just broke down :( engine won't run

[LankyTim]

Does it have a type of cold start device on it like some cars? I.E runs for the first 5 seconds with an extra large spark then a relay switches it across to a normal sized one?

[rogerthechorister]

Now tht's a good idea Tim.

Worth getting out a spark sensor to check if there is spark for 5 secs then no spark. If so you might well be right.

[stinky]

I'll check for a cold start device; I've not seen mention of one but you never know.

I may have something with the spark but it's confusing. I'll explain below.

It's definitely not the pumps, they are both working fine and fuel appears to be getting through.

The car is an early (odd firing) V6 and has no Air Mass meter; also it has mechanical injection and what appears to be a mechanical distributor, but if that is the case I can't see much point in the ECU which it does have.

I don't believe it has a Lambda sensor as it has no cat.

But there should be a knock sensor and a flywheel sensor but I haven't got to those yet.

Here's where I am at present: I took 4 of the 6 plugs out to check them and check for a spark. they all seemed to spark OK and the plugs looked good if a little dark (rich mixture I suppose) but one of them had fuel on it. At first I didn't think much of this as I'd been cranking the engine to test for a spark from the other plugs and that plug was still in, but I checked it again later and it still had fuel on it. I checked for spark and got one, but maybe not a strong one. One of the other plugs didn't seem to have a strong spark either.
I changed the plug lead to the plug with the fuel on it and now the engine runs ever so slightly better (i.e. still crap) and will tick-over roughly for about 30 seconds before keeling over.

I had to leave it then, but I'm going back today. I have some old plug leads which might be knackered but they're all I have (no-one here is open till Tuesday, national holiday) and I'm going to try swapping them around to see what happens.

I didn't fit these plug leads so I don't know how old they are, they look new but I guess they could be no good.

If it's the plug leads; I will be well-happy but also amazed; the car was running smoothly before cutting out and I've never heard of a bunch of plug-leads all failing at once.


I'll give it a go and let you know.

[rogerthechorister]

Get one or more spark testers - little yellow sticks about an inch and a half long made of transparent plastic that you put on top of the plug, then put the HT lead onto the tester. This will let the engine run (insofar as it did) while you look at the spark.

Spark plugs can degrade so that they spark in the open air but not under compression - but 6 at once would be stretching the odds.

If you are still showing spark while the engine is totally non-starting it HAS to be fuel or brains.

[stinky]

Thanks guys, but I'm afraid no luck so far.

I've changed all the plugs and I've tried all kinds of different leads, not new though. I could try to buy some new ones on Tuesday but I've a feeling I'm barking up the wrong tree with the leads. Leads, cap, plugs and rotor all seem good.
Now I'm wondering three things:

Ignition module

Distributor (although it does turn with the engine)

Blue injector relay under the bonnet (what does this do exactly anyway? when I unplug it it makes no change)

Any ideas on how I can test those three items?

[rogerthechorister]

If you have spark at all, it ain't total failure of distributor, or coil, or HT leads. All of them can get iffy at temperature but you aren't even getting hot before failure.

Running then failing indicates something that stores something is not getting fully charged and replenished. I think we can probably rule out condensor, they usually go open circuit and fry your points or S/C so no spark at all ever.

If you are getting fuel at the filter (and you are) but still having no running while you have spark at the plugs, that pretty well ONLY leaves injection probs. Relays are usually totally OK or totally not OK, but I'd be very tempted to try the injector relay. 2 options - (1) swap or (2) remove, pry open and look for dry joints then re-solder recover and replace.

Are you sure "tow to garage with "Snap-on" computer" is not an option?

[rogerthechorister]

Didn't you say B 28E engine? According to my manual that has no injector relay. There are several pages of tests in the manual, for the K-tronic injection system.

Have you got the manual?

[stinky]

Hi, thanks for that; I think it's a B28E, it's an early (1985) 2.8 V6 with the two oblong alloy intakes along the top, like a delorean engine.

It has basic electronic ignition kind of electronic/mechanical and basic electronic/mechanical injection.

The distributor doesn't have points; it's connected to a ignition module that is controlled by a hall effect sensor built in to the distributor (instead of a flywheel sensor that the later cars have)

the car does have a big blue injector pulse relay under the bonnet even though the injection appears completely mechanical (it has a black metal fuel distributor on top of the engine)

the blue injector pulse relay (896398 1323 765-1) has been replaced before (there was another in the boot when I bought it) and when I unplug the relay it makes no difference to engine performance, but I'm not sure what it does; all I have is it's name: injector pulse relay.
I took the cover off an it looks OK but when the engine is running it does nothing; the relay contacts do not close.

I will ask around to see if anyone here has any diagnostic gear; the local garage have some but I don't think they have any for my old Volvo + where does it connect on my car?
With this being such a small country, testing equipment is limited, but I'll see what I can find.

With more thought (it's worrying how the mind wanders and begins to clutch at straws when you can't find a solution) I feel it could be timing; either injection timing (blue injector relay), spark timing (ignition module or hall effect sensor), or, and please tell me if you think this is possible: the timing chain has slipped?

The manual you mention, which one do you mean, I have Haynes, Mitchell's and the owners manual?

[Glen Morangie]

Just to clarify - also I think you may have the CIS injection - constant idle speed, and IIRC this has an idle air control valve, a sort of small canister. These have a 'flap' inside which sticks - try knocking it with a stick to see if this will free the flap.
(edit) I've just been reading the Haynes manual and from their description it must be the continuous injection system if you have an impulse relay - so you should have a aux air valve instead of the iac.

Is the Haynes manual you have the one with a black cover, or the later blue one - the black cover edition has fairly detailed diagnostics for B28 engines.

[stinky]

Hi Glen, thanks for that (where did you get the diagrams BTW?).
The ignition system diagrams look correct. I have a constant Idle speed electronic valve (silver canister affair) I've checked that and it isn't sticking, + I have a spare that I know to be working and it didn't fix the problem.

I have a black Haynes, so I'll stick my head in it again; I must have missed the diagnostics.