General Relays: Fuel pump and Injection System

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General Relays: Fuel pump and Injection System

crumbtoasty

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G'day, so I have recently bought a '95 Panda Colour and it's been having the occasional non start, through this forum I've been able to rule out a few of the reasons and now I'm thinking the two relays in the engine bay (fuel pump and injection systems) might be on the blink.

So I went to Halfords and bought two that matched, but I think the 'Accessory' pins (87 and 87a) are reversed in the new relays - the fuel pump came on and stayed on when I put the relay in, the key wasn't even in.

I'm contemplating just switching the wiring behind the relay, but if anyone knows where to get the right ones I would be super grateful!

Cheers!
 
Ok. Basic stuff but try this find the hedgehog which has all the earths negative s black wires fixed to it on the bulkhead remove all clean and replace with a little copper grease
Once completed this should eliminate any Poor earth which are cause for intermittent faults
Also take out the body bolt and clean with wet & dry. Replace test
 
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Thanks mate, I'll give it a try tomorrow and let you know how it goes [emoji106] would be such a relief if it's just a dodgy earth!
 
Heya, so I've cleaned and coppered the earths, and still no love.

I'm afraid that the ecu might have been damaged by putting in the wrong relays. Now when I have the battery connected, one of the relays clicks rapidly even with the key off/out. When turn the key to on, clicking stops. When I disconnect the ecu, clicking stops.

I feel like I understand how the basic electrics work but I've got no idea about the ecu... any suggestions?
 
Still think that you have a faulty earth maybe even onto the ecu. What is happening is a voltage is making it way to earth via the coil of the relay On through coil relay off. Ect ect
Puting in the wrong relay should not damage thing but switch off item when it should be on have you refitted the old relay now !
 
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Okay, I might see if I can find the culprit earth, do you reckon there might be an exposed wire shorting something?
 
Okay!

So after a week on holiday, silently ruminating about my car troubles while boating about, I have come up with the following.

  • All earth points cleaned and coppered.
  • ECU ground wire and body is grounded according to my multimeter.
  • Checked all fuses and relays with multimeter, all working correctly
  • Good spark on all leads, and healthy sized arc from both coils
  • Good fuel pressure, and confirmed injector pulse
  • Crank position sensor is producing a reading while cranking. It's nowhere near 200mA but I reckon this might be because my multimeter isn't fast enough

I think I've gone from an intermittent start to a no-start situation. On account of it hasn't started for a couple of weeks now. :bang:

All repairs that aren't cleaning are on hold at the mo until finances work themselves out, this is driving me bananas! Any other ideas from the crowd?

Many Thanks!! :confused::confused:
 
As cranking squirt some fuel in the carb air intake using a household spray mr muscle or the like if you have a spark in the cylinder it should ignight if a few more squirts may keep it running if this works it a blocked injector or bad connection at the plug at base of spi
 
Sorry, only just picked up on this thread.

With fuel pump and injection you may not be able to use standard relays.
The old and new relays hopefully have their terminal numbers marked on them - check they are the same. If not, don't use it.
A lot of relays also have their internal wiring diagram moulded onto them. Also check this. Both old and new need to be identical.

The fuel pump is energised, for a few seconds, when the ignition is first turned on. Then again when cranking. When the engine starts, the pump relay will only remain energised if the engine is running. Looking at Haynes wiring diagram, it appears that the relay is energised by the ECU, probably from the ignition system trigger. (Haynes book says up to 1993, but I doubt there would be differences after that, assuming it is still single-point injection.) Do you have a Haynes book? Wiring diagram is almost the last page.
 
Refer to the accompanying pics.

Fuel Injection System Relay:
Terminal 30 has a permanent live feed from the battery. Red wire.
Terminal 86 (trigger) is earthed. Black/violet.
Terminal 85 (trigger) is an ignition feed, from the switch, via the ignition coil, but only as a junction, not through the coil.
So this relay should be triggered if the ignition is on.

Terminals 87 & 87b are connected together, and fed by the relay from the battery feed, once the relay is triggered.
87 feeds to the ECU, terminal 9, via a White/black wire.
87b feeds to terminal 86 of the pump relay via a orange wire.

Pump Relay:
Terminal 30 has a permanent live feed from the battery. Red wire.
Terminal 86 (trigger) is fed from the injection system relay, once the ignition is on.
Terminal 85 (trigger) connects to terminal 17 of the ECU via a orange/black wire.
This relay is triggered by the ECU earthing the wire from terminal 85.

