2000rpm then stall I'm stumped

[Patarach]

Hi everybody i recently redid my intake manifold gaskets and some of the vacuum hoses on my 1993 Ka-t and I am having a problem.

At first my car would start up and idle super rich then continue to hunt at around 1800-2500 rpm when I unplugged the tps is would idle at about 800 rpm with a AFR of 11:1.

Now my car will start up, hit about 2500 rpm and then stall out; opening the throttle does not help its like its cutting fuel. Here is a list of related mods.

Safc neo
550cc injectors
e85
removed the iacv & aac ( I am controlling idle with the throttle body screw and my tps is adjusted to read .4volts closed)
removed butterflies ( I kept the solenoid valve plug connected )
LC-1

I searched for about the last week and have found a few people with the same problem but never a solution that works.
Here is the things i checked.

coolant temp sensor
maf is good
tps seems fine .4volts closed
no vac leaks found

I am suspicious of the safc and plan to test its connections and operations more in depth although it seems like it is doing what its supposed to do.

I also plan on checking the timing again although it was dead on when It last ran and I didnt mess with it.

If anyone else has experienced this problem or I did something incorrectly please chime in if you have anything to help me pinpoint my problem. thx

[compactfean]

What maf are you using and what are your input output settings? What voltage do you have at the maf and what maf voltage do you have at the ecu?

[Patarach]

n60, 4 in 5 out although ive ran a few combinations and it has not helped much. I'm going to check the ecu voltages tommorrow, mostly to make sure the safc is working correctly.

[compactfean]

Thats what I was thinking is the safc is putting out weird voltage to the ecu.

[Patarach]

Well I tested the safc and it seemed to be operating correctly to the correction I put into it.

I then realized that I tested pretty much every sensor except the knock sensor, and when I removed the intake manifold I replaced the one on my engine (that was working fine, but kinda melted) with a spare I had from my extra KA that was not melted.

So I tested the sensor by the procedure in the FSM and it was NG. I did not have a good one on hand so I dont know if it will fix all my problems but the knock sensor would cause the problems I am experiencing I just have never had one fail and the sensor is like $100 so I'm not too excited about replacing it. will post back

[compactfean]

Get a resister for the knock sensor for the time being till you finish diagnosing. But the knock sensor wouldn't do that. l know how they work but don't have much experience with them because I refuse to run one. So someone safc savvy chime in! What is maf voltage at the ecu....especially around 2k?

[Patarach]

Ya it did not fix the hunting / high idle issue; however is no longer runs super rich it is now fluctuating from 15:1 to full lean while hunting its obviously cutting fuel.

I decided I would close the throttle plate completely to see if it would change anything and it idles lower now 1500-2000rpm and when I d/c the TPS harness if drops idle down to about 800 and runs super rich 10.8:1.

My main problem here is I'm not very well educated on how part of the closed loop would cause this.

The maf read something like ~.58 volts into the safc and like ~.38 out @ approx while cranking all the way to the ecu. Last time I checked the correction was set at like -35 so that all adds up.

I did find a leak on my valve cover gasket that was shooting oil all over where I could not see I need to fix this first to go on with diag not to mention my blow by hose is connected behind my maf so there may be getting some air in there.

[compactfean]

That's how your catch. Can blow by hose is supposed to be. .37 volts is way too low. Closed loop reads all sensors. Open loop is like idle and wot and will not read o2 sensor. Closed loop and open loop both read tps,mafs, cts and I'm not sure if knock sensor reads in open or closed but does go to a second timing map if it detects knock...some say the second map in the ecu also has a different fuel map.

[compactfean]

Hey try 2in. 5out or 2in 6out

[Patarach]

.38 volts it 65% of .58 thats a 35% decrease, what I put into the safc.

I know how the closed loop system works I just dont know what part of ti would make it act this strange.

will mess with in/out when I get to work on it next.

[Patarach]

re-installed valve cover gasket, topped off coolant, found a vacuum leak on the injector seals (that I thought I fixed) and it now idles correctly it just still seems to be missing a little bit, I am going to do a power balance test again tomorrow, I could not really tell if it was missing due to lack of fuel or ignition because it seemed like my wideband would do one thing then the other. 4 in 5 out was the best idle also.

when I d/c the tps sensor it dies I am thinking this might be normal though I did not really have time to investigate.

[compactfean]

Sounds like your timing is off if it dies when d/c tps. Set tps voltage before setting timing.

[infinitedrift]

So you found out by fixing the knock sensor that it was not your problem..my knock sensor is complety disconnect because ot broke and im having your same idling issues but when i rev the car it dies.

Have you found a solution yet?

[Patarach]

TIming was off about 5 degrees so reset that it is running a little better now. Its good enough I feel confident enough to drive it a little bit (when I get my exhaust done)

The hunting I'm pretty sure was caused by the vac leak, I also have a feeling I had some air bubbles in the coolant. If I were you I would do the 1 mega ohm resister trick before you try to diag like the guy above said to me, or ebay KS are not bad from what I have heard just make sure you have the base plate grounded.

I also have no iacv or aac all that stuff has been eliminated so I didn't have to check that.