Lumpy 3.5 with Flapper

[richardpope50]

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.

Yes, Dave but will look again and more closely tomorrow.

Agree with taking loom off but that is beyond my remit as two of us are trying to either just get the engine running OK or find out find out what is wrong. (If it was my car / engine ....)

[richardpope50]

Frustrating! OK, we spent Monday doing further checks but to re-cap the total set of tests and results ….

1. Initially engine took constant starter engagement to fire albeit a lot of pops and bangs although once the engine was slightly warm it did manage to keep going albeit very rough
It was noticeable that one exhaust pipe on the odd side and two on the even side had not discoloured anywhere near enough as the other exhaust pipes. They remained cool in the initial stages of run

2. Checked HT / ignition side - good spark all round. All plugs were cleaned and gaps checked. An RPI power amp for the coil. Coil was swapped for a known one but made no difference.

3. Dynamic timing slightly adjusted using a strobe. Now warm, it had a very sweet tickover at circa 800 rpm. However, when blipping the throttle, the engine struggled somewhat to gain revs although once at circa 2,500 rpm she settled down and ran quite well albeit with an obvious miss-fire – see Youtube video above.

4. Went through the Official Rover V8 Flapper EFi Diagnostic Manual. All tests passed (surprisingly well) except for:
4a. The Coolant Sensor was not responding and eventually found the return earth from the sender’s plug socket did not make a circuit.
4b. The Air Flow Meter’s air temperature sender appears to have failed.
4c. Injectors 4 & 6 were swapped around but unlikely to make any difference as it is a bank fire sequence. They were corrected.
4d. Injector 4 actually was found to have a poor connection in the plug of the injector diode pack. Fixed.

Note. No 9th injector / Thermotime sensor connection
Note 2. Fuel rail is wrong way round but probably makes no difference.
Note 3. The injectors were bought as a working set.

5. A fuel pressure test showed a perfect 37psi pressure.

6. Distributor is non-branded but it, cap and Magnacore HT leads were purchased from RPI so we do not suspect the distributor / HT setup. We did swap out for another but then no spark so assumed faulty.

When swapped back to the RPI sourced unit, it appeared very difficult to get the timing correct. A good number of attempts were made and generally it was felt that the engine was not in such a good running state as earlier video above. We were puzzled at this even though the timing with a strobe appeared to show it a 6 – 8 degrees BTDC. It struggles to start and indeed keep going.

https://youtu.be/suBMtJGptfI

We now do not know what to do. Any further ideas?

[DaveEFI]

IIRC, below 800 rpm on most varieties, no advance, so you should see a steady timing setting with a strobe. Is the new dizzy a repro? I've no personal experience of them, but have read some bad reports about these Lucas clones.

[SuperV8]

Difficult to tell in the vid but looks like the dizzy vac advance is connected to the wrong port.
Should be connected to the port just before the throttle plate, but in the vid looks like it is coming of the back of the plenum?

Tom.

[ChrisJC]

In my experience, ditch the strobe light and just turn the distributor until it sounds good.

Chris.

[richardpope50]

Difficult to tell in the vid but looks like the dizzy vac advance is connected to the wrong port.
Should be connected to the port just before the throttle plate, but in the vid looks like it is coming of the back of the plenum?

Tom.

Well spotted and you are correct. OK, will move it.

[richardpope50]

In my experience, ditch the strobe light and just turn the distributor until it sounds good.

Chris.

Actually we did both many times. I have to say, timing still seems to be where the problem is since it was better in video 1 compared to video 2 which is after we swapped the distributors.

[richardpope50]

Is the new dizzy a repro? I've no personal experience of them, but have read some bad reports about these Lucas clones.

It, cap and magnagore HT set sourced from RPI so should be good.

[DaveEFI]

Again just going on what I'm told in the SD1 forum, etc, but clone dizzy caps and rotor arms seem to be the worst offenders. If you are seeing jittering with a timing light, I'd be looking at cross firing. Most seem to recommend http://www.distributordoctor.com/ for decent dizzy bits, etc.

After having had a few amp failures on the Lucas dizzy DLM on my SD1, I went to a Mallory. Then EDIS when I went MS - so no real experience of what's around dizzy wise today.

But would advise you get the ignition system rock solid before trying to diagnose any injection faults.

[ChrisJC]

Is the firing order definitely right?

The vac port at the back of the plenum should just go to the Fuel Pressure Regulator. (and the overrun cutoff if the engine is from a Range Rover)

Chris.

[richardpope50]

Is the firing order definitely right?

The vac port at the back of the plenum should just go to the Fuel Pressure Regulator. (and the overrun cutoff if the engine is from a Range Rover)

Chris.

Yes, firing order is correct.
Another good point.
Engine came out of a 1983 SD1. It had twin SUs but my friend added the Flapper EFi.

My friend is contemplating taking it to a V8 specialist as we've drawn a blank so will update you. It has to be simple but after 3.5 days we could not sort it out. Willpost more when I know more.

Thanks for your help.

[DaveEFI]

Did it run properly on carbs before doing the EFI conversion?

[richardpope50]

Did it run properly on carbs before doing the EFI conversion?

Sorry Dave, no idea as that was some 10 years ago and I did not build the kit.

[SuperV8]

Difficult to tell in the vid but looks like the dizzy vac advance is connected to the wrong port.
Should be connected to the port just before the throttle plate, but in the vid looks like it is coming of the back of the plenum?

Tom.

Well spotted and you are correct. OK, will move it.

Has the base timing being corrected since correcting the vac tube?

[DaveEFI]

Did it run properly on carbs before doing the EFI conversion?

Sorry Dave, no idea as that was some 10 years ago and I did not build the kit.

Just that since you seemed to have covered all the possible injection problems, did wonder if it was something more fundamental to do with the engine itself?