Has anyone heard of a motor vac carbon cleaning system? I had this done to my land rover and it was a totally new car afterwards.... 150 clams for the service.
We used to do the exact same thing when I worked on jet engines. We would remove the fuel nozzles (injectors) and put them in a test stand. I wonder if I could get an adapter to do that... I'm only 30 min from LRAFB... Hmm... Gene
whose 328 is in my "care and custody", I've been asked to share my experiences here, in that his low, low miles 328 is in my shop for some old-fashioned TLC and a major service. As part of this service, I'm replacing the "old-style steel bodied" injectors with the newer-style brass one. A little background: I owned a foreign car repair/restoration shop for 14 years back in the late 70's through the late 80's, when CIS (K-Jetronic) was in it's peak of popularity. 95% of the mix, being European cars. We were also a Bosch Service Center and well as a Bosch Training Center. Needless to say, we did alot of CIS diagnostic work and repairs. At the peak of the CIS craze, we would easily change 400 injectors a month. The Bosch tester, or clone, as David is using was the Number 1 tool of choice for CIS diagnostics. It's primary purpose was to: 1) Verify "pop-off" pressures, or more correctly the specific pressure in which the injector would open. 2) Verify that there were no drip, or leakage below the specified pop pressure 3) Verify that the spray pattern was indeed a cone of fine, 100% atomized fuel 4) If conditions 1 and 2 were met, and the spary pattern was marginal-borderline OK, some (internal) cleaning was possible after multiple "pop" tests. However, the tool was never designed, nor specifically intended to be a cleaning solution for clogged, rust filled injectors, particulary since the mineral spirits based solvent is marginally more "solvent-based" than the typical gasoline that that's been running through the injectors for years. In a CIS system, the injector does not "fire". It is a constant spray 100% of the time, even on the exhaust stroke. The only cleaning advantage a "Pop-tester" has is the ability to momentarily shock the injector, hopefully loosening some debris. Once the internal seat of the pintel is damage, the injector is no longer serviceable. Our primary purpose for "pop-testing" injectors was to determine if the injectors were a contribitory cause of residual pressure leakage. Back in the CIS heyday, the classic "poor start when hot" was a very common problem....with the most common problems being a bad check valve in the fuel pump, or leaky injectors. That's not to say that CIS injectors can't be saved by cleaning; they can, sometimes. Wurth and a few other manufacturers made a solvent-based system in which the car was "disconected from their gasoline fuel system" and ran off their pressurized solvent. It worked well, although the time involved and solvent costs were not insignificant. In my experience, the best and most accuarte way to determine if your injectors need cleaning, or even replacement, is to measure the CO and HC levels on a warm engine, known to be in a reasonable state of tune. Injectors with poor spray patterns, or even ones that drip a bit cannot fool an exhaust gas analyzer. A typical pre-cat reading of most 8 cylinder fuel injected Ferrari will read less that 300 ppm HC and less than 2% CO, maximum. An engine with clean, fresh injectors can read as low as 180 ppm HC and less than 1.2% CO. Obviously, before condeming the injectors, the mixture must be "tweaked" to ensure that the CIS was indeed set-up properly to begin with. The "seat of the pants" mixture setting method usually ends up with the mixture on the rich side! For those who have followed my BB front end overall post, I went to the school of "Do it right, or don't do it at all". This is usually not the cheap appriach, but the end result always justifies the means, despite those assinine Ferrari parts prices. Back to the 328 at hand; we know: Less than 2500 miles since the last service Service done in it's entireity-No corners cut. Many, many moons of sitting over the last 7 years Runs very rough cold (typical of "drippy", poor spray pattern injectors) Very "smelly" exhaust Old style "steel-bodied" injectors Butt-o-meter says that the car is "sluggish" And the drum roll please: The 5-gas analyzer speaks.... HC 800 ppm CO >5% With the low/modest cost of injectors and seals, the "relative ease" of replacement and the on-hand availability of a high-precision 5-gas analyzer, this car will receive new fuel injectors and a new fuel filter! Although my goal is not to spend "other peoples" money needlessly, the cost of doing this job again by saving a few dollars by cleaning the injectors just doesn't make good financial sense to me... Your mileage may vary, David
David, So problematic [steel] original injectors may appear to be okay but if one needs to keep going back to clean a clog this is indicative of "old rusty" internals and the best way to solve this is get rid of the old steel injectors ,as I had originally planned?
