1972 Granada Mk1 coupe build - Still going... 14-10-2024

[eurogranada]

Jun 13, 2023 9:33:05 GMT Alpina99 said:

Can I start by saying I know nothing about the "dark art" (electrical issues,) but could it be either a fuse or relay that's overheating and temporarily failing ??
Nigel

No that I can pretty much for sure say is not the case. Al fuses were fine and none of the relays had abnormal temps. One thing I checked roadside.

I did wonder if the ecu itself could get too hot. As when having the dash out I noticed that with the engine running, the ecu heated up. But it also has heat sinks built in and it is srewed to the metal under dash tray plate so has a pretty massive heat sink in that I'd think.

[eurogranada]

Jun 13, 2023 12:02:54 GMT kevins said:

Looking back in the thread you am I correct in assuming have a Facet lift pump which draws from the original pick up, feeds a swirl pot and then the high pressure pump draws from this?

If so where does the engine fuel return feed into, if it's into the swirl pot you could be getting the fuel very hot in which case vapour will form in the swirl pot and the pump may overheat. When it does it again it might be worth feeling the temperature of the pump and swirl pot, ideally it shouldn't be much above ambient.

You are right, I have a facet type fuel pump (low pressure high volume) filling the swirlpot. The high pressure Bosch pump draws from that and returns to that. If the swirlpot is full, fuel is returned to the fuel tank in the back.

I've had this setup ever since building it and I've never had this problem before, even though I have for instance done a 400+ km daytrip mid summer on a hot day as well. So if it was simply heat related I think I'd have encountered it before.

What I also did wonder is if the fuel pump gets to hot. Heating up the fuel. I'll try and see if I can determine anything like that.

It's relaitvely good that the consensus seems to be heading towards fuel pump. It's also an easy fix.

[eurogranada]

Jun 13, 2023 12:36:31 GMT thomfr said:

You have two options in my view (I had a similar issue 8 years ago and it lasted for 7,5 years to be cured 100%).
1.
Throw out the sensors and replace with new, try it and then throw out also the fuel pump(s).

2. Bring it to the mechanic WITH ecu experience on old cars AND a rolling road and throw the keys and say, FIX IT!

I had with my Alfa Giulia a rather similar problem (although the car is on carbs) after a hard bump on the tarmac while practising the Teuven Hillclimb the car would just not run right anymore. Worked on it now and then for years and replaced quite some stuff but it never completely went away.
In the end I left it at my Alfa man of trust(over 40 years in the business) and he did first a complete timing basic set up. checked and adjusted 100 things and now it runs as it did 9 years ago, finally!
I do not know what the problem was but it is solved now.

Thom

Hey Thom,

thank you for chiming in!

Option 1 is most likely to happen anyway. It's easiest. A step in between may be measuring the resistance like Kevins offered up.

option 2 is a utopia I think. I was at THE granada/scorpio meeting of the country last weekend where at least two ford service dealers were among us, but even they have a hard time dealing with this type of isseu and they'd also start with the suggestions from option one.

Anyway, I'll work through it as usual.

[kevins]

There are quite a few permutations, do you know what colours you have on the sensor?



It's not unheard of for the wiring on the sensor plug on replacement parts to not match the original vehicle.
It would be worth checking the sensors and vehicle match, do you have a vehicle wiring diagram for the sensor circuits?

[eurogranada]

Jun 13, 2023 14:02:20 GMT kevins said:

There are quite a few permutations, do you know what colours you have on the sensor?



It's not unheard of for the wiring on the sensor plug on replacement parts to not match the original vehicle.
It would be worth checking the sensors and vehicle match, do you have a vehicle wiring diagram for the sensor circuits?

Good call I have the wiring diagram for them. Should be able to deduce. The new one I bought had grey, black and two whites.

I know the ones in the loom are grey, grey/red and yellow, yellow/red among others. I'll figure it out.

[kevins]

The white ones are the heater (polarity doesn't matter), there should be a resistance between them somewhere in the 2-30 ohm range (varies with temperature) check where the power comes from this is often shared with the fuel pump, dodgy relay or connector would cause breakdown and codes. The other end of the circuit usually earths through the PCM so check this pin and the PCM earth.

