93 LTX misfire??

[silver94dtx]

I having some issues with my car when I step on the pedal
The RPM goes down and engine stalls and dies. So far I've
Installed new opti, new ICM, new spark plugs, new msd wires.
I've scanned and got these codes..
#16- low resolution pulse (5.7)
#22- TPS circuit (signal voltage low)
#42- ignition control circuit

Any help would be great!!

[popo8]

Are those codes new since this issue or had they come up before this was a problem.

askin cause at first thought it reminds me of how my car acted when the fp was dying.


Larry (Popo8) Co-owner
LTXtech.com

[silver94dtx]

These are new codes.

What's fp.?

[Fastbird]

See if you can get a real time scanner on it and see what your TPS is doing. If its not working it'll cause what you're describing.

Posted from my Rooted and ICS'd Rezound

[silver94dtx]

Thanks fastbird!!

[Injuneer]

You can test the TPS with a volt meter. First with the key on/engine off, verify that you have 5V between the gray wire and the black wire. Then check the voltage between the blue signal wire and the black wire. With throttle closed, voltage should be in the range of 0.30-0.90V. If the voltage is below 0.23V it will set DTC 22.

If you are in the acceptable range for closed throttle voltage, start to open the throttle slowly. Voltage should increase smoothly, with no spikes or dropouts. It will reach 4.0V higher than the closed throttle voltage at WOT.

DTC 16 is serious. It has to be stored if the engine is running, because if it's active, the ECM shuts down the fuel system. The code sets when the ECM can't find the low resolution pulse pattern from the cam position sensor in the Opti. It needs that info to time the spark. It can be an intermittent problem that causes the engine to stall, and I've seen it set at startup when the ECM take too long to identify the low res pulse signal. Check the harness connector at the Opti for bent or corroded pins.

DTC 42 is ugly. Short to ground in the white wire from the ECM to the ICM. I hate this one, because it's hard to track down. I can send you a .pdf file of the 93 shop manual diagnostic tree for this code.

"fp" = fuel pressure

[popo8]

....

"fp" = fuel pressure


Doh...thanku




Larry (Popo8) Co-owner
LTXtech.com

[silver94dtx]

Thanks for the info injuneer... That really helps alot!! Glad to be a part of the ltxtech family. Gonna start checking the TPS tomorrow after work.