I have a 75 2.0 d-jet. i turn the key about 4 times to get the fuel pump sending gas to the engine. Starts right up. it idles a little low to begin with but then idles about 1000 rpm after 5min. So I decided to take a drive. running great down the highway no issues what so ever. After about 25 miles up the road engine dies. Battery is fine and the starter works well, not a battery issue. I can't restart it. Had to have it towed back home. Let engine cool down but still won't start. Fuel pump engages but no start. Shot some starting fluid in throttle body but again no start.

I know my fuel injection harness is not the best but it wasn't good before today. Looking on line I think it might be a cht sensor issue. Saw this online https://www.youtube.com/watch?v=fbmanDTIun8

They tested the cht to ecu and found out it was a bad cht. Once they changed it their car fired right up.

I haven't checked the fuel pressure, I haven't checked the injectors, I did check spark and I have it on the sparkplugs. I shot some starting fluid in the spark plug hole and no start.

Any ideas? It is funny that it was running great and then died.

Buck

Same exact prob on my 74 2L turned out to be either a bad relay plate, bad relay, and/or bad connections between relay plate, relay, and/or wiring harness.

Remove all the connections, clean them up, lube with dielectric grease, and slightly spread the split-pin connectors on everything (relays and terminal pins.

http://www.914world.com/bbs2/index.php?showtopic=304863
http://www.914world.com/bbs2/index.php?showtopic=310041
http://www.914world.com/bbs2/index.php?sho...&st=0&#

It is a hair troubling that you say you have spark but with starter fluid it won't start. Does it kick over but just doesn't keep running or is it no firing at all?

I would spray the fluid in the throttle body, not the cylinder head. The pcv port on the air cleaner is quick access.

A while back, mine did similar when wire to cht was loose.

You may have answered your own question. Bad harness can cause all sorts of issues. All it takes is a bump and you have a broken connection or a short.

How's the spark? Starting fluid should take care of the fuel part, compression should take care of the air part--how's the spark?

--DD

Latest on my dead engine problem.
I went and cleaned the relay board connectors and added di-electrical grease. Nothing changed.

I do have spark and fuel. I took off a injector and it sprayed fuel into a container. I do have spark on sparkplug.

I can't get engine to fire with starter fluid. (if you have a bad cht could you still have engine start with starter fluid).

I have tried to get reading on cht and can not get one. I hooked up my ohm meter with black to neg ground of battery and red to cht wire. I just took out cht from cylinder head. I placed black lead on the end that screws onto the cylinder head and the red wire on the cht wire to the fuel injection harness. I do not get a reading.

I checked throttle position sensor and get clicks while I am moving throttle cable with ignition turned on.

I did notice that when I turn over engine the suction on the throttle body is very weak. I was expecting more vacuum on my palm over the throttle body when cranking over engine. Stuck intake of exhaust valve?

I did order a new fuel injection harness from Jeff Blowsby.

Any ideas?

Buck

Yeesh...spark and fuel and no fire...? That's ominous.

Next thing I'd do is compression test on all four. Pull valve covers and see if there's anything obvious. Get someone to turn the engine over with plugs out (and coil wire detached) while you watch it.

I'll offer though that a sudden engine stopping to run without ugly bangy-bangy noises is rarely an indication of a mechanical problem.

Yeah, compression test first. Can't believe all cylinders died over night.

Is this car new to you by the way?

Nope not new to me Have had it for years but haven't driven it much since I rebuilt the car.

AAR should create high idle when first started, then lower when warm.
I would suggest you check all vacuum lines to the plenum.

You can unhook all vacuum lines, plug the plenum with electrical tape
Leave just MPs hooked up

Should start

UPDATE

I uplugged the injectors and then sprayed some starter fluid in the throttle body. Engine started right up. Since my cht is shot that tells me I need a new cht in order to get the engine FI system to work again. The fuel injection system must have just richen the crap out of the a/f ratio because of a bad cht and thats why it won't start.

Buck

You can wire in a resistor to mimic the cht.
Just to see if it starts then .

I had a cht once that began working again when I pulled it to test
I think it lost its ground path

That doesn't follow...unless a CHT prob is causing flooding...were you smelling raw gas before...?

Paul Anders does state, "The CHT sensor (TS2), if disconnected or an open circuit, will not allow the car the start." However, he does not elaborate why. And if it's because of it not sending fuel to the injectors, then unplugging the injectors should have no effect on whether or not it will start with starter spray (no fuel from the injectors is no fuel from the injectors, no matter why).

https://members.rennlist.com/pbanders/DJetParts.htm

But keep going, you're getting closer...

