Running lean, the story so far...

Running lean, the story so far...

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gmw9666

Original Poster:

2,734 posts

199 months

Thursday 1st October 2015
quotequote all
Howdy all.....I don't think I've posted on the Chim page since getting my September 1993 430 a little while back......so hi :-)



Been doing a bit of posting on the FB page so thought I'd share a problem I've got with this group

The 430 was off the road for about 4+ years before I bought it......was in pieces when I bought it as the previous owner had passed away.

To cut a long story short, I've got her back running, serviced, fluids blah and she passed her MOT with zero advisories a week or so ago

So my first big run was down to the Neil Garner event at the weekend.......she behaved without fault, great temps, drove really well with no hesitation or shunting..........just smooth power delivery

I thought whilst I was at the NG event I'd get her on the rollers to see what's what.....results below





At first I was really pleased with the results, after all the 430's only did 280 from the factory so thought all was well.........I was then told she was running really quite lean as can be seen in the Air / Fuel ratio and the fuelling line looks like a drunk spider walked across the page vs a horizontal ish line

The chaps said the power and torque lines look really quite strong given they were having to lift off the throttle. So net net, if I can sort the fuelling it looks very likely to bump my power (which is nice :-)

Was advised it could be the pump or the regulator so these were the first things I checked. The pump and reg seem to be behaving, my pressure results are = Start engine and pull vac off = 38psi, reconnect vac = 29.5psi, turn engine off = 29psi, after 1 min 27 psi, after 2 mins goes up to 28 then every min there after 30psi, 31, 31, 32, 32 etc and after 10 mins its 35psi so I'm pretty sure my lean running is neither of these hey

When I got the car I did check the pump out and it is getting 12.5v at the pump and I have changed the fuel filter for a new correct one and also checked the fuel lines for any issues......all checked out

Before the previous owner passed away he'd had the injectors cleaned (see below) so I know they are ok



So.....any last things I need to be testing that's obvious? Air Flow Meter?.........Lambda's?


Edited by gmw9666 on Thursday 1st October 09:20

gmw9666

Original Poster:

2,734 posts

199 months

Thursday 1st October 2015
quotequote all
Some of the other things I've noticed are =

Borrowed another 430 ecu and it gave a surprising result. Car wouldn't start! I could hear the fuel pump would it just cranked and cranked with zero thought about starting. I put my ecu back on and it starts straight away.

And on the fuel pump topic when turning the key the pump is "on".....ie it runs constantly vs just priming for 3 secs or so (assuming down to the old Gemini alarm which has been ripped out by previous owner and a random central locking unit (Snooper) being installed......which I've disconnected as with it connected I could not turn the car off with the key......remove the key and car kept running

I've also noticed that pin 10 on the ecu clip is missing, there is no connector and when I peeled the rubber boot you can clearly see a bare wire and tape where something's been spliced in



So took the ecu clip apart to see what is spliced. Well pin 27 (signal ground) is spliced into both 23 and 24 which are the 2 lambda sensors (the blue wires in the above pic)

Edited by gmw9666 on Thursday 1st October 09:31

blitzracing

6,387 posts

219 months

Thursday 1st October 2015
quotequote all
You are making things far too complex- the car would never run with the AFR doing what the graph shows, so take it with a large pinch of salt. You where not the only car showing some odd results lets say. For a genuine test of the mixture, put a couple of probes into the lambda output wires- black (signal) and white (ground), and extend a cable back into the cockpit and put on a volt meter. Then go for a run. Below 3400 rpm or 3/4 throttle it should cycle between 0 and about 1.2 volts. Then at WOT it should go between 1.2 and 1.4 volts and should never drop below this. A genuine lean mixture will make the voltage drop to zero. Only start your trouble shooting once you have confirmed something is really wrong.

davep

1,141 posts

283 months

Thursday 1st October 2015
quotequote all
gmw9666 said:
Some of the other things I've noticed are =

Borrowed another 430 ecu and it gave a surprising result. Car wouldn't start! I could hear the fuel pump would it just cranked and cranked with zero thought about starting. I put my ecu back on and it starts straight away.