The black is the signal and the grey the earth (I think it earths through the PCM check this is good and wiggle the pcm connector, as this also earths several other sensors which could also explain the fault codes and breakdowns).

[eurogranada]

Jun 13, 2023 15:01:23 GMT kevins said:

The white ones are the heater (polarity doesn't matter), there should be a resistance between them somewhere in the 2-30 ohm range (varies with temperature) check where the power comes from this is often shared with the fuel pump, dodgy relay or connector would cause breakdown and codes. The other end of the circuit usually earths through the PCM so check this pin and the PCM earth.

The black is the signal and the grey the earth (I think it earths through the PCM check this is good and wiggle the pcm connector, as this also earths several other sensors which could also explain the fault codes and breakdowns).

Well, I should be able to check for resistance. I can compare the new one to the older one(s).

The sensors have their own fuse but they do share a main relay with among other things the fuel pump(s). So that is something I can swap out potentially. However I don't think the problems come from a power issue with the fuse(box) or relay. As in the BOB system the main relay energizes so many components that I don't think the engine would even be able to start.

Checking if the sensor can earth corretcly is also something I should be able to do. And yes, I too believe they earth through the PCM/ECU. In the process of rewiring this I beefed up al earth wiring and made very sure they have clean connections.

All of the above has helped me form a plan though.

1. measure the resistance on several of the 4 sensors and checking the earth of the suspect sensor.
2. depending on the findings order a new sensor.
3. monitor the fuel temp on a hot day at the swirl pot and pump.
4. Swap sensor or if not applicable swap fuel pump.

The one thing that bothers me about this plan is that to test thoroughly I should make plenty of km's/miles, all with the risk of the engine dying at any time. Using motorways there's usually an emergency lane, but you also end up in a more dangerous situation with the risk of having to be recovered again. On b-roads speeds are lower but no emergency lanes available, possibly a cycle path at best. So the engine dying there is also not a great thing.Yet without driving I won't know if things are fixed.

[kevins]

Yes sometimes it's better when it just stops working altogether, only other option is to find a test track somewhere to drive it on.

[mk2cossie]

Is there some way to add a fuel pressure gauge to the fuel system?
As if the pump/s cut out, lack of fuel pressure can cause lambda sensor faults to flag up. The ECU tries to adjust the injection duty cycle, but to little or no affect.

If its only a running issue at higher speeds, could it be the fuel pump 8snt getting g any ventilation and overheating?

(Can't remember the fuel pump layout I'm afraid eurogranada, and can't remember how far through I got when trying to re-read this thread 😔)

[ivan141]

There are electric fuel pressure sensors out there, Loads of bikes come with them due to returnless fuel systems (BMW K series for example). I really dislike mechanical stuff where you have to route fluids into your cabin. That being said, if you can get away with a mechanical gauge on like a fuel pressure adjuster (common aftermarket) and you can somehow have a look at it while cranking then that might be informative enough without having to wire up a gauge.

[eurogranada]

Well I’ve investigated some…

I measured the resistance in the recently replaced lambda sensor. It was 3.8 ohm. I then measured the two reasonably accessible sensors as well. The code free one showed 4.2, the one giving the code 5.2.

As that sort of lead me to believe the sensor may be ok but the codes a result of the underlying problem, I swapped out the fuel pump next.

Using tie wraps to keep the fuel lines as closed as much as possible, I was able to swap out the pump with almost no fuel loss. I did hear the swirl pot empty back into the tank so after the swap it took a bit to get it filled far enough for the engine to run. Ideally is could use a 8mm banjo fitting for a better fit, but after a quick nip up it was at least leak free. I swapped the power feeds to the pump as somehow I felt I had them the wrong way around. But I’m not quite sure if it’s right.

Car ran fine though. So I took it for a short couple of runs and I let it heat up. Fans still kicking in! But I felt the fuel pump and swirl pot and they were hot, not lukewarm but hot. So maybe I do have a vapour issue after all. I don’t at all remember ever having touched the swirl pot before and it being this hot.

Question is why? Would air in the cooling system be a contributor? Could it be that the pump is running the wrong way round (would that even be possible and would the car even run)? Or that it is not in enough airflow being put in the wheel well before the left wheel? I can’t really put it anywhere else… the fuel lines on the engine itself are routed as original so they enter and exit the block in the factory locations. Fuel from the fuel tank is cool, the lines by feel show that. The fuel going back to the tank is also cooler than the fuel being circulated between the swirl pot and the engine.

