got this 1990 corrado...1.8... digifant?... supposedly WAS running this way... supercharger has been removed and was running without it. timing belt was quite slack and had jumped. Replaced timing belt, aligned correctly (confirmed flywheel mark 0 is really TDC) and distributor rotor directly at timing mark on distributor. Started briefly, bog bog bog with throttle... couldn't get it fired up again yet. This was the extent that I ever saw this thing run before doing the timing belt... bog bog bog and dead. Not exactly sure where to go from here... There is no hood sticker for timing specs. Not sure if base timing can be left at tdc or what. I've tried moving the distributor since. It was firing and kicking back on the starter at one point. Fired up a little here and there. I can't seem to find any information on how fuel metering is done on this thing! It's not CIS, and there is no air door or anything except a temp sensor / pot. in the boot to the throttle body... Hoping someone can direct me to a good comprehensive site that shows how this system is supposed to work, so I can hopefully figure out how to make this thing run! It doesn't even have to run right... just be driveable / moveable, as it's supposed to be heading for a VR6 transplant later...
Timing with Digifant is usually set at around 2400 rpm. Coolant temp sensor disconnected. 6 +/-1 degrees BTDC.
Borrow a workshop manual.
Remove and read the spark plugs.
Digifant with supercharged engines (G40 and G60) uses a manifold absolute pressure (MAP) sensor. The sensor is in the ECU box. There's a pressure line (rigid plastic tube) between the manifold and the ECU. The system is very sensitive to manifold pressure and any leak will frustrate reliability.
Removing the supercharger messes up the whole air delivery system as the idle stabiliser valve also acts as a boost bypass valve.
It's quite likely that Digifant has switched to limp-home mode as no boost is being made. The car will run, but significantly worse than a normal, 8-valve GTI.
You can set the static timing at 8 deg btdc. There's a mark for that on the flywheel. The distrb. finger should then point to cyl 1. This engine is not sensitive in terms of timing any thing between 0 and 8 will work. The fuel system is based on speed density so no airmeter just a pressure sensor inside the ecu and a air temp. sensor in the tube going to the throttle housing. The air temp sensor is combined with a CO pot. With this CO pot you can adjust the mixture to correct the CO value. The pot is behind that blue plug. Be aware that there are two marks on the cam sprocket. Use the one on the valve cover side no the outer. Don't worry about the supercharger and the ISV. They won't have any affect on the basic running of the engine. The ISV is only used to bleed of too much boost but without the charger there isn't any. Resistance of the cool temp sensor is normal for that temp. If you want to check fuel pressure you can disconnect the line going to the fuel pressure sensor on the other end of the fuel rail. This fp.sensor is used for the after run system to avoid vapour lock. No limp home mode. It's actually a very simple engine/computer. This engine won't produce much hp with some boost, CR is only 8:1.
It's there. Just though of checking my Vantage meter for some specs for that! Not sure if I have that coveraged... and it sounds pretty crucial to be not too far out of range.
Is the range enough to make it not run?? The blue plug is still in so hopefully nobody's messed with it!
Yes! Actually there are 3 marks. 2 outside and 1 inside. The 2 outside ones mark the 2 teeth that the inner one resides between. Very handy to locate it initially... but still a pain to sight for correct alignment, but it's correct.
Gee, sounds like maybe it should run every bit as good if not better than a stock 1.7 8V then?? I guess there's not much excuse for me to not be able to make thing run again... not know what the heck I'm doing is a good reason but poor excuse : ). Thanks MUCH! In2
Well trying to set cam and flywheel back to zero to reset distributor yeilded no mark at flywheel? WHAT?? I KNOW I had this right (and it was much easier to turn everything by the crank when the alt belt / tensioner and pulley were all out of the way!)...
Remove plugs (sure takes the load off trying to turn it over by the cam). Bringing her around and piston coming up. Then piston stops for about an
8th turn. Then continues coming up! Seems somebody put the sprocket on the crank minus a key? ...or somethings gotten munched?? Never seen this before!
I used to say the intermittents were the worse mechanics nightmare. Now I move it to 2nd, with working behind someone elses work to 1st place! Now I can take it all back apart and see what someone has done to this poor thing! All I can say is it's a good thing it's an 8V non-interference... will finish the story later if it ever ends... : )
Check the woodruff key in the crank for the timing belt sprocket, I had a friend with a G60 that sheared that key off with similar results. I've got another G60 in my garage that I suspect the same thing happened to, but I have no time to mess with the @#$%^ POS.
Got it apart. No key... Bolt was slightly loose, but I don't think loose enough for it to have fallen out by itself. Strange thing is, there is no slot in the sprocket. Theres just a bit of a lip that slips over the shaft a bit. The slot on the shaft is very short, rather wide, and tapers uphill toward the engine in a hurry. Like a wedge shaped peice is supposed to sit on it and go flat against the sprocket??
