1984 308 QV Warm start issue, not accumulator

Hi guys, I have been reading all the warm start 308 issue threads. Let me tell you what I've done so far and what is happening. Cold start, no issue. Let it sit for say 10-15 min, no issue. Let it sit for 30 min and it will start and run fine but you have to crank on it for a few seconds. Upon starting no issues. Not a big deal but from reading all the warm start threads there must be a fix. First off Larry Fletcher is a just a good guy! I saw from a previous thread the o rings on the primary pressure regulator could be an issue. So Larry was kind enough to send me those and I installed them. Didn't seem to help. I did take the vent line off the accumulator - No fuel present. So I assume its not the accumulator.

Next thing on my list is check valve on the fuel pump. But mine appears to be an original pump with the check valve built in. So I'm not sure what pump I need to replace it with as I read the version with the check valve built in is not available?

I do not have the CIS pressure tester, but if someone can point me to instructions on how to do that it seems relatively cheap for the kit ($100'ish)?

Thanks for the help
jim

 

In my case it was the valve....but just like yours, I needed to replace the entire thing since the valve is built in the pump.


Sent from my iPhone using FerrariChat

 

When you did that were you able to reuse that expensive and hard to find hard connection between the pump and accumulator? I thought I read somewhere you needed some kind of new fitting or adapter?

thanks

 

Hi Jim, not sure if you read my thread? I went through similar symptoms. Before you drop money on replacing parts buy the fuel pressure tester and check the readings. Then also check the mixture adjustment, as that was my issue. I simple adjustment could have saved me $$$ and time

https://www.ferrarichat.com/forum/threads/hot-no-start-issue-need-a-new-direction.602834/page-4

Cheers, BB

 

That was a few years ago that you couldn't get the CIS pump with the built-in check valve (so had to hassle changing the plumbing to the CIS pump with the external check valve). It's now available again -- "Bosch 69523" (just search using that on the internet, at Amazon, eBay, etc.). For example:

https://www.amazon.com/Bosch-69523-Original-Equipment-Replacement/dp/B000BZL9F4

(But agree that you, or a shop, should measure, and confirm, that the warm shut-off fuel pressure not holding is what's causing your problem.)

 

I did see your mixture thread. Thats intriguing. Not many shops around here want to mess with a Ferrari. Does anybody have info on how to check the pressure?

 

Two questions for someone are how to check the pressure if/when I buy the CIS Kit. And I assume you have to drain the fuel tank(s) to change out the pump?

Thanks

 

Probably, if you want to change the hose going from the tank to the pump inlet. If the hose from the tank to the pump inlet is fresh, you could temporarily "pinch" it closed for the swap, or be quick with an appropriate plug to block it and then unblock it during the interchanges, but be super careful -- the viscosity of gas is very low (way lower than water) so it comes out quick and fast (nor do want a bunch of it sitting in a bucket/pan). Alternatively, if just a couple~few gallons is left, you could jack up the LH side to shift the remainder over into the RH tank.

 

Afternoon Jim,
I wouldn't replace any parts without testing first, which is a very simple task.
I built my tester using 4mm bango bolts and pneumatic fittings, shut-off valve and pressure gauge. Tubbing was 4mm ID, TKL.
The whole "tester" is really small and parts cost was 15 euros.
Just an idea,

John

 

Can you elaborate on how to do the test? I dont mind getting the $100 CIS injection test kit. I just havent been able to find how to do the test?

jim

 

Thanks - Its had a good deal of maintenance done from the previous owner (Documented) and that hose has been replaced. Thanks for the tips

 

This site is a good starting point for understanding CIS and has a section on testing:

https://jimsbasementworkshop.com/CIS/



Sent from my iPhone using FerrariChat

 

Afternoon Jim,
The test can be found on the web, just look for "Ferrari documentation" Carl Rose posted that "jewel" many years ago. You can download any manual you need.
The test checks system pressure, WUR pressure and residual pressure(accumulator). The tester is connected from the center feed on the fuel distributer to the WUR.
On the web page you can find the test with pictures (pictures show a 328 but the QV is really the same engine).
Look in the manuals to see correct pressures for the QV, just to be sure.

Hope this helps!