And on the fuel pump topic when turning the key the pump is "on".....ie it runs constantly vs just priming for 3 secs or so (assuming down to the old Gemini alarm which has been ripped out by previous owner and a random central locking unit (Snooper) being installed......which I've disconnected as with it connected I could not turn the car off with the key......remove the key and car kept running

I've also noticed that pin 10 on the ecu clip is missing, there is no connector and when I peeled the rubber boot you can clearly see a bare wire and tape where something's been spliced in



So took the ecu clip apart to see what is spliced. Well pin 27 (signal ground) is spliced into both 23 and 24 which are the 2 lambda sensors (the blue wires in the above pic)

Edited by gmw9666 on Thursday 1st October 09:31
Pin 10 is part of the control circuit for the MIL lamp, so MIL lamp in dash will not work.

Re the Lambda sensor signal lines being tied to earth what tune resistor are you using?


Edited by davep on Thursday 1st October 21:01

gmw9666

Original Poster:

2,734 posts

199 months

Friday 2nd October 2015
quotequote all
Cheers chaps, some good advice.

Just by driving I'd say there is no issues, runs great so perhaps a second opinion / dyno is indeed a good option

Will post up any changes / developments as I go :-)

gmw9666

Original Poster:

2,734 posts

199 months

Friday 2nd October 2015
quotequote all
davep said:
Pin 10 is part of the control circuit for the MIL lamp, so MIL lamp in dash will not work.

Re the Lambda sensor signal lines being tied to earth what tune resistor are you using?


Edited by davep on Thursday 1st October 21:01
this one




Edited by gmw9666 on Friday 2nd October 13:58

davep

1,141 posts

283 months

Friday 2nd October 2015
quotequote all
gmw9666 said:
this one




Edited by gmw9666 on Friday 2nd October 13:58
That's an interesting one: you have a White 3900 Ohm tune resistor therefore Map 5 and closed loop selected, but with your Lambdas tied to 0 Vdc. I assume your engine has been decatted, if so perhaps try a Green 470 ohm tune resistor and Map 2 with open loop.

gmw9666

Original Poster:

2,734 posts

199 months

Friday 2nd October 2015
quotequote all
davep said:
That's an interesting one: you have a White 3900 Ohm tune resistor therefore Map 5 and closed loop selected, but with your Lambdas tied to 0 Vdc. I assume your engine has been decatted, if so perhaps try a Green 470 ohm tune resistor and Map 2 with open loop.
nope, still got the cats in from what I can tell, no cut / weld marks or anything



davep

1,141 posts

283 months

Friday 2nd October 2015
quotequote all
If you have RoverGauge or ECUMate could you verify what the Lambda voltages are? From your description of the wiring the Lambda input lines are tied to earth, which makes having closed loop and Lambda control processing a complete waste of time, and causes the engine to always run lean in your case.

gmw9666

Original Poster:

2,734 posts

199 months

Friday 2nd October 2015
quotequote all
As the car is in the garage having its exhaust replaced (just the back bit) I can confirm the main cat is definitely still in (probing the hole)

And i'll be able to plug in a loaned ECUMate tomorrow to see what's what


blitzracing

6,387 posts

219 months

Friday 2nd October 2015
quotequote all
The wiring you are looking at is the outer screening for the lambda cable- the signal is so low, it uses audio screened cables to prevent noise reaching the inner cable. The outer screen is joined between the two cables and fed to a single black earth wire on the ECU- so nothing wrong there at all. I would not mess around with a green tune resistor- it will just confuse things by switching to a Range Rover Map that will run lean anyway. RoverGauge will show you if the Lambda sensors are working below 3400 rpm, but is of no use for full power mixture tests, as the lambda feedback is switched off above 3400 rpm, so you wont get a reading from the ECU output with any meaning, this is why you have to use a test meter on the probe output to get live data.

