1977 Daimler Double Six vanden plas wont start

(Michael Lonati) #1

Hello everyone, im a mechanic and im from Switzerland.

I have a 1987 Daimler double six in my garage, the Car was driving perfectly but suddenly the engine stop running and the car wont start. So i have checked the temperature sensors the fuel pressure its all ok. When the cold start valves are priming the car start but stop right away. The injector valves wont work. has everyone an idea? thanks Michael

(Philip Lochner) #2

Welcome to the forum Michael!

If it has the original LUCAS OPUS ignition system, I would start there. It is well known to be unreliable after all these years. It typically tends to run while the ignition system is cool but cuts out when it gets warm.

If it does turn out to be the ignition, there are very elegant ignition upgrades available from Lumenition and Pertronix. My own E-type V12 is running on Lumenition which even has a distributor install kit for the old OPUS distributor.

(Michael Lonati) #3

i have no pulse on the injectors

(Kirbert - author of the Book, former owner of an '83 XJ-S H.E.) #4

With an '87 I’m presuming it’s a Lucas CEI. And I’m presuming you have spark, since you’re a mechanic and would check that first.

I’m gonna go farther and presume that the Daimler has the same little coax wire that the XJ-S has. So, follow me on this: The ignition amp is a black box on top of the LH intake manifold and it says AB14 on it. From that box, there are wires that go to the coil, wires that go to the distributor, and two wires that go rearward toward the firewall. The two going toward the firewall are blue/white/gray and both end in bullet connectors, but one is a male end and one is female. One of the two, after the bullet connector, becomes a slim white wire and immediately enters a wiring harness, wrapped in a black loom, and then crosses over the rear of the engine to the RH side where it merges with a larger harness. The skinny white wire is the only wire in the loom for that crossover to the other side.

Strip the loom off that little harness portion and inspect the little white wire. That white wire is actually a coaxial wire, meaning it has a grounded shield and a core. With age and heat it gets brittle and cracks and the core shorts out with the shield and the injectors stop. If it looks bad, strip out that 18 inches of coax and replace.

(Paul M. Novak) #5

I own, drive, and do most of the work on my Canadian market 1990 V12 Vanden Plas, which is basically a Daimler Double Six. It sounds like you might have a somewhat common problem with a break in the small fragile shielded wire that provides the signal from the Lucas ignition amplifier on the top of the left hand intake manifold to the EFI ECU to fire the fuel injectors. You will find that small white wire as it leads from the ignition amplifier and goes down into the spark plug valley on the left side of the fuel rail. If that small wire is broken, or if there is a break in the insulation between the inner core and outer shield then the signal from the ignition amplifier to the EFI ECU will be lost. There are a lot of posts in the Jag-oofers archives about this including how to test the wire to the EFI ECU pins to find if that is the problem and also what others have done to repair this shielded wire. This is a problem not only with the DD6/XJ12 but also with the XJ-S V12 cars equipped with the Lucas Constant Energy Ignition (CEI) system. There is also information about this problem in Kirby Palm’s excellent “Experience in a Book” that can be downloaded for free from Jag-Lovers.


(Kirbert - author of the Book, former owner of an '83 XJ-S H.E.) #6

Great minds think alike!

(Michael Lonati) #7

Im sorry i maked a failure the car year is 1977. sorry

(Ed Sowell) #8

Since you say “the injector valves won’t work,” I’d be looking at the EFI rather than ignition. Check the ground connection, which on my '76 XJ-S is attached to the right intake manifold near the firewall. If that’s good, check the connector plug where the power amplifier (mounted on the radiator top rail on my car) connects to the EFI harness.

If the above items check out OK, it’s probably the trigger board in the distributor, since the ECU and power amplifier are very reliable.

(Kirbert - author of the Book, former owner of an '83 XJ-S H.E.) #9

If the car is a 1977, you can forget about the coax wire discussion.

(Paul M. Novak) #10

Hmmm. Great minds may think alike but they were absolutely wrong on this one. :wink:



Hi, if the injectors don´t click, then Your ignition amplifier doesn´t work. It is a common problem.

(Michael Lonati) #12

Hello thanks but ive replaced the ignition ampilifier but the car wont start und the injectors already dont click.

(Mark Eaton) #13

Don’t know if you have solved this. It looks like everyone has jumped the gun on the diagnosis.

  1. It is an 1977 not a 1987 or later.
  2. It fires on the cold start injectors, but doesn’t continue to run.

Therefore there is nothing wrong with the ignition system.

I would trace the power feed to the injectors. I’m almost certain that the 1977 had low impedance injectors and a resistor bank to provide holding current. (Peak and hold operation). From memory it is on the right hand rear side of the engine bay in a big silver box. It can get corroded and fail. It also connects via a white rectangular connector (old Lucas style) and it could be worth cleaning the connector and re-seating it.


(Paul M. Novak) #14

I was one of the ones who jumped the gun in November when the body of the initial post said it was a 1987. I did not notice that the subject line said 1977. Once Michael explained that it was really a 1977 and the 1987 was a mistake I backed off since I have no expertise in the earlier V12 cars. I am glad that someone else does.


(Michael Garcia) #15

very matter of fact
Mr. Palm…
all 611 pages,
blooming cool!

(Michael Garcia) #16

why the photo didnt come through
jen se pas…
was of six binded
hundred page
segments of your work