VW A2: CIS Hard to start Cold & Warm, Rough Running (2 problems found)
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- Опубликовано: 22 окт 2024
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So I checked my wires, they're all good. The coil seams to be weak. Also when I turned it over today, it just groaned and before cranking, made one rotation and that was it. Also a buzzing when on accessories along with the tac going to 3k before I trigger the ignition switch.
Check your battery & connections... ground wire connections at transmission, body / chassis.
I had a rusted filler neck replaced fuel tank, neck, in tank pump, all 5 injectors they were all clogging up had large rust debris in the fifth injector . That's been cleared up and car ran and started fine during 70+ weather. With the Warm up regulator electronically unplugged. And now after cleaning the fifth injector and with wur plugged in(new connector, it turns on but as soon as u start driving it runs terrible pops and feels like it's running super rich can Barry accelerate! I stop unplug wur and it runs strong again timings at 6* btdc I believe I set it with a timing light
+dopeboy2500 Warm up regulator is a heating element that bends a mechanical restrictor to control fuel flow. Unplugging it will not / should not make a drastic change to the way the engine performs. Engine heat transfers to that mechanical restrictor and does the same thing... just not as quickly as the electrical heating element. Does the engine have a o2 & frequency valve? What is the duty cycle / dwell before the o2 kicks in? After? Fuel pressure from cold to warm?
Thanks for the video, very helpful. However, after replacing a faulty fuel pump, a leaking fuel accumulator, and new fuel filter and 4 brand new injectors, I still have a hard start on cold and a misfire-like on cylinder # 3. The spark plugs are new as well as the leads/wires, cap & rotor new as well. The vehicle is a 1990 GLi (GTX in Canada) 2.0l 16v with CIS Motronic, any guidance or help will be much appreciated.
Have you checked the mA's (milliamps) of the differential pressure regulator? Coolant temperature sensor resistance? If it starts fine when warm, fuel pressure or coolant temperature sensor resistance is not correct when the engine is cold. Bentley Publishers service manual has ECM pinout charts for power & ground checks, as well as resistance checks.
I just bought a collection of 4 1983 mk1 GTIs. New to mk1. One I am trying to get running. I have replaced the fuel filter, new metering head (from boxes of new and used parts I also got), and have good fuel pressure. The CSV has good voltage and works. I got it running for a few minutes and it ran well, now completely cold sitting overnight it will not start but will cough a few times. Dont know what to do
You need to be able to see "control" fuel pressure... when the engine is cold, control pressure should be low (1.5bar). As the engine warms up, control pressure rises and should be around 3.5Bar when the engine is warm. Control pressure is regulated via the "warm-up regulator" that is mounted to the front of the engine block next to the oil dipstick. It is common that the fuel passages inside of it get clogged-up... which raises control pressure. Remove the two fuel lines that are attached to it and check for rust / debris. Blow it out with compressed air or remove the warm-up regulator and disassemble it, clean it and put it back. It's a good idea to also blow out all the fuel lines. Check the fuel tank for rust (remove the sending unit under the rear seat). If the vehicle has an in-tank fuel pump, make sure that it works (should run as soon as the engine is cranking).
great video. exactly what I needed to see.
question for you: what does the thermotime switch do? Mine on a 16v head recently caused a dead short so I bypassed it. I traced the short to it, cleared the short by disconnecting power to it. I was surprised to see that the switch is around $240. What does it actually control?
I'm not familiar / drawing a blank on the 16V switch... can you send me a picture & location? fkh161 @ fkh161.ca
On CIS-Lambda engines, the thermo time switch keeps the ECM in Open Loop until the engine / O2 are warm enough for closed loop operation (fuel metering). The cold start thermos switch allows for cold start injector operation when coolant is cold enough... for around 9 seconds of crank time. After 9 seconds of cranking, the sensor gets warm and opens the circuit (cold start injector stops spraying). Let me know if I explained what you wanted to know or if I need to elaborate.
