Hot (No Start) Issue - Need A New Direction

Thanks everyone for your feedback. Work has gotten in the way of further investigations and looking into the suggestions you all provided.
I'll tackle the following on the weekend when i have more time, and will post the results:

1. during hot no start re-check pressure/operation?
2. during hot no start check for spark?
3. check spark plugs for flooding?
4. check aux air valve operation?
5. check fuel injectors for leaking?

Cheers, BB

 

Almost forgot, need test warm up regulator pressures vs. temp

Cheers, BB

 

Check your fuel pump relay along with its associated wirings, connections to the underrated contacts in the connector. I moved mine off the board with 10awg wires, beefy relay sockets, solid crimp joints bypassing the relay board and the connector.

 

On this page you will find a link for a pdf of the 1981-1985 Mondial QV Workshop Manual and in it you will find the K-Jet section with all of the pressure tables as well as instructions on how to test. You do not need the special test box, a standard fuel injection test kit should have all of the fittings required.

http://ferrari.cdyn.com/

 

This. It took a number of shops and mechanics to finally track an intermittent fuel pump down on my '83.

 

I used to own a 95 Mondial
It would start just fine when cold but when it got hot it wouldn't start for a long time while cranking.
Ferrari mechanics wanted to rebuild the entire fuel system
Took it to a domestic car mechanic
Turned out it was a crank sensor.

 

Hi Ferrari Chatters,

Well, spent considerable time trying to further diagnose the hot (no start) issue. Not sure I achieved much and probably ended up asking more questions than finding answers. So the short of it is that the problem continues, but I tested the following. (apologies for the long post)

1. Rechecked the pressures and they were - SYSTEM pressure 72 psi (5 bar) and CONTROL pressure 30 psi (2 bar) @startup and 48psi (3.3 bar) @Engine operating temp. AMBIENT temp on the day was 20 C. RESIDUAL pressure was 42 psi (2.9 bar) for >20 minutes. According to the Bosch FI Vehicle Application document my engine (F105) should have WUR 0 438 140 078 (I couldn't see a part number on the unit). None of the temp/press tables provided in the Ferrari manuals cover that Bosch part number? But if I compare it to the Bosch Technical Instruction manual it states 54 psi (3.7 bar) at engine operating temp. While the Forbes Aird book states 50-55 psi (3.4-3.8 bar). So can I draw a conclusion that the control pressure is 2-6 psi low? As mentioned here by others low control pressure does mean richer mixture. Could this be the cause? Its not a huge margin though?
2. WUR with engine load via vacuum line to manifold. Mine has this and I noted the although I could feel a small amount of vacuum both at idle and acceleration, it wasn't enough to pull the needle on my vacuum gauge? Maybe the diaphragm in the WUR only needs very light vacuum. Pulling the hose off made no difference to the control pressure?
3. Disconnected cold start valve during hot (no start) and it made no difference. To further confirm I removed the cold start valve but left the fuel line connected. Energized it via external 12v off and on repeatedly, sprayed fine and no leaking after the it was de-energized. So no possibility of leaking causing flooding.
4. Removed all four "easy" spark plugs i.e. the back ones. They were all black and sootie so can assume over fuelling. During multiple start attempts the engine starts to smell very fuelly.
5. Carried out a basic check for spark using the suggestion here. Connected my timing light and used the induction camp to check each lead while cranking. All eight cylinders were the same constant flashing during cranking. So I think this indicates that coils are firing through to the distributors and the leads?
6. During hot (no start) checked fuel pressure - no change from readings in item #1 above. Disconnected the safety switch plug on the fuel distribution unit during hot (no start) and this also made no difference. Though I did note that the starter relay inside the car was actuating rapidly. Not sure if that is normal, as when I cold start the car it kicks over instantly (so I never hear it)?

The only items I have left on my list is fuel injectors (leaking?) and to check the auxiliary air valve which I doubt can cause the hot (no start) issue? And of course further investigation of the electrical system. Happy to take further advise please.

Cheers, BB

 

No, it is not normal (but, if you have the specified fuel pressure, the fuel pump is working). When the safety switch is unplugged, that relay should stay always unenergized. Have you tried using a different ...101 relay in that position?

