LX9 starts, runs 10 seconds, dies. Codes 22 & 43

[jmgtp]

I hate to double post stuff since I asked about this in my swap thread but I know it will see more attention here. As some of you may know I've been suffering some bad back probs but I managed to finish up the exhaust system on my LX9 swapped Grand Prix last night and what do you do when you finish exhaust - you start it!

This is an OBD I car, 5 speed, and currently still has the tune for a 3.4 dohc - but that said it should still be able to run.

Here is the current state of things:
-All sensors are hooked up, except the o2 sensor which shouldn't matter since it is in open loop anyway
-there is no water in the engine
-when started it has good oil pressure (~60psi on dash gauge)

This is what it does when started:
-idles at 2500 rpm for about 10 seconds
-idle drops to 2000 rpm and the engine dies within 2 seconds of that, sounds like as if you just turned the fuel pump off (slowly kinda snuffs out)

Here is what I know is wrong:
-Code 22, TPS error. Not sure if this would cause the motor to die though. If I give it any throttle it dies instantly so I know the TPS wiring is bad or sensor not working
-Code 43, ESC error. I'm not sure what is causing it. The knock sensor is hooked up. What else can cause a problem with the ICM or the ECMs ability to take over spark timing?

The TPS issue I am confident I can fix, its 3 wires and I can figure out if the wiring is bad pretty easy with an ohm meter and tracing from the tps connector back to the ecm. But code 43, that one is more tricky. What is the typical cause? I'm using the same ICM that was on the old motor and it worked fine there. The knock sensor is hooked up but I'll check the wiring on it to make sure it is not shorting to ground.

Now about the motor shutting down after 10 seconds...
At first I thought the fuel pump was shutting off after a few seconds and that was what caused the motor to die. I believe there is a safeguard in place that kills power to the fuel pump relay if there is no oil pressure. The dash gauge shows good oil pressure (60psi) so I know the engine is OK but maybe that signal was not making it to the fuel pump relay. So to test my theory I jumpered the fuel pump test lead to make the pump run continuously and the motor still died after 10 seconds - that eliminates fuel pump.

Other concerns - why is it idling so high? I checked and checked and I don't think I have any vacuum leak. I did an IAC reset (well the key on/off method) but the ECM is still tuned for the DOHC so the counts might be WAY off for an LX9. I'll reset through freescan too just to be sure next time. The throttleblade is closing correctly. My one theory is that since there is no coolant in the motor the coolant temp sensor may think that the engine temp is freezing and that is why it tries to idle so high. I also used the factory LX9 temp sensor since it has the same connector but I think I may have read somewhere that this sensor isn't the same as the OBD I sensor - any fact/fiction to that?

First on the agenda for tomorrow when I work on it will be to correct the TPS problem, then burn the LX9 bin that I have to the memcal. Then I need to get to the bottom of code 43. But, despite codes 22 and 43, the motor still has spark (it runs), compression, and a constant supply of fuel - why does it die out after 10 seconds has me stumped. I'll see if I can datalog it through tunerpro to get a better scope of things but I have a new laptop now and I dont know where the definition files are.

Its slowly coming together. Despite its issues the LX9, while running, is so smooth and quiet. I can't wait to get it running perfect. I know I am very long winded! Thanks for taking the time to read.

[Joseph Upson]

Do you have datalog capability? and yes an improper TPS signal can make the engine run terrible if it doesn't corraspond with the throttle position, learned that after getting water in one, it should also have the ability to affect your ignition advance depending on the code used. You have to clear the codes to get off to a good start in the right direction. The high idle may be a direct result of the TPS code if you are not able to find a vacuum leak to account for it, another symptom I encountered with the wet TPS sensor. Make sure your PCV system is in proper order also.

[jmgtp]

Agreed, first thing is to correct the TPS problem. Then figure out the cause of code 43 which I think will be more difficult to find the issue. It could possibly be the KS picking up a ton of detonation since the tune is all wrong for this motor.

The LX9 PCV is an odd one. There is no valve to speak of, full engine vacuum on the front valve cover and the rear cover is the atmospheric or, fresh air, side. So I guess in theory even a loose oil fill cap would create a massive vacuum leak! If I had a vacuum leak that big I would think that I'd get a MAP sensor error code. I think I'll disconnect all the vacuum lines and plug them as a test, just to be sure I don't have a vacuum line disconnected somewhere causing the issue.

It looks like right now I have no TPS signal so the ecm may be going into some kind of limp home mode that raises the idle speed enough so the car can move but you can still fight it with the brakes - so thats another possibility for the high idle.

But you are right... need to fix what I know is not working first. Then I'll have to datalog it if it still doesnt run continuously. I guess what is really bugging me is that I don't understand why it runs 10 seconds then its as if someone turned the ignition off. It just seems like the code 22/43 issues wouldnt cause it to die after 10 seconds and something else is doing it.

[Jonpro03]

I know you were trying to find the tach signal. There are two white lines running to the ICM. One is tach, the other is the EST which the ecm uses to change spark timing. Make sure that both wires are wired correctly.

[jmgtp]

Fixed the TPS and now it runs without stalling though even after a computer reset I still get code 22.

Also battling codes, 15, 34 and 43. Ugh.

43 I haven't looked at yet. 34 is MAP and I don't know why it is on. Engine runs/revs fine so I'm not sure what went wrong. I checked each wire from the MAP connector to the ecm with an ohm meter and everything looks good.

I'm pretty sure code 15 is the coolant temp sensor. I used the LX9 sensor since the connector is the same but now I'm thinking that the values it outputs (resistance) is not the same as the older style sensors and that is why I have the code. Problem is that the old sensor is way too big to thread into the LX9 cylinder head. What do I do?