I wouldn't go as far to say that the steel injectors are problematic, it's just that the brass ones have a superior pintel design, and are not prone to rust. Intermittant use, low periods of sitting and low, low miles kills these cars...and having water suspendened in the fuel (trapped) in the injector is not going to be fixed by a solvent-based solution. Even under the best conditions, the steel injectors really only perform "in specs" for about 30-40K miles and that presumes constant use, which is not the typical life that 99.999999% of the drive cycles that Ferrari's see. Replace them, get the new "green" Viton seals from Bosch....and be happy. Onward, David
To me replacement every 10 years or so with use of Techron maybe 3-4 times per year would make sense. Is this sound reasoning? Relatively cheap parts and something a DIYer without too much experience can handle so no labor. Maybe even every 5 years and/or with the major. Jeff
I am doing mine this week. I have the poor hot start problem. It starts up right away cold and I have to give it 1 inch of pedal to start when warm. Hope injectors will help then I will move onto fuel pump. jim
Jeff, This does sound reasonable, as I've used Techron for years in many dfferent cars. It's a great product and at once time was endorsed "unoffically" by BMW. Another "problem" causing premature injector "failure" on the 308/328 series cars are heat-soak issues. Underhood temperature are a but higher than your typical front-engined cars, hence there's more of an opportunity for fuel varnish to form inside the injector when the vehicle is shut down. The good news is that with periodic maintenance, Techron can help to disolve these deposits. I can't speculate if you'll get 10 years out of a set of injectors, but 5 is certainly a reasonable expectation. One of the more common problems that I've run into, frequenty, after changing a set of injectors, is that the engine can be very difficult to start, even after the lines have been purged of the air. Over time, as the injectors "wear", their flow characteristics change. This, in itself, is not a problem and is corrected when the mixture is tweaked during periodic services. But....when a new set of injectors is replaced, often times, the old base mixture setting is so far off, that the vehicle just (initially) runs horrible. As the mixture adjustment screw on the fuel distributor housing is hyper-sensive to adjustment, getting her back into a "tunable range" takes a bit a practice. However, with a gas analyzer and/or a bit of patience, this is a very "DIY-viable" job. Regarding the hot start problem: This is a classic CIS symptom! The root cause: Typically residual system/control pressure leakage. Theory of operation: On a hot start (either immediately after shut down, or within 20 minutes, the system must retain pressure as there is "no assistance" from the "cold start circuit". The usual culprits: Fuel pump check valve (internal or external type), injectors (dripping), accumulator physically leaking, etc.) There are other issues that are beyond the scope of this orignal posting which revolve around system/control pressures, hot versus cold pressures that are controlled by the "warm-up" regulator that can and do contribute to "hot start" problems. If the typical problem are have been verified, a fuel pressure gauge (designed for use of a CIS system) can assist in the diagnostic process. As simple as CIS is conceptually, tracking down sources (yes-plural) of residual pressure leakages, can prove daunting, even for those who have worked on these systems since new. Time will tell if this new breed of gasoline will prove more detrimental to the serviceable life of a CIS system than the fuel we used in the past. On one hand, the more corrosive nature may help to keep the injectors cleaner. On the other hand, I suspect that there will be more fuel line/rubber deterioration then in the past...and potentially more debris "flowing" into the wam-up regulator and fuel distributor. This will not be good! Regards, David
David, Thanks for the additional info! Very helpful! Do you have a source for these you can post? Thanks. Birdman
Much better. Think about it...a pint of injector cleaner diluted into a tank of fuel, versus removing and forcing cleaner through each injector at high pressure. No adjustment. It either can be cleaned up to work or it must be replaced.
I forgot to mention, although I have not run a full tank through the car since I did this, I cannot comment on fuel economy. However, I can comment on the improved throttle response!
