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Car Forum / Volkswagen / Water Cooled Volkswagen Cars / January 2007'83 VW Rabbit CIS hard cold start
In warm weather or whenever the engine is already warm - it starts right away and runs excellent. In cold weather (below about 40 degrees F) it is hard to start. After about 6 trys it will start. What is the most probably cause - cold start valve, aux air regulator, thermo-time switch or what? What is trouble shooting sequence. I would like to start with the most probable cause. I once had a Datsun 280ZX with a similar problem. I hot wired the cold start valve to the battery (with inline fuse) with a spring loaded off button on the dash. During a cold start I would just hold the button in for a few seconds while cranking and it would immediately start. That worked for a few years until I sold the car. Would the same procedure work OK in this Rabbit? Thanks Gene >In warm weather or whenever the engine is already warm - it starts right >away and runs excellent. In cold weather (below about 40 degrees F) it is [quoted text clipped - 7 lines] >That worked for a few years until I sold the car. Would the same procedure >work OK in this Rabbit? Thanks Gene air-reg check : dis-connect both hoses on it and when COLD light from a flashlight will pass through . cold start injector : when COLD pull the injector and place it in a glass jar ( with the fuel line and wires still connected). Pull the connector off the thermo-time switch and jumper across the plug terminals. When the starter is cranked a cone shaped spray of fuel should be seen. thermo-time switch : removed the plug from the cold start valve and . bridge the contacts with a test light or voltmeter , pull the coil from the center of the distributor and ground it with a jumper wire. Again this needs to be done when it's below 32 COLD . engauge the starter and the test light should light , or the voltmeter should indicate voltage for three to ten seconds depending on how cold everything is. I vote cold start system if your red lights stay on in the instrument cluster while cranking. Does it have power after it starts when cold? I have seen 2 VWs lately with just this problem. One had a terminal slightly pulled away from the cold start injector. The other had a bad starter that would not supply power to the cold start system. later, dave (One out of many daves) > In warm weather or whenever the engine is already warm - it starts right > away and runs excellent. In cold weather (below about 40 degrees F) it is [quoted text clipped - 7 lines] > would immediately start. That worked for a few years until I sold the car. > Would the same procedure work OK in this Rabbit? Thanks Gene >I vote cold start system if your red lights stay on in the instrument >cluster while cranking. I take it then , if the led's were not lit whilst cranking your vote would be it's the starter causing the poor 'cold start' condition? If so , i'm going to remember that troubleshooting aid. >Does it have power after it starts when cold? >I have seen 2 VWs lately with just this problem. One had a terminal [quoted text clipped - 16 lines] >> would immediately start. That worked for a few years until I sold the car. >> Would the same procedure work OK in this Rabbit? Thanks Gene Not quite, I am saying that the ign switch is bad and power is shut off to the ignition while cranking evidenced by the red lights disappearing. ;-) Sometimes you can move the key around while cranking and get those red lights back on to start the engine. later, dave (One out of many daves) > I take it then , if the led's were not lit whilst cranking your vote > would be it's the starter causing the poor 'cold start' condition? > If so , i'm going to remember that troubleshooting aid. Thanks to Sam & Dave for their input. I pulled the electrical connector from the cold start valve, put a volt meter across the contacts. No voltage while cranking!! Apparently the cold start valve is not working because it's getting no "juice." So - no what, what do I check next?? Thanks Gene > In warm weather or whenever the engine is already warm - it starts right > away and runs excellent. In cold weather (below about 40 degrees F) it is [quoted text clipped - 7 lines] > would immediately start. That worked for a few years until I sold the car. > Would the same procedure work OK in this Rabbit? Thanks Gene But did you jumper the thermo-time switch connector? You have to make the computer think the engine is cold. Also, the thermo-time switch doesn't stay closed forever; at 20C (68F) it only stays closed for 1 to 3.7 seconds. Once it opens again you won't see any voltage at the cold start valve. Here's the thermo-time switch test: 1. Make sure coolant temperature is below 86F. Let it sit all night. 2. Disconnect the coil wire from the center tower of the distributor cap and connect it to ground, using a jumper wire. This prevents the car from actually starting. 3. Disconnect the cold-start valve harness connector and connect a test light across the connector terminals. Not the switch; the connector that has wires connected to it. 4. Actuate the starter and watch the test light. It should light for a few seconds. If this doesn't happen you didn't follow steps 1-3, or the wiring is bad, or your computer is broken. Mike Yeah do what Mike said and disable the ign. I would check the wiring at the cold start valve with a KNOWN working test light (or voltmeter) to check that you get power to one of the terminals at the cold start valve while your helper engages the starter. One will be power only while cranking and the other will/should be grounded when the thermo-time switch is functioning and the wiring and computer are fine. A few things to check! 