NO Fuel at the Injectors, D-Jetronic Options

[BMartin914]

Trying to figure out why my car won't start after 3 days of non-eventful driving.

Car has spark, but no fuel at the injectors. Have swapped out ecus and FI relays on the relay board and the car still won't start. Injectors are dry.

Any ideas? Trigger points could be a possibility but I pulled those out, cleaned and checked them too. Kind of stumped. Was hoping to have this thing ready to go to RRC, but now it's up in the air.

Drove wonderfully for 3 days, pulled it into the garage, parked it, tried to start it today and no go.

Any suggestions???

TIA (IMG:http://www.914world.com/bbs2/html/emoticons/confused24.gif)

[dlo914]

hear the buzzing noise of the fuel pump? bad ground?

[brp914]

Its always tempting to suspect the worst, like an ecu, but those things rarely go - 300k on my orig ecu. If no pressure at injectors there is no voltage at pump. You've tried the relay, how about the 25A fuse on the relay plate? I've had corrosion there causing the pump to be intermittant. Pull the fuse out and clean it and the connections on the plate. If it is blown suspect your AAR. If the connectors are wobbly, that needs to be repaired or the board replaced. First get fuel pressure, then worry about triggers. Cleaning them does no good, rubber blocks wear out so they dont open anymore. Focus on power supply to pump - trace that circuit and you'll get it. As mentioned, do you hear it come on for 2 seconds when turning key?

[BMartin914]

Fuel pump ahs been wired to a constant 12V by PO. Fuel pours out of the cold start line when disconnected and ignition turned on. Blocks on trigger points looked ok. Slightly worn, but not bad enough yo be concerned. I have another set where the blocks are more worn and they work fine.

Fuses on relay plate are fine. They may need a good cleaning. couldn't hurt.

[brp914]

confused - "no fuel at injectors", but fuel pouring out of cold start line? You meant no fuel coming out of injectors? Thats different, plus PO's constant 12 at pump - changes everything. Try this: hook up fuel lines. Ground coil wire. turn on ig'n. lift out distrib (w/ triggers connected) and turn rotor. Hear injectors clicking? (1,3) then (2,4) Should be able to feel them click, too. If yes then injection prolly ok. Otherwise suspect triggers or wiring harness. Test triggers with ohm meter. Got 30psi at injectors?

[swl]

if you have fuel but not squirt thenI have the same thing happening. Hope someone comes up with a silver bullet. Advise I have received beyond the trigger points is to check all the sensor connections. That's on the books for tomorrow. Your car, I think, has a resistor bank over by the battery. They are in direct line to the fi to drop the voltage. Thats an extra place you'll need to check. Gotta wonder what could have happened just sitting there in the garage. (IMG:http://www.914world.com/bbs2/html/emoticons/confused24.gif)

[swl]

my bad - it's the 1.8 that has the resistors.

[2teeners]

I had a 73 vw type 3 with the same Djet. it wouldn't run one time when the wire in the cyl head temp sender was broken. infinite resistance meant very very very lean. check that out with an ohmeter.

[sean_v8_914]

WAIT!!! (IMG:http://www.914world.com/bbs2/html/emoticons/ohmy.gif)

NO NEED TO DIS-ASSEMBLE YET
turn key on
stick your head in the eng compartment. when you manually move the throtttle flap from idle to full throttle you should hear the left injector bank click 20 times as you go thru the throttle range

you can easlily pull the injectors out on one side using only a 10mm socket and a long extention. remove the coil spark wire. stick the injectors in a cup . crank teh mojo 10 times then check for gas in the cup

i would also check fuel pressure. Kragen and autozone will lend you a gauge for free. it attaches to a fitting in between the injectors on one side

[swl]

QUOTE (sean_v8_914 @ Sep 17 2005, 08:27 PM)

turn key on stick your head in the eng compartment. when you manually move the throtttle flap from idle to full throttle you should hear the left injector bank click 20 times as you go thru the throttle range

That's a big yahoo.
Not only did I get a squirt doing this (#1 cylinder only) but somehow that has 'fixed' whatever was wrong with my system. Maybe it had to do with how that throttle switch was positioned.