 

Here is the diagram I followed to make the WUR adjustable on my 911. I had a machine shop do the drilling and tapping as the roll pin hole is difficult to drill accurately through two different types of metal. The WUR is traditionally adjusted by simply hammering the metal bung downwards but if you knock it too far down you are stuck. This modification allows you to pull it back out. The adjustments required are very small. On my 911 there is also a fine brass mesh filter on the input line which was clogged with varnish deposits that I cleaned out. After setting the control pressure to within the range recommended by Bosch my hot start problem was gone. There is also an electronic replacement for the WUR that I have seen advertised but have no experience with. If I can find the link I will post it here.

 

I found this site had some good technical resources:
http://www.ferrari400parts.com/ferrari400.php

And here is the electrical replacement for the WUR:
https://unwiredtools.com/utcis.asp

 

Thanks guys......

Steve, I'll swap around the relays and see if the starter relay stops multi-clicking. Might be a dodgy relay - but as you say the pump is still operating.

Kiwiokie, thanks for information and the links. That 400i site has some great stuff. Not sure about converting to an electric WUR, seems a bit extreme and they generally work fine for many years. I'm thinking I'll pull the WUR and rebuild it including the adjusting mod. That way post rebuild if its still delivering a low control pressure I can adjust it. I've got an old electric fuel pump and adjustable regulator, so I will be able to set up a test rig to check afterwards. I also found this great video thanks to another 911 guy!



I'm thinking I will pull the injectors too and check them for spray pattern and leaks.

To be continued

BB

 

The 911 first received CIS in 1973 and 911s were built in much higher numbers than the 308 so there are more people out there troubleshooting CIS on 911s than Ferraris. The Pelican Parts forum has the best owner base for early 911s and a user called boyt911sc is the resident CIS guru. Good luck!

 

I know the k-jet very well. worked with it fo more than 30 years now.

I think you have leaking injectors which is in my experence the most common reason for hot start issues.
the carbon build up on the tip is causing this over years ( assuming your car is regularly used so it is not stuck by corrosion).

if you pull one nozzle at the time, run the engine and put the nozzle in a bowl ( carefull for fire, two man job)..) you can look at the spraypattern. If it is uneven, which by the way it almost always is, tap the nozzle a few times with a small hammer. You will be surprised about the effect on the spray pattern: it will improve by the tap..)

If you schut down the engine, the spray must stop instantly. ( try this first without tapping so you see the as-is situation first) In many cases however you will see some small dripping, or even mild peeing. The same tapping wll in many cases impreve the situation a lot. 80-89% of the time t will cure the dripping.if not, replace the nozzle. There no cure for a worn out one but keep in mind that in europe we have cars ( not Ferrari) doing 250.000 km on the first set of nozzles easily..)

Why is the car not starting hot?
Well the dripping of the nozzle ( 8 times..as you have probable 8 nozzles dripping)) will simply cause the engine to drown. Like with the old carburettor engines, if you start them to often but the engine is not igniting, you simply drown it. In the case of the k-jet. the dripping nozzle is basically creating a self-drowning engine. Typically, the next morning ( same as with the carburettor engine) you can start the car instantly without any issue.

The loss of pressuse itselfe in the lines is not a real issue either.The pump will increase this instantly while starting. Same for the fuell accumulater. As a matter of fact, your engine will run without it.

The only other part in the system that is, by design, effected by temperature is the WUR. These rarely break and if the do they either have an effect on the car starting /running cold AND warm. High CO is the giveaway there. BTW, In a generally high temperature climate ( above 10C) you can do perfectly well without the WUR alltogether.


general commend: The K-jet s a VERY robust system. Parts of it very seldom fail. In most cases it is the man trying to solve a problem causing the issues because of the lack of knowledgde. Unfortunately, by the same lack of knowledge things are regarded a problem very often, which starts the whole issue.

 

While I do think that you should get your WUR back in specs, because it is better to be in spec than off spec. But, 2-6 psi is not going to cause this problem you are having. Your additional tests have ruled out the fuel pump and fuel pressure issues, as well as the sparks and cold start valve. All that is left is the injectors.

I recently replaced a set of fuel injectors for a 308QV with a set of new injectors for Mercedes Benz. It was just over $200US so it was cheap enough to forgo the troubleshooting steps. Pulling the injectors, measuring their flows, inspecting their spray patterns, and trying to improve 30 years old injectors is an all day thing. Swapping out the injectors takes 1-2 hours and $200. Time and money better spent.

