should be less than 1 V difference from voltage measured at battery terminals.

17 and ground TPS idle contact Less than 0.5 ohms when the throttle is closed, infinity when the throttle is opened more than 2 degrees.

18 and ground Start signal from ignition switch Turn key to "start" position, read voltage, should be greater than 12V.

19 and relay plate terminal III (white plug, back left corner) ECU control line for the fuel pump relay Less than 0.5 ohms

23 and ground TS2 - CHT, cylinder head temperature sensor > 2K ohms at 68 deg. F for all but 1973 2.0 L, > 1.2 K ohms for 1973 2.0L

When listening for the injectors where do i listen?
in the distributor?
And how loud is it?

can you explain 19 and 23
what is relay plate terminal III ?
what is "23 and ground TS2 - CHT, cylinder head temperature sensor > 2K ohms at 68 deg. F for all but 1973 2.0 L, > 1.2 K ohms for 1973 2.0L" mean?
That one confuses me.
And i have a 74.

Hey Steve,

Write to SMG914. Steve Gaglione. He has several 914's. And he has had a lot of them over the years.

He is in Tampa, and he is the consultant for Auto Atlanta. He is my inside expert, and he knows a lot about 73-74 2.0L fuel injection. He has had many, and his ownership infected me with the 2.0L 914 bug back in 76 when we lived in NW NJ. It is all his fault.

I cannot say I ever had bucking, but I have had just about everything else, including a burned piston and a sucked valve, and Steve or George at Auto Atlanta can help you. George owns AA, and he is Dr914 on here.

It takes time to diagnose problems with DJet injection, but you are on your way looking at the values already published in this thread. I have been there before, but with different symptoms than you over the last year. One by one, you can eliminate issues, and the car will run right again. The only tip I can get close with is to make sure the plug wire to cyl 3 (passenger rear plug) is far away from the Manifold Pressure Sensor. The power in the wire messes with acceleration big time from idle. Electromagnetic energy messes with the coil inside the MPS every time that cylinder fires. Move the wire coming from the distributor to up under the injector pipes that come down from the throttle body. The MPS is toward the rear of the battery. A fist sized silvery item just below your deceleration valve.

Having a 74 2.0L is worth it, but they get cranky. I know. I am on my 6th in 34 years. I have less hair on my head in the last year from mine, for certain.

Good luck,

John

for pin 19 you measure the wire from the connector pin 19 to the plug on the relay board terminal III. This is the fuel pump signal. I dont think you have a problem here.

for pin 23 you are measuring one of the tempature sensors. on the 1973 the resistance is different than all other models. It used an in-line resitor to make the mixture richer.

If you go through the FI system with this method besure to write down your measured values. You will then know the electrical condition of all of your FI components and hopefully you will find your fault.

BTW Dave Sprinkle sells a replacement TPS board.

Item 71 is your FI harness and item 90 is the relay board.

Click to view attachment

Are you sure it has to do with the TPS? Have you checked to make sure you are getting fuel to the injectors? Fuel filter could be clogged or the filter in the gas tank.

"buckiing" on the TPS is as read from 2 of the contacts on the tps board making a connection from the small particles of gold that over time has gotten dragged through the "space between" on the Circuit board from the armature's action.. this buciking usually occurs again as read at low constant speeds first (cruising a parking lot) which make sense because on your ciruit board that area would be used the absolute most as everytime you press the pedal you pass that area..

to only buck under acceleration in other words not on the highway, not on the blvd., not in the parking lot.... just on the on ramp, and when continuiing after a full stop, take off, passing ect..

so when the pedal/tps/throttle is depressed the car "bucks" but is steady at any constant speed along those same areas on the TPS when contant or not depressing the accelerator..

does not make sense for a switch unless something is loose..

fuel delivery? spark?

a 914 with Djet will buck too if the AFR is way lean a. What MPS and ECU do you have? What color injectors?
I have seen all kinds of mis matches that make the car run funny.