Original on left, LX9 sensor on right

[CNCguy]

Both sensors should have the same resistance.

[jmgtp]

That would be excellent news, in which case hopefully the code was just set because the sensor was not in water when I ran it for short bursts. I've since filled with water but still have to add some and bleed it.

The only thing that discourages me about the CTS, is that after doing a few searches I've read some posts about people drilling/tapping the LX9 lower intake to accommodate the older style sensor. I obviously don't want to have to do that considering it is in the car.

[bob442]

wow, we got into the 10's LMAO

[mickaz]

you could use an adapter to fit the CTS in the head. Thats what im running and I have no problem. I don"t remeber the PN but its in the 3500 swap thread ( sticky). And if you run the sensor not in coolant it will almost automatically go to -49 degree and shoot a shitload of gas in your car. if you O2 is old it will stall and you will plug your cat.

try changing the sensors too ( go get ome in a junkyard) sometime your sensor will not be working properly. I always have two of the sensor just to rule out the senor out of the prob.

another little place to check: if your engine throttle is closed and it revs to 2500rpm have you check for MAJOR vaccum leaks? Like the brake booster, the throttle body gasket, the EGR the UIMG, the upper Pcv valve tubing, the side port of the lx9 manifold and the Map sensor hole. if it stills idle to 2500 then it is a sensor or a tuning problem.

[jmgtp]

Well, the engine is running at the correct speed now for the coolant temp, about 1500 rpm, but its running horribly. Feels like its running on 4 cylinders, shakes, lopes and the exhaust stinks. Its also harder to start now.

The LX9 coolant temp sensor is working now, I had a bad ground in the harness before. Now that I've repaired the ground, TunerProRT showed it at 60*F before the motor ran, which is right inline with the temp in my garage and I no longer have code 15, so safe to say the CTS is not the issue.

I also corrected a bad 5v reference in the MAP sensor harness and that eliminated code 34.

The o2 sensor is threaded into the manifold but not hooked up. It would be impossible for that to be the issue though because there is no way I have run it long enough to get into closed loop.

The only code that keeps tripping is 43 which is the knock sensor. I've heard the KS/memcal filter thing before, but this is the same memcal that was used on the old motor and the same knock sensor. I burned a new bin to the memcal for the 3500 but it actually ran worse than the 3.4 dohc code so I put that back on there for now. The wire for the KS ohms out ok, and doesn't seem to short to ground but I might run a new wire from the ecm to the KS just to be certain. I'm not sure what else could set a 43, but with the engine running so violently I'm sure it is detecting an absurd amount of knock and potentially that is tripping the code 43.

So, I'm kinda stuck thinking I have an ignition problem because that's what it feels like. It just runs like crap, as if it had crossed ignition wires or was only firing on 4 cylinders.

Funny thing is that before I corrected all the codes the engine would run 10 seconds and die, but it would run smooth like it was hitting on all cylinders, granted at 2500 rpm and if I touched the throttle it would die instantly.

[CNCguy]

John,
You may want to verify that the body of the KS properly grounded to the block. I have heard of problems from excess teflon tape , rust, thread sealer etc.

[jmgtp]

Marc,

Excellent thought, hadn't even crossed my mind! I will use an ohm meter to check the resistance between the body of the KS and a good ground. I imagine it should be very low resistance. I believe the LX9 had a plug where I installed the KS and it is very possible that there is corrossion or dried up thread sealer preventing a good ground.

If all else fails, can I use a resistor to ground the knock sensor wire and bypass the sensor all together just as a test to see if my problem is the sensor/ground vs bad wiring?
I know I should not run it like this because it would eliminate the KS.

[bszopi]

Could it just be where you installed the KS? You said you installed it where there was a plug. Why didn't you install it where the stock is? Is there a difference in thread type between the 2 engines which would not allow this?

Droid via Tapatalk

[jmgtp]

The LX9 knock sensors are completly different. The sensors don't even thread into the block, they are bolted on to a flat machined surface.

There was a plug in the block (water jacket) next to the stock LX9 crank sensor. I took the plug out and threaded the KS in there. The stock knock sensors were mounted much higher, closer to the heads. I suppose if the bolt hole is the same thread size as the knock sensor I could put the KS there and reinstall the plug where in the hole where I have it now. The stock LX9 spot for the KS doesn't go into a water passage, does that matter? I think not. Would it be better to do that? I know at least the threads in that spot are clean because they had a bolt in them their hole life and no water.

[Joseph Upson]

The LX9 knock sensors are completly different. The sensors don't even thread into the block, they are bolted on to a flat machined surface.

There was a plug in the block (water jacket) next to the stock LX9 crank sensor. I took the plug out and threaded the KS in there. The stock knock sensors were mounted much higher, closer to the heads. I suppose if the bolt hole is the same thread size as the knock sensor I could put the KS there and reinstall the plug where in the hole where I have it now. The stock LX9 spot for the KS doesn't go into a water passage, does that matter? I think not. Would it be better to do that? I know at least the threads in that spot are clean because they had a bolt in them their hole life and no water.

This is a good subject although I'm not sure the knock sensor's ability to pick up a knock signal will be affected I would like to move mine up closer to the cylinder head just in case. My sensor is located in the coolant drain outlet also but still indicates detonation when it occurs.

I drilled and tapped the cylinder head to accept the 3 wire temp sensor, I don't see it being a problem doing a tap and die job on the stock knock sensor mount to accomodate the early style sensor. Although the OE sensor is different by design if it still sends the same type of signal within the frequency range it would certainly be worth the effort of wiring into place.