CVR_Rally

I did do the leakdown and it was okay. My other thread I did post pictures. I also make the mistake originally of not doing the compression test with WOT...doh! Been too busy to retest as I've been busy on the 8v rebuild.

I wish I had taken pictures of the CAM part #'s when I had them out of the car. If i get ambitious I'll take the valve cover off again, check my settings and also get the #'s.

Chris

harrisonrick

How are the spark plugs? One bad one can mimmick a lot of problems, and be spotty as far as function AOK, then suddenly a crappy loss of power. You likely know already, but use copper plugs...the old school ones are best.

When mine has been sitting (winter storage), I really need to wind it out to blow out the cobwebs...I put in 93 octane AND an octane booster every spring.

Even a fuel injector reseal/clean might improve operation.

I should comment that I run a Russell Berry MaxHP chip too. That leveled off the flat spot quite a bit from stock, and increased the redline a titch.

I still have a R chip from Russell that he gave me to try as well...might be a weekend project on the horizon!

GL, hope it works out man.

CVR_Rally

Thanks. The injectors were cleaned and tested to factory spec. Plugs are pretty new but might always we worth a change out...could use a couple other parts too in the ignition side. I do have a new coil in there.

In the end it really isn't as bad as I think I'm portraying...I just don't have another 944S frame of reference.

Yesterday it felt great with only a couple times when I would WOT and it seemed to have some up/downs till the top...then other times is spot on.

I'm doing an AutoX with it tomorrow for the first time so I'll see how it goes.

CVR_Rally

Question: How much lifter clatter is normal or should there be any at all?

Now I'm really starting to think I need to replace them. I use 15-50 synthetic oil and oil pressure looks good, however this very well may be why I have surges of power.

When I had them out I remember all the plungers being able to move with little effort. On the 8v I am working on they are under much higher tension.

The clatter is prominent when the engine/oil is fully warmed up and at its thinnest. It has always been this way since I got it.

Chris

gtroth

I've never noticed any clatter except once: for ~10 seconds at start-up, after an interrupted oil change that had a day between draining and filling the oil.

CVR_Rally

Yes the ticking it pretty clear. If I take a drive on the highway when I pull in they tick. But if the car is cold and I wait for the water temp to come up a bit I have no ticking and more power.

15-50 oil you would think would do it but maybe I need to use 20/50?

Jfrahm

So wait you think all the lifters might be bleeding down and making the car perform badly under 5K RPM? This seems unlikely.

The injectors are pretty loud. If you make a video clip and include the RPM you can time the ticking to see the frequency as it relates to RPM and that will explain a lot.

Also these cars are just not that fast, think Toyota Celica performance.

-Joel.

CVR_Rally

Oh okay that's possible. Like I said earlier my AutoX instructor said he thought it was pulling fine. Maybe I'm chasing a ghost!

I'll make a video tomorrow when I get home from work and post it.

Thanks!
Chris

CVR_Rally

Split off videos into other thread.

CVR_Rally

Changed all the usual tune up items...plugs wires, rotor, cap, and even new injectors and it still had the same on/off/on power till you got up to 5500. Knowing at that RPM the system goes full rich I dug deeper.

So after discovering that I was running too lean and not finding any vacuum leaks it dawned on me that maybe the universal O2 sensor I installed a couple years ago was always giving false readings. This isn't the first time I've run into this as someone I know with the same year and model runs better without it plugged in.

Yesterday I disconnected it and what do you know...smooth power band...felt like it is supposed to!
At this point there is no reason to keep it connected as I don't have to deal with emissions on the car and it runs great now. At some point I likely will change out the CAT with fabspeed and then I'll get the proper Bosch O2 and see if it measures correctly.

Chris

gtroth

In my experience the S runs much better closed-loop (i.e. with a working O2 sensor). Where I really noticed this was in stop and go driving - car was kind of herky jerkey going on an off throttle. New O2 sensor eliminated that. Idles better too. Something to think about.

Edit- please note that rennlist is now changing "O2 sensor" to hyperlinks on its own. Those links point to random sensors, not the right ones or anything. Stupid and dangerous.

CVR_Rally

I think at some point I'll get the correct O2 sensor and give it a go. Clearly the universal one was not even close. Day two and it's still like a whole new car. Amazing that one sensor can screw up so much.

KevinGross

Sorry I missed the original thread. Chris, if you ever come north to MA and want to drive my 87 944S as a comparison, you are welcome to.

The engine shouldn't feel that much different with the O2 sensor disconnected. We accidentally left mine disconnected many years ago when we were adjusting the open-loop basic mix. I didn't notice it until I flunked the state inspection -- oops.

The 944S does not feel like it has a lot of power below 4K. It's relative, and I think if you were to drive a 944 eight-valve for comparison, it would be a good and surprising comparison. (Hmm, like your wife's car.)

For your amusement, a bunch of years ago the British mag "911 and Porsche World" ran an article on the ten worst Porsches of all time. They included the 944S and described it as having "a flat spot as wide as Albania."

Unfortunately when Porsche introduced the 944S, in the first year it was with a new generation Motronic that rather bizarrely did not have the diagnostic port as in the prior generation. This was corrected in '88 or thereabouts, but can make looking for faults more of a challenge. If you're still stuck, it may make sense to have an indy mechanic who knows and breathes Bosch EFI check your car's running. Hook it up to a good old Sun analyzer, check the basic open-loop mix, check it closed loop, check the timing, etc. etc. Definitely make sure the engine system is intact and correct, like using a proper lambda sensor. Good luck!

CVR_Rally

Hi Kevin,
A lot of that has already been checked including setting up proper timing. If I had a proper o2 then yes it shouldn't make any difference. With it sending false information I've had some very noticeable off power issues that Musante Motorsports has pointed out to me.

In CT we don't have inspection and it's exempt from emissions so I am just going to leave it alone now or buy the proper O2 at some point and eventually it will get a megasquirt or something.

I've got to find that article lol! As for driving an 8V the blue one is half built as I've had to address the S lately. Right now it's running great.

CVR_Rally

I found a thread here on Rennlist talking about similar issues. The problem lies with the TPS WOT position isn't working.

I tested mine and sure enough closed works but WOT does not so it never goes switches loops.

Luckily I have another one that tests good to replace it with.

Chris