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Van won't run- no spark
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remraf
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PostPosted: Sat Nov 03, 2007 1:28 pm    Post subject: Van won't run- no spark Reply with quote

I started the van today and drove 20 yards to put it on a lift to fix the shift linkage. After I fixed the shift linkage the van wouldn't start.

I only had about 20 minutes to try and get it running before the shop closed up so I tested for spark with the coil wire and got nothin.

The van is sitting a lot right now while I work on it. It is leaking coolant from the heads and oil from well, everywhere. So I basically start it put it on a lift fix stuff then put it back out every week or so. Not sure this really matters, but thought it might be pertinent.

Oh yeah, 87 syncro 2.1.
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camrenj
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PostPosted: Sun Nov 04, 2007 3:21 am    Post subject: Reply with quote

Did you check your fuses? Embarassed It maybe unlikely but it couldn't hurt to check.
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82WestyMan
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PostPosted: Sun Nov 04, 2007 4:26 am    Post subject: Reply with quote

You know, it sounds like it's something simple, like a fuse, or a wire that's loose or a bad connection.
I assume you have a volt/ohm meter (if not, a good cheap one can be had at your local HomeDepot/etc for $20 or so)
I'd be working on checking to see if you have power to the coil. "No power to the coil / no spark to the plugs"
If no power there, back track the circuit until your find the problem.
How it works is this: The points have power 100% of the time, when they open and close, they power the coil and it's the "On/Off" of that power to the coil that creates the spark that travels thru the cap and rotor to the spark plugs.
remember... its not as hard as you might imagine... we're talking 'old school' technology and the systems are actually pretty simple if you just break them down... "Air Fuel mixture in, spark at the right time, 'boom' and exhaust out.... and motor goes round and round... LOL
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remraf
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PostPosted: Sun Nov 04, 2007 8:21 am    Post subject: Reply with quote

Now that I've had some time to read/think about how the van gets spark it should be pretty straightforward. I believe there are two components that provide spark, the coil and the hall unit in the distributor. Or I probably have a bad ground or cracked ground wire somewhere. I noticed a lot of the wiring in the engine compartment was brittle and in not so good a shape.

Thanks
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tencentlife
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PostPosted: Sun Nov 04, 2007 10:25 am    Post subject: Reply with quote

There's no fusing in the ignition, injection, or starter systems, so don't waste your time looking there. Bad connections, though, are common in an old system, so checking thru every connection involved and looking for damaged wiring can turn up problems.

Quote:
How it works is this: The points have power 100% of the time, when they open and close, they power the coil and it's the "On/Off" of that power to the coil that creates the spark that travels thru the cap and rotor to the spark plugs.


Uh, not hardly. There are no points in the wbx systems (not in aircooled Vanagons either, unless you have some wierd hack job). The coil gets powered when the key is on, and the ECU also gets powered via a relay at the same time. In a Digijet, the ignition system is independent of the ECU, but remraf's is a Digifant and the ignition is integrated with the FI. In Digifant, the ECU also has to get a signal from the starter solenoid trigger during cranking, and from the Hall generator. The ECU then closes the fuel pump relay, fires the coil at the appropriate time, and opens the injectors the right amount. The Hall generator only tells the ECU how fast the crank is turning, the ECU determines the actual spark timing based on Hall rpm and a load signal from the AFM. So it's not quite so simple as that. Much is dependent on the ECU functioning normally. For that reason, the best approach is to run thru the ECU wiring checks in the FI section of Bentley, and do the whole rundown religiously. That will either show up which subsystem is not supplying the ECU with signal, power, or ground, whee there are bad wiring connections, or if all of them check out, will determine if the ECU itself is at fault.
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remraf
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PostPosted: Sun Nov 04, 2007 10:48 am    Post subject: Reply with quote

tencent

Thanks for the reply. Does the power supply relay next to the fuel pump relay supply power to the ecu via ignition switch?? If it was bad would that prevent voltage to ecu from battery and prevent the coil from firing?

Aside- do you still have the 2.2 for sale??
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tencentlife
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PostPosted: Sun Nov 04, 2007 1:23 pm    Post subject: Reply with quote

Right. The main FI power relay gets triggered by #15 power from the ignition switch. The same #15 power goes directly to the ignition coil #15 pole. Number 15 hot makes the main power relay switch #30 unfused battery power to the ECU, the injector power bus, the idle control unit, and the crankcase breather and O2 sensor heaters. So in Digifant, if the main FI power relay doesn't close, nothing will work in either the fuel injection or the ignition, even though the coil #15 pole is hot.

The ECU then internally grounds the fuel pump relay coil to switch power to the pump. It does this automatically each time the key is switched on, but only for a couple seconds unless it gets a continuing rpm signal from the Hall generator, which indicates that the motor is running. Only the fuel pump is powered off the pump relay. So if that relay doesn't close, ignition can work but there will be no fuel pressure, so no injection and the engine won't start. If there is residual pressure in the fuel rail, it may start for a second and die as the pressure is depleted.

The ECU internally grounds and ungrounds the #1 ignition coil pole to fire the spark. It bases the frequency off the Hall signal, which gives four pulses for every two engine rotations, but the ECU has control of ignition dwell time and firing time, so it can advance or retard firing time relative to the Hall signal depending on load info from the AFM. In that way the Hall signal serves more as a basic engine position signal.

You can rule out the two relays in turn by bridging them. Any Bosch-type 4-pin relay has the same pin layout, and the circuit the relay closes is between pins 30 and 87. Those pins are the two that make a "T" shape to each other. If you make a short jumper wire, or even a bent paperclip, and use it to bridge 30 to 87,you will power the relay's load.