So how long does this take with the proper tools and equipment? Couple hours? My car is in for a major and I might have the mechanic do this.
This is a great thread. When I bought my QV back in 97 I had all the injectors replaced so mine will only have 11 years of whatever in them instead of 24 year's worth. I bet I should still check them
Duane, I typically allow 4 hours to replace the injectors on a 308QV/328. This would include the removal and replacement of all the the injectors and seals, as well as setting the mixtuure, potetially twice. I always check that the throttle plate "stop angle" is set correctly and then, verify the idle speed...adjusting if necessary, the idle air bleed. Then, the sensor plate is verified for the proper "height" in the funnel, before proceeding to set the mixture. This is a critiical set, as it set the "baseline" mixture. Then, we're ready to set the mixture with a 5-gas analyzer...followed by a 20-30 minute road test. The mixture is then checked again, usually a slight "tweak", and then the car can be returned to the customer, knowing that that full benefit of the new injectors can be realized. Although unlikely, all injectors fittings are checked twice, both before and after the road test, to ensure that there's no fuel leaking/seeping at the fittings. As this a high-pressure, constant spray system, leaks are a substantial concern. Several things are immediately apparent after this is done, presuming that the mixture is set (re-set) correctly: 1) Improved responsiveness (much more "snappy" throttle response) 2) Improved cold and warm idle quality 3) More power 4) Improved fuel economy Although a 5-gas analyzer is not necessary; at minimum, a 2-gas analyzer is....Setting the mixture by "feel" or "sound" will get you in the ball park, sometimes even surprisingly close, but you won't see all of the benefits of precisely "dial" her in... Regards, David
The injector tester/cleaners turn up on eBay occasionally but you can expect to pay a couple hundred for one. Not really worth it unless you just like to collect tools or you are buying one for your local FFIC chapter. (If the west coast starts an FFIC, we can talk about franchise options. ) I would say that if you don't have access to one, it might be just as easy to send them to someone to be cleaned, or order a new set. Birdman
I have added this article to the procedures on my website. http://www.birdmanferrari.com/injectors/injector_clean.htm By they way...I am always looking for good technical articles to archive at birdmanferrari, so if someone wants to write one, please do! I would particularly like a good timing belt article. I have done it twice myself, (once with Verell's help) but I don't consider myself enough of an expert to write a procedure on it. Birdman
Really nice Birdman! Very useful stuff that I've instantly downloaded to my hard disk. I haven't received yet my Ferrari but my brain is full of useful information. I've plenty of work to do!! About the rubber seal which goes between the injector and the carrier, it's possible to have the part number to order it? If you need any Photoshop stuff, please let me know and we will see. Just for thelp the Fchatters community!! Thanks a lot
Nice writeup Birdman! Tnx for previewing my injector puller tool! 3x - 4x/year is probably overkill unless you're experiencing fuel system problems. My car was a garage queen, only 2K or so miles the preceding 10 years before I acquired it. The first couple of years I had my car, it would start running a bit rough every 6-8 weeks. A container of Techron Concentrate in 1/2 tank of gas would take care of it in 10-20 miles. As time went on, the interval between performance drops increased. After the 2nd year, I never saw the problem again. However, after 4 years of excellent running I still run Techron thru once a year to ensure my injectors stay in good condition. BTW, it still has the old steel injectors. BTW, Techron will remove water contamination from gas. I've occasionally managed to get a tank of 'bad' gas (strongly suspect had a bit of water in it). A couple of containers of Techron in the tank generally took care of the problem. As for replacement every 10 years, what assumptions are you making about miles/year. Soaking in straight Techron for 2-3 days will help remove fuel varnish & other soluble build-ups, & can loosen sticking atomizers. It's a well known way of restoring flaky & stuck electronic fuel injectors. Had a professoinal mechanic show it to me when I was having problems with my Rx7's injectors. However, you still need to run a solvent under pressure thru the injector to flush it clean & verify that the atomizer is working properly.
I have an injector tester available if any of you happen to be in the Atlanta area and would like to borrow one. It's an "oldie but goodie", but still works fine for this process. I used it frequently in the past just as described above and found it to really make a difference.