After the drives I had one code bite me in the butt, but it’s unfortunately more generic… 0158 high current in HO2S22 system. I’ll need to research that… but the code on that one specific sensor has not (yet) reappeared… the same for the code on the replaced sensor.

So again, how to proceed? Adding a fuel cooler?

[sebastiaan]

If you run a swirl pot, it can get hot because you have too little circulation back to the main tank (a bigger lift pump would help) and/or your main high pressure pump (this returns into the swirl pot, right?) Is too big. Every bit of fuel that goes back to the swirl pot adds hear as it warms up when going through the pressure regulator.

Is there a way to simplify the system by adding a buffer to the main tank and having that feed the main pump? Or installing a modern fuel pickup&pump unit in the original tank?

I think you are looking in the right direction; narrowband lambda sensors are pretty reliable, so this looks like a fuel system issue to me. If it helps and if you are close-ish (i'm near Waalwijk) i may be able to help with a second set of eyes if you want.

[eurogranada]

Only thought I have on the above is rerouting the return from the engine from the swirl pot to the tank directly. That would stil mean the swirl pot is always full and can always drain back to the tank, while the engine still always gets a feed and can drain to the tank as well. Drawback: the difference in pressures between the two systems would mean I’d need to actually run an additional full length line back to the tank…

That lengthens the fuel run and should subsequently lower the temperature of the fuel.

I need to take a look at a way of doing this safely at the tank end.

[eurogranada]

I'd like some opinions on the (post) above before I do anything really. As I'd need to spend on fuel line at the least and probably some small stuff for the return hookup and a bung to close of the port in the swirl pot.

Also I'm still a bit in doubt about heat/vapour lock being the cause as this system has been plumbed like this for 7 years now and although I realise I haven't driven the car all that often for long runs, I did make several even on hot days, never before having the issue I had two weeks ago.

Also been investigating the P158 code. This is the same code as before: bank 2, sensor 2. And we all know that sensor is now new.

Now, the issue can be multiple things. Bad sensor I don't think so as it is new. Bad wiring I don't think so, but I'd need to check. Question is how? Apart from the earth that I should be able to check. I do have a wiring diagram for them but that says nothing on what you should read. I am starting to believe more in the possibility overfueling on that bank. As the internet says high voltage reading is from overfueling, low voltage reading from underfueling. And this does add up to the one time I saw multiple codes for low readings when the car was still running in some cpacatity but it not getting enough fuel.

The only thing I find strange, is why sensor two is giving this code then. As if there really is overfueling happening wouldn't the pre-cat sensor be the first to report that? Yet it stays quiet...

I've not seen the bank 1 sensor 1 code anymore after clearing and driving. I think this popped up purely due to the lean condition as the engine didn't get fuel at the time of the problem. Or disconnecting it for the resistance measurement and reconnecting it solved the problem.

I drove the car this weekend and it ran fine, but I didn't run it for any extended amount of time or distance. I'm thinking of clearing the codes once again and driving it with the replacement pump in place to see how if the code comes back. If it doesn't maybe it was the old fuel pump. If it comes back I may have to check the injectors...

I must admit this is doing my brain in a bit going in circles.

[eurogranada]

Jun 17, 2023 18:38:37 GMT sebastiaan said:

If you run a swirl pot, it can get hot because you have too little circulation back to the main tank (a bigger lift pump would help) and/or your main high pressure pump (this returns into the swirl pot, right?) Is too big. Every bit of fuel that goes back to the swirl pot adds hear as it warms up when going through the pressure regulator.

Is there a way to simplify the system by adding a buffer to the main tank and having that feed the main pump? Or installing a modern fuel pickup&pump unit in the original tank?

I think you are looking in the right direction; narrowband lambda sensors are pretty reliable, so this looks like a fuel system issue to me. If it helps and if you are close-ish (i'm near Waalwijk) i may be able to help with a second set of eyes if you want.

Thanks for your contribution. I didn't have time before to do anything other but like your post.

I'm in the Eindhoven area so not too far from you.