Terminals 87 & 87b are connected together, and fed by the relay from the battery feed, once the relay is triggered.
87 feeds the injector resistor via a blue wire and then on to the injector.
87b feeds the fuel pump via a 10a fuse and brown/white wires.


When the ignition is turned on, both relays should trigger and the pump should run. Probably for only a few seconds.
Then pump should run again while cranking and stay running if the engine starts.

You need to check methodically through. Start with main feeds from the battery and earths.
Then check for a feed to terminal 85 of the injection system relay as the ignition is turned on.
Check this then feeds the ECU and the pump relay.
Check for output to the pump at the relay, and at the pump. Also check the pump earth.
Pump is in the tank, accessed under the rear seat.

(Now, what was I supposed to be doing?)
 

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Thanks for quick replies!

So there is definitely fuel going in, I've cranked it with the air intake off and I can see the fuel squirting in.. the throttle body is a bit dirty but I can't see that being a non start issue. I have some electric contact cleaner would that be ok to clean the throttle body with?

One thing I did notice was when the throttle opened up as it cranked it seemed like the fuel splashed out a bit more.. don't know if that's significant.

Yeh I had a play around with the relays and I found out that the ones I had put in were different. Anyway the originals were working fine so I've left them in.

Spark plugs were replaced a few months ago. I feel like all that's left is timing? Which is possibly Crank Position Sensor or ECU right? :bang:
 
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Basics. Is there a spark at a plug?
Have you got a spare plug? Any spark plug. If so, pull off a plug lead, stick the spare plug into it, rest the plug body on the engine and crank it. Should have a nice fat spark.

I don't think it has a crank sensor, as the ECU does the fuel only, spark is still old school distributor, but electronic, not contact breakers.

Off with the distributor cap, check the cap and rotor arm for cracks or burning, or tracking across from one terminal to another.

If that's all ok, check for a feed when the ignition is on.

The coil is triggered by I think a Hall Effect trigger inside the distributor. This is a magnetic pickup, so produces a magnetic pulse which turns into a wave form electronic pulse, so measuring that might be difficult. A simple voltmeter on the coil may show this.
 
I'm no expert so I don't know exactly what I'm looking at. There's a sensor down underneath the alternator pointing at a knobbly gear which is what I'm assuming is crank position sensor?

Spark comes from two coil packs near the spare tire. No distributor to be found.

Spark is at all plugs but I can't remember if it was a good strong spark, I'll check later
 
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I don't think it has a crank sensor, as the ECU does the fuel only, spark is still old school distributor
Yep, ignition is run off a crank sensor too, the stuff from the Haynes is no good for this age as it only shows the old distributor system, if you want a closer guide get a Cinquecento or Seicento manual as it's the same single point twin coil system the 1108 used on these. Where that leaves you I'm not sure as there would be no fuel either if the crank sensor was not working which would have been my first guess for a fault (that's what did it for mine anyway).
Maybe portland_bill might have some other thoughts if he now knows what system we're dealing with - I'm none too hot on injection.
 
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Cheers mate, I've just cleaned the TB and crank sensor. Not that I thought it would help (it didn't) but it gave me something to do.

I'll have a look in the other forums see what I can find. Thanks for the redirect.
 
Ok one thing none of us have mentioned check T D C. Indicated by a nic in the fly wheel which can be found at th front of the gear box with 0 " marks and also on the bottom crank pulley as the timing belt may have slipped and it could be firing at the wrong position there is 2 white marks on the belt should also line up with the marks on the pulley. Hayes here please as it's hard to describe
 
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Ok, I'll have a squiz at tdc tomorrow... I reeeeealy don't want to do a timing belt... mark on the cover says it was done Feb '16 so should be ok but worth checking
 
It would appear that the late Panda used the crank sensor, so referring to the Cinquecento manual will give us the wiring diagrams and possibly some diagnosis. Sorry, can't do that tonight, out all day tomorrow, so might be able to look again tomorrow night.

You still need to check for sparks at the plugs, and that the pump runs when it should.
Checking the cam timing is a good shout. shouldn't be a problem, but always worth checking.

PS: I've put my Cinq Haynes manual on the desk as a reminder.
 
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