[Car_Overhaul] One Thing Leads To Another..

[Kane 34]

Ah OK so does that mean the only thing that could be causing the fuel pump not to operate is the lack of signal from the CAS?

 

I'm struggling to understand why there is no reading showing at pin 5 of the fuel pump relay with ignition or during cranking as all of the other pins are displaying voltages.

 

I am going to replace the coil which I believe to be faulty so hopefully this will help with the lack of spark but I still have to sort the fuel pump problem as I'm not too keen on having a constant fuel feed if I was ever to have an accident in the car.

 

Anybody got any more suggestions as to why we're not seeing any feed to the fuel pump itself?

[jackherer 543]

You wont get anything without a working crank sensor, if the ECU doesn't see the engine turn over you wont get spark or fuel.

[Kane 34]

OK doke I'll get one ordered up as well. Is it better to get a known good used item or a aftermarket part? Or even better are they still available at the dealers?

[jackherer 543]

A good used one is fine.

 

Are you running ML4.1 or M1.3? (two row or three row ECU?) If it's 4.1 have you got CAPS? Even if you have 1.3 it is still useful for some things. http://www.bx16valve.co.uk/Files/caps.zip

[Kane 34]

Thanks Kieran.

 

It's ML4.1 (2 Row), I do have caps but only on an old notebook as I couldn't get it to run on Windows7. I'll look it out next time I'm back at the house.

[Kane 34]

Sourced a replacement coil and CAS, thanks Anthony, swapped out the old ones but still no luck with it starting. No change from previously so I don't think it was either of them after all.

 

I then moved onto the ignition amp. removed it from the plate applied new paste and stuck it back on, still no change. I've got a spare ignition amp which I tried with no change. Now I don't know for certain if either of these work but it'd be pretty unlucky having both fail I think.

 

Any other suggestions on areas to troubleshoot? I think I'm going to have to work my way through each ecu terminal one by one and check the voltages are what they should be. Am I right in thinking CAPS displays what readings to expect?

[jackherer 543]

Yes, CAPS tells you what to check for on the ECU plug as well as relay terminals and various other places. It's hard to know where to suggest you start seeing as you have made the entire loom so CAPS is the way ahead, if a voltage is out of range it should be fairly obvious why. I've been thinking about it a bit since I last posted and the first thing I would check for is 12v at the coil + terminal (LT not HT!) with the ignition switched on.

[Kane 34]

A day of troubleshooting with CAPS is on the cards then. As for the coil, when plugged in I checked with the ignition on and was seeing circa 12v across all four terminals. Should I only be seeing a reading over the two +ve terminals?

[GLPoomobile 958]

I would check for is 12v at the coil + terminal (LT not HT!) with the ignition switched on.

 

That was going to be my next suggestion. When I had issues, I found CAPS to be invaluable in solving it. I was able to check what each pin on the 2 relays was doing under different conditions (ign off, ign on, and engine running), and through that noted I wasn't getting a 12v supply to one of the relays when I should. Traced that back to the coil and found no 12v there either. Traced that back and found the loose connection in the brown plug under the dash. Without CAPS I would have been stabbing in the dark for a hell of a lot longer.

[jackherer 543]

The four terminals on the coil are actually only two connections electrically, two + and two -. The + supply is constant when the ignition is on so you can easily measure that, the - is rapidly pulsed by the ignition amp to actually make the spark so it's more difficult to measure.

[Slo 283 1 Cars]

The coil is just a very long wire coiled up obviously so if you connect positive to 12v or + then the other end will also be 12v which is what you are finding, when you connect the already live negative end to earth or - thats when the coil starts to build up the charge. It actually fires a spark when its disconnected so dont go holding a negative cable to it trying it out or you will find it will get you

[Anthony 1,000]

Am I correct in thinking that the fuel pump relay isn't clicking on when cranking and you've not got any spark?