@@EXOVCDS
Thanks for the answer. The location is just below the water neck on the distributor side of the head. There are two sensor locations below that water neck (that feeds the heater core). Of the two, The one closest to the firewal and vertically oriented is the one I'm having trouble with.l
@@justindoan6798 The thermo time switch should have continuity (0 ohm resistance) when the engine is cold. After 5min it should be open (infinite resistance). When the sensor is shorted, the fuel mixture will stay rich and the ECM will not go into closed loop.
@@EXOVCDS thanks again. Should be easy enough to test that. I'm pretty sure mine has failed as the 12v supply side of the sensor is shorted to ground which causes the fuse to pop.
Your a2 videos are extremely helpful. Thank you for your consideration! I have an 86 golf CIS that has issues idling on hot starts. If I don't keep some throttle on it, it bogs down and dies. However, after I drive it through a few gears, the idle is fine. I've replaced cold start valve, cleaned the control pressure regulator, and checked the spark plugs. I'm thinking it's either leaky injectors or a fuel pump/filter issue. Any ideas?
CIS plain or CIS-Lambda (with O2 sensor)? Thank you for watching!
CIS-Lambda. Just had exhaust installed and inspected, so the O2 should be good.
The motor also cuts out at WOT, which I suspect is a similar issue. Almost certain it's fuel related.
Does the O2 cycle? Does the frequency valve at the air flow meter buzz while the engine is running?
Haven't checked the cycle, but the meter does buzz while running.
Hey I'm having idle issues injector sprays when cold not when hot 02 reads .55v the fifth injector has 2 sets of wires on the bolts brown and blue is clean ground then brown & white 635,ohms to battery power. I tried to test fuel pressure but the set up at oreillys didn't. Really work on this set up any other things I can check for?? Cold starts are bad takes six starts to get it to idle start right up when hot any help would be so useful!
+dopeboy2500 Remove the fuel lines from the control pressure regulator and check for dirt / debris in the openings, clean / blow them out: www.specialtauto.com/images/warm-up-regulator-051.jpg
Recently I bought an 88 Jetta GL with the 8V engine code RD and the CIS FI system. Its cranking a lot to start when cold and puffing quite a cloud of smoke when it starts. Rough idle for the first few seconds of cold running unless I hold the throttle at about 1200 rpms or higher. I've checked the Idle Control module and it seems to be operating correctly. I just watched your video here regarding the WUR/CPR and tried to locate and inspect mine... it seems to be absent and the plate where it attaches looks conspicuously cleaner than the rest of the engine. Can I assume a previous mechanic removed it and the car still functions? Should I replace it and expect the cold start issue to be eliminated to some degree? What's the reason why my engine wouldn't have it or had it removed and what long term concerns should I have?Thank you!
You probably have CIS-E which uses a differential pressure regulator that is mounted to the side of the fuel distributor.
I was going to suggest more... but I see you are not subscribed to my channel! =(
Just kidding!
Make sure that the differential pressure regulator receives power / is working. You need to check the mA current that goes through it, using a multimeter. When cold, there will be high mA's. Warm idle is be around 10mA. Is the temperature sensor working correctly? A wrong temperature reading when cold, can affect the way the engine runs. O2 sensor disconnected, key ON. What is the voltage on the green O2 sensor wire (the one FROM the ECM, not the actual O2 sensor wire)? Should be around 0.45 to 0.5vDC. Yes? No? Are all the small ground wires attached at the side of the cylinder head by the coolant flange and at the intake manifold? Have you got a service manual? It lists ECM pinout tests / checks (voltage, resistance tests etc).
Yes! It is the CIS-E at least from the marks in the service manual that came with the car and the owners book and window sticker. Yes a 30 year old original window sticker is in the glovebox! 1 owner car from 1988 to 2017
I will need to check all of those Thomas thank you. I haven't checked anything on your list other that that the O2 sensor is plugged in - heard they get cut or broken off over the years. I don't know yet if there is power but will start going over that list. Since buying the car, aside from enjoying the time behind the wheel I've been listing and fixing small mechanical things I note like lighbulbs, fuses, latches and pricing bigger ticket items such as axle replacements and stuff.I finally did subscribe to your channel since you seem to be a wealth of excellent VW experience and knowledge and your garage resembles mine with all the Vw and german car decorative enhancements. Incidentally, I've previously owned a 97 Mk3 Jetta, 00 Mk4 Jetta and currently have in addition to the 88 Mk2, another 97 Mk3 Jetta and a 15 Passat keeping company with my 65 Beetle (under restoration in the other garage bay) so yeah, I might have drank the cool aid.
