Too rich / too lean

[Dangerdoc]

Hi guys,

Sent the car off to the specialist tuners to have it set up well and truly properly on petrol

System: 3.5L V8 EFi Flapper 1987 on a 26D engine modified heads for injection spray pattern, 4CU ECU. New injectors and K&N air filter.

So garage tells me that the engine is running spot on after a few minutes of heating up, but too lean when cold - they say it is the ECU.

Gave them the spare ECU and then they say it is now running too rich.

They sent the air flow meter off with both ECU units to be re-tuned. They fitted them today and now say it is running WAY too rich.

After discussions they stated that they think the ECU needs re-building and that there may be some differences in view of the new engine.

For those that are not in the "know" the old engine was a dedicated EFi unit. The 26D engine is designed for carbs, not EFi, but by modding the heads (a little nick with a file to accomodate the injector sray pattern), removing the bronze bush for the automatic transmission (as it was setu for a manual) then also swapping the rocker covers for the EFi variant then the system should run fine.

What I am looking for feedback on is why is it that they can have such massive problems when all that was originally wrong was that it was running lean when cold.

Am I being "had" ???

Doc

[Teesdale_landrover]

are they testing emissions at idle and constant throttle?
or has it been on a rolling road tune using wide band lambda?

[stevieturbo]

So where is the specialist tuning in simply monitoring, swapping of un-modified factory parts, and giving a poor diagnosis ?


Now...obviously there are limitations with older vehicles as to what can be modified to try and correct things, but what are you expecting them to do ?


Have the offered a diagnosis other than an ecu.....which in all fairness, is a rather amateur diagnosis, unless there is some reasoning to back it up.


Clearly if a car runs one way when cold, and different when hot...the first thing you would consider, is the coolant temp sensor !!!!!

Not the ecu.

On a side note....
If you could find a competent tuning shop that offers piggyback computers, that alter the signals to the ecu ( ie, airflow meter to ecu ) then you could have some control over fuel etc.
Not sure what would be involved on such an old vehicle though, as there would be no factory support from piggyback suppliers in terms of getting it working.

Or isnt there someone that can adjust the factory ecus, or is that only the later models ?

[Dangerdoc]

To be honest guys, I am not sure what they are actually doing.

The lads doing the tuning came recommended and are at Middlesex Tuners - Hmmm - moderators, am I allowed to name them? Hope I haven't stepped on toes there, seriously I mean that.

The temp sender and also the thermotime switch, in fact the oil and every other sensor are all new. I suppose that means that they may also be faulty.

They stated that when cold it was running lean, but fine when hot after a few minutes. Originally they also stated it was an air flow meter problem and it needed to be sorted out a bit. Granted they checked first before breaking the warranty seal - I said go for it - they then stated it was an ECU fault also.

Now when they re-fitted the kit (after sorting out the AFM and ECU), they now state they cannot get it set up correctly, well that is not my problem as if it was only running a bit lean when cold, it should run like a dream when warm - esecially after rebuilding, so not expecting to pay for that.

What bugged me was when they stated that they thought it was the engine variant as now it seems the engine is pulling huge amounts of air through the AFM when on idle - "Over vacuum" ? is there such a thing.

I'd be happy with a bit lean when cold, and fine when warm / hot, but not happy with lean when hot, well maybe a tiny wee bit as that is a bit dodgy I am led to believe, lol.

I cannot see that the carb engine with a wee lick of a file for the injector spray pattern on the heads, plus the EFi rocker covers can make a massive difference to the vacuum. It is the high compression version 9.35:1.

I also do appreciate it is the primitive EFi system and only so much can be done. Not looking for some track machine, just running properly so as to not wreck a brand new genuine landrover engine.

Let me know please.

Doc

[stevieturbo]

It sounds like they are saying every bit is faulty, yet cant fix any of it.....


despite pulling bits apart to try.

Or am I taking a too simplistic approach here ?

[ramon alban]

Hello Doc, Just addressing your original post first, observations in red

specialist tuners

Hmmmn?

System: 3.5L V8 EFi Flapper 1987 on a 26D engine modified heads for injection spray pattern, 4CU ECU. New injectors and K&N air filter.

I think Efi flappers ah la SD1 Vitesse from 1982 on, had waisted valves and I believe relieved induction tracts to improve overall air flow.

So garage tells me that the engine is running spot on after a few minutes of heating up, but too lean when cold - they say it is the ECU.

Too lean when cold could indicate a minor air leak into the plenum.

Gave them the spare ECU and then they say it is now running too rich.

Perhaps two different spec ECU's or one is faulty.

They sent the air flow meter off with both ECU units to be re-tuned. They fitted them today and now say it is running WAY too rich.

Way too rich means they set up the internal AFM spring too weak so the flap opens too easily and asks for too much fuel.

After discussions they stated that they think the ECU needs re-building and that there may be some differences in view of the new engine.

Now it seems they are lost, the problem of overfuelling should be addressed back at the AFM.