So bridging the left relay would switch on the ECU and all the other loads I listed on that circuit. Try that one first, see if it starts, and if it doesn't, verify that you hear the fuel pump run. If it doesn't run, bridge the right-side relay too, which will power the pump all the time. Then try to start. If it starts then, the fuel pump relay isn't closing. This can be due to a bad relay (try a known good one in its place), or it can be an internal fault in the ECU.

If it doesn't start when bridging the main FI relay, but you hear the pump run, verify spark. If there is no spark, the fault could be in the Hall gen, its wiring, the coil, the ignition high-tension components, or internal to the ECU.

Because of the Digifant ECU having all the functions integrated, the best way to approach problems of unknown origin, especially no-start situations, when you don't know by the symptoms which subsystem to suspect, is to grab your VOM and go right to the ECU multi-pin connector and test each circuit from the pins there as explained in Bentley. It doesn't take long, and those checks test both the wiring and sensors at once. Just make sure the key is off before unplugging the ECU.

Doing those tests and a fuel pressure and volume test should turn up any basic problems in the engine electrical system and in fuel supply. In addition to those things, the basic tests of ignition high-tension components (coil, cap and rotor, igntion wires and plugs) that you would do on any spark engine covers all the engine operating systems pretty comprehensively. So if you don't have an intimate sense of what symptom reflects what cause, going at it comprehensively will probably get you to the source of the problem at least as fast and more surely than taking a head-scratching scattershot approach.

Now, in your particular case, since you said that the wiring was brittle in places, I'll tip you off that the Hall sensor wiring harness branch, which has three small-gauge wires in it, is particularly sensitive to breakage of even the insulation on any of the wires, because the signal it generates is so low-power. So pay particular attention to that when you do the ECU pin checks. Usually, though, if those checks from the ECU connector show continuity thru the Hall circuits, you will get a spark. Broken insulation on one of the Hall wires will usually manifest as a high-rpm miss, but the engine should have spark and start.


Yes, the 2.2 is still for sale. Click on the link in my sig for the ad. I should also have new AMC heads ready-to-go for sale soon at prices less than the usual suppliers.
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remraf
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PostPosted: Sun Nov 04, 2007 7:47 pm    Post subject: Reply with quote

Tencent

Thanks for all the info. I wish I could email a 12 pack.

The AMC heads you mentioned, are they stock or are you selling them with valve work/porting etc..?
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tencentlife
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PostPosted: Sun Nov 04, 2007 8:17 pm    Post subject: Reply with quote

New AMC heads. I replace the exhaust valves with a top quality stainless valve, and hand lap all the valves. The keepers get ground for the proper fit. I can do seat blending, mild porting and port-matching if desired. I would recommend seat blending at minimum.
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awojcicki
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PostPosted: Mon Sep 08, 2014 7:49 am    Post subject: Reply with quote

I am posting in this thread because (1) I see there is comprehensive information in just one page of posts on this topic and, therefore, ranked high on Google, and (2) the source of my no-start problem was different than what has been mentioned in detail, so I hope this may serve others who may have the same issue.

For my 1987 Vanagon 2.1L Westy it was indeed the fuel pump, but it took several hours to reach this conclusion since it was testing fine according to the electrical checks with the ECU and of course, I could easily hear it running as usual with the key in the 'ON' position and also while cranking, over and over again. Smile

We are traveling 9 months so far in South America and just left the van parked for a month while camping outside La Paz, Bolivia (only drove it once during this time and over the past week or so did not crank it up at all--I know, lazy move). So, I thought that simply missing the first few crank attempts flooded the engine and I just needed to get the motor up and going--and at this altitude, sometimes it takes a sensitive foot to just rev it to 1000 rpm without the engine cutting out. I had a hard time starting at over 4000 m in Potosi, so I assumed this was the same simple reason, and after successive crank-up failures I decided to push start the van. However, this didn't succeed either.

After draining some oil (because I just topped up and thought maybe it was overfilled as the dipstick showed above max and caused a fouling of the plugs), then removing, checking, and cleaning all my spark plugs, cleaning the air filter and even spraying carb cleaner directly into the intake hose to test spark (which it did run the engine for a second), cleaning the grounds (again!) under the coil, we started to suspect the fuel delivery system. As per Bentley we removed the injectors side by side and only felt air coming out in puffs, but at least I was happy that they seemed to be working properly and therefore, the ECU was probably not the culprit.

I also had checked the fuel return line by disconnecting it from the fuel pressure regulator and saw some residual fuel leak out, but nothing more when attempting to crank.

So then I got into my favorite Vanagon repair position on the street and began with dismounting the downstream fuel line to the fuel filter, thinking (read hoping) there may be a block there. My girlfriend cycled the fuel pump with the key from 'OFF' to 'ON' and even started to crank after I saw nothing coming out of the filter. I don't have much experience here, so I thought maybe there is just a large volume in the fuel filter to fill and I couldn't see it passing that quickly, and couldn't differentiate between the residual fuel there and "new" fuel pumped through from the tank. After removing the filter completely I did the same to check the output of the fuel pump, and also saw no fuel output, even when several seconds of trying to crank. I removed the fuel pump and just to be sure there was no blockage upstream from it I checked the fuel hose from the tank by lowering it just enough to see fuel easily come out.

As per the advice of the good folks at Van Cafe before setting out on this trip, I did buy and carry with me a new Bosch fuel pump and filter, so I replaced both and to finally wrap this story up, I checked the pump output as above and sure enough, within the second cycle of running the pump with key in 'ON' position I saw a healthy volume of gasoline spill out. I re-secured the filter and hoses, and the van cranked immediately on first try.

Thanks to all of you on here for helping us out along the way, the information is priceless, as this is just one of the many adventures we've had along the way as proud Vanagon owners.
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