 

Thanks guys, getting the WUR within spec (minor adjustment) and bench tested and testing the injectors is this coming weekends job. I figure to replace the injectors you've got to pull them anyway, so I may as well test them to confirm 100% if this is the real issue. Plus I'm the sort of person that needs closure

Unfortunately here is Australia things are not that cheap. Double the price for injectors, even if I buy them from US (bad exchange rate and shipping companies charge crazy prices for little parcel these days). Plus I image new injector seals would be a good idea? I believe there are different types?

Cheers, BB

 

That decision is fine … when your labor is free to you. When it's $100 / hour, you want closure sooner rather than later.

Best wishes in any case.

 

I agree, if only you could still find the steel injectors... The current brass replacements are crap. I would spent the time to try to impove the old ones any day above replacing them with new brass ones.

 

This company claims to restore CIS injectors:
https://www.fuelinjectorspecialists.com/

I have read that Jim Doerr at 928 Classics has the proper equipment to clean and test CIS injectors and fuel distributors and does a thorough job:
https://928classics.com/index.html

 

From my last post the plan was to bench test the WUR and the INJECTORS.

Today was the WUR. Now that I pulled and cleaned it I could see the Bosch part number (see below). From my research it appears 0 438 140 is the base number as cast into the housing (and fitting to lots of makes), and that 132 (stamped into the housing) would be the calibration for that model car. I imagine the internal resistor value, bi-metallic strip or maybe even the spring would all contribute to its warm up characteristics. Here's the problem, no Ferrari manual I've found or been pointed to by other posts shows the test characteristics of the 132 calibration. This made verifying if the test results were correct difficult. Here are my bench test results:

SYSTEM PRESS = 5.0 BAR (I dialled this in to simulate the same pressure the Ferrari pump is providing)
CONTROL PRESS (COLD) = 2.1 BAR
CONTROL PRESS (WARM) = 3.4 BAR (after 4 minutes)

If I compare these to the generic test specs from the Bosch CIS Technical Instruction book:

SYSTEM PRESS = 5 BAR
CONTROL PRESS (COLD) = 0.5 BAR
CONTROL PRESS (WARM) = 3.7 BAR

So that indicates that I've got too high pressure when cold and too low pressure when warm? But the Bosch book is generic to all CIS installations - Mercedes, BMW, Porsche, Audi, Volvo and Ferrari (among others). So if I compare the test results to the specific Ferrari specs that appear closest to my vehicle we get:

SYSTEM PRESS = 5-5.6 BAR
CONTROL PRESS (COLD) = 2.5-2.9 BAR (@ 22C ambient from the table D39 Fig.33b)
CONTROL PRESS (WARM) = 2.5-2.9 BAR (from the table D40)

In this comparison I've got too low pressure when cold and too high pressure when warm? The total opposite? All tests were without vacuum, as I didn't want to complicate thing even further (yet). See tables below D39 Fig 33b for cold test which requires you to cross reference the ambient temperature to get the pressure. In my case it was a 22C day. Note that this is from the 85 Mondial QV book and the WUR is 083 calibration. My 132 calibration does not appear in this book even though my car is 85 ... but 308.

Has anyone seen a Ferrari manual that quotes the specifications for the 0 438 140 132 WUR?

Thanks to kiwiokie I also found some great Bosch original specification documents (see below for the WUR). It shows calibration 132 being for a Ferrari 308 GTB US. My German is not the best and Google was only some help, as the German's have engineering specific words that are not part of the normal German vocabulary (hence difficult to translate) and they can have multiple meanings depending on the context. Does anyone have any insight on what they are referencing as 3,5 bar and what 7.83 is indicating? I know that the short paragraph where they mention 140 128 is talking about a different setting?

Something does not add up here ....or am I looking for perfection in an imperfect world Remember this all began with the hot start issue! The way the CIS works higher control pressure = leaner and lower control pressure = richer. So depending on which specification I compare to, I'm either a too rich or too lean when attempting a warm start up. I think I need a beer!

I'm going press on with pulling and testing the injectors when I further digest the WUR dilemma or when someone comes back with an amazing answer that will solve the mystery

Cheers, BB

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The cold control pressure chart and warm control pressure chart are shown in post #19 of this very thread. Ferrari PN 121743 = Bosch 0 438 140 132 (Used on '84-'85 US 308QV and US 328).