I went to VW and got a "woodruff key" that was supposed to be for it. (of course, engine itself may not be original) It's a little half moon shaped thing and doesn't fit at all. I might just grind it until is can fit in there enough for the sprocket to just jam against it and tighten the heck out of it with an impact gun... as soon as I get a 12 point 19mm socket... can you believe I only have 6 point (what next). Might even add a little loctite. Seems the wedge is supposed to sort of help center the sprocket?? Either that, or this sprocket doesn't even belong on this engine! It's gonna have some run-out for sure because neither the bolt hole nor the recessed area that goes over the shaft a bit will center it exactly. This thing very much just bolt to the end of the shaft rather than really slipping over it. It's only supposed to be a temp fix for this engine anyway, but I hate not making things right if you know what I mean. Oh well....
Check the woodruff key in the crank for the timing belt sprocket, I had a friend with a G60 that sheared that key off with similar results. I've got another G60 in my garage that I suspect the same thing happened to, but I have no time to mess with the @#$%^ POS.
Part of the sprocket eh? That makes much more sense... of course, why the dealership lists a woodruff key and had it in stock for said vehicle is a bit of a mystery! I ground the ends off it and laid it on there sideways and tighten the sprocket against it. Then got the belt back on it and had to loosen it again and turn the crank a bit because I was coming up 1/2 tooth off (funny it happened to all line up so nicely when the thing was loose 1st time around!). I found a cheap cheesy 19mm 12pt socket (3/8 drive) and put it on my impact gun and wacked it pretty good... until the socket spit open. Then put my 19mm snap-on wrench on it and beat it with a hammer. I think it will hold. AAAAND, owner now tells me he's planning on fitting a different supercharger to this engine. So this "temporary" fix he wanted will hopefully hold up! My impact gun is not very big. Maybe I better get a bigger one and a better socket and really wack it tight? ; ) You know, I didn't think it was loose enough for anything to fit out from behind it, and I know nothing dropped out when I removed it. But I could see a mark where it looked like a key was pushed against the sprocket. That must be where it broke and worked back and forth long enough to smooth it up and make the sprocket not fit very tightly. It should get a new sprocket, but dealership is 80miles round trip and time/ budget dictates that it doesn't so time will tell. He knows what I've done, but he'll probably sell it later and someone will have no clue what's going on if it slips again!
I set the distributor at zero as well. Hit the key and it runs! Maybe not super fantastic yet, but IT RUNS. A beam of light was coming out from under the hood up to the clouds and there was a chorus of singing... well, that's what I told the owner anyway! I still need to put the cover back on and pulleys, belts,... then I can set the timing... with it RUNNING! he he he Check coolant (winter is coming) and take it for a drive to see how bad wheel bearing are!
Seems I never have much luck working on VW's! My Rabbits used to be a hobby (and pretty cheap) and time was not an issue. The last job I did for this guy was the timing belt on 1.8T in his Golf. That was another quick job that turned into days when it started overheating shortly after. Turned out the "upgrade" to metal impeller water pump was a BIG mistake. Turned out impeller was slipping on the shaft! He's worse of a vw-nut then I used to be, so eventually he'll give me a job that goes good... I hope...
"dave AKA vwdoc1" wrote in message news:VPzGk.2488$x%. snipped-for-privacy@nlpi070.nbdc.sbc.com...
Thanks Dave! This one really looks like it never had the tapered chunk in there ever. Only a slightly shine in that area, otherwise perfectly round. I'm going to call VW for a price and availability and then get back to my customer. I comfortable it will run a while like it is for his original intention, but if he's talking running this engine for real and putting a charger back on it I'm not so comfortable. Afterall, this little sprocket drives everything, not just the timing belt! And the load on it under acceleration will be trying to loosen the bolt. My "ground key peice" I clamped in there likely doesn't really bite the edge of the sprocket by much. I'll follow up when I'm done with it to let you know what we did.
Years ago, I used to be on the group often. Seems pretty dead now. There's hardly anything posted... I would have expect to have to scroll way down by now to find this thread. Garbage, spam, flame-wars (fun to read but tried to stay out!). Then I had trouble with my isp and couldn't get the group for awhile... long enough to realize that I needed to give it up! Was wasting too much time then, but it was always fun!
Luckily it is not really an interference engine, but I would prefer that you install the correct part. ;-) So it is running now? Got your 19mm or 3/4" 12 point 1/2" drive socket?
If the bolt is not torqued down enough then it can snap off that key!!! Hope it will not damage that crankshaft!!!
You will either need a very good impact gun, and I have still repaired broken sprockets after someone else has put the bolts on with an impact gun.....................OR....................... You will need to torque down the bolt properly. Using a non-shedding rope and installing/stuffing it down into one of the spark plug holes should stop the crank from moving in one direction allowing you to torque that bolt down. Some people have used a strap to wrap it around the attached pulley and then to a good spot on the engine or body of the car. Or if you can hold the flywheel or sprocket. Did you see that tool that was made? I could use one! lol
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