Nars VR6 Corrado

[scarsofcarma 10]

 

I always wanted one of these, and once I test drove it I couldn't say no to trading my FB RX7 for it. It has the following modifications done to it already:

 

• Energy Suspension poly bushings in the control arms, sway bars and rear upper shock mounts.
  
• Bilstein sport shocks
  
• H&R Sport springs.
  
• GIAC performance chip
  
• K&N air filter
  
• HID headlights
  
• Drilled Brake Rotors
  
• Steel-braided brake lines
  

 

It has a lot of miles on it though, Over 199k, and I'm worried that it may need a rebuild. I started it this morning cold, for the first time, and I noticed there was a mixture of oil and water being sprayed out of the tailpipe.

 

It doesn't want to overheat, but it seems sluggish and doggish at low revs, and it wants to backfire a lot.

 

Any tips or ideas would be appreciated! Meanwhile, I'm going to start trying to find a link to a FSM. There are other little problems with the car I can see already but I need to do more research before I can start speculating.

[scarsofcarma 10]

Eureka! Found a Bentley Corrado manual in .pdf....

 

(MODS) This looks pirated to me, link removed.

Edited February 22, 2014 by davidwort

[VAG-hag 0]

Mmmmm california

[GlosterOx 0]

Looks good Nars, see you have the extra VDO gauges below the ashtray - Nice addition.

 

Worth changing the expansion cap to the later blue one when you get a minute, very cheap from the dealers. Give it perhaps a full service including plugs and HT leads and see what it runs like then?

 

I wouldn't worry too much about the mileage, if they are well maintained and allowed to get up to temperature properly before giving it some (80c+ oil) then they are good engines - Mine is now on 223K miles.

 

Ian.

[scarsofcarma 10]

Ok so first of all I decided to do a pre-test at my school today.(Smog technician training is one of my auto courses). This is the results of today's pretests on top of the results from last year. (Which is the only prior smog record I have.)

 

 

After that I thought it'd be a good idea to do some maintenance, so I removed the distributor for inspection. I realized the rotor wasn't solidy affixed to its shaft. It was just wobbling on it, which concerned me cause that could cause weird spark timing. I checked the manual and it said you're supposed to glue it unto the shaft, so I did that. I also noticed the hall-effect sensor was covered in grime, so I cleaned that as well before I reinstalled it.

 

 

Then I started pulling spark plugs. (These were Denso's.) Three of them were badly badly gunked up, so I replaced the whole set with some new Bosch plugs.

 

 

After I changed the oil I went for a test drive. The car starts easier and idles smoothly now. But it still feels a little sluggish and unresponsive at cruising speeds under slight throttle. Wide-open-throttle however is another story. It really comes alive and zips through the rev's with no hesitation whatsoever.

[robrado974 1]

Well done on your purchase and recent maintenance . It looks like a well looked after car , body and bay wise .

Rob

[scarsofcarma 10]

What about this GIAC performance chip that's supposedly in my car? What's the story on those? Is it something that could be causing some of the drive-ability issues? ...namely running too rich or screwing with the timing? Is it removable?

[seanl82 23]

What about this GIAC performance chip that's supposedly in my car? What's the story on those? Is it something that could be causing some of the drive-ability issues? ...namely running too rich or screwing with the timing? Is it removable?

 

 

Its quite possible yes. GIAC have a good reputation in tuning circles though I believe, but removing the chip will rule it out and its not difficult to do. Its just an eprom in the ecu, some are push fit but some are soldered. If you dont have the original chip it'll probably be easier to buy a good used replacement ecu with the same part number. Good luck with getting it all sorted!

[geoffersmaher 10]

Very nice, hope you enjoymit

[scarsofcarma 10]

So today was a rather productive day for the Corrado. I did an alignment on it. Can anyone tell me what good aftermarket alignment kits are for the rear end? Since it's non-adjustable from the factory back there...

 

But it started to misfire really bad today, like obviously only running on 5 cylinders. So I brought it back home and started diagnosing things...

 

 

First thing I realized is that after I changed the plugs the other day I forgot to plug the hall-effect back in on the distributor! :bonk: I also diagnosed that it was cylinder #6 that wasn't sparking and pulled all the new Bosch plugs back out. Cylinder 6 was totally fouled again. But after searching about it, apparently these cars don't like the Bosch plugs they foul too easy. I read the NGK copper's are more reliable so I'll swap a set of those in tomorrow. But there's no doubt this engine leaks a bit of oil into cylinder #6. I should start thinking about a swap or a rebuild... :shrug:

 

I also changed the engine-speed sensor down on the block cause the wiring looked pretty old and cracked on it. I wanted to swap the 02 sensor also... just because it's the only other sensor I have spares for... but it's mounted at a pretty awkward angle on the exhaust mid-pipe before the cat. There's no easy way to get it out without removing the mid-pipe from the down-pipe. I'll wait on the 02 sensor until I'm ready to do new exhaust gaskets, cause I think I have a leak at the manifold, but I couldn't see any cracks thank god.