When listening for the injectors where do i listen?
in the distributor?
And how loud is it?

turn on you ignition and open the throttle from inside the engine compartment. the clicking is faint as it is the injector solenoid that you are listening for. a tube or stethoscope could be useful in listening to an injector.

listen at the injectors.. just off each fuel rail..

Sounds like a lean miss to me as well. When you say "under acceleration", are you opening the throttle and then holding it open to accelerate, and then it "bucks", or does it just buck AS the throttle is opening? If it's the the former, I doubt it's the TPS.

I would sooner suspect MPS curve, or fuel pressure is low, or maybe you have wrong injectors (yellow is wrong, green is right).

As Belyseng asked- which MPS do you have and what color injectors?

Also, find your cylinder head temp sensor wire- it comes out of the engine shroud next to #3 spark plug wire, kinda out of sight below the #3 intake runner tube. Trace it to the harness and tell us if there is a big 270 ohm power resistor plugged in series before the wire enters the harness.

Also, is this new behavior, or a recent change in behavior for your car? Did you change anything just prior to experiencing the bucking?

Jim

I think if you changed your avatar then it would start running right.

These cars are sensitive.

I will look to see what mps, ecu, and injectors i have.
This is not a recent change. I bought the car in Oct.
Was doing the same thing for PO and I am just now diagnosing, as i am now ready to put the car on the road.

Ok, I understand but people put different Fuel injection parts together thinking it doesn't matter. IT DOES.
Note the ECU number
Note the MPS number and if its been drilled at the end.
Look and all the injectors and note what color they are.
Check your fuel pressure with the car running.

Darn near every year was different in regards to the FI parts and you can't mix and match esp 1.7, 1.8 and 2.0L.

hopefully tomorrow i can get to my dads where the car is garaged.
Anything else before i print this out to take with me?
since he has no internet!

My results are in dark red
i am not sure i did this right,


1 and 13 TS1 - air temp sensor 300 ohms @ 68 deg. F 237ohms at about 80 ambient temp
3 and ground Fuel injector - cylinder 1 < 3.0 ohms 3ohms
4 and ground Fuel injector - cylinder 4 < 3.0 ohms 2.7ohms
5 and ground Fuel injector - cylinder 2 < 3.0 ohms 3ohms
6 and ground Fuel injector - cylinder 3 < 3.0 ohms 2.8ohms

7 and 15 MPS primary coil 90 ohms 95.8ohms
(check each lead and make sure there is no continuity to the MPS case) none

8 and 10 MPS secondary coil 350 ohms 359ohms
(check each lead and make sure there is no continuity to the MPS case) none

9 and ground Accelerator Pump Contact Track #1 10 indications of continuity from fully closed to fully open throttle what? I do not understand.

20 and ground Accelerator Pump Contact Track #2 10 indications of continuity from fully closed to fully open throttle what? I do not understand.

11 and ground ECU ground circuit Less than 0.5 ohms .4ohms

12 and 21 Trigger contact switch #1 Alternating continuity as the engine is cranked am i supposed to crank the car with the computer unhooked?

12 and 22 Trigger contact switch #2 Alternating continuity as the engine is cranked am i supposed to crank the car with the computer unhooked?

16, 24 and ground ECU power source from main power relay on regulator plate Turn key to the "on" position, read voltage, should be less than 1 V difference from voltage measured at battery terminals. 16=11.95 24=11.94 battery 11.94

17 and ground TPS idle contact Less than 0.5 ohms when the throttle is closed, infinity when the throttle is opened more than 2 degrees. what? I do not understand.

18 and ground Start signal from ignition switch Turn key to "start" position, read voltage, should be greater than 12V. 0?

19 and relay plate terminal III (white plug, back left corner) ECU control line for the fuel pump relay Less than 0.5 ohms did not test as the car does run and and drive

23 and ground TS2 - CHT, cylinder head temperature sensor > 2K ohms at 68 deg. F for all but 1973 2.0 L, > 1.2 K ohms for 1973 2.0L 2450 at about 80 ambient temp