Hi everyone, Finally -about 9 months into this- think I have isolated my idle run problem (symptom: running rich and "popping" in exhaust). The K-Jetronic/lambda uses an "oil temperature switch" to signal the ECU to accept input from the throttle microswitch idle position; effectively once warm with completes the circuit to ground to adjust mixture accordingly. This is shown as #154 on the FIG 2 wiring diagram; note this is exclusively a FI control switch and *not* the oil temperature switch FIG 5 #13/part# 107576 that signals the dash gauge, nor the coolant tank switch #158, nor either oil pressure/low oil pressure warning light switches. It is shown as red/pink-striped wire into one side and black out the other, leading me to infer this is a two-terminal switch. The left fenderwell multi-connector indeed has two red/pink-striped wires joining at the plug on the engine side, leading me to beleve the wiring diagram is accurate and the switch is located *somewhere* on the engine side. Retrograde grounding this terminal simulates a closed switch, and car idles properly. Anyone know exactly where this switch is located? I've (erronously) replaced the dash oil temp switch, but have scrutinized as best as possible the lower aspect of the motor & searched the FC archives to no avail. All suggestions much appreciated. If anyone needs help on the K-Jetronic/lambda system I've had to learn a reasonable amount and will be happy to share. Thanks in advance, Carl
Carl, It's on the other side of the oil sender. See diagram. Let me know if you have trouble finding it. How did you dignose it?
No, that one is for the low pressure warning lamp. I'm not sure about Carls problem, maybe it's a US thing?? I have seen a temp sender fitted into the oil coller banjo fitting on the lower block connection on Mondials I think...bit sketchy though! There can be a switch on the oil cooler on some cars, but thats for the oil radiator fan.
Mr. Phil you *do* know everything! I found it last night (after posting) in -of all places- the owner's manual. It's listed as part #115652 into the banjo fitting for the return line from the oil/air spearator to the sump. This signals the ECU to (I think) 'lean" the mixture slightly (as engine is warm & no longer requires richer mixture) and accept input from the throttle position sensor "idle" position. Ordering one tomm. Thanks again to yourself & Carmine. Carl
FoUK has [18] listed as #115652 WATER TEMP SENSOR The Owner's Manual, as Carl points out, has it as oil temperaure switch. Which is it?
Hi Carl If I knew everything I'd be sunning myself on my yacht in the Bahamas by now....... But thanks anyway!
Hi Mr. Handa! This switch essentially "tells" the ECU that oil temperature is warm & to obey the throttle microswitch idle position for warm; in a nutshell, it closes a path to ground for the ECU O-2 sensor circuit in this manner: throttle switch (has black wire in center position that goes to ground) -->red/pink stripe wire to this "FI oil temp switch"---> back to ECU. The "idle" position on the throttle switch "connects" the two. So cold engine warm up: No ground signal to ECU--> run slightly richer mixture (higher RPMs) Once warm: switch closes to complete path to ground and "sends" signal to ECU. Apologies for long explanation. Several ways to test: * I backprobed the red/pinkstripe wire at multiconnector and connected other end to engine (ground). Immediate change in idle characteristic, no longer "spit" from exhaust. * Remove connectors from switch (both female spade) and bridge. See if idle changes. Note you cannot bypass by bridging the two terminals in the thottle microswitch connector because this is "before" the switch in the circuit. Here's a thought (haven't tried though): if the switch is functioning properly removing the throttle microswitch once car is running warm should produce a change in idle (increased RPMs) immediately (removing ground input to ECU). Today I verified continuity of the red/pink-stripe wire to multiconnector & honestly, switch is listed at $16. Need to drain out a couple quarts to replace. For the effort needed to get to switch & remove, I'm simply going to replace (since I've effectively bypassed to prove fault). Does this help out Mr. Handa? If you'd (or anyone else) would like will write this one up with pictures once new part arrives? Carl
Actually Mr. Phil you *do* know everything...you know that if you were on a yacht in the Bahamas you'd be bored! Carl PS: Do you remember your "God's green earth" line from a couple years back? Still think about that one (such a concise & poignant use of the vernacular!) and smile...
