D-Jet Question - Issue

Kind of expected that. Thanks again.

I've got a NOS 1 for $ or I have a good used tested 1 for $75.00 plus shipping.

I thought I'd peddled the distributor from an 8k barn find I had a year or so ago....but found it along with the relays and an NOS harness (if it gets that far), so dont think I'll have to mess with this one.

Thanks Hiperfauto. Seeing that book brought back memories. Oops should have said nightmares. The lower contacts can be cleaned by pulling a piece of paper thru them. The contacts on the throttle switch can be cleaned with a pencil eraser.

A bit of an update.

The main ground on the intake had a size too small bolt in it and was loose. One of the spade connectors on the fuel pump relay was loose as well. All tight and clean and the pump now cycles. We pulled the distributor. The dual switches in the bottom didn't look bad but were oxidized. Cleaned them and replaced the condenser and contact switches. Got plenty of spark now. Injectors are all grounded but still no pulse. Even the cold start injector doesn't spray. Starting to wonder about what JohnMc mentioned with the ECU. Does it even have a ground? Is there anyway to check it for power, working, etc?

This car had the stock/aftermarket AC - the controller/vents were pulled and wires cut. Am wondering if they cut or pulled something loose when messing with it. Weather is turning fast - next decent day I'll push it outside so I can open the doors and crawl under the dash to see if anything's obvious.

Everything checks out (continuity) with the wiring and even the ECU looks like it was installed yesterday. There's plenty of spark, fuel and even 12V at the system relay but still no injector pulse.

Trying to locate a known good ECU to try. Had I finished this car it would have gone carbureted.

I see in your post you wrote the injectors are grounded? The ecu grounds them to fire them doesn't it? There should be 12v from the key to the injectors and the ecu grounds them to spray. if it is like most bosch injection systems. If you have good input signals and still not getting it to work then an ecu may be what is bad.

dl242gt said:

I see in your post you wrote the injectors are grounded? The ecu grounds them to fire them doesn't it? There should be 12v from the key to the injectors and the ecu grounds them to spray. if it is like most bosch injection systems. If you have good input signals and still not getting it to work then an ecu may be what is bad.

Click to expand...

Djet is backwards, constant ground and pulsed 12v

Not on D-Jet. The ECU provides power to the injectors and each one is grounded at the intake.

Ok just wanted to check. But in general if it's got good inputs and still no output try another ecu.

On the old injected beetles I've experienced random instant failure of those ecu. I think that is early L jet on those.

Now that it sounds like the ECU is powering up (and a fuel pump priming cycle is evidence of that) - try this.

Turn the key on. The fuel pump should prime. With the key on, and without cranking, press the accelerator all the way down. Do you hear injectors clicking?

D-Jet is sometimes rather crude, the acceleration enrichment is done via the throttle switch, Instead of a position sensor, what it does as it opens the throttle is that it sends extra signals to the ECU. Basically the same thing that the two contacts in the distributor do. They signal an injector bank fire (injectors fire in pairs).

If you don't hear injectors clicking when you do that, then it's possible the throttle switch is bad, or the injectors are physically stuck (a test light on an injector plug would figure that one out), or the ecu is bad.

You could also slip those contacts out of the distributor and manually open and close them to trigger injector bank fires. That way you can listen to them instead of just seeing if the car starts or not.

I think those ECU's are generally fairly tough things, they're not really electronic as much as electrical. Well, I guess non-digital would be a better term.

Will definitely try the throttle test - thanks. Stealthfti was over last week and checked the resistance-ohms-continuity on about every switch under the hood. Only thing we thought was bad was the coolant sensor so used another. Cant imagine what all could go bad at just 40k. All the grounds are tight and clean - did a continuity test on #16 and #24 and all checked out. Cleaned and reinstalled all the connections at the relays. Looks like someone ran the power (green) wire from the system relay directly to the positive battery terminal. Ends of the terminals look replaced anyways so not sure if that was the way they originally did it.

The PO should stay away from cars. From asking him more directed questions, what we think happened was this.....car ran fine when he had it. He either fried the contacts in the distributor (or they just oxidized from sitting). Proceeded to 'fix' the no-start issue by replacing the FI and CSI relays. May have crossed wires while doing so and shorted something out. Only idea I have.

The electronics guru that resto's my clusters is going to take it and check it out. In the meantime, I have a known good 017 coming (the one in the car is an 009). Going to try that one out. I just peddled a great running 034 a few months ago as I had no intention of keeping this DJet on the car when rebuilt. Always works that way.

The green wire is supposed to go to the battery positive terminal. You can clearly see it on page 13 of the 1800E Engineering Features booklet.

http://volvo1800pictures.com/document/volvo_1800E_engineering_features/volvo_1800E_engineering_features.pdf

Here's another D-Jet fuel injection service manual. Sorry, no cartoon Vikings in this one.

http://volvo1800pictures.com/document/1800E_fuel_injection/1800E_Fuel_Injection_3.pdf

Bummer.....its not the same without the vikings.

Thanks.

And again - if the car has been sitting a good long while, those injector pintles could just be physically stuck. Check to see if they're getting 12V+ pulses from the ECU, and if they are, and they aren't clicking and releasing fuel, then take them all off (release all 4 injector holding rings, leave the hoses attached , gently twist them a little to break the stiction, and then carefully pull the whole rail and all 4 injectors out of their holders). And then *carefully* press the center pin on the squirty end. I've never really seen a more moderns style injector stick like that, but I've had it happen many times on the D-Jet injectors, sometimes after sitting only a month or two. Once popped open, fresh fuel flowing through them will clean out the dried gunk quickly.

You can also sort of half-assedly do a crude flow/balance check like that - put little cups (like cough syrup measuring things?) under all 4 injectors. Turn the key on, don't crank, but press the accelerator several times. maybe repeat that process a few times (key off, key on, fuel pump prime, press the accelerator to the floor) and see if all 4 little cups have pretty much the same amount of fuel in them. You can also eyeball the spray patterns as well by doing that (stand up by the engine with the key on, manually open the throttle and the injectors will fire in pairs as it opens).

We checked it at the harness with a noid light and it was DOA while cranking. Even the cold start injector had nothing. I've checked continuity from all the injectors, relays, etc to the ECU plug and all is well. The main ground on the intake was loose (1 size bolt too small) and once that was straightened out, the fuel pump cycled. The switches in the distributor looked fine but had no continuity, and thus we had zero spark. Cleaned-replaced-gapped them along with a new condenser and now have all the spark we need. But the injectors are still dead.

I have a feeling he did something stupid to the ECU while playing with wires and relays there was nothing wrong with. Still looking for the drywall screws or JB Weld to make it an official previously owned Volvo. lol

Does the ECU switch off when it's craning? Perhaps the PO in his solenoid rewiring managed to hook the main relay to a 'regular' switched 12V+, one that turns off when cranking?

Good question. Not that I know of but how could I tell? Maybe put a test light somewhere?

PS: The cold start functionality changed depending on the model year (I forget what year/ECU code). Early ones were controlled by the ECU directly, it looked at the coolant temp sensor, air temp sensor, decided when to fire it. Later on, for whatever reason, they simplified it and it's no longer ECU controlled. It runs a wire from that unused terminal on the starter (that goes how while cranking) over to a temp switch (that shuts off when the block is warm) to the cold start valve, to ground. No electronics involved.