That's quite the collection of cars! Nice to see someone being passionate about looking after their vehicles!
Hey, thanks for the video. I recently picked up a 1987 GTI 8v with CIS-E. I've managed to get it running with some good fuel and a jump start. It runs great. Only until it's warmed up. When it's warm it starts misfiring pretty badly and eventually stalls out. during this time when it's missing, it barely responds to throttle input. could have it totally floored and it would only rev to 2k. Any ideas ? I might go after the o2 sensor next.
any help would be appreciated, thanks !
Make sure that the ECM is actually awake. Those systems can run on mechanical injection alone and because the electronics isn't powered up, can't adjust fuel as the engine warms up. If the O2 sensor does not have 0.45V when the key is on (at the O2 signal wire / disconnected from the o2) then the ECM is not awake.
Thanks for the response thomas ! I just tested the o2 signal wire and it had about .5, almost .6v
I'll get back to you after work tonight.
Have you got the Bentley Manual for it?
Follow the pin-out chart to test all grounds, powers, sensors / inputs.
Have you got an adapter to measure the differential pressure regulator milliamps?
In-tank fuel pump ok?
I'll have to make an adapter for it once i get it running. As far as I know it is. However, the car completely refuses to fire up now. Lots of fuel, great spark. didnt flood it'self out yesterday but today I feel it has. interesting.
I have a 1988 vw fox. Cis system. Its runs rough (lacks power, struggles) until the Temperature gauge is in the middle.. Any ideas what it could be?
Check the warm-up regulator / control pressure regulator. If it has an O2 sensor, check that the thermo switch is ok. Make sure that the frequency valve (if it has one) is buzzing all the time (next to the air filter).
I’ve got an 84 rabbit, cis. I installed rubber fuel lines new pumps, gas tank and fuel filter (barn find). Car takes about 30 seconds of cranking before it starts to buck and kick to start. Once it starts coughing it’ll run and misfire for a few seconds until I floor the car to get it above 2000rpm where it smooths out then idles. Then it runs perfect. After that I can shut it off and start it without an issue. But when it sits for a few minutes. It’ll take a while to start again. Any ideas??
Plain CIS or does it have an O2 Sensor as well? Incorrect fuel pressure when cold, would be my first guess (since it runs fine once warm a bit). You need to check "control pressure". Should be 1.5 bar and rise to 3.5 bar once warm.
Thomas EXOVCDS thanks for your reply! Yeah I’ll have to check fuel pressure of course. Just even when engine is hot if you leave it for 10 mins it will be hard to start
@John Magee hence my O2 Sensor question. If there is one... there's also a "frequency valve" that is used to regulate fuel mixture. If the valve / system is not working, correct fuel pressure alone may not be enough. The more info I have the better I can guess / help.
Thomas EXOVCDS yes I do have an 02 sensor, I also hear the frequency valve working
Duty cycle of the valve needs to be checked... but first, cold & warm control pressure need to be verified.
Where can I make donations too?
ive had a similar problem with the way mine is running, i replaced the fuel pump relay and i got fuel, it still ran rough cold and warm. I started looking at my ignition system and pulled the Distributor/ coil wire of the coil, and pushed it back on, and it went from not starting back to running rough. Any idea of what it could be?
Check the resistance of the ignition wires... the coil wire 2k to 4k ohms and the plug wires 4k to 6 ohms... these are just general specs.
If the wires are older than 5 to 8 years, replace them... along with distributor cap & rotor.
Ok, cap and rotor are brand new and I have 1 year old ngk performance wires and same age iridium plugs.
Matt Chirhart I would have to see the secondary ignition waveform with a Scope, to see if the running issue is due to an ignition or a fueling problem. Ignition wires can test ok with an ohm meter, but fail when the engine is running. If the engine is running better after you repositioned the wire, then there must have been an issue.