John

 

Can't argue against a pressure test, but it seems like the car might be running rich. Have you taken off a spark plug and checked if it is black/fouled? Are the spark plug gaps fresh and the gaps correct? Might be good to do some further very basic things before going further.

 

Thanks!

 

Well I have all the documentation from a year ago when I bought it. Plugs were done then. But I have not checked them. With this version of hot start it does fire up and run fine after a 30 min warm start just takes a little cranking but not much. Its just a little more than when its cold. I do think there is an issue but its not like others I read where it won't start at all, not sure if that lends itself to mixture or pressure leak

Jim

 

Still worth removing one easy to access plug and take a look, easy to do and might give some clues. The fact that there are no other symptoms presenting, eg. surging or rough idle, points to something minor I would think. A car starts cold well when the mixture is rich, when hot not so much. Has this hot start issue been with you since you bought/serviced it or only more recent?

 

You know thats a good question. Until I started reading all the ferrarichat post I didn't think too much about it since it started every time. Thinking back its probably been doing since I got it. I'm the second owner, bought it off a buddy and he had it serviced at a well known Ferrari guru in Chicago. All the major and minor service, two pages worth . : : : Anyway I would have thought they would have caught this but maybe not.

 

My theory is you are running a bit rich, and a blackened or fouled plug would show that. Might just need the mixture adjusted. The mixture screw and air bypass screw need to be itterated in very small adjustment increments, with a gas analyzer hooked to the exhaust to set mixture correctly. It is easy to be out a bit, and most are set a bit rich as the car tends to idle best a bit rich, but might affect the hot start. Just a theory, but I am just trying to make sure some basics are not causing the issue before considering other causes.

Sounds like you had service done by people who know the cars, but they may not have fussed with the mixture if things ran and started ok at the shop and they did not do other serrvice that would have warranted a mixture setting being checked.

There is no reason why the car should not start nicely cold or hot with few cranks. Do you depress the throttle pedal a bit when starting warm? I have a 3.2 engine, which has somewhat different electronics and sensors, but my owners manual specifies starting cold without the throttle pedal pushed, and slightly pushing it in to do a hot start, not sure that is relevant to the QV.

 

You know I should actually read and see what it says. I usually do not give it any throttle when starting. Yeah I'll check an easy to get to plug. thats not much effort and see what it looks like. Problem is finding someone around here that could or would do a gas analyzing

Thanks for all the advice
Jim

 

https://www.gunsonshop.com/contents/en-us/p245_G4125_Gunson_Digital_Exhaust_Gas_and_CO_Tester.html

It is not as accurate as pro test equipment, but this helped me diagnose a rich condition that ended up being my fuel distributor internal rubber diaphram having failed. Some garages would use a three or four gas analyzer for emissions testing, but most new cars with their on board computers made this expensive to maintain equipment redundant. A garage that works on older Mercedes or Porsche cars would have the same Bosch fuel injection systems that Ferrari used and might have the old gas analyzers still in service, Euro cars up the mid 1990's all had similar fuel injecton systems.

 

Well I do like gadgets and that isn't a horrible price. So what reading on that did you get with it adjusted correctly?

jim

 

My car is the 3.2 Swiss model with cat converter and O2 sensor. So I measured at a port on the cat designed for measuring, and with O2 sensor disconnected I set things at about .7 CO as per the Bosch manual for my somewhat special KE3 fuel injection system unique to the Swiss 3.2 engined cars. After cat and with O2 on would read between zero and .2 CO. This later system was designed to reduce emissions, so the QV system would not be as clean at idle which is where all the emission controls were mostly focussed on.

I recall from the 308 shop manual pre cat being somewhere around 1 would probably be about right, probably would read about .5 or less after cat.

For my local Drive Clean emission test (which they discontinued a few years ago), the gas analyzer they used had a max CO at idle for a 1988 Ferrari 328/Mondial 3.2 programed to pass if the reading was .2 or less at the tailpipe after cat.

 

Keep in mind the gunson measures only CO, which is important for mixture setting. But a 3 or 4 gas analyzer measures unburned hydrocarbons, CO2 and NOx which can all provide important diagnostic information.

But I found the Gunson sufficient to set up the mixture correctly after helping ID a problem. So for the cost it seems a useful home shop tool.

 

Thanks for the info