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My 3.4 has an HD6 set of carbs with a Choke Operating Solenoid. There is a tube called a "Starting Pipe" that I found in a parts diagram. Where is this Starting Tube located? What is it's purpose?
This feeds the manifold with rich mixture of fuel air for starting and warm up. (auto choke).
Pipe (32) fits to the starting carb (Choke Operating Solenoid) and the two other pipes.
Rgds
David
Last edited by David84XJ6; 04-08-2024 at 10:52 PM.
This feeds the manifold with rich mixture of fuel air for starting and warm up. (auto choke).
Pipe (32) fits to the starting carb (Choke Operating Solenoid) and the two other pipes.
Rgds
David
My solenoid does not have any exposed blade connectors. Apparently they are clipped onto pins on top of the solenoid. Are these connectors available anywhere?
What about an Ohm range for testing the solenoid?
thank goodness for modern computer controlled injection systems where cold starting issues are addressed as a non-exceptional part of the overall injection system. in fact, it would surprise me if the software involved contains any special provisions for cold starting at all. as exhaust gases are being monitored at all times and fueling adjusted accordingly.
thank goodness for modern computer controlled injection systems where cold starting issues are addressed as a non-exceptional part of the overall injection system. in fact, it would surprise me if the software involved contains any special provisions for cold starting at all. as exhaust gases are being monitored at all times and fueling adjusted accordingly.
On my 99 Mazda truck (which is a very old injection system by todays standards) it has a sensor that measures the temperature of the coolant in the rad.
It looks much like the sender to the gauge and acts the same way; more or less.
The sensor tells the computer the coolant is cold, and upon cold start up, the computer keeps the injectors open a number of milliseconds longer to over come the cold engine, thus enrichening the mixture, and therefore combustion takes place.
There's one flaw in the "hisser" choke system, is that it can't automatically adjust itself for warmer or colder conditions.
The choke system does not have the ability to measure the ambient temperature on cold start up.
Whether that temperature is the coolant or air, or both.
If the choke is set to start in my heated garage, then it will start and run correctly, but if I park it outside and now it decides to freeze, it will not start even the though the choke is activated by the Otter switch or by a manual switch under the dash board.
I have to manually go in there and enrichen the choke (almost guess) how much to open the needle valve to allow fuel into the engine through those series of pipes that are circled in the screen shot.
Note that there are 6 of them in the end that go right into the intake manifold, one for each cylinder.
On the reverse of that; the choke is now set too rich to start in my heated garage, if I attempted a cold start in the garage, it would get so much fuel, it would most likely flood.
That choke is such a poor design because if this major flaw, and for people that don't understand how it works, it can be an endless source of frustration.
Obviously don't have the same variables in temperatures in the UK that you have in Canada but even so as it gets colder in the winter I have to adjust the choke needle just a little every month to get it started and then as spring comes around I am back under the bonnet winding it back the other way.
it would surprise me if the software involved contains any special provisions for cold starting at all. as exhaust gases are being monitored at all times and fueling adjusted accordingly.
Cold start and warmup are actually the most difficult phase of engine operation to program for EFI. Feedback is inhibited because the O2 sensors need to be very hot to give proper readings, and they take time to warm up. As a run of thumb, a cold engine needs about 75% more fuel at cold start than it does for warm running, but that will change by engine, manifold and EFI type and temperatures. The exhaust gases are also deliberately rich on startup in order to get the catalyst working and get it hot quickly, which takes fuel.
There has been a lot of engineering resources devoted by the OEM car makers to the start and warm up phase of engine control. Ford even has multiple patents on a control strategy for warm up fuelling. If you have access to academic papers, some details are in this paper: https://digitalcommons.mtu.edu/michigantech-p/2918/
Cold start and warmup are actually the most difficult phase of engine operation to program for EFI. Feedback is inhibited because the O2 sensors need to be very hot to give proper readings, and they take time to warm up. As a run of thumb, a cold engine needs about 75% more fuel at cold start than it does for warm running, but that will change by engine, manifold and EFI type and temperatures. The exhaust gases are also deliberately rich on startup in order to get the catalyst working and get it hot quickly, which takes fuel.
There has been a lot of engineering resources devoted by the OEM car makers to the start and warm up phase of engine control. Ford even has multiple patents on a control strategy for warm up fuelling. If you have access to academic papers, some details are in this paper: https://digitalcommons.mtu.edu/michigantech-p/2918/
i can't say how difficult it may be, but once coded should cover all bases WRT ignition, whether it be starting or running, or hot, cold, or something in between. IOW, if the code was searched for a subroutine named "ColdStartTempLT100( )" it would fail. which is the point i was trying to make in my previous post. i most likely didn't make that clear...my fault.
Last edited by hueyhoolihan; 04-09-2024 at 03:22 PM.
The 3.4 came with a new set of .030 pistons and rings. The pistons are the 4-ring type, two oil rings instead of one. I've heard there is a better oil ring that will fit these pistons. The current rings are one piece, the newer style are 3-piece I think. Has anyone had any experience with these newer style oil rings?
My 3.4 engine has a steel pan with an attached sump. The manual shows oil capacity at about 8qts. The engine has almost 8 quarts with no oil showing on the dipstick. The dipstick is shown in the attached image. I tried a 1973 4.2 dipstick which is much longer and it hits the screen basket in the sump with no oil showing. It could easily take several liters more to show on the dipstick.
How much oil does this type of oil pan require?
My MK2 Jaguar workshop manual states for all MK2s (2.4, 3.4, and 3.8)
13 Imperial pints
!5 1/2 US pints
7 1/2 litres
I have found those figures to be reasonably accurate.
Yes, as Bill wrote for the Mk2. The XJ sumps were a little larger, and the early XK120 took around twice the volume of oil, 12 litres sump, 13.5 litres total. But, I believe they are all alloy rather than pressed steel.
The engine is build is complete and has about an hours worth of run time on the test stand. This was my first engine build and it was very satisfying to see it run. Now all I have to do is modify my car to allow the 3.4 and the Moss 4 speed to fit.
I appreciate all of the valuable information I received from the members that have responded to my questions. Thanks!
I need a distributor for my 3.4, it currently has an XJ6 points type. This XJ6 distributor has a hole and crack in it where it had an internal failure that damaged the housing. There was a brass part like an advance weight and a couple of the nuts like what's used on the internal wiring loose inside the housing. I've seen a couple of distributors on Ebay that also had the same kind of damage. Is it user error or a design flaw that caused these failures?
04-08-2024, 10:30 PM