I'll look into it, thanks for the tip.
Are the bolts holding the regulator on 5mm hex bolts?
Yes.
+Thomas EXOVCDS thanks Thomas. Your videos are great, very informative. Looking forward to seeing more CIS when it comes through!
Hello, I have a 1990 VW Fox with the CIS system in it, I replaced the low pressure fuel pump and fuel pressure regulator. Idle on start up is rough and it will die coming to a stop or if I'm slowing down. I fixed a vacuum leak and turned up the idle but it still dies and runs rich.
Garreth Ballard Does it have an o2 sensor & frequency valve? Have you checked cold & warm "control pressure" at the fuel distributor?
+Thomas EXOVCDS I'm thinking it's a the crank sensor but I'm not sure where it is.
Garreth Ballard That engine (as far as I know) does not have a crank sensor. Does it have an o2 sensor & frequency valve? Open the hood, record the engine (move the camera slowly) and post a video on youtube. Post the link here so that I can see the engine & components.
+Thomas EXOVCDS it does have an o2 sensor, I'm not sure about the frequency valve. I'll post the video link here soon.
+Thomas EXOVCDS ruclips.net/video/SFFhxFGghS4/видео.html
My VW mk2 1.8.mono-jetronic 66kw is running really rough when the engine is cold, immediately after i start the engine there is no idle at all, when i press the gas pedal and try to keep engine at some idle speed it runs really bad, sounds like its choking or something, but when is heated up - different story, idle is at steady 1000 rpm, sounds like it should, i dont get it, please give me a hint. I watched your video and i think that i can try to remove and clean that control pressure valve, but i am not sure that is the right place to start.
Does your intake look like this? upload.wikimedia.org/wikipedia/commons/7/79/Monomotronic.jpg That's a throttle body injection unit... or do you have the metal CIS fuel lines that go to each injector (from the air box)?
yes sir, looks exactly like that!
Then this video does not apply to your engine... different fuel injection system / you don't have that part. Check your coolant temperature sensor... the ECM might think that the engine is warm (when you start it cold) and then it does not provide enough fuel. Once the engine is actually warm, it runs fine because the fuel amount is correct.
First, thanks for your replies. I think you might be right! It makes sense! Today i have changed the coolant flange, the old one had a faulty sealing gasket and refited old sensors. There are 3 sensors, two on the top (blue and red in my case ) and black is at the bottom. Wich one is coolant temperature sensor? Is there any difference between those three or they are all technically the same sensor types? Can i change their places those just for test? Thank you once again for effort!
p.s: How can i make a donation?
Zoran Cvetkovic Blue (2 wire) is usually for the ECM... yes, you should be able to swap the plugs of the sensors to see if it makes a difference "the next time you start the engine cold).
On my website: fkh161.ca/ you can pick a donation button (there are 3) . $1, any amount or $10
Let me know what happens with the starting issue.
This is not a North American car I assume? If you need information (wiring diagram etc), I might be able to find some.
Hey Thomas that was my coworker commenting for me I had log in issues had to make a new account . So I checked my frequency valve and it does not buzz with a new relay (98 golf). Nor does it buzz when the large gauge pins are jumped. I checked the brown wire with green stripe that's ground and I'm getting high resistance to battery ground. I had rusty gas all over my fuel system to the point where the car didn't run. I recently opened up my fifth injector to find a little pile up of rust and also had some dark brown fuel in my warm up regulator a while back but fuel filter was changed twice. Can I ground the frequency valve by back probing the brown wire to battery ground? Thank you again with any help
+Lawrence Thomas Can you send me a picture of the engine bay / air flow meter? So I can see if it is CIS-E or CIS-Lambda? email to fkh161 at fkh161 dot ca
I have a 1.8l cis-e that cranks but won't start. There's fuel to the fuel distributor (100-125psi inline pump), but no fuel to injectors unless I lift the plate, it still won't start with the plate lifted. Any ideas?
