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slickS14
03-25-2005, 10:04 AM
I have an S14 ITS car with a KA24DE that I'm having what appears to be timing issues. AFter I warm the engine up and unplug the TPS to check base timing the engine speeds up to 2000 or so rpm instead of falling to like 700 or so. I put a timing light on it under this condition and it is around 41 deg of timing and starts to rattle like spark knocking...It will not respond to distributor adjustments or idle screw adjustment. With the TPS plugged in it idles around 900 to 1000 rpm smoothly. The engine is freshened and I have double checked camshaft timing and distributor alignment for proper timing. I have previously marked it during dyno tuning so I feel confident it is ok. I thought I was running lean but I just went to the chassis dyno 2 dys ago and the fuel ratio looks good but it appears I'm having the equivilent to spark scatter after about 3000 rpm.The engine just doesn't have any power, it's about 30 or so down from previous testing. Any ideas what else to check? The only code recorded in the ECU is 105-EGR which is removed. I have tried two ECUs and its the same.

slickS14
03-26-2005, 11:59 AM
Ok? ANyone? Joe or Tristan? I'm going nuts over here with this thing......

Joe Harlan
03-26-2005, 06:00 PM
Check you MAF and tubes for leaks. Also check all the block to harness grounds front and back of head. I would back some of that timing out even though it is high idle cause you shouldn't see that much even under normal conditions. Are you disconnecting the TPS per the FSM?

Joe

slickS14
03-26-2005, 07:51 PM
Yes, I'm disconnecting the tps per the fsm to set/check base ign timing to 20 deg. Right now I can't do it though because of the way the motor climbs to 2000 rpm or so and throws all the timing in it can which was about 41 deg last I checked. How can the AFM affect that? I checked all of my air hoses to and around the intake and all is connected. No vaccuum leak at intake that I can find with carb spray method. Thanks for taking a guess...

timrogers
03-27-2005, 11:42 AM
I think you need to set your base idle. The link is for the SR20DE forum, but I'm pretty sure the proceedure is the same for the KA24.
http://www.sr20forum.com/showthread.php?t=81412

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Tim Rogers
-ITA NX2000 slowly in the works...
Sugar Hill, GA

Tristan Smith
03-28-2005, 12:46 PM
Sorry Chris I have no clue. Go through all the connections, and hoses, ect. Make sure all are where they should be, and recheck all you ground wires, like suggested above. Did you move out of the shop on Druid Hills? I haven't seen you stuff there for a while. Where did you end up?

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Tristan Smith
Buffalo's Southwest Cafe
ITA Nissan 240sx #56

slickS14
03-28-2005, 02:31 PM
Hey Tristan...Happy Easter. I've checked stuff until I can't see straight. I'm thinking its a ground or maybe a broken wire in the harness, continuing to look tonight. My friend works at Peachtree Nissan is bringing his Consult scanner over to have a go at it.
We moved from Clairmont about 5 weeks ago to West Hospital Ave off of Chamblee Tucker Rd, still in the area. I can't stand electrical work or gremlins, Id rather build a new car now....frustrated. Thanks anyways...

timelapseracing
03-28-2005, 02:56 PM
Do you have the stock ignition switch in? I had a very similar problem because I bypassed the stock switch. It has a circuit in it which is completed by the presence of a key. Without that circuit the symptoms I had sounded like yours, with the addition - it wouldn't advance at all.

Jason.

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1989 ITA 240sx - #21 MARRS Series

http://www.mindspring.com/~timelapseracing

slickS14
03-28-2005, 04:20 PM
No, the ignition switch is gone, I have a Moroso switch panel with circuit breakers. The thing is that this problem is new and that panel has been in for two years so I don't know if thats it but thanks.

Joe Harlan
03-28-2005, 04:50 PM
The only change is the engine was out and back in after rebuild?

slickS14
03-29-2005, 02:05 PM
Yep, pretty much.... I actually added a cone filter in place of the factory air box I was running but I can't see that making a difference.

Joe Harlan
03-29-2005, 07:38 PM
I really suspect the harness. Try doing a wiggle test near the TPS and the MAF

slickS14
03-30-2005, 08:53 PM
Thanks, have been wiggling and still am..hahaha... The scanner doesn't show any problems, all sensors check out properly within specs as well so I'm still at aloss. The only thing I can imagine is a distributor beginning to fail or the AFM failing slowly? It seems to be heat related too... It actually worked ok last night at about 160 degrees water, disconnected TPS and the thing dropped right down to 750 rpm and dead on 20 degrees ign timing..tried it again a little hotter 185 to 190 deg water and it started acting up again...let it cool and it still acted up...

Joe Harlan
03-31-2005, 10:01 AM
Check the values on you coolant sensor..

Tristan Smith
03-31-2005, 06:46 PM
Swap out your distributer, if you have another lying around. There have been 240sx guys that swear the heat from the headers can adversely affect them, Causing them them to start bouncing the timing all over the place.

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Tristan Smith
Buffalo's Southwest Cafe
ITA Nissan 240sx #56

slickS14
04-03-2005, 03:40 PM
Well, I swapped out the distributor and it appears to have fixed the problem. There was a wire to the distributor that was partially broken too that I found after swapping out the unit. The wire in question is the one that I t-tapped in for the autometer tach. Got rid of the t-tap connector and soldered in the replacement. So far so good at the shop, heading back to the dyno this week to try and confirm teh problem before heading to Savannah in a few weeks. I'll keep you posted.

slickS14
04-20-2005, 07:18 AM
OK! Have found the problem Houston..... After all of this time (and money) the problem was the lower timing chain tensioner! The damn thing has a freeze plug type piece in the top of it and it somehow came out. I ran the motor with the valve cover off and noticed the upper chain was slack. I disassemble the front covers and the little plug fell in the floor when I removed the lower cover. I guess the lower tensioner was bleeding off oil pressure and the upper chain was running on spring pressure alone. No apparent damage was suffered thank goodness but I know now why the cam and ignition timing where flying all over the place. We'll see what happens in Savannah this weekend at the double SARRC.

Joe Harlan
04-20-2005, 09:05 AM
We tig weld the plug into place. Not sure how the IT folks would feel about that so at a minimum you could stake it into place. Nice catch!

slickS14
04-20-2005, 03:36 PM
Joe, I was wondering if I could/should weld that sucker. I'm not sure how that would be a violation but I DON'T want to get this thread hijacked by the Rules Patrol that seems to hit everythread on this forum. Thanks for the tip though, I wasn't sure how the metal would react to welding it. Why is that there anyways?

Joe Harlan
04-20-2005, 04:01 PM
If you tig it use a silicon bronze filler so you minimze the heat. I believe it is there because it fits a differt application also that uses that hole. I am not sure how I feel about modifying the stock part. I think I would get a new one and stake it in as an acceptable repair method. Or better yet cause hardware is free what about tapping it and puttind a pipe plug in there? I will ook at one and see if that would work.

its66
04-20-2005, 04:34 PM
If they are like the ones on the 12 valve engines, tapping will work just fine. http://ITForum.ImprovedTouring.com/smile.gif