Edited by blitzracing on Friday 2nd October 19:17

gmw9666

Original Poster:

2,734 posts

199 months

Saturday 3rd October 2015
quotequote all
Well popped and viewed the car this AM.....wasn't able to start her as the diff is out having new bushes so the below is what we could tell just on the ignition.

Please note the speed sender is on the bench with the diff hence why its flagged as an error lol

So the only error reading is low fuel pressure.....now bearing in mind the pressures I took previously off a plumbed in fuel pressure gauge looked spot on.....COULD......the low pressure be the pump being on the way out?......and also why its running continuously vs getting to pressure then cutting off?




spitfire4v8

3,990 posts

180 months

Saturday 3rd October 2015
quotequote all
There is no fuel pressure sensor so the low fuel pressure flagged is a deduction probably based on either an excessive amount of closed loop fuel trimming, or the lambda voltage going to zero volts under wide open throttle ?

blitzracing

6,387 posts

219 months

Sunday 4th October 2015
quotequote all
Dont forget there is no time stamp on the error codes, so you dont know when they where flagged in the cars history. Worth doing an ECU reset and see if the fault re occurs. Going back to causes, you have checked the fuel pressure, but this has little meaning without the car being under full load when its demand is at its greatest, but that makes it difficult to measure. I do remember a really odd fault that flagged that error was the inlet pipe that fed the AFM had collapsed, depriving the engine of air.This will cause the plenum pressure to be lower than it should be at WOT, and that will lower the fuel pressure. I dont understand however how the ECU picks this up as the AFM voltage would drop as well.

gmw9666

Original Poster:

2,734 posts

199 months

Wednesday 7th October 2015
quotequote all
Thought I'd update on things

Whilst the car was in David Gerald they have a look at my flying loom area and said its not standard and looks like Mr Dodgy Alarm man has being in this area......so cant hit the rollers until my wiring is back to standard

So now I'm going to have to teach myself wiring.....should be fun lol

So......starter for 10.......the back of the ECU and Fuel Pump Relays have the following wires, I've reference the bible as well as pages from Blitz's page (ta :-)

ECU Relay
30 = Brown
86 = Black (but has some tape close to the relay and turns into a thin brown wire)
87 (middle one) = Brown / Orange rings + another Brown / Orange rings
87 (side one) = Brown / Orange stripe
85 = Blue / Red

Blue Fuel Pump Relay
30 = Green / Brown
86 = White / Slate or Grey stripe + White / Purple stripe
87 (middle one) = White / Orange rings + another White / Orange rings
87 (side one) = White / Purple rings + White / Grey stripe
85 = Blue / Purple stripe


Also knowing the pump is running from the get go.......a Red / Yellow wire is spliced into the Red wire on the ignition.......this wire can be found also on the central locking unit connector under the dash and behind fuse 5 on the fuse board in a yellow block

anything look odd?




gmw9666

Original Poster:

2,734 posts

199 months

Wednesday 7th October 2015
quotequote all
Bit more peeling back to see what's what

The brown wires seem to be soldered and twisted together

Certainly been played with grrrr

ooooh and even if I take the 2 fuses on the flying fuse thing on the right the ignition / fuel pump STILL works





Edited by gmw9666 on Thursday 8th October 07:50

gmw9666

Original Poster:

2,734 posts

199 months

Thursday 8th October 2015
quotequote all
last update I forgot to add yesterday

When I turn the ignition key........you can hear / feel the ECU relay click.........then 3 seconds later you can hear / feel the fuel pump relay click almost like its suppose to after 3 secs.......i.e. shut off at that point but despite the relay clicking it still continues

davep

1,141 posts

283 months

Thursday 8th October 2015
quotequote all
gmw9666 said:
last update I forgot to add yesterday

When I turn the ignition key........you can hear / feel the ECU relay click.........then 3 seconds later you can hear / feel the fuel pump relay click almost like its suppose to after 3 secs.......i.e. shut off at that point but despite the relay clicking it still continues
gmw9666 I posted this up some months back perhaps it'll help. You'll no doubt appreciate it's difficult diagnosing wiring problems without actually being with the car. I'd use a multimeter to do continuity checks on any extra wiring to verify what is actually going on before removing.

