Hey guys
I just turbo charged my KA over the weekend. I have yet to drop the car back on the ground an test it on the road but when I started it up 2 things worrys me.
First problem:
She starts like a dump truck. My KA before the swap started like a champ 2 sec every time engine lights up and runs like butter. Now i have to crank longer and when it starts its shudders to life.
Second problem:
This is the strange one. When I rev the engine the RPM goes up and down as it should before resting on a smooth idle. The idle is a little high at about 1000 when engine is hot mainly because the intake is charged with a little pressure.
The problem happens intermittently i will rev the engine up to about 4000-5000 rpm and let the engine cycle down before the RPM picks back up on its own up to about 3000. It holds there for a few seconds before it slowly slowly falls down to 1000.
The TB works fine and never gets stuck. The only ideas i have is maybe the blow off valve isn’t working the way it should, or not set right? The other idea i had is because the BOV is attached to the mani pressure if the IACV is also attached to that it might not drop the pressure in the manifold properly. In other words the plenum is being pressurized through the IACV.
The boost gauge shows -20 psi when idling. -30 when cycling down same as it did when it was NA.
I don’t really hear or see the BOV working at all when i rev it up but then again I cant get the car to go into boost when its in the driveway.
Just an other heads up I am so new to this its not funny. This is the first time I have ever ever played with a Turbo charged car. So bare with me if I know how to do complicated tasks but have no clue about simple fixes and operations.
check your timing. and im not sure if you have to gap the plugs differently or not
If the timing is out it would have to be cos the computer is doing it. mechanically this engine is solid. Spark plugs are fine. But I will get that checked. Never thought of that.
---------- Post added at 01:38 PM ---------- Previous post was at 01:36 PM ----------
The ECU was tuned by enthalpy. So who knows what its set for.
make sure ur bov is running right. remove egr. if i remember right u can set idle speed with adjusting a screw on the side of the iacv or tb. when you snap throttle from any rpm above 3 you should emidietly biuld alot and i mean alot like -9psi (i think) of vacuum if you got ur boost gauge hooked to tb(make sure the boost gauge is safe to run on tb). make sure you have vacuum when idling too. contact the ecu tuner to find out what maf and injectors you should be running and if you should remove iacv
The screw is fully in so the IACV is at its lowest setting with out some form or mod. right now I idle at about 900 RPM and its even the vacume will drop an extra -5 psi over the -20 that it runs when idling. I checked the BOV it seems to be a heavy spring. I cant get it to open under idle. I think ill try pulling it appart and cutting the spring. Then at least i can set it.
The other thing i checked last night was to see when i let the engine cycle down I hear no PUSSSHHH… no movement at all in the BOV, hell i dont really hear fluttering either. I can however hear the turbo wind down.
If the bov is operated by manifold vacuum and my max vacuum is -25 psi give or take then when i rev the engine the BOV should be fully open as it drops to idle. Is that right?
I am faced with the same issue as of right now and as far as I was reading around it could be a couple of things.
• Recommended a z32 fuel filter
• New spark plugs – make sure u adjust the gap somewhere from .038 - .025 (BKR7E)
• Sparkplugs cables
• INJECTORS … there is a lot of readings on zilvia.net
• IAC unit
• Possible distributor cap and/or rotor
If you figure it out let me know coz I have to fix mine as well.
your bov must open when you lift off with any boost generated. to find out when your bov opens you can get a vacuum tester and measure the force needed to open the bov. play with the spring until the vac generate at lift off matches it. then set it to the amount of vac you making at idle to set it to open at idle.
Thanks Karkas. yeah that BOV is closed at all times and its at its lowest setting i even took the screw out. I think the spring is too heavy. ill have to grab a lighter spring or try to see if i can cut the one i have to release some of the preload.
The engine ran Perfect when it was NA i mean like new. I didn’t even have the common RPM dip that most KA’s will develop over time. The engine had a full over hall in the past year so new ignition system from rotor to plugs. Plugs are a few months old. IAVC and all other intake parts were completely pulled apart cleaned and put back together. So the whole intake has 0 carbon buildup. This KA is one of the nicest ones out there trust me on that.
It is only the turbo add-ons and ECU that have been changed.
The injectors though. that’s a different story. They are SR injectors and have been sitting for a very long time. The other thing is i have yet to get to a gas station to pump it full of 94. Could be a combination of both either way engine idles and revs smooth even on the 84 I have to say the ECU tune by enthalpy works very well so far.