For those that are not in the "know" the old engine was a dedicated EFi unit. The 26D engine is designed for carbs, not EFi, but by modding the heads (a little nick with a file to accomodate the injector sray pattern), removing the bronze bush for the automatic transmission (as it was setu for a manual) then also swapping the rocker covers for the EFi variant then the system should run fine.

I may be wrong here but would not a carb engine be 9.35 to 1 CR whereas Efi should be 9.75 from that era. This also implies that making that engine run as an Efi could take quite a bit of intuition with the available components.

What I am looking for feedback on is why is it that they can have such massive problems when all that was originally wrong was that it was running lean when cold.

It would question their claim of being specialists, and they do not seem to have the necessary intuition to TEST the components involved.

Am I being "had" ???

Apart from changing over components and sending an AFM off to be calibrated, has there been any mention of ignition timing, fuel blockage possibilities, measuring fuel pressure is between 26 and 36 psi, checking sensors, looking for throttle pot defects, seeking air leaks, or wiring/connecttor problems, checking engine earths, comprehension of how the system works, referring to period Efi Technician Manuals commonly available in the trade or any logical analysis of the symptoms?

If mostly "not" - then yes they may be "hadding" you.

[ramon alban]

Hello Doc - my observations in red.

The temp sender and also the thermotime switch, in fact the oil and every other sensor are all new. I suppose that means that they may also be faulty.

If the sensors are new but the wiring and connectors are old then what the ECU sees may not be what the sensors send out.

Testing the system and its components properly involves making measurements at the sensor AND at the ECU connector plug.

See my website index of Efi components for how those tests must be completed.

They stated that when cold it was running lean, but fine when hot after a few minutes. Originally they also stated it was an air flow meter problem and it needed to be sorted out a bit. Granted they checked first before breaking the warranty seal - I said go for it - they then stated it was an ECU fault also.

This is a symptom of confusion and "diagnosis on the hoof". Shifting the blame to any component that defies being challenged. It is not TESTING.

if it was only running a bit lean when cold, it should run like a dream when warm

There is no logic here: Several components may be altering their signals/characteristics from cold to hot. EAV, AFM air temp sensor, Coolant temp sensor, cold start system. They all interact in some way or another with fueling and air supply management.

Its obviously not running ok when hot and as mentioned in prior post, undiagnosed air leaks can cause havoc.

especially after rebuilding,

You have worse situation after rebuilding (whatever that means) so it could be that they have introduced new problems, such as a maladjusted AFM now running the systen far too rich.

What bugged me was when they stated that they thought it was the engine variant as now it seems the engine is pulling huge amounts of air through the AFM when on idle - "Over vacuum" ? is there such a thing.

Crap. The afm flap pretty much opens at the same rate as the throttle plate.- give or take - look at it this way:

nil throttle = afm flap shut
full throttle = afm flap wide open

With a near linear response in between as the flap responds to the increasing volume of air allowed in by the throttle.

The engine can only pull huge amounts of air when the throttle plate is open. Otherwise the air can only be drawn in by the idle gallery, or via the air rail connected to the EAV, or idle speed control valves on auto cars and A/C cars.

All other controlled air must come via the throttle plate which at idle should be shut, or very nearly shut.

Now "idle speed hang-up" can keep the throttle ftom closing due to friction or maladjusted throttle linkages etc, but when that happens - idle speed is noticably raised.

I'd be happy with a bit lean when cold, and fine when warm / hot, but not happy with lean when hot, well maybe a tiny wee bit as that is a bit dodgy I am led to believe, lol.

My understanding is that the '80's Flapper Efi systems run a bit on the lean side and it is not a problem unless the engine is being continuously thrashed inducing unnecessary over heating.

My vitesse has always run a bit lean for 15 years and it has suffered not one jot.

I cannot see that the carb engine with a wee lick of a file for the injector spray pattern on the heads, plus the EFi rocker covers can make a massive difference to the vacuum.

Me neither

I also do appreciate it is the primitive EFi system and only so much can be done. Not looking for some track machine, just running properly so as to not wreck a brand new genuine landrover engine.

It was not primitive in 1987, it went like shove off a shittal and if it was untouched in the interim it still would.

You almost certainly do not have all the original components of your 1987 flapper. In which case it is a collection of unoriginal parts. Its a carb engine, its got two ECUs, - are either of them original? the AFM may be maladjusted, frankly its a mongrel.

That said it can still be made to work properly but you gorra find a trainer who it good with mongrels, or learn to do it yourself..

Hope this helps, loadsa reading material available if needed.

Ramon

[Dangerdoc]

Hi Ramon,

Thanks for your digest and response. I had a feeling this topic would raise your blood pressure a tad, and maybe a few hairs on the old back of neck area. lol

Anyway few things:

Original ECU, both of them and 4CU models, flapper AFM so no temp sensor on air as in hotwire, no EGR on back of plenum, no air-con so basic 3.5L flapper, early type.

I agree with the wiring being a bit possible sus - needs checking at sensors and pins.

The statement I made regarding lean at cold and running well when warm was mis quoted by me. It should have detailed the tuners stated they were delighted when the car was running warm and all was well.

