Okay -- I've been paralyzed indecision. I've got rotting at a
friend's house a 73 142 with nearly no rust (a little around the
back windscreen) and almost all the original paint. A year or so
ago I found a perfect condition interior from a 142 and put that
into the hulk. It turns out that even though the car has 380,000
miles the carpets are in perfect condition as well. The only real
problems with the car are a totally wallered out suspension, no
fuel pump, and a totally messed up injection system.

So there is this thread in the 120 section about installing D
or K jet in a 122. It got me to thinking that it may be simpler
to just install K-jet on this car. I've already got much of what
I'd need though not everything. I'm sure with a couple months of
junkyarding I'd be able to find a complete setup. I've also been
thinking of installing SUs on it as well, though that seems to be
a real shame.

I actually really dislike the D-jet design and find the K-jet
to be a more elegant setup. Ideally I'd rip everything out and
install megasquirt but I'm not there yet.

Any suggestions? Any gotchas about installing K-jet on a 73?
chris

I have a 71 with K-Jet. '74 144's with K-Jet here have a cable throttle(RHD), do they there? I used a D-Jet manifold & welded a piece of 10mm aluminium plate on to it to sit the control pressure regulator on. D-Jet mainfold has mechanical linkages here. Didn't bother with the cold engine idle air bits, just blocked that up. Fuel pump is different too, I put the '74 fuel pump, accumulator & bracket in the boot, in the RH spare wheel tub, naughty, but I was feeling lazy at the time. You could use the D-Jet location for the pump & I reckon the accumulator could go anywhere, maybe put it & the filter behind the grill or on the firewall.

Cheers,
Paul.

Just a comment. Today's FI is still struggling to get as accurate as K-Jet. Perhaps not the most expensive FI, but definately your average FI is not as good. The only real problem with K-Jet is that the air has to move that heavy metal flap, so the engine response is a bit slow. But appart from that, it is very reliable and accurate. If you can in your neighbourhood, don't add the Lambda sensor set-up. It just complicates matters. I'm going from twin Strombergs to MegaSquirt, once I can justify spending the cash. But I'm an electronics guy. Mechanical FI is still the best.

Well you better call up all those auto manufacturers and tell them what you know about K-jet being better. Somehow they are meeting all the new emissions regs with pulsed injection that is worse than K-jet. That will be big news to them that they have been doing the wrong thing for all those years.

Why K-Jet is great:
Very simple design. Not many moving parts. Can accommodate some motor
changes without freaking out (different cam, larger pistons, etc).

Why K-Jet isn't great:
There's always some giant flap in the way of the air. Low RPM fuel
atomization isn't great. Slightly funky when integrated into an O2
sensor feedback system.


Lots of vendors, including volvo, stuck with k-jet everywhere they could
for as long as they could. They moved on to timed port injection for one
reason only -- emissions regulations. At low RPM/throttle settings, the
K-Jet system squirts a bunch of fuel into the intake port where it pools
up and then gets sucked into the chamber in one gulp when that valve opens.
That fuel won't get atomized as well as if the injector had squirted it into
the port right before the valve opened so you get higher emissions on the
K-Jet system. At higher RPM/loads, any system is going to have the injectors
running for long periods of time relative to how long the valve is open so
all of them have that k-jet behavior, unless you're talking about the cars
with injection systems that squirt a stream of fuel into the port instead
of injection systems that make atomized sprays of fuel.

For simplicity, though, the k-jet is darned good relative to its
complexity, and for this application, that's more important than emissions.
chris

Maybe the new FI are designed to produce less emissions from gigantic engines.
They certainly aren't geared anything toward CAFE standard fuel efficiencies.
As such they still lack simplicity and efficiency of the K-jet.
Personally, I never qualified MPG per available HP. Some people might.

Go K-jet!

I like K-jet as much as the next person. Turns out pulsed injection makes more power on a toyota echo and a doge viper, and makes fewer emissions, and makes better fuel mileage than K-jet can. Kjet is crude by comparison to modern systems of all types. That's all I am saying. It's like Neil saying that sidevalve engines make more torque than them new fangled overhead valve engines. Doesn't make sense.

It turns out that the world has made my decision all the easier; there
are two 75 240s in my local salvage yard. I'm going to assume that all
the stuff I'd need will be there.

How does k-jet deal with the fuel pump wiring? I'm worried that the
wiring of k-jet will be complex though given the simplicity of the whole
design I'm hoping that I'm just paranoid.