 

If so, that suggests to me that either the ECU isn't working (be it power, wiring or faulty) or that it's not seeing the engine turning over, which logically has to be a wiring fault given that you've tried two different crank sensors now.

 

When the ECU is working and seeing the engine turning, it will energise the fuel pump relay and will fire the coil and injectors. Thus that you couldn't hear the fuel pump relay and had to hard wire the pump, together with the lack of spark, points to me at the ECU not triggering the various circuits.

 

There's two relays - one should click on with ignition (this powers the ECU IIRC) and the other should click on when cranking (this powers the fuel pump). Start here and make sure that there's 12v present on the input side (if not, check connection to the shunt box) and that they click on as they should - you can always bypass them for testing by using a length of wire to join the two thick wires on each relay, thus ensuring the circuits the relay feeds are powered.

 

(it is NOT safe to drive like this long term as the fuel pump will constantly run which is a bad idea in an accident!)

 

If the relays are working, double check your loom wiring is correct - as has been said, CAPS or Autodata is good for this, or worse comes to it I've a spare Mi16 loom here that I could bell through for you on any bits you're stuck with.

[Kane 34]

Yeah Anthony the fuel pump is not clicking on cranking and no spark whatsoever. The second relay is turning on when the ignition is switched on it's just the fuel pump relay that isn't.

 

I presume it must be ecu or faulty wiring that's the culprit, I have checked the feed from the shunt box and I'm getting ~12v there so don't think that's the issue.

 

I'll have a go at using CAPS and see how I get on. I'll report back once I find out the issue

[Kane 34]

OK might have sourced the problem but want to double check the wiring with you all. I think my CAS isn't operating as it should because my wiring is incorrect.

 

Now from the ECU pin 25 the green wire of the multicore CAS cable goes to pin 1 of the CAS plug, that I've done.

 

The problem I think I have is relating to pin 23 of the ECU. I have the black and red wires of the multicore cable going into pin 23 but am wanting to confirm the location on the CAS plug that these go to. Do both the red and black wires go into pin 2 and then loop into pin 3 or do they split? If they do split which way round do they go?

[S@m 156]

Here is the diagram of the crank sensor wiring from CAPS, i thought it better just to post this rather than trying to explain it.

 

[Kane 34]

Ah thanks for the picture Sam I had a look on CAPS but couldn't see it, I'm still trying to understand all of the program.

 

Just so I'm clear on the diagram, there is a bridge going between pin 25 and 23 at the ecu end and also the two wires from pin 23 are located at pin 2 CAS plug with a further bridge to bridge to pin 3?

[Tom Fenton 1,526]

No. Pin 1 of crank sensor to pin 25 ECU. Pin 2 of crank sensor to pin 23 ECU. The rest of the wiring is to tie the shielding of the cable down to an earth at pin 23 to stop electrical interference. However the car will likely run without the shielding connected to anything, so for testing purposes wire a core from pin 1 to pin 25 and another from pin 2 to pin 23 then try it.

[Kane 34]

It runs! Turns out numb nuts here wired in the CAS incorrectly so pins 1 and 3 were the wrong way round, switched these and it fired up straight away. I assumed that the pin layout would be similar to the other junior power timer plugs but as it happens it isn't. So for anyone else struggling with a similar issue make sure you read the pin numbers on the CAS cable itself!

 

Oil pressure climbed up on the gauge to the second top bar so that looks reasonable, all sounding ok with no apparent issues. The one thing I have noticed is that it's developed an oil leak on the front of the sump which I'm fairly annoyed about as I know how much of a pain these are to seal, especially when the engine has been full of oil. I'll need to whip the sump off, clean it up and reseal after one of the initial oil changes.

 

I'm not 100% happy with the wiring on the coil as I reused the old terminal by splicing onto the new loom wiring so will be changing this with genuine terminals I got from Tuesday last week. Yet again getting skinned by the dealer because minimum orders, £11 for a bag of 20 when I only needed 4!

