S13 KA24DE Won't stay running, surges up and down when throttle is steady at 5%

[drifter92]

new thread made, issue is better now, but still hunting idle.

[drifter92]

anyone?......................

[OutlawLui]

Try running it with maf disconnected . See if it will idle smooth

If it's still the same

Try connecting the maf and disconnect the tps and try to see if idle is smooth

[EnnEssEnnKAT]

Sort of seems like the timing chain/cams/crank pulley timing is off. I chased down a similar problem after reassembling. Car will run and drive good with them out of sync I drove it for months before diving in further and set it a couple times before actually getting it to idle stock sounding and perfectly smooth. Hard to redo it and get it right after its all back together bc you can't see the crank gear.

Sent from mTalk

[drifter92]

Try running it with maf disconnected . See if it will idle smooth

If it's still the same

Try connecting the maf and disconnect the tps and try to see if idle is smooth

I have tried all the basic things and nothing makes it better, only worse.

Sort of seems like the timing chain/cams/crank pulley timing is off. I chased down a similar problem after reassembling. Car will run and drive good with them out of sync I drove it for months before diving in further and set it a couple times before actually getting it to idle stock sounding and perfectly smooth. Hard to redo it and get it right after its all back together bc you can't see the crank gear.

Sent from mTalk

I have photos taken during assembly that show the timing marks all lined up and correct so I am not taking it all apart again. I have assembled KAs many time and never made a mistake either

[EnnEssEnnKAT]

For your ignition timing, where does your distributor sit in terms of it's adjustment range? Is the top 10 mm bolt that is holding the distributor in right in the middle of the adjustment hole?

[drifter92]

For your ignition timing, where does your distributor sit in terms of it's adjustment range? Is the top 10 mm bolt that is holding the distributor in right in the middle of the adjustment hole?

Using a timing light eliminates the possibility of being "a tooth off"
I am so tired of hearing this, please if I am mistaken correct me, when you stab a distributor correctly, you remove the cap and make sure the rotor is pointed at spark plug wire #1 when the distributor is stabbed fully, and that the distributor is in the center of the adjustment range. I have done this 100 times and never had an issue. Then, later, I go back with a timing light when its running and move it to 20 BTDC and its always damn close before any movements.

What I am saying with this engine is I am using a timing light, and it wont run well at 20 BTDC because of a sensor or something pulling timing so when I move it to 20 BTDC with the engine warmed up it tries to die and then it wont start at 20 BTDC because of that issue. It will only start again if I move the distributor to the "wrong" location again, and no amount of sensor unplugging corrects the stumble problem.

When I hold throttle at 5%, the engine revs itself up and down like the video, and it seems like its breaking up and doing weird shit which causes the RPM drops, then whatever happened gets better and it revs up again.

[drifter92]

it runs awesome if you rev it and floor it or anything, but it wont stay running without throttle and wif you hold the throttle a little bit RPM jumps around and surges from 2K to shaking at 200RPM and back to 2K then back to shaking at 200RPM then 2K..... and so on, while you are still holding the throttle at a steady position, around 5-10% throttle.

[EnnEssEnnKAT]

Using a timing light eliminates the possibility of being "a tooth off"

I am so tired of hearing this, please if I am mistaken correct me, when you stab a distributor correctly, you remove the cap and make sure the rotor is pointed at spark plug wire #1 when the distributor is stabbed fully, and that the distributor is in the center of the adjustment range. I have done this 100 times and never had an issue. Then, later, I go back with a timing light when its running and move it to 20 BTDC and its always damn close before any movements.



What I am saying with this engine is I am using a timing light, and it wont run well at 20 BTDC because of a sensor or something pulling timing so when I move it to 20 BTDC with the engine warmed up it tries to die and then it wont start at 20 BTDC because of that issue. It will only start again if I move the distributor to the "wrong" location again, and no amount of sensor unplugging corrects the stumble problem.



When I hold throttle at 5%, the engine revs itself up and down like the video, and it seems like its breaking up and doing weird shit which causes the RPM drops, then whatever happened gets better and it revs up again.



Yeah sounds to me like if it won't run when it is showing 20* btdc then your mechanical timing is off.. Post those pics of your cam timing with all of the timing marks on the cams, idler, and crank pulley gears lined up with the timing chain colored links with cyl #1 @ tdc so we can take a look.