I'm not quite out of the woods yet - #4 isn't squirting but hey at least I know that there is nothing fundamentally wrong!

Thank you. Thank you. Thank you. (IMG:http://www.914world.com/bbs2/html/emoticons/boldblue.gif)

[rhodyguy]

another happy customer!! i bet you solve the problem shortly. just imagine the field day a dispreputible shop could have had with you. "you need a new mps", "a new fuel pump", "new injectors", "new brain", etc..."oh the tps was out of adjustment". "we think we got it and your bill is $900". (IMG:http://www.914world.com/bbs2/html/emoticons/smile.gif)

k

[BMartin914]

To clarify - No fuel at injectors means no fuel coming from injetors. Pressure was adjusted 6 weeks ago and was fine when checked with a gauge. Judging from the amount of fuel coming from the cold start line I'd say pressure is A-OK.

I will try the injector and TPS later when I see the car again tmorrow.

Thanks.

[sean_v8_914]

you might be able to soak an injector in some FI cleaner to loosen it up.

make sure each cup has teh same amount of fuel

[BMartin914]

When I tested them yesterday (left bank) I pulled them out of the runners, disconnected the coil wire, laid the injectors on a piece of cardboard and had an assistant turn the motor. The injectors squirted out NO fuel. Not even a dribble out of either injector. Makes me think it is a management problem and not an injector problem since it ran two days before.

[brp914]

please verify if your triggers are ok: Ig'n off. lift out distrib. pull off trigger connector. put ohm meter between ctr and either of the outter terminals. rotate rotor. verify that circuit opens and closes once per rev. repeat with the other outter terminal.

engine will run with tps not connected. worry about that later.

check resistance of head sensor - if infinite engine will not run. I dont remeber proper value, but if 1500 ohms cold, engine will run.

[swl]

Ben,
Despite my earlier jubilation I'm still having intermittent problems. I think I have it down to the #10 wire on the MPS. Here's how I found it if you want to have a go at it. You'll need an ohm meter. The pin outs are from the 74 D-Jet but a quick glance I can't see any diff with the 75. If in doubt consult the current flow diagram in Haynes. (figuer 9.90)

Before you do though try appling 3-6 volts across the injector with the fuel system pressurized (the 3 second key on should be enough) and see if it squirts that way. Be careful of sparking in a fuel rich environment! If yes then it does look like management. If no then it must be fuel delivery(unlikely since you saw gas in the system).

Here is how I narrowed down my search. The values shown are just what I saw not necessarily what they should be - there could also be scale errors. What you are looking for most likely is an open cct where there should be some resistance or a straight short.

Remove the ecu harness at the ecu.

Pins 2, 14 and 25 are not used and act as a marker for counting down to other pins.

Pin 11 is system ground measure to case – should be 0 ohms. If good then can be used to measure other signals to ground.

Fuel injectors – pins 3,4,5 and 6 to ground - 3 ohms

MPS – two circuits – pin 7 to 15, 100 ohms, pin 8-10 - 30 ohms

Temp sensor 1 – pin 1 to 13 - 300 ohms

Temp sensor 2 – pin 23 to ground 3500 ohms (I understand that's the cylinder head and should be less than 2200)

Trigger points – depends on where the distributor is but 21-12, and 22-12 should have one open and one closed. Switches on half rotation of the distributor.

You can also switch your meter to volts and measure pins 16 and 24 to ground with the key on - you should see 12V

Pin 18 should show 12 volts when you crank the starter.

Pin 19 is used by the ecu to turn on the fuel pump relay.

I haven't worked through the throttle switch pins yet other than to note that pin 17 was switched to ground with the throttle closed.

[swl]

So does anybody know if it is safe to try to push a connector out of it's plug for some r/r. Is it just press fit in there or is there a stop. I know there is somebody here that rebuilds that harness but with the border hastles/expenses (csob) I'd rather try to repair it myself.

[bd1308]

hey you have to get a tiny screwdriver or this wierd looking tool thing......

if you look at the plug-in side of a connector, you will see a tiny little cutout where that tiny screwdriver will fit...press in and pull out the corresponding wire.