Cooling fans permanently running

[espritdave1]

Hi guys.

i've recently had the header tanks off my S4 for refurbishing, and ever since my cooling fans have run constantly as soon as the ignition is on.

If i start the engine i get a check engine light and it runs very rough.

I wondered if it was a sticking relay, but it doesn't seem to be.

If i pull the front relay, it cuts off the fans but i still get the check engine light.

Any ideas?

Cheers, Dave

[Bibs]

Fans and CEL indicate a problem with the ECU, perhaps it's just not happy a sensor isn't connected. Espritmon/Freescan will show you the error code you need to diagnose the fault, if not you can short the ALDL (paperclip between the black/white pins with engine off, ignition on) and count the flashes.

[mr.oogieboogie]

on my s4 when the temp sensor had gone it threw the check light and a couple of code 26a and code 26b but you may have the twin tank setup so could be sensor and relay

[lotus4s]

Go back and check over the area where you were working on the header tanks. Sounds like a sensor is unplugged or vacuum line loose. Check all the connections.

[espritdave1]

I've checked over all the connections and pipework, everything seems fine.

would the fan fail light cause the car to run so roughly.

I took the plugs out yesterday and they were soaked with fuel.

Tried the paperclip but didn't get any flashes.

I will see if i can get freescan on it.

[Bibs]

No flashes means you're not doing it right. You'll initially get a 1-2-1-2-1-2 (ie 12) to show that you are doing it right. You engine is in limp home mode with the CEL on, it won't be running 100%. Find out what error it is before anything else.

Just to clarify the paperclip method:

Turn everything off. Remove the relay cover in the boot where you'll find the ALDL cable (it's more reliable than the one under the glovebox. Ideally with a couple of inches of insulated wire rather than a paperclip (although one will do!) connect the black/white wired terminals on the ALDL connector. Switch ignition key to position 2 (so that the dash lights up) and count the flashes. You have a CEL repeated in the relay box, a green light, you can use that if it's easier to see. First you'll get the 'you're doing this right' 1-2-1-2... then you'll get the error code eg for a code 26 if will flash twice then 6 times, twice then six times etc.

[lotus4s]

Is your fan fail light on? The light itself won't cause the engine to be in "Limp" mode but if there's a problem with the fans then it will.

[espritdave1]

Bibs.

When you say white/black, i assume you mean the black and the black/white terminals, just had a look at the ALDL in the boot and they are the colours

Just don't want to burn anything out.

[espritdave1]

I'm wondering now if the fans running are related to the coolant tanks removal.

I've checked the codes by bridging the aldl with no codes flashing up.

So got freescan running today,with ignition on but engine not running.

At first it gave me no data at all while the fans were running, then after a few mins the fans cut out and freescan started throwing out data.

I checked the error codes again and there were none with freescan either, so just to make sure i pulled the MAP sensor pipe, and straight away and it threw up

a code 34 (map sensor) error so i know that freescan is OK.

As soon as the fans cut in again, freescan stops giving info.

Once i start the car it overfuels like crazy and floods itself in a matter of 30 seconds.

my question is, with no error codes what would cause the fans to cut in and out and from cold and what would cause the car to overfuel so badly.

[dodgy]

So the fans are going through the cycle when then engine is NOT running ??

[espritdave1]

Hi Dodgy.

Yes, the fans come on as soon as the ignition is on, but engine off.

they run for a couple of mins, then go off for 30 seconds or so, then cut in again and stay on.

[Fuucka]

I have a 91 esprit, does the same thing, did you ever fix the problem?

[Vulcan Grey]

Does what exactly?

Fans on all the time it's usually either a bad ECU or the wrong kind of relay.

[benjamincalleja]

this is whats happened with me with my 88 turbo, ever since i had the tanks replaced and the temp gauge sender replaced (which must be unrelated) my fans cut in at 80 degrees then just never turn off again, doesnt cycle!!!  otter switch??  the otter switch is only a year old though...

[Escape]

Have you tried replacing the relay? I had some problems with a sticking relay recently.

 

this is whats happened with me with my 88 turbo, ever since i had the tanks replaced and the temp gauge sender replaced (which must be unrelated) my fans cut in at 80 degrees then just never turn off again, doesnt cycle!!!  otter switch??  the otter switch is only a year old though...

[benjamincalleja]

the fan relay?  I replaced that maybe two years ago but should I grab a new one? 

[Simon350S]

It's gotta be worth a shot for a couple of £

They can fail relatively quickly if they are cheap ones and often stick on once activated.

[benjamincalleja]

i got it from SJ, part no SJ089M0008....

[Simon350S]

Drive around the corner to your local motor factors and walk in with it in your hand.

You'll be walking out in no time at all with a replacement for less money and no postage costs.

[Escape]

the fan relay?  I replaced that maybe two years ago but should I grab a new one? 

 

I spend quite some time solving a problem on an LPG system that turned out to be caused by a relay sticking after first activation. Traced all of the wiring before I got to it, so next time I'll be sure to start with the easiest things first!

Easiest for you would be to simply swap the relay with the one for main beam, as they are the same type (5 blade with 2 internally joined outputs).

[benjamincalleja]

hmmmm today i changed swapped the relay as advised (i dont have a new one, i just swapped the main beam with the fan relay) and also changed the otter switch for a brand new one but the problem is still there....from cold the fans kick in at 80 then never turn off until you turn the car off...

[benjamincalleja]

silly idea but trying to think laterally...the garage would have had to disconnect all three sensors on that pipe to do the fuel tank change work, what would happen if they reconnected the wrong ones?  Is that even possible or are they one-fit only for the switch they go in to?

[benjamincalleja]

WAIT sorry was just checking my relay labelling diagram in the manual and all i did it seems was change over E and C which is Main beam relay and HRS relay....not very helpful....did not touch "D" fan relay...soooo ill check that tomorrow and see....dammit if that works then i just changed a working Otter switch for no reason!!

[benjamincalleja]

I ask because i notice the purge pump temp switch, the lowest one on the thermostat outlet pipe is activated at 70 degres and cuts off at 60 degrees....if the wiring has been switched between that and the otter switch that would explain why my fans are NOT on when i first turn the car on, kick in at 70 and then just never turn off....can anyone confirm??  I will try to replace the fan relay as well

[Simon350S]

Sorry, can't help you with that one.

If you've got the wiring diagram you should be able to work out which wire is going to which sensor just by looking at the colours.

A multimeter is your friend, you'd be able to work this issue out pretty quickly if you have one and are a bit handy with it.