Need help fast! Injector points?

[mkinne]

Need some advice fast. 1.7L starts but soon dies.
Here are the symptoms so far:

Happened suddenly. Was running fine until just before reaching work.

Fuel pressure 30psi as long as pump is running. Pressure steady while engine cranking and sputtering. This means pump and reg OK, yes? Fuel filter less than 6mo old. Yes, there is gas in the tank.

Can almost keep it running if I tap-dance on the throttle. Also, with key on, engine off, move throttle, I can hear injectors click. This means TPS working, yes?

Can't remember if TPS signal goes thru injector points, or if they are totally separate. If separate, could this mean injector points are bad? Had dizzy apart about 6mo ago. Everything looked fine.

Any way to tell if problem is injector points OR in brain?

Any particular ground wires to check?

Anybody know of a place in the Inland Empire (So. Cal) where I can get a set of injector points (if needed) tomorrow? Don & Glenn's? Phone#?

Hope this makes sense. Writing fast 'cause I need to catch a ride home. Will check back tonight. TIA

Matt

[Jim Smolka]

I recommend jumping the power contacts around the fuel pump relay so that power goes to the pump when the key is on. Then try and start the car. Then, check your Fuel pressure while it is running.

Also, check points and look @ distributor to make sure it is not cracked. Of course check wires connections.

Next, borrow the brain tester from Pelican.

Just a starting point.
When you get it running, let us know what the fault was.

Jim

[7391417]

About checking the injector points, The first time I checked mine I was looking at the contacts (The actual points) of the fuel injector points. They looked fine to me, so I just cleaned them up a bit and put them back in. Well pretty soon the fuel injector problem got worse and gas mileage was way down. Found out that one pair of fuel injectors were constantly on. I pulled the fuel injection points again and this time realized what I should have been looking at in the first place! The dist. shaft has a cam lobe on it which actuactes "mini fixed place pushrods" on the fuel injection points. The little rods on mine where completely worn down causing the points to stay contacted all the time. Just thought you might want to look at that.

-Brent

[mkinne]

Thanks for the response Jim.

The fuel pump seems to work fine. Key on, runs couple seconds, up to 30 psi, slowly leaks down to 20 psi after pump stops.

By way of experiment, I found that the injector points also trigger the fuel pump to continue running. Heres what I did ... Unplug the injector points and connect a jumper wire to the center terminal in the plug that goes back to the ECU. Key on, and quickly tap the other end of the jumper wire, back and forth, on the other terminals in the plug. The pump will run for a couple seconds when you tap one terminal, and stop if you do nothing else. Tap the other terminal and it will run again. Tap the same terminal twice and it will NOT run. I managed to keep the pump running continuously for about 20sec. Steady 30psi. Also, I could hear injectors clicking with each tap. Not sure exactly which ones.

Also played with the TPS. Key on, rotate the butterfly, and two injectors (1 & 4) go "brrrrp". (like in D-jet article.) Put car in 5th gear and push a little to rotate engine (and dizzy). Rotate butterfly and other two injectors (2 & 3) go "brrrrp". Now unplug the injector points. Rotate butterfly and two injectors go "brrrrp". Push car, rotate butterfly, same injectors go "brrrrp". So ... the ECU must be counting (or looking for alternating) pulses from the injector points?

From the electrical diagrams (Haynes and PP), it looks like both the TPS and injector points connect directly to the ECU and the ECU sends signals to fire the injectors. Since I can get all injectors to fire using the TPS or "false" injector points, does that mean the ECU is good? (I hope)

Pulled the dizzy. Injector points look OK but are original, AFAIK. They make contact fine at stand still. Could they be worn enough to make the ECU miss counts?

Two auto parts store in my area (both familiar with VWs and Porsches) say these injector points are no longer available. (Hope PP still has some.) Going to pull the dizzy from dad's 914 tonight and swap points.

Any other suggestions?

Cap, rotor, plugs, wires, all less than 8mo old. No visible cracks. Clean inside and out. I had one person suggest a bad coil. Anyone else thinks so? (I think dad is gonna lose his coil tonight, too)

I can start the car and keep it running by pushing the pedal up and down. As soon as I stop moving, no matter what throttle pos (1/2, 1/4, no throttle, ...), the engine sputters and dies.

Thanks in advance, again.

Matt

(looking back, this was a long post)

[mkinne]

Hey Brent
Just saw you post

Makes sense what you say. I checked exactly that with the dizzy on the work bench. The mini-push rods are worn but not completely gone. Rotating the dizzy by hand, I get clean makes-and-breaks. Maybe they are not so clean when rotating at engine speeds?

BTW, the problem car is also '73 1.7

Matt

[mkinne]

Heres more ...

Added 5gal of gas and changed fuel filter. No change.

Swapped coil. No change.

Swapped injector points. No change. Mini push-rods on both sets look about same. Approx 1.5mm long.

Will a '73 2.0 ECU work on a '73 1.7 engine?

Guess I should have mentioned before, car will not run at all with TPS unplugged. Cranks strong, almost fires, dies as soon as starter pulls out. Like I said before, with TPS plugged in, I can keep it running (rough) as long as I keep moving the throttle.

