Chris28

A while ago my car started bogging/misfiring whenever the engine had a heavy load. As long as I accelerated slowly, everything was fine. Once I put the pedal more than half way down however it would bog really bad and start to what sound like misfire. I put new plugs in it (bkr5e gapped to .038) and for the most part that fixed it. Every now and then it would bog under high load but only for a second.

Now that I've boosted it, the problem is back, this time it seems as if the car is backfiring also. I'm running 370cc injectors and a tune to compensate for them, and I'm running a walbro pump and an adjustable fpr so I don't think it's a fuel problem. Plugs are now bkr7e's still gapped to .038. I have hotwirez so my wires are pretty beefy, I don't think those are the problem. Could a vacuum leak be doing this? I can faintly hear a hissing sound near my intake side when the engine is running, but if it's a vacuum leak why did new plugs fix it the first time? My timing is set correctly, that was my first thing to check so I actually brought it somewhere and had them time it with their timing gun.

On top of that, my cruising AFR's are really high. Idling is around 15 and boosting is around 12, but about 20 psi vacuum cruising and my AFR's go way up, around 17 to past 18.

If anyone is good with KA's I'd pay them to drive it and see what I'm talking about. I'm going to check my TPS today and maybe get a new distributor, it really seems like a spark issue to me. Thanks.

-Chris

SCREECHO

Sounds like a head gasket. Prior to boosting it, what were the supporting mods, i.e. arp studs, and a mls or cometic or a copper head gasket? That is just the bogging issue. takes a second for the water to get burned. now I know your thinking, but I dont have white smoke, could be just a hair drip inside. ka24's have that aluminum head that is known for pushing gaskets, and warping when hot.
For your vaccum and afr, Its been a minute since I messed with a ka24 but what about the egr diaghram? Had a 22rte give me shit for a day on a weak vaccum line.
Then again as you said your going to check your TPS, the most common sympton of a TPS Going out is stumbling during acceleration.

Chris28

Engine is totally stock. I have ARP head studs but I was planning on waiting until I blew the HG to put them in along with a new fel-pro gasket. I don't think it's the head gasket, the engine ran fine for the 5 or so months that I ran this tune minus the turbo. I'm getting a new TPS tomorrow, I'll see if that fixes the problem.

I'm about to order an egr block off plate, right now I just have the egr tube ghetto capped with some heater hose, a bolt, and 2 hose clamps. I don't think anything is getting past it, but I'm going to totally block off the egr for good measure.

Also, the bogging issue really only happens after 1st gear. 2nd gear I can kinda feel it, 3rd is pretty bad. It's like the taller the gearing the longer I'm in the trouble range so the more I feel it. It's weird, I'm about to replace all my vacuum lines and see what that does.

Thanks for the reply.

M▲dh▲tter

how much vacuum are ya pulling?
IMO ya should be running BKR7E's
my ka24de-t does the same once in a while but i know my issues are the vacuum leak, only pulling 11 lbs. As well as I still running a stock fpr w 750cc injectors and a walbaro 255hpi. the oher day i when out and pulled the plugs and noticed. hey I need to change my valve cover gasket. but other than that she will pull 17 lbs all day long and loves it.

if ya want call me, we can shoot shit over the cella's aight.
804.334.5568 ~skott b