Inline Conversion, Digifant II, no fuel, injectors not fire

[ebennett]

I did a motor swap in a Vanagon, I have an inline 4 cylinder with Digifant II injection/computer. If I spray starter fluid in the intake it fires right up but won't stay running. Once the starter fluid runs out the van stops, it appears it isn't getting fuel.

1) My fuel pump works and pumps while I am cranking, so does the idle stabilizer. Fuel pump primes the system if I turn the key to the on position and the idle stabilizer buzzes.
2) My injectors test about 16.7 ohms each and 4.7 ohms with the harness
3) vacuum line to the fuel pressure regulator is hooked up
4) I have tested the line pressure, I'm getting 29-36psi

The fuel pump pulls direct from the bottom of the gas tank; gas tank-> primary fuel filter->fuel pump->secondary fuel filter->injector assembly->vacuum operated pressure regulator->return to gas tank

Am I missing something? I tested the resistance across the injector wire harness, 4.7 ohms - correct

I know wired the system correct, I used my bentley and everything checks out, J17 fuel pump and J176 computer are the only relays that I needed. I swapped the ignition module and distributor for kicks, nothing. I am using a ABA distributor as my bottom end is a 2.0L ABA

I also bolted the ECU to the fire wall of the Vanagon, the way I bolted it made a direct ground between the ECU cooling fins and the body of the car, could that have screwed things up?

Can a bad mass air flow sensor cause the injectors to do nothing?

Bentley suggests using a test LED to test the ECU if it is sending a signal to the injectors at the plug that goes into the harness, I used a volt meter, it danced all around when I turned the key, it appears to be working.

Lost here.........
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GDTRFB

[ChesterKV]

Hey Conversion Dude,

Perhaps you have the FUEL FROM GAS TANK and FUEL RETURN TO TANK accidentally crisscrossed. It's a bit common actually.


- Chester
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1984 Wolfsburg 7-passenger stock sunroof
1992 Subaru Legacy EJ22 boxer motor installed.... van is now sold.... currently playing with a 1987 Toyota MR2 with 1.6 liter twin-cam motor. Better than the Subaru boxers....... I'm impressed. Well, okay, in an "apples and oranges" kind of way.

[Captain Pike]

Make sure the pump stays on during the starting and running conditions. Hot wire the pump to eliminate the relay question.
I just fixed a 914(everything ),now on a 98 volvo s70 engine swap(f.ed belt)Maybe thurs or fri if you need help. PM me.
_________________
LEARN TO SELF RESCUE
59 Panel bus, 1966 Single cab. 73' 181. 73 Westy. 91' H6 Vanagon 3.3L.
.....................All Current.......................

[ebennett]

I know I have the fuel hoses on correct, fuel in directly to the rail, fuel return to tank is the bottom of the regulator.

I already hot wired the pump, oxygen sensor and hot side of the injectors, they all share the same relay on this digifant II set up.

I think I might have nuked the injector driver on the computer.......I bolted the ECU to the body of the van, metal screws touching the cooling fins and the body of the van.....grounded. In the Jetta there are plastic tabs between the body and the carrier that holds the ECU and ignition module. maybe the direct grounding of the ECU and a less than perfect ground between the block and the body and the thing got nuked.

I am going to try and find a running Jetta or Golf with digifant II and see if it will start on my ECU.

Check out this link, sounds like my issue


http://www.carelect.demon.co.uk/vwp1.html

I used the factory ground between the trans and the body and I made several grounds between the cylinder valve cover/intake manifold and the fire wall of the van, maybe it wasn't good enough. I am going to try and source another ECU and hook up a ground direct between one of the starter bolts and the body.
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GDTRFB

[ebennett]

We it looks like I've nuked another ECU! I found another Digifant II ecu, I hooked it up and was careful not to ground the body of the unit or the ignition module. Turned the key, it fire for a second, then nothing, now the injectors are dumping gas! The opposite extreme mentioned here.

http://www.carelect.demon.co.uk/vwp1.html

I should have added a ground strap directly to my starter?

Hopefully third computer is a charm.

Hey Bill want to buy my van dirt cheap? All new brakes, shocks, slotted rotors, side canopy. I'm leaving town this weekend (not in my vanagon as planned) and might not be back for 3 months to 3 years
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GDTRFB

[kayakwesty]

is your harness clean?

Sounds like you have a wire going to ground or a true short and your harness is bad and eating ECU'S

ECU's are tough you shouldn't be going thru them.

How did you make your harness, did you cut alot of wires?

My grounds, I have the ECU factory mount from the donor car mounted to the body supporting the ECU just as VW did

I have my factory ground wire mounted onthe valve cover and a ground strap from there to the body...

that's it
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1984 Westy 2.0 Jetta ABA Motor/1.8 head converted to auto tranny, with 180,000 on body, 55K on engine and transmission

B.5.5 Passat Wagen with 30v V6-67000 Miles

DAS AUTO

CHANGE YOUR FUEL LINES!