Any advice? Somebody? Anybody?

Matt



[This message has been edited by mkinne (edited 12-02-2000).]

[JP Noonan]

I would take another look at the IGNITION points. I set mine wrong (too small a gap) and the only way the motor would stay runnning was if I kept the accel pedal down.

Also look at the condition of the vac line to the MPS, and the resistance of the CHT sensor. If there is an inline resistor between the CHT and the harness remove it.

[Conrad W Peden]

Do the lobes on the dist. shaft that the points ride on wear to the point where new points don't work? Say if they weren't lubed or too much crud in there.

I just had mine adjusted and now that this question has come up I made me think.

This could also lead to premature points wear, well at least the cam followers would wear. Which would lead to the gap being wrong which could damage the points. Right?


Mind you, I'm about two months away from finishing my resto. so I'll find out then.
------------------
CWP/VIR
72 914 L20E in rusto.
73 914 L20E 2.0L in resto.



[This message has been edited by Conrad W Peden (edited 12-02-2000).]

[mkinne]

Also should have mentioned I have point-less ignition (Compufire). Been in there so long I forget what regular points look like.

I like the MPS suggestion. Hoses look good but could the MPS fail such that the ECU will go to an extremely lean condition? I beleieve the ECU determines the duration that the injectors should be on based on temperature (CHT), pressure (MPS), engine speed (injector points), and throttle movement (TPS). Could the ECU be broadcasting zero duration to the injectors?

Which, exactly, is the CHT sensor? I think I know, but I would like to be sure that I am checking the right one.

[Conrad W Peden]

I meant injector points.

Unless there is a point less injector points availible?

------------------
CWP/VIR
72 914 L20E in rusto.
73 914 L20E 2.0L in resto.
http://members.rennlist.com/a914lover

[mkinne]

Heres more ...

CHT measures 660ohm cold. (can' get it hot) D-jet article says 2-3kohm cold, 1kohm hot. So, ECU thinks engine is very hot. Would this create extremely lean condition?

MPS has four terminals; 7, 8, 10, 15. D-jet says should be 90ohm between 7 & 15, 350ohm between 8 & 15. I measure 88ohm between 7 & 15, open circ (infinite ohm) between 8 & 15, 325ohm between 8 & 10. I'll assume that D-jet meant 350ohm between 8 & 10. Sounds like MPS is OK?

Tried 2.0L ECU. No change.

Tried spare ignition module. No change.

Tried both of above with TPS plugged and un-plugged. AS before, car will not run at all with TPS unplugged.

Out of curiosity ... I see another sensor on top of the engine, right hand side, under the air distribution can (not the oil pressure sensor). Has one wire going to it. What is this?

Its been a wonderful weekend.

Matt

[mkinne]

So ... I'm on way out the door and spot some electronic junk. Quick look through and I find a 2.2kohm resistor. Splice it in to the CHT and it now measures 3kohm, total. Hop in, car starts right up, idles a little rough, but its running by itself! After 5min its idling smooth, a little slower than usual. Not fully warmed up yet. Responds nicely to throttle. Great! I'll order a new CHT tomorrow. JP gets the prize (everybody cheer).

Then I think about the TPS again. Lets unplug it and see what happens. Turn engine off, unplug TPS, engine will not restart. Cranks like crazy, but no fire. Slight smell of fuel that I didn't notice before. Way too rich now?

Half hour later, it still wont start. Think I'm on the right track but still something missing. Any more suggestions.

Matt

[Dave at Pelican Parts]

>CHT measures 660ohm cold. (can' get it hot) D-jet article
>says 2-3kohm cold, 1kohm hot. So, ECU thinks engine is very
>hot. Would this create extremely lean condition?

Yes. When you pump the throttle, you are adding extra fuel (through the "accelerator pump" contacts). If you are running rather lean, this extra fuel will help the car to keep running.

BTW, the hot measurement should be less than 1K ohms. Generally, very much less. Often, below 100 ohms.


>MPS has four terminals; 7, 8, 10, 15. D-jet says should be
>90ohm between 7 & 15, 350ohm between 8 & 15. I measure 88ohm
>between 7 & 15, open circ (infinite ohm) between 8 & 15,
>325ohm between 8 & 10. I'll assume that D-jet meant 350ohm
>between 8 & 10. Sounds like MPS is OK?

You have an old version of the article. This typo has been fixed in the past year. Yes, the MPS sounds OK.


>Tried 2.0L ECU. No change.

In 73 only, the 1.7 and 2.0 ECUs are the same. No surprise there.


>Tried spare ignition module. No change.

Good thing to try--the ignition is often at fault in cases like these. But I'm pretty sure that you found the problem in the CHT sensor.


>Out of curiosity ... I see another sensor on top of the engine,
> right hand side, under the air distribution can (not the oil
>pressure sensor). Has one wire going to it. What is this?

This is the Thermo-Time Switch. It enables the Cold-Start Valve when the temperature is low enough. I have heard 50F and 40F as "low enough"--not sure which if either is correct. The CSV should only get power while the starter is cranking, and only get ground when the TTS is closed. The CSV needs both power and ground to open, otherwise it doesn't let any fuel into the intake.

