Help needed with warm up injector

Your result seems impossible (since an alternator should never produce ~19V DC). The "BAT" symbol in your multimeter display indicates your meter's battery needs replacing -- so you might be getting crazy results. I'd suggest that you replace the meter's battery and remeasure (and first try measuring the car's battery with the meter just to confirm the meter gives the ~12V result with the engine not running and maybe ~14V with the engine running).

Also, your operational description is a little off. When the coolant is very cold AND the starter motor is cranking is the only time that you should get +12V for a second or two at the cold start injector connector. When the engine is running (i.e., the starter motor is not cranking), you should measure 0V at both cold start injector connectors -- even if the coolant is cold.

 

Yes, this is definitely wrong, and must be corrected.

This does not concern me yet, and may be OK. The coolant needs to be be fairly cold (like less than 35 deg C) for the cold start injectors to squirt so unless you waited overnight for things to completely cool off, you really can't confirm/deny this test.

I get to use the word "impossible" twice in one thread . Seriously, the two cold start injectors are run by the same (single) relay S so they should be doing the exact same thing. About the only thing that I can think of is that you've got the wrong 2-pin plug in the wiring harness connected to the passenger side cold start injector. There are many other (of the same style) 2-pin plugs used for the electric heaters built into the AAVs and WURs -- these plugs should have a constant +12V whenever the fuel pumps are running.

The first thing to do is to look at the wire insulation colors on the 2-pin connectors going to the cold start injectors -- the US driver's side should have two CB (orange-white) wires and one N (black) wire; the US passenger's side should have one CB (orange-white) wire and two N (black) wires;

If your (presently used) passenger side cold start injector connector has either one P (beige) wire and one N (black) wire (which is for the heater in the passenger side WUR) or two P (beige) wires and two N (black) wires (which is for the heater in the passenger side AAV), you got the connectors switched around. I really hope that this is the problem, otherwise, someone would've had to have made some serious (and unknown) wiring changes to get the behavior that you report.

A minor side note is that these other 2-pin connectors for the AAV and WUR heaters should only go +12V when the fuel pumps are running -- since you report that you get +12V with the key "on" but the engine not running, this would occur only if your fuel pumps also ran with the key "on" but the engine not running -- do they?

The (single) thing that controls the operation of both cold start injectors is the thermo-time switch -- item 38 (PN 113980) in this SPC page:

http://www.ricambiamerica.com/parts_catalogs.php?M=FE&P=&V=diag&I=3282

The food chain is:

When the thermo-time switch is closed (cold), the same +12V that goes to engage the starter solenoid (i.e., key in Pos III) is conducted by the thermo-time switch to close relay S. When relay S is closed, this puts +12V (simultaneously) on both cold start injectors, which open, and squirt fuel, until either the thermo-time switch opens (it also has an internal electric heater) or you stop cranking the starter motor.

 

Yes it's ok to only have one "safety switch" connected = that is how they came originally.
The one swtich controls a relay that cuts off power to both fuel pump relays.
M

 

I recently spent a lot time trying to work out why my cold start injectors were not working on my manual RHD 412.
Like you I spent ages tracing the wiring back to the main fuse box (with the help of the 412 circuit wiring book, testing the cold start thermo switch etc etc.). The fault finding then led me to the auxiliary fuse box located in the glove box. Much to my surprise there was no relay plugged in, instead there was a factory sticker covering the empty relay "socket" saying that it was for 412 Automatic's only. That explained why there was no power in the cold start system.......
My point is that the 412 manual doesn't use/need the cold start circuit at all, so how important is it really ? ( I know yours is a 400A )

M

 

Yes, but it is more often referred to as the "cold start injector" or the "auxillary starting assembly" in the F documentation (because it mostly operates during cold starting, not during engine running to warm-up -- unless it's really, really cold, and you blip the throttle).

This looks wrong to me based on the beige color and the non-black wire having no white stripe (unfortunately, "beige" can often appear brownish or orange too). The schematic shows two black wires there, but having only one black wire is OK (they may have put the junction for the second black ground wire somewhere inside the harness and just show it symbolically on the schematic at the connector).

The color of the non-black wire here looks a little more "orange" to me (which is good), but you really need to expose more wire length to see if you can see any evidence of a white stripe too. The reference that I'm using is the schematic in your 250/82 OM so it's always possible that they did something diabolical like substitute C (orange) for CB (orange-white). My hope would be that at least "beige" and "orange" (however they each appear) are consistent throught your car so comparing them to each other may help discern who's who.

Yes, that's the AAV.

Yes, this is OK/stock. As Michael indicated, they only use one of the safety switches to control the fuel pumps, but you really didn't answer my question -- (even though the safety switch seems correctly connected) do your fuel pumps run with the key "on" and the engine not running?
The wire colors here should be ZB (purple-white) and N (black) per your OM schematic.

I'd also look at the wire colors at the 2-pin connectors on WURs just to get a complete color catalog of the wires in all the 2-pin connectors. As I indicated, the difference between orange and beige may be very slight (and the color is more important than the number of wires).
Also, with the engine running/idling, you could unplug and measure the voltages at all of the AAV, WUR and cold start injector 2-pin connectors -- if this were correct, the result should be:

both cold start injectors = 0V
both WUR heaters = +12V
both AAV heaters = +12V

might help sort things out...

Having that constant +12V on the passenger cold start injector is a flaw that can't be ignored IMO (and, of course, you'll have to leave it unplugged until fixed). (To allow myself a joke) Can't one argue that the wiring of any 70s-80s F was totally messed up even when it left the factory new?

No worries. Although I know it's probably a frustration for you, for me, it's nice to discuss/investigate a new problem that we haven't gone over many time before.