1. Check for power at the cold start valve terminals while cranking. 2. Also check for ground at the other cold start valve terminal. 3. You can also check the thermo-time switch and it's wiring at the switch. > But did you jumper the thermo-time switch connector? You have to make > the computer think the engine is cold. [quoted text clipped - 16 lines] > > Mike Have you checked or replaced the Infamous CPR ? Control presssure regulater if its bad your car will run good at one extreme either cold or hot , what it does it acts like a choke it richens the overall fuel delivery for a few minutes then leans out as it warms up yours may be stuck on lean they are not fixable only replacabe there is a few tests you can do but it involves pressure gauges etc the best thing since they are expensive 60 USD plus is to get one from a wrecking yard. I have 3 spares and other must have cis goodies for my 82 2 dr jetta sunroof .... let me know what worked > Yeah do what Mike said and disable the ign. > I would check the wiring at the cold start valve with a KNOWN working test [quoted text clipped - 30 lines] >> >> Mike Thanks to all that responded. I believe the problem was in the CPR, thermo-time switch or aux air regulator. These items are very expensive new -- and there aren't many Rabbits in junk yards any more. To solve the problem I hot wired the cold start valve to the battery (inline fuse) with a spring loaded to off button (like a door bell button) on the dash. During a cold start I hold the button in for 2 seconds maximum while cranking and it immediately starts. Problem solved. Gene > In warm weather or whenever the engine is already warm - it starts right > away and runs excellent. In cold weather (below about 40 degrees F) it is [quoted text clipped - 7 lines] > would immediately start. That worked for a few years until I sold the car. > Would the same procedure work OK in this Rabbit? Thanks Gene I doubt it is the CPR as if it were you'd have other issues. Also the AAR probably isn't your issue either - easy way to check and make sure it's functioning, with the car warm and idling keep screwing the idle screw in until the engine almost stalls, then screw it in some more. The AAR should bring the idle speed back up. I found this out the hard way on my '84 GTI; I'd misadjusted the idle so it was running with the AAR open all the time, and it ran great but would always stall in traffic when I shifted. In frustration I kicked the idle up to about 1500 RPM and heard a click, then everything was normal! The thermo time switch is probably your problem, a quick search shows it at gprparts.com for about $70 which is a little extortionate. But I bet if you follow the test procedure in the manual you will find that this part is bad esp. since hotwiring the cold start injector seems to work. good luck nate > Thanks to all that responded. I believe the problem was in the CPR, > thermo-time switch or aux air regulator. These items are very expensive [quoted text clipped - 15 lines] >>would immediately start. That worked for a few years until I sold the car. >>Would the same procedure work OK in this Rabbit? Thanks Gene  Signaturereplace "fly" with "com" to reply. http://home.comcast.net/~njnagel I agree with Nate..............not the CPR or the engine would not continue to run easily/powerfully while cold. The AAR should have a little door that is open when cold, then when it heats up due to wiring and heat radiation from the engine that door closes. It can be adjusted just a little to allow more air into the intake manifold if needed. I don't think that is your problem either. It could be a bad starter that does not send power to the Cold Start Valve, or it is not getting ground. It should get the ground as the wiring passes through the thermo time switch and possibly from a relay. Not up on that '83 Rabbit and so it is not fresh in my mind. Geez I am not up on the '84 GTi system either! lol It was kinda easy to check for either power or ground, but if your remedy works and you are happy, then it is all good! BTW How did you ground the Cold Start Valve? later, dave (One out of many daves) >I doubt it is the CPR as if it were you'd have other issues. Also the AAR >probably isn't your issue either - easy way to check and make sure it's [quoted text clipped - 35 lines] >>>would immediately start. That worked for a few years until I sold the >>>car. Would the same procedure work OK in this Rabbit? Thanks Gene Dave wrote "> BTW How did you ground the Cold Start Valve?" With an alligator clamp on the end of a solid core wire to the negative battery terminal. I could have just as well attached it to any bolt/screw on the body. When "special" wiring such as this, I use solid core wire as it will hold the bends you put in to "snake" around. When using this procedure for cold weather starts I recommend -- engage the starter first and then immediately push the button for no more than 2 seconds as it squirts a big batch of extra fuel. You don't want to "flood" it. It should start immediately -- mine does. Gene > BTW How did you ground the Cold Start Valve? > > later, > dave > (One out of many daves) |
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