If the CHT is unplugged, the FI sees that as Super Duper Ultra Cold and adds a ton of fuel. That's usually too much for the engine to start.

If the mixture is super duper rich, adding starter fluid (which acts kind of like fuel) won't help it to start.

If you short the CHT lead to ground, does the car want to start then?

--DD

I'm a bit late to your thread but when you say you 'do not get a reading', you mean you get infinite ohms, correct? An ohm meter will give you the ohms it measures, so if an open circuit, you're reading is infinite ohms. Sound like your CHT is bad. Infinite ohms on a CHT tells the FI that it should go super rich.

Put a new CHT sender on and it should fire right up.

But check to see if the old one is just having grounding issues first...

I went out last night and ground out the FI lead to the cht wire. Shot some starting fluid in and the engine started right up.
So the lesson is if your engine doesn't start and you think it might be the cht, disconnected the cht from the FI harness, ground out the cht lead and shoot some starting fluid into the throttle body. If engine starts than replace cht.

How do you check for grounding issues?

Remove the cht
Clean it
Use an ohm meter and the values for testing it from the brad website

Freeze it and test
Boil it and test

You can make a tool
Buy a 3 inch extension in 3/8 drive
Cut one corner off with a dremel, grinder
Use a deep 13mm to pull the cht with the wire running through the cut corner of the extension

I took out the cht last night. I could not get a reading. Cleaned it, Boiled it, and froze it. I couldn't get a reading any way any how. I think it is bad to the bone bad.
Buck

sounds like it if the meter is on the Ohm setting...
so there is a part number on it.
there were 3 or so... different ones made with slightly different settings
ideally you would match yours, but they are not all available any longer.
I think 914 rubber reproduces one of them... also worth checking some of the VW parts places....

Great to hear it. Are the chts NLA?

I believe one of the 3 is not available right now
I believe it has a different warm up curve than the available ones. But the same resistance fully warm

I haven’t shopped CHT’s recently

The early 73 2.0 CHT is the outlier, all the others are generally interchangeable but the 73 2.0 has some significant differences as it allows the 2.0 to run with the 1.7 ECU.

also last i checked was the one that was difficult to come by as the other sensors spanned all the d-Jet using VWs.

Ugh. In Indiana you are going to want a functional cht.

Trying to figure out why my cht went bad. What causes a cht to go bad? Could it be cracked wires from my F.I. harness caused a short? Is it something to do with heat from the cylinder head causing a cht to die. Curious minds want to know.

Thanks,
Buck

if you hit it with starting fluid and it would not kick, it is totally flooded OR you have an ignition problem.

Totally flooded usually means a head temp sensor but when the car cools down it usually starts again. Hence I would check the dwell on the points and then check for spark


You have an easy problem to solve

they wear out...
I assume most failures are an internal short
they are old... everything eventually wears out.

they carry a ground signal modified with heat controlled resistance.
they don't carry positive power... only ground.
not likely to "short" out or be impacted by the wiring harness
the failure is internal to the unit.... if there is not continuity to both ends.

too many heat and service cycles would be my guess



as mentioned by others... a failed CHT causes an extremely rich condition
and a no start condition.


it does not cause a lean condition... I suppose it might be possible to fail with high resistance... but I've never heard of that happening. They loose continuity, causing the ECU to go extremely rich. you should have "wet" plugs that would like to be cleaned off

Just to add. I just plugged in the F.I. injector harness into the injectors and grounded out the F.I. harness cht lead to ground. Car started up right away but was increasing rpm then would want to die until I pressed the gas pedal and then went high rpm and than wanted to die. I also had the air temp sender unconnected which might have caused the high rpm. But by grounding out the F.I. cht lead to ground I caused a lean to the ecu.


Just one more day until my cht shows up!

Buck

My guess is fuel pressure - do not do anything else until you measure the rail - if you have done this during this process - apologies for missing your response

...

Just installed my new cht and she starts right up. The moral of the story is :

Thank the 914 gods for making 914World.

Buck

Great news! Wait 'til you plug in the new FI harness, you might find a few extra ponies!

Or at least will have peace of mind that the harness won't leave you stranded some where.

That is great. Interesting to know how critical that cht is for running period

Without a ground through that single wire from the cht the car will not start or run. Period. Resistance to ground is what controls the mixture enrichment. While the thermister itself is a pretty reliable device, the way the design coupled it to the head is not.

If you got a new harness from Jeff you probably kust solved 90 percent of you D-jet problems.