308qv, won't rev & popping, wur?, CIS expert needed

if you can give me till later today/tonight i can give you some help. i have the bosch books and have been over the CIS extensivly as i have now supercharged mine keeping the CIS.

from the hip, burning eyes? raw fuel not being burned? if so the lambda (frequncy valve) isn't adjusting the fuel rate. but i'll need to double check the books.

scott

 

If you mean your eyes are burning from a too-rich mixture (blue smoke out tailpipe), then there are typically only a few causes I know of. IN CIS, it is more common to err to the too lean mixture.
A too rich mixture is less common, and may be due to a blown O2 sensor relay and/or fuse (fairly common). These are on the accessory electrical panel.
One other culprit to check would be the cold start injector AND ITS RELAY perhaps being continually on.
An injector failure causing a high rate of fuel flow might also cause a very rich mixture - PULL the PLUGS and examine for uniformity and burn pattern. This is what I would do next.

Good luck and let us know.

best
russ

 

It sounds like one of the 2 Magnet Marelli Digiplex digital ignition advance computers have gone bad. Or, perhaps just unplugged. Try checking the connections, first. If that doesn't work you may have to replace them. I say "them" because if you just replace one of them, the other will most likely fail soon after. They are located underneath the carpeting on the drivers side of the rear luggage compartment. And do not run the car if they are bad. It not only could screw up alot of other things. But it will dump alot of Raw Gasoline into Red Hot Cats, and Voila! Another set of pictures for "Wrecked Exotics". Good luck!

BTW....Does anyone know if/where those Digiplex Computers can be rebuilt? That would save you a ton of money, because new ones are about $1500.00......EACH.

 

O.K..... Just trying to help. Good Luck!

 

fuel pressure can only be checked cold after the car has sat for more than 4hrs, bosch recommends overnight not driven for a cold pressure check. most times it tested warm, fuel presure at 37psi is normal and good. the pressure test lists 2.7bar @ 10min and 2.6bar @ 20min. your injectors open @ 3.0~4.1 bar. remember they are not electronicly controled but mechanical. the lambda which was added controls the fuel via feedback. so if it's runnig rich then i'd suspect the O2 or the frequncy valve. i can scan the shop testing procedure later for.
if your O2 sensor is not puting out a signal then the system runs 95% duty or full rich. bad for the cats!

 

I had a similar problem with my '85 QV last year. Burning excessive fuel, burning eyes, and tough warm starting. I replaced the WUR, and all the problems went away. I did get some popping, but revving wasn't an issue.

 

where are you checking the system pressure? for testing the WUR the engine block needs to be cold not warm. your pressure could be good but the throughflow is not. testing it you'll know, most times the WUR is good and the distributor is not. but a rich consition is rarley a result of bad control pressure, it's usualy lean.

there is more than one location for testing fuel pressure, one is testing the WUR and the other is control pressure to the distributor and then you have the pump pressure.

if you have a book store nearby get the bosch FI book by bently. ISBN 0-8376-0300-5. loads of info and how to test the system.

what are you using to test the pressure? a gauge for pulsed injection will not work with the CIS. a special two inlet gauge is used.

 

okay, the WUR is realy called the control pressure regulator becouse that's what it does. it controls the regulator which in turn controls the metering piston that sends out the fuel in the distributor block.
high pressure from the regulator will cause a lean condition and low pressure will cause a rich condition.

i don't think your running lean, if your eyes are watering is it from raw fuel or ammonia? the cats react with the unburned fuel and the byproduct is ammonia which can cause the burning eye problem. also your cats wont last long that way, they will eventually burn up and ignite. car-b-q style.

give me a few minutes and i'll PDF up some of the testing proceedures for you.

 

okay i've got 10 pages of PDF for testing the CIS. to large to post here. any ideas on hosting? or i can send them direct.

 

Here is a link that might help. In my case the eyes burning was a too rich situation caused by a bad WUR. I was also going through excessive amounts of fuel, and spitting unburned fuel out of the exhaust. If this is the case, it will quickly trash the O2 sensor and cats.


http://www.auto-solve.com/mech_inj.htm#view

 

hey scott,

if you can upload it using http://flyers.cdyn.com/upload.cgi, I'll
stick it at http://bingo.cdyn.com/ferrari/ for downloading

when I get a chance next week, I'll be putting all carl rose's docs on the
http://bingo.cdyn.com/ferrari/ site as well.

wrt lambda adjustments to the mixture, unplugging the O2 sensor should cause the injection ecu to revert to open loop operation. Attached is a 328 picture of where the sensor output wire is, and one way of measuring it. The voltage should fluctuate between 0-1V in closed loop as the mixture is tweaked via the frequency valve. If you unplug the green wire, then the O2 sensor output should stop oscillating because the frequency valve will run at a fixed duty cycle.

given the warm fuel pressure is ok and assuming spark is good, it seems like it'd have to be the lambda or a vacuum leak messing up the mixture.
Image Unavailable, Please Login

 

phil the link doesn't work.

 

me idiot...try http://flyers.cdyn.com/upload.cgi

 

Hi Larry,

To only add to what others have posted above:

* Your control pressure (metering unit-to-WUR) should increase as engine warms. On my 328, cold was 19 psi (or close) warm 50psi. System pressure should be 70-72psi.

* The suggestion on the CSI is good. Unplug the connector, see if condition changes.

* If you search google the 928 guys disassemble & "adjust" the fuel pressure pins on the WURs. Larry Fletcher (also on FC, also with 308 as I recall) is an authority.

* If you'd like to borrow one to test, I have a 328 unit but I don't know how applicable this is to the 308 QV.

Certainly seems WUR is the culprit here, but don't overlook the flywheel sensors.

I think you already know how to do this, but I've an article on 328 fuel pressure testing if you'd like (drop me an email at [email protected])

Best,

Carl

 

pdf version is posted at http://ferrari.cdyn.com now. thanks carl!

a low control pressure would make the mixture too rich, so that does agree with the exhaust smell. The o2 sensor would be pegged near 1V output once the o2 sensor was heated up.

 

i have a problem with this as that pin is set by bosch. yes by moving you'll re-set if you will the pressure but it's not the right way to do it. it'll cause more problems than it solves. bosch has the pressure control adjusted by shims on the pressure regulator piston. this is the piston that is accuated by the WUR on the distribution block.

larry knows his stuff, i was just looking for his number. i need to call him as he teased me with a programable WUR.

 

scott,

I have the files at http://ferrari.cdyn.com/incoming for now

 

Hellö,
You also need to check your airflow sensor plate height. This is often overlooked and very impörtant.
If you need to contact me I will be back from Europe Sept. 14 and you can call me at 251-929-3771. I am at a internet cafe in Germany now checking messages.
Larry

 

I had the same thing happen to my 84 308 about 6 years ago. A connection up by the fuses was the problem. I don't remember the details now but I remember my mechanic feeling it, describing it as being hot as a firecracker and telling me that "Fiats do this a lot to". He made a better connection and solved the problem. The car would barely drive in there that afternoon but it left strong as ever an hour or so later and I really don't think he ever lifted the hood.

Anybody have any idea what he fixed? Could this be the same thing?

 

PM me the name of "your mechanic" if you don't mind. My 3.2 snaps and pops in the mornings sometime for a minute or two. Been told it's the WUR, but I'm not totally convinced. Sounds electical to me - bad spark plug extender - something like that. Thanks