05-23-2011 got it running - see end post.


75 2.0 with d-jet injection. just for a brief history, similar happend last week, and i replaced the coil- it had leaked.

Started fine, idle was good cold, - last week it began to idle rough and would just drop off, once i got it running again, it was really rough, but i got it home, -
found the coil was going bad, replaced, seemed to run fine. - sat 4 days , decided to drive it today.
It started fine, ran great, idle was smooth first 2 stops, 10 minutes after starting it, pulled up to a light, and idle just dropped out, had to feather it, kept it running thu the light, pulled into a parking lot, where it stopped. Could not get it to start again, even 20 minutes later.
Has new coil, points etc, fuel pump is running fine, MPS is newer, so are all hoses and injectors, fuel lines and filter.

I really think it is not fuel but electrical,- would a temp sensor cause it to begin to run rough, not want to idle properly when warmed up??

Phil\
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new addition 5/3--- have not got it to run, about had it with the f.i. sh--. now considering the dual carb conversion-
any new input on that, cost etc. thanks
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I thought bad CHT's caused it to run rich but not, not run at all. Does it still have points? I was having poor running with my air cooled Vanagon; stalling and not able to start but would start after awhile and could get home. I swapped out a used condensor and ... knock on wood ... so far so good.

Next time ground out the cht lead and see if it runs.

It won't want to start if you unplug the CHT sensor.

--DD

I might have a short in the wiring somewhere, barely started and limped home missing seems to.be firing on a couple rather than all 4 so now it does not matter cold.or hot. And it was like a switch was flipped. Running fine. Then bam. I had for gotten but it did the same thing last year, never figured out why, and for no specific reason suddenly ran fine again up to today.
Pjw

Hmmm, does this ever sound familiar. My '74 did the exact same thing last fall on the way to work as well, just before time to park for winter. I have had it out for 3 days this spring (driven daily) and seems to run not bad. I can detect some surge just as I put my foot into it but no stalling as of yet. Going to pull in off the road for a front strut cartridge replacement this weekend and I will probably swap out the points with Pertronix from a previous engine build and see what happens. Keep the thread updated if you find something. Wait...I know!, these little bundles of addiction just don't want to sit around in a parking lot, ignored for 8 - 10 hours!

Jim

you got that right!
so last night all i got done was test the head temp sensor, hooked up a new one just in case, no change. then put new plug wires on- no change, changed out the coil, no change. took cap and rotor out, no wear- they were fairly new-no change, tonight i will put a different points plate and triggerpoints plate iin to see if there is a change with that.

also will check the grounds and the relays and voltage regulator-
? volt meter had been at 13.7, is now showing 12? does this indicate anything?

pw

Yuppers, any 12v system should charge @ 13+ unless there is an issue with the regulator or the alternator itself. Try putting a high load on the electrical system (lights on high, full fan, rear window defrost (if equipped) wipers, the whole enchilada) to see if your voltage drops further. After a few minutes, if you see your voltage drop then something is wrong in your charging system. You can try raising the idle slightly to see if your voltage comes up, that would tend to be mor a regulator issue than an alternator. Check you belt tension, temperature differential can result in intermittent problems. If these simple test shows an issue, pull the alternator and take a trip down to your local parts supply house that offers free alternator testing. if it checks out, swap out the regulator. It would be wish to check one issue at a time so you can prove out what you have done to repair the problem so you don't spend needless $$$$.
If you can easily check the cell level in the battery, check that too. If your voltage drops too far it can produce a weak spark and result in some of the problems you have described, but generally it will also prevent a restart as there will not be enough reserve left in the battery to crank it over. This may or may not cure your running problems but you still need to address this one as it is a simple one to diagnose and repair. hope this helps.

Jim

The stock voltmeter is in a crappy place in the electrical system for telling you the health of the charging system. It will, however, give you hints about the light bulbs and such in your car; if the voltage doesn't drop as much as it "should" when you turn a light on, you have an idea that the bulb may be out...

If the meter is suddenly reading lower than it was, you have some sort of extra draw. Somewhere. You might want to find it.

When the car runs like crap, can you isolate the problem to any one or two cylinders? You can pull a plug wire or injector wire while the engine is idling to see if that cyl is contributing to the engine running; disconnecting a dead hole will make for no change in the way the thing runs.

--DD

If it is electrical, chances are you have an open circuit, not a short. Short circuits do happen when wire insulation gets chaffed and 2 wires touch each other or touch a grounded surface. This condition will mostly cause fuses to blow or lets the smoke out of the wires.

Mostly in these old cars you have open circuits where a wire isn't making a proper connection. Many times this is caused by oxidation on the spade connectors where it looks like a connector is connected but a micro-film of oxidation prevents good electrical conduction. The actual contact area of a connector is minute and any oxidation between the mating connectors could cause unusual and intermittent operation.

Sometimes simply disconnecting and reconnecting connectors allows the connector surfaces to bite through oxidation and make better contact.

You could try re-seating all connectors including the ground connectors on the engine case.

If you check for battery voltage, do it with the car running and measure at the battery connectors, then from chassis ground to the positive battery terminal connector, then from engine case to positive battery terminal connector.