 

Good eye Steve!

1.) For starters, I believe the cold start injectors only squirt for a brief moment when the key is switched to the 'start' position...I don't think they continually squirt while the starter is cranking if you lay on the starter for a long period of time. I don't think it operates like a warm up injector (where it would continually squirt until the engine warms up), this is where the function of the WUR (warm up regulator) kicks in. I think this is one of the reasons why when you stop cranking, the OM instructs you to turn the key to the 'off' position, then turn back on to the 'start' position. Oh by the way, with the battery disconnected, I tried something. I turned the key to the 'start' position, then back to the 'on' position, then tried to turn it to the 'start' position again without returning the key to the 'off' position as instructed in the OM &...it wouldn't turn to the 'start' position. So I think there is a mechanism inside the lock that prevents you from doing so & the OM instruction is a reinforcement.

As a side note: I've noticed on u-tube vids. & such that when owners crank their injected V-12's, they'll sit there & crank & crank until it starts. I have found that just cranking the engine over for about 2 seconds, then stop & wait for about 4-5 seconds, then crank again that the engine fires right up. For a couple of reasons I'm thinking that 1.) the fuel evaporates during the 4-5 seconds that it is sitting & 2.) on the second crank, the cylinders get another squirt from the cold start injector. I have found this to work beautifully on all injected cars, not just Ferrari's.

2.) It's interesting to hear that your car has the fuel pump relay connector hooked up to the passenger side air mass meter. I have only seen them hooked up to the driver's side (on a LHD cars), only one side has a connector hooked up to the air mass meter to sense air moving past the plate, which then activates the fuel pumps.

3.) The connectors that connect to the cold start injectors are the same type as the ones to the aux. air valves, the WUR's, & the 'one' air mass meter. The wires attached to each individual connector is of a specific length that it would be difficult to hook one connector to the wrong device. The only place this could happen is on the side the air mass connector is located. It is of similar length as the cold start injector (on that one side) & it could accidentally be switched. The air mass meter connector is brown where as the rest of the connectors are black. Yours are hooked up correctly so that's not it (unfortunately, or it could be a quick fix).

 

You can download a copy of the 400i 250/82 OM here for your records:

http://www.ferraridatabase.com/The_Downloads/Manuals_Owners.htm

(That pdf that you have is the relevant electrical stuff from 250/82, but material in Section 3, regarding the injection system, would be useful for you too IMO.)

 

After having a closer (magnified) look at your photos, are you sure that this isn't a CB (orange-white) wire (wrongly) connected to your AAV?
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Understood -- and it does seem unlikely that they could be swapped without sort of mis-installing of the entire harness.

One thing is that you sort of started this thread in the middle by giving a finding without giving a symptom -- was: A) your car working fine before, with the passenger side cold start injector plugged in, and then it started running badly so you investigated and found the (always) +12V on the cold start injector, B) the passenger side cold start injector has always been unplugged before, C) something else? More background please...

 

Very strange.

On my car the the wires to the AAV are not as long as the wires to the cold start injector so it's impossible to swap them over.

I would look at the fuse panel and the connector between the panel and the wiring to see if the wires had been swapped. It's possible that someone in the past has done a repair to the connector (burnt out wires for the fuel pump is common ) and inadvertently mixed up the position of the circuit on the connector. That would account for the "as molded" fit of the wires in the engine bay, yet the unexpected electrical "behaviour".

I'm not sure this has been covered, but how is the other side wired up, and does it behave the same way ?

If the wires are reversed between the AAV & the cold start it's going to run rich on that side. I'm guessing this is why Mike ( the mechanic ) was able to lean it out and still get high readings. Tends to confirm that the cold start injector is running all the time.

M

 

I might be missing something but it sounds like Mike leaned that side out all the way, did he leave the screw set to “all the way” lean? If so the cold start injector is probably supplying the required fuel for that bank to run. A potential problem with this is since the injector is at the back or the manifold the cylinders in the front could be running very lean which could cause some problems with the exhaust valves. Just something to think about.

 

Precisely. The voltage to the cold start injector stops after a few seconds because the thermo-time switch heats up and opens (even though you keep cranking the starer motor).

Yes, but the AAV also absorbs heat directly from its environment so the AAV wouldn't always be open if no voltage is applied to its internal electric heater, it would just close more slowly, but when the engine was fully warmed up, it would probably be fully closed OK. However, having the cold start injector always spraying is (way) bad because it doesn't add fuel as uniformly as the cylinder injectors as Jim mentioned -- so that's probably why that bank could never be adjusted properly (even though the total amount of fuel entering the engine was optimized as best as possible when the cold start injector was always spraying).

Agree, but just turn the mixture screw CW enough until that bank starts to run well (not a fixed amount) and then maybe a touch more if you have no other equipment/instrumentation available.

PS You haven't answered the question "Do your fuel pumps run with the key "on" but the engine not running?" -- not a big issue, but something to add to your "sorting" list if they do...

 

I had a similar issue with a 380 SL where I had sporadic " rich running " conditions which we could not trace which turned into a cold start not starting problem.

We spliced into the cold start circuit and installed a remote voltmeter which allowed us to view voltage cycles to the suspected circuit, and added a momentary " On " push button wired to a 12VDC source to the Cold Start valve.

It allowed us to verify start up / cold conditions and having a " quasi " remote switch to pulse the cold start valve.

Bill, you may consider a revers set up where you can eliminate power to the Cold start valve after warm up and verify running conditions.

 

+1!

& if they don't, try unplugging the brown connector @ the air mass meter to see if the pumps come on. If they do, at least it eliminates that connector.
The fact that 'gooey' electrical tape is in the mix definitely shouts out that someone has been into that harness & quite possibly switched things up.