The swirlpot itself is filled by a high volume low pressure pump. So that should cycle enough. But the fuel to engine and back to swirlpot circuit is short and it is a high pressure pump. I'm not modding the tank with an in tank pump setup. It's a pretty big job requiring welding and I spent quite a bit on coating the tank so I don't have rust issues anymore...

I've already posted what I possibly could do to lengthen the sytem and ensure more cool fuel is used. But I've by now also posted some doubts. As the system has never before given this issue in the 7 years I've been running it...

[kevins]

So I'm clear, the low pressure lift pump takes fuel from the tank to the swirl pot and this returns to the tank, the high pressure pump takes fuel from the swirl pot and the engine returns to the swirl pot?

If so you might want to check there is a decent flow back into the tank from the swirl pot, a restricted flow on the low pressure side could lead to high fuel temperatures.


For the lambda sensor the post cat ones are supposed to be monitoring catalyst performance the pre-cat ones control fueling, A faulty post cat sensor shouldn't affect how the engine runs, it might be worth checking all the lambda sensors go to the right pins on the ECU, if they were mixed up it could explain what is happening.

[sebastiaan]

Jun 19, 2023 7:20:19 GMT eurogranada said:

The swirlpot itself is filled by a high volume low pressure pump. So that should cycle enough.

Don't be too sure. A Facet red top "competition" pump flows around 160 l/h, so a 2 liter swirl pot would be flushed around twice a minute (a bit more but meh, close enough). If you have a Walbro 255 or similar (pretty ubiquitous) that flows 255 l/h, so you're cycling the same fuel through the swirl pot.

Could you post up which pumps you've got in there and a picture of the swirl pot? 

I get where you are coming from with the not modding the tank; been there, done that, got the leaky tank T-shirt....

And is it really 4 O2 sensors on this engine already? Surely the BOB predates EOBD and the necessity to do cat efficiency monitoring, so I'd guess there's only two?

[eurogranada]

Jun 20, 2023 7:25:43 GMT sebastiaan said:

Jun 19, 2023 7:20:19 GMT eurogranada said:

The swirlpot itself is filled by a high volume low pressure pump. So that should cycle enough.

Don't be too sure. A Facet red top "competition" pump flows around 160 l/h, so a 2 liter swirl pot would be flushed around twice a minute (a bit more but meh, close enough). If you have a Walbro 255 or similar (pretty ubiquitous) that flows 255 l/h, so you're cycling the same fuel through the swirl pot.

Could you post up which pumps you've got in there and a picture of the swirl pot? 

I get where you are coming from with the not modding the tank; been there, done that, got the leaky tank T-shirt....

And is it really 4 O2 sensors on this engine already? Surely the BOB predates EOBD and the necessity to do cat efficiency monitoring, so I'd guess there's only two?

Ok, I guess I had different expectations from high volume, lol. But I can't remember the flow rates now although back then I probably compared them against others. If an injection pump has an even higher volume than the high volume low pressure one, then I may certainly be cycling the same fuel.

I have that facet type fuel pump for tank to swirlpot. And a bosch 3,5 bar injection pump for the engine. Pretty standard stuff.

The swirlpot is a square box, probably to be seen in earlier pictures in the last few pages of the under bonnet works.

I can't remember if this has all the side mounted take-offs on the same level, otherwise I might be able to play with that a bit to try and get a better flow. Otherwise only thing I can think of is to let the engine also drain back to the original fuel tank.

And yes, the BoB engine has 4 02 sensors. One before and one after the cat on each side.

[westbay]

I always thought swirl pots should be nearer the tank and not under bonnet (heat, safety etc) ...

"And yes, the BoB engine has 4 02 sensors. One before and one after the cat on each side." check these are correctly connected, i.e. is it critcal the before and after are connected to control box correct ports etc

[eurogranada]

Jun 20, 2023 11:36:07 GMT westbay said:

I always thought swirl pots should be nearer the tank and not under bonnet (heat, safety etc) ...

"And yes, the BoB engine has 4 02 sensors. One before and one after the cat on each side." check these are correctly connected, i.e. is it critcal the before and after are connected to control box correct ports etc

I just put it where I had space. In 7 years never had an issue with it before….

The connectors make it so you can’t plug in anything wrong. And although there is always the possibility, I don’t think I made an error wiring them.

There are more possible causes for the O2 message, I’ll try and get to the bottom of it.