Will I be able to use any fuel distributor from any B20 or B21 or will
I only be able to use the B20 fuel distributor? Should I worry about
using used fuel injectors? With modern fuel injectors I wouldn't use
used but the k-jet injectors seem to be nozzles so they shouldn't be as
likely to wear. I'm hoping.
chris

you need a wiring diagram and a manual for a 74 140, this will explain everything. you might need the fuel tank from the 75, not sure about that, but you will need a feed pump in the tank regardless of which tank you use. everything else between the tank and the head should transfer. intake, air cleaner, fuel pump and accumulator, etc. and, yes, kjet injectors wear out. the seats and springs inside get worn. buy a kjet fuel pressure kit, too, so you can see if the pressures are ok. pressure is everything on a kjet. me, it's too hard or i'm too lazy to change a djet to a kjet. the money you spend on the changeover and getting it running will pay for alot of fixes on the djet..

You don't think that just the primary k-jet pump from a 75 240 would
do the proper job? Also, 140s and 240s have different K-jet B20 intakes;
I think I have a 240 K-jet intake already, as well as a fuel distributor.

If I were to refurbish the D-Jet, I'd want rebuilt injectors, a new
block temp sensor (anyone know of a source and price?) and a known good
map sensor. Would a 164 map sensor be functional on a B20? All those
crumbling wires on D-Jet make me nervous.
chris

A single main pump should be sufficient - that's what I have in my '74. Anyways with the earlier fuel tank, I'm not so sure the later in-tank prepumps would work.

Keep the board in touch of your progess ... it seems that I'll end up with a '73 144 that hasn't ran in 6+ years. I suspect it was just the MAP sensor then, but there are enough missing parts under the hood now that another form of getting fuel into the engine is the best bet.

-- Kane ... or perhaps an engine swap ...

nope, my 76 had a pre-pump installed sometime in 78, after all the "stalling" problems surfaced. that's why the concern about the fuel tank, you may need the 240 tank to have the right hole for the right fuel sender to hang the feed pump onto. i believe it's the same, but i know the 240 tank will go in if need be. the intake and everything under the has to be b20-b21 will not work.

the map sensor from the 164 is different. new kjet or rebuilt djet injectors are a given, too much trouble otherwise on a resurrection. don't throw parts at it, check it out and make sure it's the temp sender, could also be the air temp sender, trigger points, or, just broken wires. i had a mercedes djet car that 3 people could not get running. every single part, including the harness and the ecu, was replaced. whoever replaced the trigger points put the distributor in wrong, and everyone else after him fought that. they threw parts at that problem, i found the timing off. napa used to have a tray full of wire ends for the djet cars. most import only stores, too. take 1 in for a sample. maybe python 800-959-2865 has a rebuilt map sensor, if you need 1. or a rebuilt ecu. good luck, chuck.

I'd make it K-jet, if only to avoid the crumbling wiring. I've replaced fuel pressure regulator the injector hoses with (3/16" I think, softened in boiling water)nylon air-brake hose, in case you mess up one of those.

I much prefer my K-jet to my previous D-jet. I like the idea of being able to use the D-jet manifold and mechanical linkages also, but there may be more fussing than just switching the entire manifold, nuless, of course, that you've done that recently and don't want to buy another manifold gasket.

Performance I think is wholly offset by lack of susceptible electronics.
Go K-jet.

Sadly, a 74 tank will not fit a 73 without modifications. They moved
the tank around to make the car safer in rear impact collisions and they
moved the fuel filler hole and put it behind a door.

I guess I should really just try to get it running without trying to
do wacky things to it.

I'm sure I'll have more questions as I get deeper into things. The first
order of business is to check the wiring out as much as possible. Anyone
have a wiring / diagnostics diagram for D-jet on a 140? I really should
try to find a 71-73 green book.
thx,
chris

sorry 'bout the mix-up on the 73-74. i thought the 73s were identical, i'd forgotten about the filler neck. guess it's the 74-75 164s that are the same as a 240 in the back. good luck, chuck.

sorry 'bout the mix-up on the 73-74. i thought the 73s were identical, i'd forgotten about the filler neck. guess it's the 74-75 164s that are the same as a 240 in the back. good luck, chuck.

While you are at it get yourself the Bosch Fuel Injection manual. It explains how it all works and why and offers some suggestions on how to tinker with the system for unexpected problems or altered applications (although they are not very flexible). The air horn in which that flapper moves is very well researched for each engine application and, although somewhat flexible, can't tolerate much change without causing major fuel delivery problems.

Mike!

That's right Mike - the sensor plate limits the kind of camshaft you can put in a K-jet engine, if you want it to idle at all. Another reason why pulsed is better.