OK, this one has a little different flavor to it I think.... I've replaced the fuel pump (including external check valve) and the accumulator with new parts. The injectors are original (28 years old) so there may be some pressure drop/leakage. Here's the symptoms: 1. Car is a '82 gtsi - starts great cold and has good compression, 2. Car runs great, both cold and warm, no hesitation or issues, 3. Car is difficult to start when warm. About the only way she'll start is if the throttle is applied to at least the half-way point during cranking, 4. If I disconnect the cold start injector on the plenum, the car starts when warm without application of throttle and catches quite quickly and smoothly. My sense is that the CSI is adding fuel to the mixture when warm (don't think it should be doing this). By applying the throttle during cranking, I'm guessing the mixture leans out enough (despite the CSI activated and flowing fuel) to actually start. I'd like to retain the CSI - for cold starts during the winter. Basically, I'd like the system to operate as designed. If I understand it correctly, the CSI is activated based upon a temp reading of a sensor screwed into the top of the block somewhere around the oil filter housing. Is the next logical step to replace that sensor? Thanks in advance.
What version US or euro? If US, the "sensor" that you are looking for is a thermoswitch (item 106 on your OM schematic) mounted on the thermostat housing -- it has two terminals, and each should have a single RV (red/green) wire attached. The logic for this thermoswitch is: cold = closed warm = open When the engine is fully warm, remove one the the RV wires from the thermoswitch and measure the resistance between the two terminals -- if the resistance is low (switch closed), you need a new one (although your test that unplugging the CSI helps is a clue that this thermoswitch is bad as its function is to "unplug" the CSI when the engine is warm). Image Unavailable, Please Login If euro version, the suspect would be the thermo-time switch
Injected 308s have a thermo-time switch in the valley just inboard from the oil filter. When it fails, fuel it squirted into a hot engine by the cold start valve, flooding the engine from starting instead of being timed to shut off after a few seconds and not doing anything to a warm engine. A partially open throttle can sometimes overcome flooding (didn't for me), as can a 30 minute wait for the excess fuel to evaporate. To prove this condition, remove the connector from the cold start injector. BTDTHTS ____________________________ http://www.FerrariDiagrams.com Should explain where the cold start injector is located so I stole a picture for you and added the red arrow pointing at the csi. It is at the right side of the air plenum (your plenum may be red) and has a gas line from the fuel distributor plumbed to it with a banjo fitting and an electrical connector below it the gas fitting (blue). Pictures of the thermo-time switch are not available since it's mighty dark in there. The tts can be replaced without removing the plenum but requires patience, several end wrenches (can't remember the name - sheep foot?) and helps to utter special words which I can't repeat. My mechanic took the best part of an hour while I held the light. Cost of the switch about $100. Image Unavailable, Please Login
Thank you Steve, thank you Paul - that's very helpful, much appreciated. I'll go dig into some of the details here and report back. Cheers.
Hi Steve, I have a US version gtsi. I pulled both the RV wires from the sensor and measured resistence at cold and hot. Please excuse my non-technical/non-electrical language here, but I measured no continuity (in other words, "open" I would call it) across the terminals at both hot and cold. From your description, it sounds like there should be continuity ("closed") at cold, but not at hot, is that correct? If the above it correct, then I may have found a faulty sensor, but probably not the fix to my difficult hot starting issue, right? In other words, if that sensor is supposed to be open when hot (and it is) then theoretically I shouldn't be getting add'l fuel through the CSI. Thanks in advance Steve.
