Jretal

obviously I'm going to have to pull the spark plugs to do the testing,

I'm guessing that I will need to pull the fuel pump fuse (is there a fuse or a relay) but I'm not sure which one... anyone have any tips?

I'm using the stuff my dad used on his old 914, but that was carberator... so when you pull the plugs there's no vaccuum therefore there's no fuel getting pumped. Obviously this is a different story with the fuel pump

thanks for the help guys. Keep your fingers crossed for me that the PO was wrong and the headgasket wasn't shot =P

ddg=shinebox racing

Count the number of revolutions and do the same amount for each cylinder.
I usualy have the gauge propped up so I can see it from the drivers seat...

Jretal

The setup I have actually has a push button trigger that I tap into the starter, and then a gauge that I hold over the hole... not the tap in type. Old school stuff...

I was hesitant to run the engine since it's low on coolant (or has none). Will it affect the compression if the engine is cold? Just curious, I've never had to do this on a car before.

Thanks!

'81 tic-tac

hot engine will differ compression values slightly vs. cold.

Jretal

and fire her up (if the battery held its charge at least) and see what I can find out

Jretal

So I topped off my coolant, hooked up the A4, and fired her up today!

isn't it so sweet when they work together to help eachother out =P
<img src="http://pictureposter.audiworld.com/21175/img_0400.jpg">

Here are the numbers I got (cyl 1 is the front of the car cyl 5 is the back of the car)

Cyl 1: 160 psi

Cyl 2: 150 psi

Cyl 3: 170 psi

Cyl 4: 140 psi

Cyl 5: 130 psi

So, obviously #5 is the low cyl, but is that enough to warrant a dead hg? Oil is still clean as a bell, exhaust is clear (no white puffs from burning coolant). And the engine isn't running rough. It was at first, but seemed to calm down after it ran for a bit. It was also burning off some oil from the exhaust manifold (was getting some smoking) but that stopped after it ran for a bit. I'm thinking that MIGHT be why the PO's mechanic told him the HG was dead... not sure. I have pictures of the spark plugs as they came out of the car too, so if those might be valuable let me konw.

Also, think I MIGHT have found the source to the coolant leak (to answer: where the hell has the coolant been going) Looks like the gasket to the fitting where the radiator hose to the block meets is where it's coming from (anyone know what this is called? the gasket i mean). Could also be the hose. Kinda accelerated the leak when I released the cap to the reservoir (not the brightest move, but I knew it was under pressure) and saw some coolant come from that area.
<img src="http://pictureposter.audiworld.com/21175/img_0401.jpg">

BIG concern to me was that if I would sustain a higher RPM, or rev it to say 2500 and hold it, I'd get my oil pressure light Wasn't too happy to see that... any ideas? It a safe bet to say that my oil pump is dying?

Also, found some vaccum hosing off the IM that seems to be collapsing (rubber one b/n IM and idle stabilizer):
<img src="http://pictureposter.audiworld.com/21175/img_0412.jpg">

It's fine with the engine off, but when it starts it starts to collapse, then then squeezes together more when I lay on the throttle.

Also, when I do a hard quick rev, I get a knocking/pinging sound (sounds like cyl 5 honestly). Not sure what kinda gas he had in the car, but it's on E, so I'm guessing whatever IS in there, isn't worth $hit since it hasn't been driven in 8+ months at this point.

I was able to take the car for a quick spin up and down my street (has no insurance or registration, so no street driving). It is thunking pretty bad in the front when steering, but that's most def the ball joint the PO told me was shot. I have new ones in the garage ready to go on, so I'm not too worried about that. Also rode like hell, but the tires are way underinflated (dry rotting) so that is why on that point. Other than that, I couldn't rev it too high because the oil light would come on

Also, car is idling at around 1200 rpm, which is high. It was higher when i first started it, but after letting it run for about 30+ min it let down a little and the lifter noise quieted down as well.

I can't think of anything else at this point. My passenger's side window will go down fine, but won't go up. Like it doesn't get power... I'm guessing the regulator is dying, but I'll cross that bridge AFTER I get the engine running (i.e. no oil pressure light flashing on at higher RPMs).

Alright guys, that's about it from me. Thanks for any help you might be able to offer!

'81 tic-tac

Cyl 1: 160 psi
Cyl 2: 150 psi
Cyl 3: 170 psi
Cyl 4: 140 psi
Cyl 5: 130 psi

cyl 4 and 5 are kinda low.. if you can test again, test each cylinder again but try adding some motor oil to #4 and #5 in through the spark plug hole and see if the values rise. it's called a wet test. i think ur headgasket is alright. if it were blown u would see a much lower value in one cylinder or so. your rings are probably worn down or something. to find out for sure u can bring it to a shop and have them do a leak down test.

AH here we go...
from the website
All a "wet test" entails is a bit of oil in the low cylinder...
11. Add one capful (1-2 tablespoons) of oil to the cylinder with low compression.
12. Let it sit for a minute to allow the oil to flow down and coat the sides of the cylinder and piston. If there are any gaps in the rings, the oil will seal them for the next few minutes.

13. Crank the engine for 4 revs, remembering to floor the throttle.
14. If the reading improved significantly (more than 30 psi), your rings are probably worn.

15. If there is little or no improvement, take it to a garage that can perform a leak-down test to determine where the compression is escaping (intake, exhaust, crankcase, gasket, etc.).

16. Replace the plugs, preferably in the same cylinders they came out of. You may want to clean or re-gap them first, or put in new ones. A dab of anti-seize on the threads would be a good idea.

the link to the website is below




yeah what do ur spark plugs look like anyway?

im tired and didnt read all of ur post, forgive me.<ul><li><a href="http://www.geocities.com/dsmgrrrl/FAQs/compression.htm">http://www.geocities.com/dsmgrrrl/FAQs/compression.htm</a></li></ul>

Jretal

I will give that a try tomorrow (if I have time from studying for my test on thursday) and see what kind of numbers I get. I was expecting that if the hg was totally bad, I would get like below 100 psi for the piston, so I know something is worn. Also, the compression tester I'm using is a rubber nipple that sticks into the cyl... so there is probably a lil room for error here... as you can see:
<img src="http://pictureposter.audiworld.com/21175/img_0410.jpg">


Here are pix of the plugs (some are kinda blurry, sorry... borrowing my roommate's digi cam, which sux a fatty.

cyl 1:
<img src="http://pictureposter.audiworld.com/21175/img_0405.jpg">
cyl 2:
<img src="http://pictureposter.audiworld.com/21175/img_0406.jpg">
cyl 3:
<img src="http://pictureposter.audiworld.com/21175/img_0407.jpg">
cyl 4
<img src="http://pictureposter.audiworld.com/21175/img_0408.jpg">
cyl 5:
<img src="http://pictureposter.audiworld.com/21175/img_0409.jpg">

cyl 2 and 3 had a bit of oil around the threads of the plug, but the tips pretty much looked the same. They weren't soaked in gas (running overly rich) or anything to that extent. I will give the oil trick a try though... if you get some energy though, try the rest of the post to see if you can help with some of the other issues... mainly the oil pressure light coming on

thanks!