ifixcars1

ok now this is strange. my LS idles perfect. It accels smooth. at mid rpm, possibly around 2500 rpm, not sure cuz the tach is broken, it cuts out like the spark just shut down, then comes back causing a tremendous surge. prior to the occurrence the engine was running normally and my woman was driving it daily with no concerns. since it started acting up, i have replaced the following.
Fuel Pump- wife said car runs like fuel pump is going out so to shut...er I mean to satisfy her diagnosis, I installed a new one.
tp sensor- code 41 - car runs better, still jerks.
water pump- actually found broken bolt in pump causing coolant loss
thermostat- just seemed like a good idea at the time
cam sensors- code 13, since water pump. I installed used sensors and harness but car runs better, problem still there.
cleaned grounds on left and right fenders- no affect
cleaned maf- runs worse, $160.00 at junkyard, car runs better still. problem still there.
Cams are in sync with crank and each other. coolant is full.
put 4 gallons of gas in yesterday.
any help would be greatly appreciated.

ifixcars1

oh and code 13 did not go away but cel went off

deanshark

Did you clear the code, by pulling the fuse or battery cable for 30 seconds, after you changed the cam sensors? Code 13 could also be the crankshaft sensor or ECU. Did you check the resistence on the used cam sensors you put in? I first thought it was your timing was off but then was thinking the crank sensor.
The resistence for the crank and cam sensors is;
Cold 835-1400
Hot 1060-1645

I can see your point on changing the fuel pump. Ya gotta keep them women happy and do what they say even when you know they are wrong or.... ya don't get any.

LEXTEK1

Karmen Vortex AFS. Dont clean it! It wont like it....
Code 13: Make sure the cam sensor(CMP) G2 or Bank2 wires are not damaged and/or rubbing the T or D belt's.
Even 1 Tooth off on T belt timing =code 13 but not your jerk!
Make sure NE wires(CKP) are not damaged or the connectors have broken.
TPS code 41: If comes back, check caps in ECU
Check caps in ECU anyway!
Check the caps in the ECU, sorry can't say that one enough. You are in TX and the heat kills 'em.

These are classic signs of the 93 ECU when caps are failing......Not always the problem but more often than not.

This is a description from TMC on code 13:
Circuit Description
Camshaft position sensors (G1 and G2 signals) and crankshaft position sensor (NE signal) consist of a signal plate and a pick up coil.

The G1, G2 signal plates have one tooth each on its outer circumference and are mounted on the left and right bank camshafts.

When the camshafts rotate, the protrusion on the signal plate and the air gap on the pick up coil change, causing fluctuations in the magnetic field and generating an electromotive force in the pick up coil.

The NE signal plate has 12 teeth and is mounted on the crankshaft. The NE signal sensor generates 12 NE signals per engine revolution. The engine control module detects the standard crankshaft angle based on the G1, G2 signals, and the actual crankshaft angle and the engine speed by the NE signals.

Info on code 41:
Circuit Description
The throttle position sensor is mounted in the throttle body and detects the throttle valve opening angle. When the throttle valve is fully closed, the IDL contacts in the throttle position sensor are on, so the voltage at the terminal IDL of the engine control module become 0 V. At this time, a voltage of approximately 0.7 V is applied to the terminal VTA of the engine control module. When the throttle valve is opened, the IDL contacts go off and thus the power source voltage of approximately 12 V in the engine control module is applied to the terminal IDL of the engine control module. The voltage applied to the terminal VTA of the engine control module increases in proportion to the opening angle of the throttle valve and becomes approximately 3.2 - 4.9 V when the throttle valve is fully opened. The engine control module judges the vehicle driving conditions from these signals input from the terminals VTA and IDL, and uses them as one of the conditions for deciding the air-fuel ratio correction, power increase correction and fuel-cut control etc. The sub-throttle position sensor is built and operates in the same way as the main throttle position sensor. This sensor is used for traction control. The sub-throttle valve is opened and closed by the sub-throttle actuator according to signals from the TRAC electronic control unit to control the engine output.

HINT:

Diagnostic trouble code 41 is for the throttle position sensor circuit. Diagnostic trouble code 47 is for the sub-throttle position sensor circuit.
When the connector for the (sub-) throttle position sensor is disconnected, diagnostic trouble code 41 or 47 is not displayed. Diagnostic trouble code 41 or 47 is displayed only when there is an open or short in the VTA signal circuit of the (sub-) or main throttle position sensor.
Signals from the (sub-) throttle position sensor are also input to the TRAC electronic control unit, So when a malfunction occurs on the TRAC side, code 41 or 47 may be displayed.

The code 41 is a circuit failure on the TPS.

Check the caps in the ECU!

ifixcars1

I am also thinking crankshaft sensor. when i changed the water pump, the coolant was dripping on the sensor. at that time I cleaned the connector and tightened the pins. It cleared up but the cel was on. thats when i installed the cam sensors and wire harness. problem came back and is getting worse. i have since recleaned the ckp sensor and successfully turned off the cel. but the jerk is still there

ifixcars1

Thanks Don, thats a lot of good information. And I understand about the caps. Have you ever seen a ckp fail at 2500+ rpm but operate normal at lower rpm?
Thanks again.
Tom ***
Ford Senior Master Tech

LEXTEK1

I personally have never seen a hard failure of that sensor. I have seen plenty damaged and with corrosion in the connector. Check your continuity from the CKP and CMP back to the ECU. Do the wiggle on the harness across the engine while you listen to your DMM scream at ya. New connectors are available and you should consider them. The coil connectors are the worst about breaking. PM me if you need pinouts on the harness. The G sensors or CMP sensor wires are bad about getting in the way of the belts. It rubs the shielding wire and can cause havoc with static from the belt arcing across or downright cutting through the wires.

To me, and I'm not there with you to see, the TPS circuit in the ECU has had the cap go bad. When at idle the cap can still deal with the low voltages. When you tip in, it can no longer handle the increase in voltage and the circuit begins to fail. 2500 RPM may be the common point of collapse right now.

Cap problem on the CKP circuit in the ECU can cause similar issues.

ifixcars1

I probably won't have time to work on it again until monday but i will let you know what i find

sam12345

iTrader: (1)

Hey not everybody who drives a 93 LS400 are jerks

ifixcars1

Endeavor to persevere sam. You too will achieve jerkness.

sam12345

iTrader: (1)

You've got to laugh once in a while

deanshark

I was thinking that also, sometimes we are. But sooner or later all our 93s end up with the jerk, it's inevitable. Man, all you guys from Texas. I feel bad for you all with that crazy heat you've been having this year, and it seems like it aint gonna stop. It's like our 5 feet of snow we had last winter.
With that heat in mind, like LEXTEK1 said, Check the caps in the ECU, sorry can't say that one enough.

sam12345

iTrader: (1)

I live in west texas so its normal over here.

FrankReynoldsCPA

Yeah, it's those of us with the 92's that you have to watch out for.

fluxedup

Wow, this sounds just like my '94. If heat causes this I am in the place for it. Summers here in Phx it rarely dips under 100, couple or three months at 110 +. We have a problem with drivers with road rage and its worse in the summer......now we got crazy drivers and crazy cars? LOL