Your result is a little strange. If you check your US schematic, you will see that that thermoswitch is in series with the CSI internal coil; consequently, if it always has no continuity (i.e., an infinite resistance), your CSI would never fire, cold or warm, and it would make no difference to unplug your CSI during warm starts because that thermoswitch having no continuity would already have "unplugged" the CSI. One caution is that your meter is reading the resistance -- so if it measures "nothing" (i.e., 0) that is actually perfect continuity. Your meter should read something like "inf" in the display if there is no continuity. Yes, that is my present understanding (but I've been wrong before ): cold = continuity = a low resitance value like 0 ohms to a few~10 ohms (so the CSI will fire) hot = open = infinite ohms = "inf" It may be that your thermo-time switch has also failed, but on a US version (my understanding is that) this should only impact slightly-warm restarts IF this thermoswitch is working correctly; however, if your thermoswitch has failed in a "closed" condition, then you have the "euro" situation where a bad thermo-time switch will impact all warm restarts. Sorry for the long rant, but, if this thermoswitch is really "open" all the time, you should be having trouble with cold restarts not warm restarts (and unplugging the CSI should make no difference) -- so please clarify if you can.
Steve, Thank you, I do follow what you're saying. Incidentally, not the first time I've been called "a little strange." I think what I'll do (because I can't think of a better option!) is replace both the thermoswitch on the thermostat body, and also the thermo time switch in the valley...and see how that affects things....couldn't hurt I don't think! Will report back with any interesting findings. Thanks!
I have a simmilar problem with my 85 Mondial QV, cold starts are perfect, warm starts requires a little cranking untill the engine starts, 12 months ago had a full service, new belts, valve timing done, new injectors, new plugs etc, I have dissconected the plug to the CSI and still makes no difference, to cold starting or warm
I still suspect you are losing residual fuel pressure in the system when its hot. As I noted earlier, replacing the check valve/fuel pump resolved my hot starting issues which were exactly as described in your post. Since you have tried that with no success there is one fairly simple procedure you may want to try next, which is to replace the two O ring seals in the fuel pressure regulator located on the airbox side of the fuel distributor . I have a set of new seals that were generously provided to me by Larry Fletcher at CIS Flow Tech. Larry suggested this as a possible culprit of pressure loss. Send me a PM with your address and I will send the seals to you. If the seals don't fix your problem you might want to contact Larry and talk to him about your issues. You will find him to be extremely friendly and knowledgeable about your CIS system
Thank you Dean, that's very generous of you - will shoot you a pm. That may well be the source of a hot pressure loss. The other possibility is that the injectors are a bit leaky....I managed to replace two with the plenum in the car, but the rest obviously weren't coming out without first stripping the screw in injector holder. I could probably replace all of the injectors more easily with the plenum/intakes on the bench so that may be a winter project for me coming up. But, I would like to look into the pressure control valve on the injector body so those seals would be very helpful. Thank you Dean!
ps. would anybody happen to know the bosch part numbers of these two thermo sensors? I imagine they're bosch sensors common to other application (but that's just a guess). I seem to be "search impaired" as after 45 minutes of searching I'm not coming up with anything... Thanks!
I'm working on a hot start issue as well on a friend's '82 GTSi. Fires up just fine from cold but is a mother to get started if it's hot. He had someone rig up a toggle switch under the dash to give 12V to the cold start injector so he can use it to assist the engine in firing when hot, but I told him the correct solution wouldn't have been difficult to effect. Oh well, the car is now in my workshop anyways and I'm going to get my pressure gauges on it so I can see what the heck is going on. I'm suspecting any of the usual culprits; fuel pump/check valve, fuel accumulator, primary circuit regulator valve in the fuel distributor, etc... Will report on what readings I see with the gauge hooked up and see how fast the pressure drops when I shut it down. I'm suspecting it's not going to hold for the required 20 minutes! Cheers, Aaron
I believe that the thermoswitch is not a Bosch part, but it isn't that expensive from the domestic F part suppliers = F PN 115652 (about $22). I've got the thermo-time switch for your year/model/version as F PN 113980 = Bosch 0280130220
Hello Dean! I wanted to say Thank You to you for sending along those seals - that is very thoughtful of you. Much appreciated! I will replace those seals this upcoming weekend and will report back. Again, thank you Dean!
