Lumpy 3.5 with Flapper

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SuperV8
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Re: Lumpy 3.5 with Flapper

Post by SuperV8 »

richardpope50 wrote:
Mon Oct 01, 2018 4:47 pm
Does it matter which way up the AFM is installed? I noticed that the installed unit is 90 degrees to the standard Land Rover installation.
Yes in theory the flapper meter should be installed horizontally - if installed vertically then the flap will also be working against gravity which will change its response although in practice it may work fine as long as its calibrated correctly in that position?

Tom.


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richardpope50
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Re: Lumpy 3.5 with Flapper

Post by richardpope50 »

Thanks Tom. Will suggest my friend changes it in due course.

OK, more progress ….

Started to go through Rover EFI Diagnostic Manual tests and found
1. ECU’s temperature sender (probably) not working.
2. Injector 4 circuit had a broken (probably intermittent) connection (so that explains yesterday).

Current situation is that on cold start it is very difficult to get started with loads of pops and bangs and a real struggle to run. Within a minute all is well and it ticks over as a very sweet V8 should do. There is no cold start injector so this may cause this.

Main problem is that if you blip the throttle then it does not smoothly increase the revs but is lumpy in doing so. However, when you get to, say, a constant 2,500 rpm it seems all OK or possibly with a small amount of rough running.

(I cannot seem to be able to upload a video to Youtube of this to show you.)

So current real problem is when engine is under load whilst blipping the throttle, the engine struggles to rev but once there, it seems more or less OK.

Still have some manual EFI tests to go through but any ideas on the problem?
Richard.
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Re: Lumpy 3.5 with Flapper

Post by DaveEFI »

The ATS in the AFM has only a minor influence on the fuelling.

In this mild weather, the cold start injector isn't really needed, although it might make it start quicker.

A common problem is a worn TPS. This senses the rate the throttle is opened, and adjusts the enrichment accordingly. The engine will run with it unplugged. If no difference, likely faulty.

Also, check the fuel pressure. Too low and it will run weak. With the engine stopped and the pump running, you should see at least 36 psi. 38 psi better. An easy place to fit a gauge is in the cold start injector pipe.

As you probably know from your Megasquirt, a slightly rich mixture makes little difference to the running. A slightly weak one, a great deal.
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Re: Lumpy 3.5 with Flapper

Post by richardpope50 »

OK, got it posted.

Video of a warm start (so none of the pops and bangs. Shows it at tick0ver and blipping the throttle to circa 2,500 rpm. Definately something wrong. Note there is also a clang which appears to be a backfire through the plenum and is causing the flapper to close hard against its close stop. This is very noticeable on a cold start.



Tomorrow I'll capture a cold start and any improvements we make.
Last edited by richardpope50 on Tue Oct 02, 2018 4:39 pm, edited 1 time in total.
Richard.
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Re: Lumpy 3.5 with Flapper

Post by richardpope50 »

Thanks Dave, really good points.

Fuel pressure is something we considered but do not have a pressure gauge (at least at the moment).

Will try the TPS test as well.

Seems it could be the carbon brush / bar in the AFM.

Will continue going through the book's tests tomorrow .....
Richard.
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Re: Lumpy 3.5 with Flapper

Post by Ian Anderson »

Have you tried starting at night with the lights off to see if the leads are cross firing and shorting to each other?

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Re: Lumpy 3.5 with Flapper

Post by SuperV8 »

richardpope50 wrote:
Tue Oct 02, 2018 1:07 pm

Current situation is that on cold start it is very difficult to get started with loads of pops and bangs and a real struggle to run. Within a minute all is well and it ticks over as a very sweet V8 should do. There is no cold start injector so this may cause this.
I removed my cold start injector and it never gave me any starting issues, from memory would start fine down to arround 5 degs, didn't try when freezing/show as it's not the sort of car you drive in those conditions :shock:

Tom.
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Re: Lumpy 3.5 with Flapper

Post by richardpope50 »

No, not started at night (good idea) but all HT kit seems 100%. It even has a power amp for the coil so we get a good spark.

Finished the EFI Diagnostic Manual tests today and only additional fail was the Air Temperature Sensor. So total list of fails is coolant sensor with new one on order, no cold start stuff so ignoring this and the ATS fail. Also having the AFM installed 90 degrees out. As said above, no serious fails here. Indeed flapper and throttle pot progression readings were very good / smooth.

We have noticed that the fuel rail is back to front but assume this is no problem. Will correct in due course.

