Doesn't start, trying to figure it out. I got the bentley manual's that I'm reading though.
As far as I can tell (based on pictures) it is a 20v MC motor?
Floors were soaking wet, not sure why. I'm currently in the process of drying them out. Wet vacc'd them, have a fan for circulation, and have been using baking soda that I read online that can help
In 1990, there is a split between MC1 and MC2. Look at the side of the engine, and see if there is 1 or 2 knock sensors. If it's 2, then you have an MC2, which has slightly higher compression, better cam, and K24 turbo. It's also possible it will have a 2 piece manifold.
"If you can't find one, make one"
Dallastown, PA 1991 Audi 80 quattro (20vt project) 1991 Audi Coupe Quattro (project: my first 20v) 2007 Mitsubishi Raider(Dakota in disguise) 2019 Chevy Cruze RS hatch (wife's little red sporty car)
oh, ha, just read your post again. I guess those are the differences.
I got a S&G kit to test the K-jetronic CIS stuff to look into why it doesn't start.
I think it has a MAC-14 ECU.
I did a output test - fuel pump turns on, freq valve clicks, wastegate clicks, carbon canister clicks, but cold start valve has no click. I'm thinking that's where I start.
I’m not sure if this would help but it’s fairly quick to jumper power to the cold start valve . If that was your issue you should have a start but then you’d still have to dig in to why it’s not working .
The two wires I touch together every time I fire up my 80 do exactly that . Just takes about a one second squirt and no matter what I do will not start without it .
A 20v CIS can be impossible to start with a vacuum leak . I purchased an 85$ smoke tester on eBay and it has come in handy . Uses baby oil . You could put something together to use compressed air and soapy water . Finding a leak could help.
Also of course checking fuses and relays . Have you looked at SJM autotechnik ? Their site has some good troubleshooting info and other useful stuff for MC engines .
Thanks I'm going to try working on it this weekend. Any particular areas that I should look for vacuum leaks other than, well, all the rubber parts/tubes?
JRH wrote:Thanks I'm going to try working on it this weekend. Any particular areas that I should look for vacuum leaks other than, well, all the rubber parts/tubes?
Those cloth lines , sometimes the cloth looks ok but its weak underneath.
Any rubber hose that has a clamp if someone tightens the clamp too tight can tear the hose. There is a big vac line at the valve cover, some lines one going to the wastegate frequency valve, to the igloo, and I think maybe one going to the warmup regulator on the block, one goes to the ECU, charcoal canister.
Thanks. Found a leak in the PCV system - a 3 way rubber tube had a tear in it. I just plugged the crankcase vent system where it attaches to the intake manifold to disconnect it from the system. Also, weather is in the 40's today - up from 20's!
Car started right up! That was probably a vacuum leak, and also maybe the cold start valve isn't working. I'll try to unhook it and see if it will spray separately.
In the mean time, do you know where I can get that 3 way rubber connector that connects from the valvecover? It's the center portion of the photo:
There is also an OEM block hose on eBay, but it's more expensive that the 034 upgrade...
Also, if the cold start injector isn't working, I have a couple of them I can send you. I'll just have to find them... Not sure where they are due to the move.
"If you can't find one, make one"
Dallastown, PA 1991 Audi 80 quattro (20vt project) 1991 Audi Coupe Quattro (project: my first 20v) 2007 Mitsubishi Raider(Dakota in disguise) 2019 Chevy Cruze RS hatch (wife's little red sporty car)
I did also get an S&G gauge kit - it seemed like the control pressure and fuel pressure were within spec (compared to the bentley manual). Wonder what could cause a change in idle then - maybe more vaccum leak stuff?
That looks about right. Looks to be a pretty fine mist with a wide pattern.
"If you can't find one, make one"
Dallastown, PA 1991 Audi 80 quattro (20vt project) 1991 Audi Coupe Quattro (project: my first 20v) 2007 Mitsubishi Raider(Dakota in disguise) 2019 Chevy Cruze RS hatch (wife's little red sporty car)
Thanks. I put it back on. The variable idle I traced back to the CIS frequency valve (K-lambda). When it turned off the idle would rise. I unplugged it and the idle is steady ~800-900. Maybe something with the O2 sensor isn't right.
I already checked the fuel pressure is good, and it keeps pressure when shut off.
You may be able to cure the variable idle by adjusting the idle mixture. To do it correctly requires adjusting the idle mixture and the idle air screws simultaneously and requires a dwell meter and a digital multimeter. http://www.sjmautotechnik.com/trouble_s ... ml#mixture
You may need to shave down the insulation on your No. 1 plug wire for the timing light to work reliably.
Leaky injectors with crappy spray patterns will cause all kinds of cold and hot start problems.
THe variable idle was solved by unplugging the CIS frequency valve. It would be ticking, turn off for a few sec, then start ticking again. Not sure why- maybe something with the ECU/lamba O2 sensor? Either way, for better or worse it is idling steady now. Probably not as fuel-efficient, but whatever.
still doesn't like to start when cold. I need to try jumping the cold start injector to see if that is the problem. The spray is adequate according to a reply here - so maybe it is something along the lines of it not being activated by the ECU? I think it is in line with the thermotime switch and I need to check that also.