A post without pictures is useless

http://www.kayakwesty.com

http://www.waldensridgewhitewater.com/

[Vanagon Nut]

Check the temp sensor and wiring to/from it. (I'm guessing digifant uses one).

Although not directly related, the Jetta Motronic engine management relies heavily on info from the temp sensor.

Also check that you have the various components connected to the correct grounds.

On the Motronic engine management, there are specific grounding points for the various components.

i.e. my Motronic ABA, would start cold, run poorly, but not restart. (ran REALLY rich. Like fuel was getting dumped in) Problem: ECT (engine coolant temp sensor) and TPS weren't grounded. I grounded them. It ran way better, but I still got fault codes for the ECT TPS and CMP. I connected each item to it's correct ground. This cured the TPS and ECT fault codes though I still have a CMP fault. (I'm hoping it's just dizzy position!)

Does Bentley specify which ground is used for the various different digifant engine management components? i.e. "sensor ground". "Ground to engine block" etc.

And for sure. I thought the Jetta ECU should be grounded. But, and IIRC, even though there are 2 screws holding the metal end of ECU to the mounting bracket, I'm pretty sure the Jetta Motronic ECU gets it's ground via wires to/from ECU. This may be the same for the Digifant ECU.

Hope that helps!

Neil.
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1981 Westy DIY 15º ABA

1988 West DIY 50º ABA

VE7TBN

[ebennett]

My install is pretty clean, A2 Bentley manual, section 15, current flow diagrams page 205, main electrical of 91-92 Jetta, German production.

The only wires I cut are from plug T6c, for some reason my T6c plug only has 5 wires, I don't have connection T6c/6-W/R - emissions I believe?

T6c/1-R/W - comes from fused side of J17 fuel pump relay connection 87. to 02 sensor
T6c/2-R/Y -> to J17 fuel pump relay connection 85
T6c/3-R/G -> to the connection 50, starter solenoid
T6c/4-BK/Y -> to J176 ECU relay connection 87
T6c/5-R/BK -> to J17 fuel pump relay connection 87, same as 02 sensor and fuel pump but connects before the fuse


T6c/6-W/R -> I don't have this wire

I also don't know what T2m/2-G goes to?
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GDTRFB

[Vanagon Nut]

[Captain Pike]

Park it here, I'll fix it.
_________________
LEARN TO SELF RESCUE
59 Panel bus, 1966 Single cab. 73' 181. 73 Westy. 91' H6 Vanagon 3.3L.
.....................All Current.......................

[ebennett]

[Vanagon Nut]

[ebennett]

1)Are you certain there is power getting to the relays?

Yes, relays are working the way they are supposed to, fuel pump runs, idle stabilizer buzzes, spark plugs spark, I've checked all that

2)(I get the impression this is a "new" Vanagon to you?)

I have owned it for 2 years, "new" in the sense that I performed my own inline conversion

3)Is the ignition switch working properly?

Part of confirming that the relays worked was confirming that the ignition switch supply power to (30) in the "on" position and (30) and (50) in the "crank" position

4) Are you certain the "internal ground" on J176 is just that? I found that on my Motronic relays, some had an internal connection from 30 to the + side of the relay coil. Negative is supplied from ECU.

Interesting thought but on page 205 of the current flow diagram it shows separate connections.

5)Are you using the correct relays? (i.e. maybe you're using one with a positive internal connection to relay coil?)

Relay diagrams on the side of the relays shows no positive internal connection and relay testing showed nothing "crossing over"


Thank you for your help, I am putting this to rest for now and maybe return to it when I return to the area or just try and sell it as is. Selling it would suck because there is no way I can sell this unfinished project for what I have into it. Van needs an exhaust down pipe made and the new ball joints and tie rods I bought installed it she is good to go (unless there are other problems) I did everything, resealed the gas tank, stainless steel brake lines, slotted rotors (race car!!) all new KYB shocks.....

Like a bad hand in poker you just have to put it down.
_________________
GDTRFB

[Vanagon Nut]

[Captain Pike]

To all my Dig2 brothers. CIS injection works like a charm.
NO BRAIN______NO PAIN
_________________
LEARN TO SELF RESCUE
59 Panel bus, 1966 Single cab. 73' 181. 73 Westy. 91' H6 Vanagon 3.3L.
.....................All Current.......................

[mrjoshm]

The fuel pump pulls direct from the bottom of the gas tank; gas tank-> primary fuel filter->fuel pump->secondary fuel filter->injector assembly->vacuum operated pressure regulator->return to gas tank

i am not sure if maybe you are using an aftermarket fuel pump but stock digifant II cars have 2 fuel pumps. an internal pump in the tank which primes the external fuel box where the main pump is located..

[kayakwesty]

[Captain Pike]

[ebennett]

6 years later I realized I never concluded this post.

I needed to build a custom distributor to get the Mk3 distributor to work with the Mk2 digifant fuel injection. 4 window vs single window for the hall sensor. Once I had that figured out the van fired right up.
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GDTRFB