I'm not sure what exactly is going on with unplugging the Throttle Switch. From the fuel smell, I'd say you may have flooded the engine or perhaps accidentally unplugged the ignition. Let it air out, plug the TS back in, and try again.

--DD

[mkinne]

First ... Thanks for all the feedback, Dave. The first thing I did, last nite, after the car would not re-start, was to plug the TPS back in. This did not help. Sorry for leaving that bit out.

Second ... Damn, damn , damn, damn, damn!

This is getting crazy.
After final post last nite, I tried to start car again. Crank, crank, crank, but no vroom. More fuel smell. Maybe flooded? So I hold my foot to the floor, crank, sputter, and its alive again. Let it run for a bit, seems smooth, no smoke. Shut it off, lock up the shop, go home hoping that a new CHT sensor will fix everything.

Today starts out good. first place I call can get the sensor by afternoon. Pick it up after lunch, wait for quitting time, and go to work on the car. CHT is a %&*@#! to get out. Almost thought I had to pull the intake manifold. Old and new on the workbench. Tiny numbers match. Good! Lets check ohms. New one shows 1.8kohm (urrrh?) Old one shows 1.3kohm (Arrrgh!) What happened to 660? Is my DVM bad? check it with some known resistors, everything OK. Well, old CHT is a little rusty. Musta been a bad ground? Put the new one in, more %&*@#!

Check all connections, hop in, try to start the car, and its WORSE THAN YESTERDAY! Now I can't even keep it running by moving the throttle. It fires, runs erratically, and dies after a few seconds. Fouled plugs from being flooded last nite? No time to chaeck today, and I wont even have time to look at it until maybe thursday.

What is going on here? Some body must have an idea?

Matt

[Dave at Pelican Parts]

Did you unplug the extra resistor?

--DD

[Pritchard]

I have had a similar problem with my '74 2.0L. I found after a new CHT and many hours of frustration that I had a defective Vacuum advance unit on my dizzy.It would not hold vacuum on the retard side. I replaced it and the problem went away. This may not help you, but it couldn't hurt to check.

Lots of luck!

Pritchard

[mkinne]

Dave - Yes, extra resistor is out. I had hoped that new CHT would not need it.

Pritchard - Vac Advance unit seems to work fine. Holds vac and moves smooth. I have an extra dizzy from a 2.0L. It has two vac line connection points. Mine has only one. 2.0L dizzy seems to have same range of motion as mine.

Matt

[JP Noonan]

Opps, guess I wasn't right after all.

If you have a vacuum pump have you tested the MPS to see if it holds vacuum? Don't go crazy but it should hold at least 5-7 psi, maybe even go up to 10 psi and see if it leaks down. It shouldn't, I had a leaking MPS on a 2.0L and it ran similarly to your car. Hard to start, and whould die at stoplights. I just remembered that.

[mkinne]

Think I finally got it fixed.

Swapped in an MPS from a 2.0L and it started right up. Seems to run smooth, but I expect it is alittle rich now.

So ... What is wrong with the old MPS? Ohms check out nearly identical to the 2.0L unit. Holds vac or pressure just fine. Anybody know how these things work? As I understand it, there are two coils inside. Sounds like a transformer. Maybe the vac moves one coil relative to the other causing a change in the output voltage? Anybody know the nature of the voltages involved?

I'd like to find out whats wrong with the old one. Maybe fix it if possible. If not, I'll be looking for a 1.7L MPS. Any sellers?

Matt

[Ed Atkinson]

Why do you think all the cars built now use a "hot wire" sensor.. because the MPS was a mechanical part [subject to failure].
Aside from mechanical engine problems or ignition problems; Matts start and die problem HAD to be: lose of fuel pressure or MPS! CHT sensor usually causes: NO start or RICH condition! The engine will run without the air sensor; The TPS sensor is mainly only for idle, accel, and full load conditions; The trigger points are for injector timing..and the ususal failure is operation on only two cylinders, as it is rare for BOTH sets of contacts to fail at one time. The MPS is kind of like an old AM radio tuner.. as Matt said.. transformer.. the failures are usually: loss of abillity to hold vacuum or the core is stuck and unable to move [sending a full load reading to the ECM] In my 30 years of working on these cars; I have never found a MPS that showed a bad resistance reading [well maybe a few] and I do have the Bosch tester; as the manual says: "Try a GOOD KNOWN unit"!
Sorry but I am not able to read these pages each day to help you all out!
Matt the 2.0 MPS will work FINE on your 1.7 and give you a little extra power and a little less fuel economy!
The early sensors have a screw adjustment for fine tuning!
I have used these sensors for turbo applications; as they are able to go to an even richer condition... ie: 0 manifold pressure to even 10 PSI manifold pressure!
I hope you are following me on that..
Anyway...Goodluck with your cars and anyone feel free to e-mail me for help!
The D-Jectronic system is actually VERY simple! And this is why it is STILL used today in new cars!! Though some changes have been made! Ed Atkinson