Car wont start, can anyone help please

[e21-Mark]

I would also try jump starting or adding a new battery, so that you can be sure the ignition system is getting enough juice to create a fat spark.

You could also check the coil connections and earths. A dodgy earth can cause all manner of starting/running issues.

[m3gaz]

I've just been through this scenario.A new battery solved the problem.There just wasn't enough life in the old battery to give it what it needed,although it was turning over ok.Maybe a battery test is worth a go.

Gaz

[cookster]

Update 2#

Ok, so I wasn't testing for the spark properly and have now done so (borrowed a neat little tester) and the spark is strong.

Used jumper leads across the fuel pump relay and the fuel pump runs and supplies petrol under good pressure to the jetronic.

Can hear relay switching but think its faulty as the fuel pump doesn't run with it in, but does with the jumper leads.

Retested all fuses, and as one of you said the fuse looked good (but was knackered, and my fuse swap was an old one too).........and with the relay in and the new fuse in, as soon as I crank the engine, it tries to fire up, but the fuse blows. I think it could be a short in fuel pump relay.

Do any of you have a relay I can try/buy off you to see if this cures it (rather than try to get one from BMW) (parts are VERY expensive here in Oz).

Your thoughts and comments most welcome. I will get some pics onto Joroen's E21 Facebook Page today.

Cheers
Mark

[Jeroen]

Have you tried starting the engine with the fuel pump relay bridged? Then you know for sure if its the relay, especially if it's switching meaning connections 85 and 86 are live. Then you also exclude the chance of wiring or pump issues.

[nas80]

take the relay to an electrical parts store. im very sure its a basic one. they use the diagram on the side and will be able to match it with another relay.

[cookster]

Have you tried starting the engine with the fuel pump relay bridged? Then you know for sure if its the relay, especially if it's switching meaning connections 85 and 86 are live. Then you also exclude the chance of wiring or pump issues.

Hi Jeroen

I have jumped the relay, jumping connections #15 and #87 (i think from memory) which engages the fuel pump (FP) to test that. I thought that with the FP relay in I could hear it clicking upon activation of the ignition switch, but that clicking is coming from another relay. I tested that theory by taking out the FP relay and could still hear another relay operating.

Thanks Nas, but I've tried all of the local autospares/auto elec shops locally and none have this relay in stock or anything that looks like it (it has 4 prongs and one prong is smaller than the others). BMW AU want $283 for a new relay and add the insult of saying that there is none in stock. Anyhow I have now ordered a replacement from sunny USA for $45.

Do you know if there is there any other jumping of the relay I can test? I figure that one part of the relay starts the fuel pump for starting (??via starter motor) and the second part of the relay (probably #31 and #31b from distributor??) keeps the fuel pump running once started.??? All big question marks on this bit for me.

I am figuring that the relay has collapsed internally causing a short and that is why the 16a fuse is blowing (when I try to crank the engine over with the FP relay in place). I've done this with the fuel pump disconnected too, just to eliminate a short/failure at the pump end.

Once I get my new relay, the easy thing is to try that, and hope it fixes it, but if not i'll have to widen the search to a feed/short from the starter or distributor (but I just hope its a simple relay for now)

Thanks all
Mark

[Jeroen]

But did you get the car running with the jumper wire installed then? At least that gives you some more direction, but if the fuse remains in tact with the jumper installed instead of the relay it is likely that the relay is bad, you may want to open it up to check and perhaps even repair it.

[cookster]

But did you get the car running with the jumper wire installed then? At least that gives you some more direction, but if the fuse remains in tact with the jumper installed instead of the relay it is likely that the relay is bad, you may want to open it up to check and perhaps even repair it.

Hi Jeroen,

with the jumper lead to 15 and 87 on the FP Relay it just cranked over (with the fuel pump running), but because the 31 and 31b weren't connected I think the link to the distributor isn't there.

With the FP relay in (and a new fuse each time) the car tries to start but the fuse blows before it fires up.

The relay looks like its a sealed unit and i'm not sure what i'll find inside so reckon I might be better waiting for the new FP relay to arrive?

I'll review the 31 and 31b connectors on the net and see if I can figure out which jumpers I need to get the whole thing 'jumped' without the relay.

Cheers
Mark

[Jeroen]

Agree, with a new relay already on its way perhaps it's better to just have a little bit more patience.

[cookster]

Agree, with a new relay already on its way perhaps it's better to just have a little bit more patience.

Yes, the last thing i want to do is accidentally cause more damage............although its killing me not being able to drive my e21............having just fully serviced the car and with new shocks and brakes, it was flying the other day.........i took it upto 140kmh (on a private road of course) and wondered if I overdid something. If the relay doesn't work I'll have a look at the start up valve.

Regards
Mark

[cookster]

Update #3

My new relay arrived from the USA today and the car is fixed!!! Yippee.

I've also changed the fuel filter just to make sure that the work of the pump is as easy as possible.

Thanks for all the comments and advice.. Also Jeroen, your car key ring arrived today and its a beauty!

Cheers
Mark

[Jeroen]

All great news then, and the mail wasn't too slow then. Enjoy, both the real car and the miniature version!

[e21-Mark]

I'd missed the final update. Good to hear your problem is now sorted! Might be worth getting a spare relay to can put in a stash of spares, to guard against it ever happening again.

[Oz E21]

Hi all,
Could I please get some confirmation on the bridging of the relay. Are pins 15 and 87 used?
A photo or any help would be very much appreciated as I am also trying to trouble shoot the fuel not getting to the injection.
Also, it seems an incorrect relay was previously used. What is the correct relay code/model for the 323i?
Thank you kindly.
Neb