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Ben's V8 project

21K views 167 replies 20 participants last post by  grillage 
#1 ·
Looking at a 93 4.2l V8 this weekend that is currently not running. Owner says it needs a cam sensor. Any easy fixes for this? Also, how best to diagnose?

I am bringing my vag-com with me to pull codes but I don't know if thatll show up.

Anything Else I should look for?

Thanks!
Ben
 
#2 ·
I'm pretty sure they will run with a bad cam sensor. If they lose the crank sensor they don't start. Sensors are nearly identical and beside each other under the drivers side header. Plugs are up on top of the fire wall I think? It's a pita, but they can both be done by jacking the car with the LF wheel off. When I did them on my 91 they were about $75 each 10 years ago.
 
#3 ·
Those sensors won't keep the car from starting.
Must b something else wrong. I would need more
Info
Though.......
 
#4 ·
Ronald G Wainwright+ said:
Those sensors won't keep the car from starting.
Must b something else wrong. I would need more
Info
Though.......
That's what I thought. I'm a little weary

thanks
 
#7 ·
If the crank sensor is bad it'll cause a no start when it's hot. Once it cools the car will start..... Until the sensor gets hot again. Then once u turn the car off it won't start again.... Till it cools.
The rpm sensor will cause the car to stall while drivin cause it's not sensing a signal. But again once it cools it'll restart.
 
#8 ·
#9 ·
Ronald G Wainwright+ said:
If the crank sensor is bad it'll cause a no start when it's hot. Once it cools the car will start..... Until the sensor gets hot again. Then once u turn the car off it won't start again.... Till it cools.
The rpm sensor will cause the car to stall while drivin cause it's not sensing a signal. But again once it cools it'll restart.
Hey Ron, while that's true of a failing sensor, if the reference sensor were dead, it's the same as a missing pin=ECU gets no signal=no start. Not sure why, but I've never personally had a reference sensor go bad, it's always been the RPM, but replace both while in there. I'm running the cheap $25 5000/200 ebay sensors in both cars now for years, and all is good. Grillage, the car not running allows you to pick it up cheap. As long as the timing belt didn't break/tranny's OK the rest is manageable. 2 of the 3 not running parts cars I bought had bad tranny's and was not told that, but for $300-$500, I got a bunch of nice parts. Buy it cheap and get it running....Tom
 

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#10 ·
Tom, thanks for all the info - I am of a similar mind - the last thing I want to do is get it running and start negotiating price. I'd rather come to a price and then start trying to fix stuff. He's asking $1,500 but I won't pay near that. No one but one of us is going to buy a non-running 20 year old audi.
The only parts car I've ever bought was a similar situation. A non-running 94 Cabriolet. I got the engine running, replaced timing belt, bled coolant and then -thunk- no transmission. Damn thing wouldn't go in reverse. I ended up pulling the heads, the new timing belt kit and every sensor, wire, and remotely useful part for my other 94 Cabriolet and scrapping the shell for $300 cash.

If I can get the thing cheap I'll be okay.
 
#11 ·
Ronald G Wainwright+ said:
Those sensors won't keep the car from starting.
Must b something else wrong. I would need more
Info
Though.......
NEGATIVE ON THAT! Both will keep it from starting, if dead. If running, and crank sensor fails, it will continue to run using signal from the pass side hall sensor in the distributor, at full retard. If the engine speed sensor fails while running, car will die.
 
#13 ·
Ok so when this kid gets the car we'll c.
 
#15 ·
Ronald G Wainwright+ said:
Ok so when this kid gets the car we'll c.
Can I be a kid tooooo.
 
#16 ·
toml99 said:
Ronald G Wainwright+ said:
Ok so when this kid gets the car we'll c.
Can I be a kid tooooo.
Me three! I too want to be subtly demeaned based on my perceived age, makes me feel young again.
 
#17 ·
::Oprah voice:: Every1's a kid! Ur a kid, ur a kid. & ur a kid..... Get the idea!
 
#19 ·
Well here are some pics....

The fleet...


The subject...




Damage to both front corners...



The engine needs some work for sure. Lots of oil coming from the DS head - hopefully just a valve cover issue.


PO put the rag on the radiator hose to keep it from rubbing on the fan


The goal here is to get the engine running and decide then whether to fix the rest of the stuff. The engine could end up in my cabriolet long term if all is well.

The bad with the car as it sits now is...

The interior is not great. The seats are both ripped and they smoked heavily inside the car.
The passenger side door has been taken apart and not put back together well. It doesn't open from the outside and the window doesn't work.
Battery is dead from sitting
The front end damage is a big turn off. Short of finding another PS fender there's not a lot I can do.
Hood struts and trunk struts both toast. (See wood holding hood open)
Bald front tires.
Missing the chrome "8" from "V8"
The car will not start. Cranks but no turning over.
PO said it died mid drive to work. He claims to have had someone confirm there was not spark but I have not tested myself yet.
I was thinking (as the conversation above was) that the crank position sensor was bad. I hooked up my vag-com to the car and was able to see a crank position fault when it wasn't started yet but it went away after I would crank and fail to start the car. That seems to rule this out.
What's the easiest way to test the fuel pump? Are these common failure items?
 
#20 ·
Looks like someone did a really bad job installing the air filter... lol j/k.

nice pickup, she needs some work, but not many 20+ year old audis do not.
 
#21 ·
I'm sorry to say I TOLD U ALL SO!!!
Maybe one if the above geniuses can continue with the diagnosis theory's for u! Lol.....

But I will ask, when cranking does the tach jump?
& there are tests to c if the pump works or not...... But if the cars really got 127k on it IMO that's a little early for the pump to fail.
 
#22 ·
The fuel pump can be tested by removing the relay and shorting the contacts. But no, the fuel pump is not a common failure point.

If you decide to part out the chassis, please PM me in the future. I have the same car as you :)
 
#23 ·
Thanks guys. I'll check the tach here in a minute. I edited my above post. The PO said it did NOT have spark. I typed that wrong before. I'm fogging to go out and run a few tests in a few. Unfortunately the battery is dead so I have to jump from my s6. It makes hearing a fuel pump not easy. I was able to confirm that the fuel pump fuse is good though
 
#26 ·
Ronald G Wainwright+ said:
I'm sorry to say I TOLD U ALL SO!!!
Maybe one if the above geniuses can continue with the diagnosis theory's for u! Lol.....

But I will ask, when cranking does the tach jump?
& there are tests to c if the pump works or not...... But if the cars really got 127k on it IMO that's a little early for the pump to fail.
:?
 
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