Sent from mTalk

[drifter92]

Yeah sounds to me like if it won't run when it is showing 20* btdc then your mechanical timing is off.. Post those pics of your cam timing with all of the timing marks on the cams, idler, and crank pulley gears lined up with the timing chain colored links with cyl #1 @ tdc so we can take a look.

Sent from mTalk

Intake cam is 248 exhaust cam set to 3 teeth CCW, so thats why there are 2 marks in green on the intake cam. Cam lobes face away from each other on cylinder #1 at TDC

6 links between cam chain timing marks also, which is correct

https://i.imgur.com/alIUNxG.jpg?1

https://i.imgur.com/ItEWSuF.jpg?1

[drifter92]

the breaking up thing is an intermittent issue, it runs good, then stumbles, then runs good, and oscillates between those 2 every 2-3 seconds and surges up and down. It is not a mechanical timing issue.

[EnnEssEnnKAT]

Intake cam is 248 exhaust cam set to 3 teeth CCW, so thats why there are 2 marks in green on the intake cam. Cam lobes face away from each other on cylinder #1 at TDC

6 links between cam chain timing marks also, which is correct

https://i.imgur.com/alIUNxG.jpg?1

https://i.imgur.com/ItEWSuF.jpg?1

Gotcha, yeah the only reason I am really beating this one is bc I had an issue with my timing and the car would not run with the distributor set at 20%, the car would just die once I adjusted to 20*. I am not familiar with the cam swaps but I've read a lot of good things about them. I run S13 cams in my s14 engine, and don't have any problems but did not clock the cam gears one way or another. It also seems like you've chased up a lot of the sensors and inputs to the ecu to see if any of them are causing the issue. Did you try running without the TPS plugged in, or without the MAF plugged in? I think the car will run with most everything unplugged except for the disti of course. If none of those are working, it could be a mechanical issue not necessarily timing but maybe a vac leak/cracked hose or a chipped valve. I had a chipped valve, literally a piece missing after one injector wasn't working and I ran the engine.

[drifter92]

Gotcha, yeah the only reason I am really beating this one is bc I had an issue with my timing and the car would not run with the distributor set at 20BTDC, the car would just die once I adjusted to 20*. I am not familiar with the cam swaps but I've read a lot of good things about them. I run S13 cams in my s14 engine, and don't have any problems but did not clock the cam gears one way or another. It also seems like you've chased up a lot of the sensors and inputs to the ecu to see if any of them are causing the issue. Did you try running without the TPS plugged in, or without the MAF plugged in? I think the car will run with most everything unplugged except for the disti of course. If none of those are working, it could be a mechanical issue not necessarily timing but maybe a vac leak/cracked hose or a chipped valve. I had a chipped valve, literally a piece missing after one injector wasn't working and I ran the engine.

Yes I tried without the TPS and MAF and a bunch of sensors in all different variations and nothing helps. It does not have any vacuum leaks, I tested it up to 9psi with no leaks at all, and very very little leakdown out of the crankcase.

[EnnEssEnnKAT]

Yes I tried without the TPS and MAF and a bunch of sensors in all different variations and nothing helps. It does not have any vacuum leaks, I tested it up to 9psi with no leaks at all, and very very little leakdown out of the crankcase.

I don't have a whole lot more ideas left, are your two belts connected? It certainly see a like you've checked just about every electrical component but any one of them could be intermittently failing and causing that sporadic issue. A real good way would be to get a consult diagnostics tool and check the sensor signals. Otherwise the huge amount of work you've done to check the electronics with no success might point towards a mechanical issue.

Sent from mTalk

[drifter92]

Ok I had a big breakthrough last night, the car will stay running on it's own now that I have an air filter in front of the MAF with at least the top half of the OEm airbox installed, I dont have an s13 lower airbox to use at the moment.

So now the issue is "hunting" for idle and the ignition timing not being happy at 20 BTDC, it runs best at 30 BTDC when warmed up to 167 degrees. I need to bleed the coolant system better, but I am definitely seeing a change in ignition timing as the coolant temp sensor warms up which is probably a good thing? idk

I am going to work on it more today