Have now ordered a fuel pressure testing kit so next task is to check all that but will have to wait until next week when it arrives.

If the fuel tests fail, then we will swap the dizzy and HT stuff.

Will update next week after fuel tests. Thanks for your help.
Richard.
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Re: Lumpy 3.5 with Flapper

Post by DaveEFI »

If the CTS is faulty, that has a big effect on the mixture. They usually fail open circuit - telling the ECU the engine is cold. And it goes fully rich for a cold start. But you should have the resistance figures by temperature in your guide.

If you have a 180 ohm or so resistor lying around, that simulates a hot engine. Until your new CTS arrives.
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Re: Lumpy 3.5 with Flapper

Post by ChrisJC »

I thought the cranking of the engine before it started was a bit 'leisurely'. Have you got a good engine earth?

In my experience, there is no need for powerspark or any other fancy ignition booster. The standard on-distributor amplifier is pretty damn good.

You could try tweaking the timing just to see if that makes any difference. Mark the distributor so you can put it back again. I used to set the clamp nut so I could adjust it whilst running, then just adjust it until it ran best. I never bothered with a timing light.

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Re: Lumpy 3.5 with Flapper

Post by richardpope50 »

ChrisJC wrote:
Wed Oct 03, 2018 8:54 pm
I thought the cranking of the engine before it started was a bit 'leisurely'. Have you got a good engine earth?

In my experience, there is no need for powerspark or any other fancy ignition booster. The standard on-distributor amplifier is pretty damn good.

You could try tweaking the timing just to see if that makes any difference. Mark the distributor so you can put it back again. I used to set the clamp nut so I could adjust it whilst running, then just adjust it until it ran best. I never bothered with a timing light.

Chris.
I have to agree with you about cranking. The video clumks are the starter not turning the engine over. Least of my friends problems but it may be swapped later.

Power amp is installed and appears to work so will stay but we may change dizzy for a different setup next week if fuel pressure tests all pass.

Timing: done that and that improved the tickover to make it a very sweet and quiet engine. I hope to video the cold start and you will hear the pops and bangs!!!

Dave. New CTS ordered but there may be a wiring issue too so will investigate further.

(We have to tow the car to my place each time so next week is the next test day.)
Richard.
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Re: Lumpy 3.5 with Flapper

Post by DaveEFI »

The popping and banging suggests weak mixture to me. That would suggest the CTS was short circuit, rather than open circuit which is the more usual fault condition. Have to checked its resistance by unplugging the ECU and measuring at that connector? In case there is a wiring fault.
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Re: Lumpy 3.5 with Flapper

Post by ChrisJC »

I'm sure Richard has measured at the ECU connector. In my experience, this is essential as it verifies the wiring as well as the sensor, and I have found a few bad joints that way over the years...

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Re: Lumpy 3.5 with Flapper

Post by richardpope50 »

ChrisJC wrote:
Thu Oct 04, 2018 7:22 pm
I'm sure Richard has measured at the ECU connector. In my experience, this is essential as it verifies the wiring as well as the sensor, and I have found a few bad joints that way over the years...

Chris.
Yes I have. ECU pin reading showed open circuit and later I was only able to do a continuity check on pin 5 and not pin 13 which is why I referred to wiring problems. I also note that the loom wires are brown + white / slate whereas all wiring diagrams show Black + white / slate. A new CTS is in the post but obviously the wiring needs sorting.

We now suspect the fuel pressure being low and could be the pressure regulator or the wrong fuel pump. As the car is not at my house but towed here for each it is difficult to keep checking - and my friend does not really understand wiring looms and engines! That's why it is not easy to easily check things.

I have followed the official Rover EFI Diagnostic Manual tests as linked to in early post and above posts show the problems found.

Thanks for suggestions and will come back on fuel pressure tests after gauge kit arrives.
Richard.
Dax Rush 5.0l TVR V8, EFI with Megasquirt ECU and wasted spark, Racelogic Traction Control and Quaife LSD ....... Now nut and bolt restoring a TR6

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Re: Lumpy 3.5 with Flapper

Post by DaveEFI »

Did you look a both ends of the CTS wiring - including at the ECU plug? Could be the loom has been repaired at the CTS end using what was available, colour wise.

With most old flapper looms, it can make sense to remove it to the bench, and examine every connector and wires close to it easily, and repair where necessary. Also makes it easier to re-wrap, which it almost certainly needs.

If you need to replace any wire ends etc with good, give me a shout. Can likely find you some decent used bits of the correct colour etc to repair it with.
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