1984 Ferrari 308GTS QV showing 38k miles Here's what I have done myself: New: 1 Fuel lines 2 Fuel Pump 3 Fuel Filter 4 Fuel Accumulator 5 Both Distributor Caps 6 Wires and extenders 7 Coolant lines 8 Vacuum lines 9 Battery 10 Fuse blocks 11 All relays 12 Flasher switch 13 Spark Plugs 14 Throttle position switch Speedo sent out & rebuilt Several Amp connectors replaced around engine Cat removed and O2 sensor gone AFR meter (wide band) installed On order: Thermal time switch and check valves for air injection system. Noted Conditions/experiences: The frequency valve buzzes The WUR measures 13.8 ohms resistance across contacts The TPS was found to be mis adjusted so the the microswitch that should be closed on idle was open circuit and the contacts that are to be closed at WOT did not show closed circuit under any conditions. The TPS was replaced with a new one. Adjustment to the Air Adjusting Screw and the Mixture Adjusting Screw have been attempted by me, someone who knows just enough to be dangerous. Tested the Additional Air Valve with a heat gun and it seems to open and close properly. The car did run reliably last year for a short amount of time after replacing items 1-13, then, when a friend of mine suggested and adjustment to the Mixture Adjusting Screw and the car sat over the winter everything went to ****. Driving the car resulted in a back fire like situation and a loss of power after 4 miles of driving (the time it takes for the fans to kick on at that ambient temperature). Now on a cold start the car runs irregularly between 900 and 1100 rpm with the AFR fluctuating between 12 and 14 on start and going to 15-17 after a minute or two. At this point I am ready to miss a couple of months of driving and send out the WUR for a rebuild as I can not buy a replacement anywhere. I am also considering replacing the injectors as I am sure they are original and having the ECU checked/rebuilt. I also need to verify that all engine wiring is good and replace a few more of the AMP connectors. I have read many threads but still can’t make sense of this puzzle. Any advice from you guys would be great. Thank you. Tim
What are your system and control pressures? I don’t think you can tune CIS using AFR alone. While 911 focused this is a great resource for CIS troubles: http://jimsbasementworkshop.com/CIS/
Hey Archer, Sorry to hear of your troubles. One bit of advice: you've got a lot going on there with having replaced various parts, possibly a bad mixture, and other potential issues. I'm almost wondering if you're doing too much at one time, instead of structured stages. I suggest getting the system you currently have in place properly diagnosed, before you just start ripping more parts out that may or may not in fact need replacement. (Analogy: it's hard to know if the AC works well if the engine doesn't run. So let's get the engine running before we replace the compressor, wiring, hoses, and condenser.)
To Thorn: Understand that philosophy well. All those changes did take place incrementally, over an 18 month period. For instance both distributors were cracked and had seal leaks, plug wires were compromised, wiring was screwed up by 3 alarms and several radios, etc. Idiots that worked on the car fried the voltage regulator that in turn fried numerous components. It's been a real learning experience.
Ah, I understand your strategy better now. It can certainly be frustrating having to not only deal with aged issues, but also having to correct problems caused by a previous mechanic... "Ok, what's here... what isn't here... what SHOULD be here?!"
You have to consider the fact that the car is 34 years old so in that regard all that you have done so far is not in vain. You may have in fact resolved one issue while another completely unrelated issue has arisen. I bought my 308 October 2016 and though I did put 10,000 miles on it I now have it in a billion pieces replacing the head gaskets. I bought it in part to tinker with and this is definitely 'tinkerin' so for me it's not at all a "nightmare" It was time for the motor to come out and get sorted and part of the appeal of the 308 was getting intimate with it like this. I know that when it comes to DIY with these cars you really are pretty much on your own, there's no step by step, lead you by the hand Haynes manual but the workshop manual has all of the technical data if you can sort through it. Keep up the faith and I'm sure you'll eventually prevail. It's worth it.
To kcabpilot: I hear you man. Unfortunately I have only driven the car a little over 300 miles since I bought it from Wayne Carini . I envy your 10,000 miles of fun. You were a LOT smarter than I was in selecting the right 308 and you are infinitely more capable in mechanical ability. I'll keep at it and hope I can get it reliable before the snow returns. In the meantime I may learn some things that I can pass on here to other 308 owners.