 

Last thing I diagnosed was that the K&N air filter the PO installed fits like garbage. Gonna put in a regular air filter that seals properly tomorrow as well.

[scarsofcarma 10]

Ok so after installing NGK plugs, a new WIX air filter (and the other stuff I mentioned in the previous post) driveability has much improved. The misfire is gone and there isn't any of that partial-throttle sluggishness I complained about before.

 

Still feels like there's room for improvement though, but given the internal oil leaks and smoke at wide-open-throttle any other fixes would be band-aids at this point.

 

Also, I can feel the clutch slipping a bit so I might as well rebuild the motor if I'm gonna put in another clutch.

[scarsofcarma 10]

So unfortunately even though the tailpipe emissions are fine... the Corrado failed smog today because there's too much 'visible smoke' during the snap-test (quickly revving from idle to 3k). There's no way to fix that without rebuilding the engine.

[scarsofcarma 10]

In other news, I finally got a chance to do a complete brake inspection today. The front rotors and pads are badly scoured and basically junk. The rear rotors are even worse. They are cracked in four or five places like pizza slices.

 

I already ordered some new Powerstop drilled/slotted rotors... and I am gonna browse for pads and fluid. I need to research what brands are really decent for german cars?

[scarsofcarma 10]

So after I performed that brake inspection the other day up on the lift... I noticed my pedal was really soft and low as I was driving away. I didn't even crack into the hydraulic system... all I did was remove the calipers off the brackets and remove the pads before reassembling them cleaned and properly lubricated.

 

I tried to vacuum bleed the brakes just now, flushing all the old fluid out with new DOT 4, but literally no fluid would come out of the rear brake circuit. I removed the bleeders assuming they were clogged... but that's not the case they are fine. It's as if there was no fluid in the rear calipers at all! I disconnected the brake line from the calipers to confirm that... then I tried to pump fluid through the hard lines to the calipers with the pedal and still nothing! I played with the rear load-proportioning device also and no difference.

 

So then I turned the car to the 'On' position and pumped on the brakes and fluid finally started to come out of the rear brake circuit. So I continued to try and bleed them alternating between ignition 'On' and off so I could at least get fluid into the calipers.

 

But now that I managed to do that, the pedal is still very low and unresponsive. And the brake warning light that used to dimly come on intermittently when I hit the pedal is now full-bright whenever I touch the pedal.

 

This is my first ABS equipped vehicle, and I was told you should still be able to bleed it manually. What I'm afraid of at this point, is some kinda failure with the ABS controller... or perhaps a pressure differential valve, sometimes referred to as a "brake failure valve", which performs two functions: it equalizes pressure between the two systems, and it provides a warning if one system loses pressure. The pressure differential valve has two chambers (to which the hydraulic lines attach) with a piston between them. When the pressure in either line is balanced, the piston does not move. If the pressure on one side is lost, the pressure from the other side moves the piston. When the piston makes contact with a simple electrical probe in the center of the unit, a circuit is completed, and the operator is warned of a failure in the brake system.

 

Any ideas about this would be appreciated... cause the car is literally scary to drive at this point!

 

I need to dig into the manual and examine this cars brake systems more thoroughly... I'm aware that in some cases, you can accidentally force the pressure differential valve stuck if you bleed it manually with the pedal too forcefully. And also, there is sometimes a proportioning valve with a tab that you have to hold in the 'open' position so you can bleed the brakes properly. But when I glanced at the bleeding instructions in the manual I don't remember seeing any special tools or procedures?

Edited March 6, 2014 by scarsofcarma

[Roger Chatfield 0]

You have a Corrado and your neighbour has a CRX, how cool is that, I want to live in your neighbourhood.

 

BTW, massive CRX fan here....lol

 

Rog.

[scarsofcarma 10]

You have a Corrado and your neighbour has a CRX, how cool is that, I want to live in your neighbourhood.

 

BTW, massive CRX fan here....lol

 

Rog.

 

Too bad that neighbor is a mean old man and not a car guy lol. But yeah I agree CRX's are sweet. I wouldn't mind picking one up.

[scarsofcarma 10]

K so this is what I did wrong... there is a procedure it just isn't clearly stated in the manual.

 

Rear axle:

- Ignition off.

- Press brake pedal approximately 20 times (to empty high-pressure accumulator) until there is a noticeable increase in pedal force.

- Attach bleeder bottle, rear left and loosen bleeder screw by one turn.

- Fully depress brake pedal and hold it down with pedal locking device.

- Ignition on, high-pressure pump running (pay attention to running time max. 2 min !).

- Close bleeder screw when brake fluid emerges with no bubbles.

- Check brake fluid level.

- Release brake pedal.

- Wait until high-pressure accumulator is full (high-pressure pump switches off).

- Ignition off.

- Attach bleeder bottle, rear right and loosen bleeder screw by one turn.