Here's a thought (haven't tried though): if the switch is functioning properly removing the throttle microswitch once car is running warm should produce a change in idle (increased RPMs) immediately (removing ground input to ECU). Carl[/QUOTE] Carl, Since I don't have a lift available, I would be VERY interested to know if this quick test works or not...sure would be easier than the alternative.
Carl, Since I don't have a lift available, I would be VERY interested to know if this quick test works or not...sure would be easier than the alternative. [/QUOTE] If everything is in order it does work. I use it as a quick test of the functioning of the system all the time.
Just want to post some follow-up here to prevent misinformation. The red/pink-stripe wire is *not* the idle circuit wire and the above-referenced switch is *not* an idle-circuit switch; it closes when oil temperature is warm to permit full-throttle enrichment. Idle circuit is the pink/black wire. Back to drawing board on this one (sigh). Carl
I've been wondering about this too. My QV hasn't been running quite right. Looking at the wiring diagram for the FI system, they list one of the sensors as an oil temp. sensor. To the best of my knowledge, K-jet always uses (used) an ECT (Engine coolant Temperature sensor). There are two sensors in the top of the engine under the plenum. One is the thermo-time switch (fires the cold start injector during cranking for cold enrichment), and the other is the ECT. This makes me wonder if it is simply an error in the manual(s) possibly a translation error? The sensors under the plenum look like a real bear to access ... Oc course the above applies to 'normal' CiS (or K-jet) on more common cars. It is not uncommon for Ferrari to add other sensors and such to the system. Please LMK if you find any more information about what is listed as the oil temp sensor and how it ties into the FI system if at all.
Hi Alfa, One of the sensors under the plenum is the thermotime switch and the other is the coolant sensor for the dash gauge. I can attest - they are *challenging* to access. TTS controls the cold start injector only. Coolant temp sensor for FI is screwed into coolant overflow tank. The above-referenced sensor on the oil sump actually closes when oil temp is warm to allow full enrichment when throttle miscroswitch is fully "opened". Very curious as to "normal" running behavior of 308 K-lambda or 328 when throttle switch disconnected when car running; anyone volunteer to remove theirs & report back? (won't hurt anything to do) Carl
Carl did you replace the oil temp switch? Next time I drive mine I will pull the tps harness connector and tell you how the engine responds. You stated earlier the rpms should rise?????
Carl: Congratulations on your progress -- you seem to be on the cusp of a profound discovery Although my car has a problem by not stepping-up to a high idle when cold (it does not get very cold here so not a huge problem) I did test the TPS this AM. After initial start-up (Approx 50 Deg F) disconnection of TPS switch caused the idle to go from 900 to 1,500 RPM. Also, the mixture seemed to be rich when connected and leaned-out when disconnected. After about 5 Min (phone call interuption) disconnection of the TPS yielded no change in idle RPM. When warm, disconnection of TPS switch aslo caused no change in idle RPM. Right after car intial test, phone rang so missed opportunity to take more data -- will do, and report more info after I run a few more cycles. Mark
Just as a follow-up to this thread: replaced my FI oil temp switch last Saturday evening. Apologies should have taken pictures. Procedure as follows: 1. Drain out about 4 quarts of oil. 2. Push alternator orange vent hose back up & remove the circular bracket (for easier access). 3. Remove two spade terminal wires into switch. 4. Loosen top 19mm bolt (I used combination wrench swinging towards alternator side. There is room in there. Be careful not to hit the (+) battery connection at solenoid). 5. There is a copper crush washer above & below "union" when you remove the through bolt. 6. Pivot union downward & remove return hose (6mm socket). 7. I found easiest to clamp union in vise (with wood protection) and loosen temp sensor. It's identical to the one on the coolant tank. 8. Replace sensor & small copper crush ring. Reverse above and re-add oil and you're done. Carl BTW sensor is open at room temp and closed (continuity) when warm.