 

Unfortunately I had to leave the car until next week as I'm off up north to start a new job tomorrow. I'll hopefully get a few hours next weekend when I'm home to give it a run in and oil change before heading in for an mot.

 

I'd like to say thanks to everyone for the help over the past few weeks. I'd definitely be sitting here not having a clue without your help so cheers.

[S@m 156]

Nice one, very pleased for you mate, bet you grinned like a cheshire cat when it finally fired - i know i did when i got mine started for the first time . Will be even better when you go for a spin.

 

With regards to the spare terminals you've got left over - i bet you'd shift them pretty quick in a for sale thread since there are plenty more of us with scabby looms that need a refresh.

 

One last point, to access the diagrams on CAPS you have to first select the component you're interested in on the main page (after choosing the 405/BX), so for example select the CAS section then click on 'Local Wiring' at the top left and it brings up the diagram.

Edited August 31, 2014 by Sam306

[Anthony 1,000]

Well done on finding the issue and getting it running

 

PS. I'd buy some of the coil terminals off you from that bag of 20 you had to buy.

[dobboy 231 2 Cars]

Hooooorrrrraaaayyyyy!!!!!

 

Well done indeed.

[Kane 34]

I had a slight smile on my face yeah haha! Just can't wait to get back down the road to take it for a drive, hopefully the maiden voyage will go smoothly.

 

PM on its way regarding the spare terminals Anthony.

[Kane 34]

After being away the past week at my new job I got back home late Friday night and if it wasn't pitch black and chucking it down with rain I would have been out attending to the finals checks in preparation of the first trip.

 

Not to worry I was up first thing this morning and straight out at the car. Quick once over to check everything and all seemed ok so packed up some additional fluids and a fire extinguisher just in case.. Set off from the house with my mate in the back seat as an aid to adjust my bias valve (located in the boot), following up behind was my old man in the van which was fully laden with all tools imaginable to man.

 

Got the engine up to temp and proceeded with the 'hard' running in procedure. Varying load through each great, stabbing at the throttle from 2 to 4.5k and then coasting back down. After 25 miles or so all temps were reading perfectly fine so headed back to the house.

 

Chuffed would be an understatement to be honest as I wasn't exactly sure how this was going to go with it being my first engine rebuild.

 

The only slight problem I encountered out on the run was that there was an intermittent flat spot which occurred when flooring it in the top gears. Essentially when I put the foot down (mainly in fifth) it would start to pick up then all of a sudden there would be a lull in all power. This would last for a second or so and then the engine would pick up again and away you go. If you backed off the throttle when it occurred it would right itself straight away. Anybody got any suggestions for this?

 

I also mentioned in an earlier post that I'd developed an oil leak which I thought was coming from the sump after more investigating I found it was actually coming from the oil temp switch. Dummy here didn't refit it with a seal so was just pissing out when the engine was running. I was slightly relieved that it wasn't the sump as I have read that these can be troublesome to seal but also was a little peeved as I had to remove the inlet manifold etc to get into the sensor. Managed to get it out and refitted with a fibre washer I had, cleaned up the engine bay and put it all together again. New oil and filter and fired her up on the first turn of the key

 

Now for the mot, only issue I have to resolve before then is to replace a faulty brake light switch as mine only comes on when it wants to not when I do. Should have it booked in next so fingers crossed it sails through.

[jackherer 543]

Nice one, sounds pretty promising. The flat spot might be a sticky AFM flap.

 

For future reference it's quicker and easier to cut a spanner in half with an angle grinder than it is to take the inlet manifold off

[Kane 34]

Any tips on how rectify a sticky flap? would this problem not occur over any gear as opposed to just upper gears. The only reason I say this is because I didn't have any lull in 1st, 2nd and 3rd only in 4th (a couple of times) and in 5th (more often)

 

Ah that sounds like a more sensible option I'll be sure to do that next time

Edited September 6, 2014 by Kane