As far as I can make out the 14CUX Fuel Pump Relay and Main Relay operation on my '92 TVR Griffith works as follows:

1. Prior to ignition a battery voltage of ~+12 Vdc (Brown) is applied to the Fuel Pump Relay (COM pin 30), the Main Relay (COM pin 30 and Coil pin 86), and ECU +ve supply (pin 15) where it maintains battery backed memory and error code values.

2. When ignition is switched On, a battery voltage (White/Slate) is applied to the Fuel Pump Relay (Coil pin 86) and to ECU ignition sense (pin 19). The ECU, via pin 16, now earths the Fuel Pump Relay (Coil pin 85, Blue/ Purple), the relay is energised feeding +12Vdc (White/Orange) to the Lambda sensors, the fuel pump (White/ Purple) via a fuse and the Inertia Switch, and the Purge Control Valve (if fitted).

3. Next the ECU, via pin 12, earths the Main Relay (Coil pin 85, Blue/Red), and the relay is energised feeding +12Vdc (two Brown/Orange) to the injector circuits, the AFM, and ECU pin 2, where Main Voltage is monitored for injection pulse width purposes.

4. During step 2 the ECU starts a fuel pump delay count, if this reaches zero before cranking occurs the ECU removes the earth from pin 16 (Blue/Purple), and the Fuel Pump relay is de-energised.

Bear in mind other cars may work differently, but I HTH.

The above is based on this circuit diagram for a 14CUX loom:


gmw9666

Original Poster:

2,734 posts

199 months

Thursday 8th October 2015
quotequote all
thanks Dave

1st point....why don't you live nearer? lol

On a serious note....thanks for the above, I do have the diagram and have been comparing

Your 4 steps are helpful as I'm stuck at step 1, see below

Prior to ignition a battery voltage of ~+12 Vdc (Brown) is applied to the Fuel Pump Relay (COM pin 30) =YES I HAVE THIS, the Main Relay (COM pin 30 and Coil pin 86) =YES I HAVE THIS, and ECU +ve supply (pin 15) =YES I HAVE THIS where it maintains battery backed memory and error code values.

Where it gets odd......I Also checked the other main / fuel relay pins and found on the main relay the Blue / Red wire (35) is also getting 12+v…….if I am correct this goes to Pin 12 on the ECU.....when checking pin 12 on the ECU, no reading 0v so I'm assuming the voltage is coming from the relay to this vs from the ECU which is suppose to ground pin 12 to energies per step 4



Edited by gmw9666 on Thursday 8th October 16:33

davep

1,141 posts

283 months

Friday 9th October 2015
quotequote all
gmw9666 said:
thanks Dave

Where it gets odd......I Also checked the other main / fuel relay pins and found on the main relay the Blue / Red wire (35) is also getting 12+v…….if I am correct this goes to Pin 12 on the ECU.....when checking pin 12 on the ECU, no reading 0v so I'm assuming the voltage is coming from the relay to this vs from the ECU which is suppose to ground pin 12 to energies per step 4
Pin 12 is the ECU's earthing line for the Main Relay and should be O Vdc for the Main Relay to energise. There has to be a potential difference between pins 86 (+12 Vdc) and 85 (earth) for the coil to energise and pull the contact in.

I assume you mean Blue/Red (85) on the Main Relay and that it's showing 12 Vdc, if this is the case with ignition On there is a problem, since there would be no potential difference and therefore the relay will not energise. I doubt this since your car has been running fine so the injectors and the AFM are getting a +12Vdc supply. I'd do some continuity checks between the Main Relay (87/87a) and the injectors, AFM, ECU pin 2 (Brown/Orange) circuits to verify this.