I would do the injectors as a matter of course. It may not be your problem, but it can't hurt and should be done anyway if they are original. You can buy a tester/cleaner from mercedessource and other places to check the cracking pressure and observe the spray pattern. Apparently new injectors aren't always the greatest quality, so even new injectors should be tested before install. Is it possible the cold start injector is running/leaking after the car is warm making the mixture overly rich?
To ztarum: Yes on the cold start injector potential. I did unplug it yesterday and allowed the car to run a few minutes. It seemed to run marginally better but still struggled a bit. Maybe it's an intermittent failure. I wonder if injectors in the horizontal orientation are more prone to issues than those in a vertical orientation? Injector replacement is definitely on my short list. Thanks.
Rather than spend more money on components I would buy the gauges and see where you are at for system and control pressures. Pelican has a gauge set that looks decent: https://www.pelicanparts.com/catalog/SuperCat/0801/POR_0801_TOLTOL_pg15.htm#item65 I struggled for years with a hot start on my 911SC before biting the bullet and buying the gauge set. I started with draining and cleaning the tank then replaced the old screen with a new one. Then old rubber fuel lines. New fuel pump and check valve. New fuel filter and accumulator. Removed and cleaned the WUR. There was a filter on the inlet side that was full of crud. Made the WUR adjustable and brought it into spec. My injectors had been replaced recently so left them alone. CIS now works great! Starts first crank, fast idle works correctly and drops to smooth idle when warm. No problem with hot starts. When CIS works as intended it is a great system but it is a system of dependent parts that all need to operate within spec.
To kiwiokie: Point taken on getting diagnostic tools. I don't have much choice so I'll need to work smarter. The Bentley manual for the 911 has detailed instructions on how to do the testing. On my 308 I drained the tanks early on. The in-tank screen filter is unobtainium. The 308 tanks are fiberglass and it's fiberglass fragments I saw drain from the crossover pipe. I have also read here in the forums that like you guys have found crud in the WUR filter. I'll need to investigate that. Thanks for the link. I'll be calling Pelican later.
IMO... owning a 308 is like a women.... you don't know what you're gonna get after you marry them... so each 308 out there has their own temperamental issues...
for what its worth - on my qv I had a cracked o ring under the screw in the plenum tube. so when it got warmer the o ring let in more air to buypass - raising the RPM but it was not adding more fuel... so rain hot and lean. also I had a lot of electrical issues from the "rear pass. side Digiplex unit... there were some wires that became cracked and brittle... so if you hit a bump - it would cut out... etc... so don't ignore electrical issues.
I think you are on the right track with getting a rebuilt WUR. In my experience they tend to fail towards the lean side and that is what your AFR is showing. Are you using a wide band gauge to see that, like AEM or Innovate? Aaron
To spirot: I believe I read one of your old posts to that affect. I'll hope I can order the right o ring and replace it. The wiring on this car scares me. There are so many multi conductor connectors and it's the two next to the oil cooler that really bother me. These are not sealed and in a harsh environment so electrical resistance issues must be common. I have also replaced several of the AMP connectors as the horses's asses who have worked on the car seemed to have grabbed them with pliers and torn the boots and in 2 cases so far, the wire was showing bare. To: ATSAaron: It is a wide band AEM model. I have one on my 87 Carrera as well. Yes, a WUR rebuilt will put my mind at ease about that part at least.
Seems strange based on the Bosch book on fuel injection and engine management. But given 33 years of trouble free driving with my 85 IU don't have any hard experience disconnecting the sensor. FWIW, Image Unavailable, Please Login
Check for small cracks in the distributor rotors. Coils are cheap enough so maybe replace or check them. Check coil grounds. Check Digiplex box grounds. Check ground from battery. May be something simple but overlooked. Have you sprayed a little water mist on the spark plug wires in the dark? Look for cross talk. Some wires just don't work well with the 308.
Both distributors are new as well as the wires. Coils are well wired too. I have cleaned Digiplex contacts several times. Battery ground is good. Thanks man!