UPDATE:

Frustrated with the F.I., - considering dual carb conversion and electronic ignition;

looking for opinions, feedback from those with experience, and any for sale?
-fyi- i have had a 69 austin healy with dual webber carbs. i know they can present their own problems and issues.- i always had issues with the points and coil etc, so thats why i am considering the change with that combo.-

thanks

Did you check the trigger point wires?
To sort out my FI I pulled the connector from the "ECU" and probed all components. DO NOT probe the ECU.
here is a pin-out and value chart from the other 914 place:
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

Wow, thanks for all the info, - probably need someone with more experience than myself to sort it all out, but i will give it a shot before i do anything drastic.- like i have said before - if running good, it was great- 29-34 mpg, etc. but sitting more than driving due to f.i. fuel/electrical frustrating.

thanks- i'll let you know if i figure out anything.

It's fairly easy to do. Take the ECU out and remove the connector and probe the components with an ohm meter. The hardest part is getting the ECU out...

yes, so how exactly do you get the ecu out?

I'm going to 2nd the FI trigger points. They do go bad. The point blocks wear and so do the contacts. I don't have the exact test, but there is a pass/fail contact test.

About five or six years ago I had a board member stopping by on a trip. He called from about 60 miles away and said the car had been running pretty good, and then just lost power and eventually died. I towed him in and we checked the FI system to find bad trigger points.

remove the battery, loosen or remove the two top inboard bolts, loosen the large screw that is on top of the ecu bracket and slide the ecu towards the center of the car. It can require some maneuvering.

EDIT: remember probe the components; DO NOT probe the ECU.

no progress-

but tonight i plan on checking thru the electrical system and will be installing a petronix, so thought it would be a good time to run down and test all of the circuits, grounds etc.

where do i locate all of the system ground locations?

Are they accessible from above or below?

Thanks.

FI grounds are on the rear of the case ... top side ... multi spade connector under one of the case bolts.

Another person is having a similar problem. It appears the points are not holding adjustment as they close up. Suspect the dizzy or the cheap ass Autozone points. I'll get around to changing the dizzy one of these days.

D-Jet has some of the worst electrical plug/connectors there is on a vibrating engine. Once the little rubber boots dry up, they literally vibrate and fall out.

Check the plug for the FI trigger points at the dist. It may have come loose.

As others have mentioned, pull the trigger points and replace them, not cheap, but they do wear and cause issues in pairs of cylinders.

Thanks for the suggestions- plug is good, - I have seen your thread from the L-jet installation on yours, and saw you made some changes with dizzy etc. How long do the injector trigger points last, because i took an look, they look new, i put them in 18 months ago and they only have about 4000miles on them, seems they should be still good- yes they are expensive-compared to the other t.p.'s.

- i took the distributor out, changed out the points and the vacuum advance, rotor, etc, still no change,- just got the condensor so tonight i will switch that out as well. but anyway neither the points or the t.p. points seem to have any wear or corrosion at all.

-also going to replace the fuel filter tonight as well,

-How do you like the petronix?- i have one but have not put it in, - wanted to try to figure out what the problem is first, then give that a shot.

FYI- last year i put all new injectors, MPS, wires, points, plugs, fuel lines, vacuum, etc. - and 2 weeks ago running and idle great having just had valves set and full tune up and timing,dwell etc right on- 34 mpg on last 2 tanks(driving to work- 45-mph some stops) so thats why it seems so

-also tested the CHT - is not the problem

Trigger points are reliable. I have never had a problem with them.

Points replacement modules, Petronix, Comufire, etc work really well if they have solved the problem of burnout when the key is left on with the engine not running.

Did you ever change your High Tension wires (spark plug wires)?

Yes, also changed those in the last year@2000 miles ago.

I have little experince with the Porsche FI but I had Webbers on my 2.0 and wished I had FI the whole time. Carbs on a race/track/autocross car cool. DD/Street not as well.

**UPDATE**- Running!- and here's what it was.---(drum rollxxxxxx)

Points and coil- not fi points,

Initially i installed the in-line fuel pressure gauge and new regulator- because i had one and needed to know if pressure was set correctly, - blew out some lines, put some fuel tx in tank etc new filter-- still did not run.

-changed out the plug wires, pulled the plugs, checked, gapped etc. -
- had pulled distributor, cleaned and reset points, changed the condensor, still no go.
-i had ordered an electronic module(hotspark) and the matching proper ohm coil
so when that came i installed and wired the module with the new coil, and ---

immediately started- so it was electronic not fuel,

runs very smooth right now, but was not able to dial in the timing as of yet, and i'm not sure i have the hoses all hooked up correctly right now.-(vacuum advance and retard). idling at 1400, if i go lower, it surges - i had that problem before and did not get it set until we did the valves and then timing,then the surge went away and had perfect idle speed)
so i know i have to set it at 3500rpm but could not get timed right for some reason- moving the distributor would not get it lined up at that RPM- yes hoses were disconnected at the time.

recheck valves? what else?- timing mark is correct

any suggestions on that? otherwise very close and atleast it is running, will see how long the hotspark lasts.

phil