tmking66

Ok, I just replaced an engine that had blown an apex seal on the front rotor. The replacement engine has decent compression (90 or so on each rotor). The engine when it starts runs rough (missing backfiring slightly) and will not stay running if I let the rpms fall below 3000 rpms. The first engine was running great before it coughed up the apex seal. I did not change anything in the swap. all parts from the original engine were swaped onto the new block.

Any ideas/suggestions as to what I may have done wrong? I have checked all hoses and they all seem to be connected correctly.

I did notice that the oil pressure gauge is now reading off the scale on the high side. It never did this before. Could this in some way be related to my problems?

Any help is appreciated.

Kingbob

oil pressure is most likely unrelated.

It sounds like a vacuum leak. If this is a NA then check the intake hoses going from the airbox to the TB. They can be put on wrong and it will look right, but leak like crazy. Make sure you have the hose on the underside of the same intake hose plugged up. My friend missed this hose and had his car down for two weeks before he found it.

Syonyk

A huge vacuum leak will cause this, as will having the CAS a tooth off (severely retarded timing).

Check the timing first. Since you can't exactly get it to idle down, you may be able to just pull the cover off the CAS, set the main pulley to a timing mark, and compare it to a working FC with the engine aligned the same way. If it's off a tooth, it will be REALLY obvious. If it's within a few degrees, this isn't the problem.

Once the timing is set, check for vacuum leaks. There's a huge opening into the side of the intake (at least on the S4s) under the bypass air controller - I neglected to plug that up, and had about the same issue.

This honestly sounds almost exactly like my project FC a few weeks ago. It'd run, but it wouldn't run below 3000 RPM, had no power, and backfired like a cannon. I fixed the timing, closed up some giant vacuum leaks, and it runs a lot better now. I won't say it's perfect, but it's at least idling down and running fairly smoothly.

-=Russ=-

slpin

iTrader: (9)

you forgot to hook up the oil pressure condensor thats why it reads shitty
syonyk has the answer^^

tmking66

Where exactly is the oil pressure condenser and where does it connect at?

I will check the timing and look again for vac. leaks. Thanks for all the help so far!

Go48

iTrader: (7)

Also, check to verify that you plugged in the connector on the AFM.

tmking66

Well, I should rename this post (will not run at all now that I "fixed my problems")

Here is what I have done so far. I found one vacume leak. I had not connected the hose to the brake booster. I pulled the crank angle sensor to check the timing. I set the main pulley on the leading mark, lined up the marks on the CAS and dropped it back in. I have checked and rechecked all vac. lines and electrical connections and everthing now seems to be in the proper place. HOWEVER, now the car wont run or start at all!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! !!!!!!!!!!!!!!!!!!

When I try to start the car now, if the fuel pump is turned off, it will fire up for maybe a second or two and then die. With the fuel pump on it will not start at all. Cranking the engine with the fuel pump on wont start but while cranking if I turn the pump off it will fire for a second and then die. What little it runs without the fuel pump on it sounds very sluggish.

Also, the oil pressure is still reading off the scale (high) and oil is leaking badly around the oil filter. Never heard back on the location of the oil pressure condensor and can't find it in my manuals.

Help

87rx7girl

http://video.google.com/videoplay?do...90075874019145
http://video.google.com/videoplay?do...69089994850213
i had a problem like that . wouldnt idle or stay steady... and died under 2k....

vac leak....
the tube conencting my bacv and intake was disconected in the back. i didnt see it..
. did you check out primary injectors?
posibly you damaged one when the seal broke?

but ya... i'd start looking for vac leaks
have a buddy sit in there and hold the rev steady. and start going at the vac lines with a can of carb cleaner. if your buddy tells you it changed the rpm. you know the area to look in.
good luck!

tmking66

I wish mine ran as good as the one in the video! This one wont stay running for more than a second since I "fixed the timing" I set the crank angle sensor correctly according to the fsm and haynes manuals. Now it wont run at all. I got to thinking that when I was installing the engine I noticed that the 19mm nut on the main pulley was loose. Could that pulley be on wrong and if so how do you adjust the pulley to where the timing marks line up correctly?

When I pulled the CAS out the first time the marks on the bottom of the CAS did not line up and I had the engine set at top dead center when I pulled the CAS therefore they should have lined up but now that I adusted them the engine is MUCH worse than before.

87rx7girl

the videos have a comment on the side..... it didnt even stay unless my foot was holdin the rpm.... prob didnt read that part. but its running now..... i still say. get a buddy over to help you with the vac leak thing... carb cleaner.

if you spray carb cleaner on a vac leak. the rpm will raise.

tmking66

This engine wont stay running long enough to spay anything I care where you hold the gas. It dies within a second or two of trying to start.

Anyone on the front pulley idea??????

87rx7girl

... i aint sure where it is.... but maybe look in the FAQ about the "light test"

you can hook up an led.... and get it to blink a code. then you take the code and look online for what it means.. it would tell you the sensor thats getting the wrong reading
good luck!!!