I'm just starting work right now... will have more time to reply once I get home tonight (6pm west coast pacific time). For now, here's a basic cis troubleshooting chart:
www.cabby-info.com/images/FuelSystem/CIStroubleshooting.jpg
What year / model vehicle is yours?
***** its a 1980 rabbit, with a 1986 golf motor
Quite a few variables that could be the issue here... have a look through this KE-Jetronic PDF to learn the system:
www.berlinasportivo.com/Technical/lancia/Thema832/Bosch-KE-Jetronic-OCR.pdf
Once you understand how it works, you can figure things out.
Is the ECM "awake"? Can you check for fault codes? Is this a resent "transplant"? When was the last time it ran?
You didn't mention spark... do you have spark? How did you test?
***** awake? How do I check sodes on cis? Used to run fine then sat for 7 months. Theres spark, grounded spark plug and it sparks
I'm at work again, will write more later.
So the same principles apply to an audi 5 cylinder with CIS?
You asked the same question under a different video... I replied and you never replied back. If you want help, you need to reply when I reply. Or at least a "thank you" when I do.
Thomas EXOVCDS omg I’m so sorry! I didn’t realize I did! Please forgive me! I do find you videos very useful!
Sorry... didn't mean that to come across as harsh as it probably sounded. CIS is CIS... no matter how many cylinders. Things might look different, but the principal is the same. If you have specific questions, I just need the year, make, model & engine and I can try to help with more specific information (as long as I can find it).
Thomas EXOVCDS its an 1990 Audi 200 quattro turbo.. the engine is the MC2 5 cylinder engine.. the car sat for a year before I bought it... I bought it in July of last year... so for 2 weeks the engine would die out on at random.. then that problem went a away... I’m guessing bad gas was the reason.. but now that winter is here the car has been very hard to start... damn near impossible on very cold mornings! And it misfires but as I drive it kind of smooths itself out... I was told injectors...
Have a chat with my buddy Badgertronix ruclips.net/video/X_qGcZpR7rg/видео.html
He is very familiar with the CIS on 5 cylinder Audi vehicles!
Hey the email u sent me was weird and didn't work. I do have lambda cis with a thermo time switch frequency valve and a warm up regulator jh motor with a h head.
+Lawrence Thomas Fuel pressure is a big "need to know" for running issues.
Here's a CIS troubleshooting chart that might help a bit:
www.cabby-info.com/images/FuelSystem/CIStroubleshooting.jpg
As for cold start injector... remove it (two 5mm allen bolts) and hold it against the intake manifold with the ground wires that are attached to it. Have someone crank the engine... the valve should spray for up to 9 seconds while you are cranking (if the thermo time switch is cold). If you have a hot start relay, it might pulse spray on / off.
To make sure that the engine does not start or a spark ignites the fuel, remove the center wire from the distributor cap and ground it to the engine with a jumper wire. That way, spark from the coil goes straight to engine ground.
If your valve does NOT spray, disconnect the valve and attach a test light or noid light across the connector for the cold start valve. If the light light-up... replace the valve (it is plugged or stuck).
If the light does NOT light-up... time to trace the power & ground wires.
The frequency valve should buzz when the engine is running... does it?
Hey there the frequency valve has no buzzed since I swapped the engine . I know it's suppose to and I suspect that the issue I've emailed u this already earlier about the thermal time switch I tested the connector that plugs into it at 100*F. And it pulsates doesn't stay on for 3-7 s comes like it should from the alldata testing I found.
Any way to test the frequency valve?
Lawrence Thomas Frequency valve should have power all the time on one wire "as long as the engine is running"... the other wire is grounded / controlled by the ECM. You can put a testlight across the electrical plug instead of the frequency valve to see if the light lights-up / flickers. There are a bunch of ground wires that need to be attached... at the cold start valve and at the battery negative cable.
Okay I will check that port with a test light tomorrow. As for the grounds I don't have the nicest ground just not sure how to put a free market one on since the original one is a heavy braided one running under the air box
Aftermarket ground I mean I can get at length any connector style at work just not sure how to join all the other wires to one to have a clean low resistance ground
Never mind found it