- Press brake pedal slightly.

- Close bleeder screw when brake fluid emerges without bubbles.

- Release brake pedal.

- Ignition on.

- Wait until high-pressure accumulator is full (high-pressure pump switches off).

- Check brake fluid level.

[scarsofcarma 10]

Ok so even with the proper bleeding procedure and using a gallons worth of fresh brake fluid.... my brake pedal still feels like garbage as soon as I switch the car to the 'on' position. If this were a normal hydraulic system this feels exactly like a failed brake booster.

 

Why is the ABS letting me push the pedal to the floor? I feel it pulsing and whirring like it wants to hold me back but fails miserably. Is this a bad accumulator or pump perhaps?

[scarsofcarma 10]

It sounds like the high pressure pump was overheated. The max run time on that is 2min with a 10min cool down period in between any subsequent attempts to bleed the system.

 

The rear brakes are controlled exclusively by the high pressure accumulator. In other words, there's no rear axle braking affect without accumulator pressure.

 

Get the wheels off the ground and test if you have rear brakes. If not, a gallon of brake fluid not withstanding, do it again - with a ten minute cool down period between wheels for the pump.

 

You mentioned the ABS light came on during your first attempt. If it's still on, read the codes. The solenoid valves are easily overheated. The system may be partially shut down due to the affects of overheating. I overheated the DSG to the point of shutdown on my GTI going around Road Atlanta, lame.

 

Hey thanks for your contributions to my project log. It's been a big help.

 

I wasn't aware I had to wait 10 mins before every run of the ABS pump. I read in the manual that you only have to let it cool for 10 mins if you let it run for more then 2 minutes? So yes I ran the pump repeatedly for about a minute bleeding the rear brakes, with short intermissions while I topped off the brake reservoir. But I can guarantee that there's no air in the rear brakes at all. I flushed all the old fluid out.

 

The front brakes don't bleed too well manually though, I've noticed that when someone pushes on the pedal, the fluid starts to come out of the caliper, but doesn't keep going. It actually wants to go back in like there's a suction effect going on? I was going to try the front brakes again with that pressure bleeder someone posted a link for.

 

My brake-warning light has always been dimly 'on' ever since I got the car. It was only after I had the car on a lift and did a brake inspection that the brakes felt this bad. And as I said, I didn't even crack into the hydraulics. All I did was remove the pads, measure and inspect the rotors and then re-install the pads.

 

And to reiterate my symptoms, with key off the brake pedal t's nice and stiff. When I press it with key on, there's a little bit of resistance, but it keeps sinking, and I can feel the ABS pump whirring and trying to resist the pressure of my foot... but it fails to keep it off the floorboards. And the brake warning light comes on full bright when I touch the brakes now.

 

Mateok, when you say check the codes, does that mean the ABS computer can enter a sort of 'limp' mode if its been overheated? Is there a way to restore the pump to full functionality by clearing the codes with a diagnostic scanner?

[kerrly 0]

Thats a nice corrado and it looks like its now in good hands.

 

Very jealous of the VDO gauges, id love a set of those!

[scarsofcarma 10]

Ok so it's been a little while since I made any posts regarding the Corrado. This was from a couple weeks ago... finally clicked over 200,000 miles... My engine really is DONE at this point. It burns a whole quart of oil in about 30 miles of driving. Smokes A LOT. I have to pull the spark plugs every couple days and clean them after they start to foul or it'll starts misfiring. As soon as I gather up more funds I'm gonna look for another motor.

 

 

 

My new Powerstop brake rotors finally came in.

 

 

I took it into the shop at school yesterday to try and work on the brakes some more. I did more research about the ABS, and took the time to pull out the ABS computer to check for any kinda wiring problems. I did notice the main grounding wire was chafing through its insulation against one of the mounting bolts rather badly. Only way that could happen is if someone unbolted it and repositioned the wire at some point in the past. That was an easy fix, but it didn't make any difference towards my problems. I bled the front brakes again but realized they are fine... there's no air in em at all.

 

I couldn't get ahold of an adapter to connect a scanner to the OBD1 connector to clear any codes... so at this point I'm giving up trying to repair the ABS. I'm just gonna toss it all and convert to a traditional brake system with a vacuum booster. All my other cars were non-ABS anyway so it's what I'm used too.

 

Random question: Does anyone know why a timing chain would break on a VR6? Is that a common problem? Is there any serious damage done to the engine when that happens?

[Portent 0]

The timing chain can break over time simply due to mechanical stresses, although the tensioner is another possible failure point.. If the chain breaks then it is likely to destroy the engine.

[scarsofcarma 10]

So after some deliberation I've decided to sell this Corrado ($1450 as is seems fair), or trade it (for a MK2 GTI, or a Scirocco). There's a craigslist add up for it now. I'd appreciate it if you'd spread the word to anyone who might be interested. Thanks!

 

http://sfbay.craigslist.org/eby/cto/4404256672.html