Now therein lies the rub. They have attempted to re-configure the ECU to combat the lean aspect when from cold to running warm. Now it seems breasts aloft all the time.

What this suggests is that if all was running well with all the proper testing gear in place when the engine was warm and all the levels were correct i.e. fuel / air, throttle response, timing, idle speed, CO levels and the like then there is really bugger all wrong with the wiring.

Now they have fiddled with the bits one wonders if they are creating more work than they need to.

I will challange any time against work when they fiddled with the ECU for a "rebuild" and the like as it seems they have made the situation worse. Not what they are being paid for.

I will call them tomorrow and get an update about the situation.

Doc

[ramon alban]

flapper AFM so no temp sensor on air as in hotwire

Hello Doc - check this out

• The AFM incorporates an Air Temperature Sensor (ATS) to measure the temperature of the air which, of course affects air density, and sends the resulting signal to the ECU via pin 27.
• These measurements are combined by the ECU to determine the total number of air molecules entering the engine. The ECU uses this information to help decide how much fuel the engine needs and adjusts fuel injector duration accordingly.

sampled from Page 4 of the AFM PDF.

[Dangerdoc]

Hi Ramon,

I know you have a real deep knowledge of these things, but I was always led to believe that the Air Flow Meter did just that on the early units, Air Flow.

Then along came the Hotwire system with the two wires that allow the Air Density to be determined and hence the relevant level of air molecules.

I often read these situations where persons confuse the two.

Please do not mis-interpret this post as being a statement that you are confused, I just need to be very clear on the type of meter being used.

From the tech diagrams, the fuel pump are activated when the flap moves and the variable resistor is what provides the signal for the flow of air. There are no temperature sensors that can derive air temp hence density on the flap type flow meter.

Doc

[ChrisJC]

From the tech diagrams, the fuel pump are activated when the flap moves and the variable resistor is what provides the signal for the flow of air. There are no temperature sensors that can derive air temp hence density on the flap type flow meter.

Doc

There is an air-temp sensor in the flap-type AFM. Between pins 6 & 27.

Regards,

Chris.

[ramon alban]

Hello Doc,

I was always led to believe that the Air Flow Meter did just that on the early units, (measure) Air Flow.

Then along came the Hotwire system with the two wires that allow the Air Density to be determined and hence the relevant level of air molecules.

I often read these situations where persons confuse the two.

Err? Yes!

From the tech diagrams, the fuel pump are activated when the flap moves and the variable resistor is what provides the signal for the flow of air.

There are no temperature sensors that can derive air temp hence density on the flap type flow meter.

Inside one of these:



is this:



and it work like this:



FPC =Fuel Pump Contacts
AFP = Air Flow Potentiometer
ATS = Air Temp Sensor

• The AFM incorporates an Air Temperature Sensor (ATS) to measure the temperature of the air which, of course affects air density, and sends the resulting signal to the ECU via pin 27.
• These measurements are combined by the ECU to determine the total number of air molecules entering the engine. The ECU uses this information to help decide how much fuel the engine needs and adjusts fuel injector duration accordingly.

[Dangerdoc]

Ok, I am going to make an appointment for Ramon and Chris to come around to my place, give them some big sticks and they can beat me with them.

No not a sexual deviant, but deserve it for not paying attention to the detail !

One learns every day and I do learn from you lads - a lot.

Grateful as ever.

Latest installation is that they say the throttle potentiometer is faulty.

I'm off up there tomorrow to have some stern words and get the reading they have from the TPS and to grill them about what they have done in terms of diagnostics and the way ahead.

So much for highly recommended companies. I am a bit miffed in all the ways you can imagine.

Doc

[ChrisJC]

A TPS failure won't affect normal running of the engine. In fact it can be run without it.

The TPS information is used in two ways by the ECU:
1. Sudden change of TPS signal is used to pulse all the injectors simultaneously. This happens even if the engine isn't actually running, as long as the ignition is on (i.e. the ECU etc is powered). If you open the bonnet and rapidly operate the throttle levers, you will hear all the injectors click. This gives enrichment when you 'plant' the throttle. Lack of TPS here just gives a flat spot when you plant the throttle.
2. Max TPS signal gives full load enrichment. Lack of this means you'll be a bit down on power at full chat.

Chris.

[ramon alban]

Latest installation (information?) is that they say the throttle potentiometer is faulty.

I'm off up there tomorrow to have some stern words and get the reading they have from the TPS

Hello Doc, Probably one of the easiest components to check.

Do what CHRIS says, and then do the same very slowly there should be nil injector clicking until full load,

Then connect your multi meter as designated in my test instructions.

Rotate the throttle very slowly with ignition on, engine not running, and observe the voltage reading go from 0.325 volts up to 4.3 volts in a smooth fashion with nil unstable reading on the meter.

if its not smooth its badgered.

if its not 0.325 volts at rest it needs re-setting

If it wont go to 4.3 volts approx, then the throttle is not opening fully.

These are all faults and should be fixed. Unless you choose not to and then you get crap mpg, poor engine response and kangaroo progress - but a Chris says the engine will run, but with nil "shove of a shittal" either.

Ramon