 

Hi Steve,

Thanks for the reply. Not sure how I missed your posting? Are we sure Ferrari PN 121743 = Bosch 0 438 140 132 (Used on '84-'85 US 308QV and US 328) works like that? Per the picture of my WUR above it has a nipple next to the electrical connector that has a vac hose running to the intake near the throttle body. Would this not mean its sensing load via engine vacuum rather than atmospherics pressure? Maybe someone has wrongly fitted a vacuum hose on my car?

That being said, and ignoring vacuum as I did in the tests if I compare my results with this correct specification the WUR is all good!

My results:
CONTROL PRESS (COLD) = 2.1 BAR
CONTROL PRESS (WARM) = 3.4 BAR
PN 121743 = Bosch 0 438 140 132 Specs:
CONTROL PRESS (COLD) = 1.95 - 2.6 BAR
CONTROL PRESS (WARM) = 3.3 - 3.7 BAR (@29.98 bar press)

Cheers, BB

 

That hose, item 48, here (from the '84-'85 308QV SPC using K-Jet with Lambda):
https://www.ricambiamerica.com/car-diagrams/ferrari/v6-v8/308-group/308qvus/fuel-injection-system-fuel-distributors-lines.html
connects to the upstream side of the throttle plate -- i.e., it is sensing the atmospheric (barometric) pressure of the air entering the engine.

On the K-Jet without Lambda 308 models, there are two hoses as shown here (from the euro 308QV SPC):
https://www.ricambiamerica.com/car-diagrams/ferrari/v6-v8/308-group/308qv/fuel-injection-system-fuel-distributors-lines.html
Hose 50 is the same as hose 48 in the prior diagram (connected upstream of the throttle plate sensing the atmospheric pressure), and (smaller) hose 48 connected downstream of the throttle plate sensing the intake manifold pressure.

 

I'll throw my two cents in. Component wise, the CIS system on the 308 is the same as my '84 BBi. I too was having a similar problem.

The car would start right up cold. But let it get hot, and it would crank forever before it would start again....but, it would start. Also, after initial start up, when pulling away to go drive, the engine would die when stopping at a stop sign when the idle decreased. Eventually it would run "OK". And yes it does have "Birdman" fuse blocks. It also had new fuel pumps (internal check valve type), accumulators, and filters. Thank you Rock Auto.

I have the "Official" Bosch/Ferrari injection manual that was published for the 400i and BB512i systems. It gives all of the tests, pressures, trouble shooting, etc., etc., and I'm sure it's the same as the Bosch manual. Initially the system showed decreasing pressures after running, so there was a problem somewhere in the system.

Anyway, my local mechanic (two hours away) who is pretty familiar with the CIS system, took the time to really evaluate the system and here's what fixed the problem. I had both Warm Up Regulators rebuilt. They were full of debris and didn't work correctly. And, from what I understand, the WUR's function for all modes of engine operation, not just warm up. Installed new small check valves at the Fuel Distributors, and installed new injectors. As a side note. The air bypass valves had been re-calibrated to function properly on a previous garage visit, and the car has new Cold Start Injectors.

Now, the car starts just fine cold, won't die when coming to a stop and the idle goes down, and when warm...and I mean warm (after driving on a 90 degree day) it starts right up after sitting. Believe it or not, the last piece of the puzzle that seemed to bring it all together were the new injectors.

 

^Agreed on the WUR. A better description would have been Control Pressure Regulator.

 

Not to be critical but I think you have waded in a bit too deep here and need to go back to the beginning. First off you have one symptom and that is hard or no start when warm. All of the troubleshooting tables for CIS mark the same rows in that column and one of those rows is leaking injectors. So, until you have determined that you do not have that condition you're basically stabbing in the dark and many of the things you are checking are not on the list and while they would cause other problems they would not cause the symptom you are experiencing. So I would suggest concentrating on those specific items, many of which you have already eliminated such as fuel pump not operating or binding sensor plate. The best way to do this is systematically and try not to jump all over the map at the same time. Another thing is, if you can, get it into the actual condition - that is, warm and won't start, because it's much easier to find a problem when it is actively manifesting itself.