Low Resolution Pulse Failure?? 95 Caprice LT1

[TheRealPistolP]

I got a code for low resolution pulse failure and secondary air injection pump malfunction. The injection pump is bypassed on my car so I canceled that out. But my car has a slow start up and recently it has struggled to get out of 1st gear before cutting off completely. The inside lights and power locks also seem to work sometimes. What is wrong with my car? Could it be a short? Can you explain what low res. pulse failure is? Im stuck.

[j cAT]

Originally Posted by TheRealPistolP

I got a code for low resolution pulse failure and secondary air injection pump malfunction. The injection pump is bypassed on my car so I canceled that out. But my car has a slow start up and recently it has struggled to get out of 1st gear before cutting off completely. The inside lights and power locks also seem to work sometimes. What is wrong with my car? Could it be a short? Can you explain what low res. pulse failure is? Im stuck.

post the code not the definition of what is some explaination of the DTC failure. I have good knowledge of on these air pumps and the failure components... I believe bypassing this air pump on the 1995 model is a violation of the clean air act ..1996 vehicles could have this bypassed but there is a proceedure to have this done correctly..

check the fuel pressure should be around 45-48 psi..check for vacuum leaks PCV /hoses etc...check that NO exhaust gases got to the MAF because of the air pump/check valve failures.

pull the codes first post results..

dont worry about the doorlocks/interior lights now..

[TheRealPistolP]

Originally Posted by j cAT

post the code not the definition of what is some explaination of the DTC failure. I have good knowledge of on these air pumps and the failure components... I believe bypassing this air pump on the 1995 model is a violation of the clean air act ..1996 vehicles could have this bypassed but there is a proceedure to have this done correctly..

check the fuel pressure should be around 45-48 psi..check for vacuum leaks PCV /hoses etc...check that NO exhaust gases got to the MAF because of the air pump/check valve failures.

pull the codes first post results..

dont worry about the doorlocks/interior lights now..

The code number was 16-low resolution pulse circuit failure. The other code that came up was for the secondary air injection pump malfunction but I couldnt get the number. But like I stated in my 1st post it is bypassed. Could that be the problem? And can you explain what low resolution pulse circuit failure?

[j cAT]

Originally Posted by TheRealPistolP

The code number was 16-low resolution pulse circuit failure. The other code that came up was for the secondary air injection pump malfunction but I couldnt get the number. But like I stated in my 1st post it is bypassed. Could that be the problem? And can you explain what low resolution pulse circuit failure?

the pcm/computer must receive from the crankshaft sensor pulses.with this code it is not getting this input.. check the connector/wiring if good replace the crankshaft sensor..

with other causes this could also be connectors/wires at the computer/pcm location..

[Blue Bowtie]

To elaborate on the Cat's response, from memory, the crank sensor in this case is the low-res signal line from the Opti-Spark unit. Only the '96 had a separate CKP in the timing cover.

Since the electrical problems are apparently involving several systems and not just the engine management, you might want to inspect the connectors and grounds. One very important connector is the main power node in the UEC, where the battery cable connects to the electrical center. The OEM studs were cast zinc (die cast) and subject to erosion and failure, causing all sorts of electrical problems.

[j cAT]

Originally Posted by Blue Bowtie

To elaborate on the Cat's response, from memory, the crank sensor in this case is the low-res signal line from the Opti-Spark unit. Only the '96 had a separate CKP in the timing cover.

Since the electrical problems are apparently involving several systems and not just the engine management, you might want to inspect the connectors and grounds. One very important connector is the main power node in the UEC, where the battery cable connects to the electrical center. The OEM studs were cast zinc (die cast) and subject to erosion and failure, causing all sorts of electrical problems.

I should have mentioned the underhood fuse box 12volt power connection from the battery as a place to check for a corroded/heat damaged connection.. that could upset the signal to the distributor or pcm ..

[TheRealPistolP]

Originally Posted by Blue Bowtie

To elaborate on the Cat's response, from memory, the crank sensor in this case is the low-res signal line from the Opti-Spark unit. Only the '96 had a separate CKP in the timing cover.

Since the electrical problems are apparently involving several systems and not just the engine management, you might want to inspect the connectors and grounds. One very important connector is the main power node in the UEC, where the battery cable connects to the electrical center. The OEM studs were cast zinc (die cast) and subject to erosion and failure, causing all sorts of electrical problems.

Prior to the current problems the car wouldn't turn over sometimes. It would crank but not start. I would unscrew the positive line to the battery and tighten it back it and the car would start right up. Hopefully I can change the wires and be good to go. But thanks for the input.

[TheRealPistolP]

Originally Posted by Blue Bowtie

To elaborate on the Cat's response, from memory, the crank sensor in this case is the low-res signal line from the Opti-Spark unit. Only the '96 had a separate CKP in the timing cover.

Since the electrical problems are apparently involving several systems and not just the engine management, you might want to inspect the connectors and grounds. One very important connector is the main power node in the UEC, where the battery cable connects to the electrical center. The OEM studs were cast zinc (die cast) and subject to erosion and failure, causing all sorts of electrical problems.

Originally Posted by j cAT

I should have mentioned the underhood fuse box 12volt power connection from the battery as a place to check for a corroded/heat damaged connection.. that could upset the signal to the distributor or pcm ..

Its all starting to make sense. Im not good fixing cars. I have a cousin who is, who hasnt had the time. Trying to get my car to the shop without paying a tow truck so thanks for the input.

[j cAT]

Originally Posted by TheRealPistolP

Its all starting to make sense. Im not good fixing cars. I have a cousin who is, who hasnt had the time. Trying to get my car to the shop without paying a tow truck so thanks for the input.

If it cranks good but no cold start this is usually the fuel system. so check the fuel pressure with a pressure guage, then go thru the other items for testing. dtc 16 is a pcm input signal failure. cranksensor and all the wiring with this circuit.

[j cAT]

Originally Posted by TheRealPistolP

Its all starting to make sense. Im not good fixing cars. I have a cousin who is, who hasnt had the time. Trying to get my car to the shop without paying a tow truck so thanks for the input.

another item which hopefully for you is not the case of this. the internal opti-distributor ignition module may be fried. this occurs when water/coolant enters the distributor then the voltage starts flashing over all the internal parts. cap/rotor/opticalsensor and the electronic module.

you get the engine wet lately ? check the water pump weep hole for coolant leak. this drips into/on the distributor.

[TheRealPistolP]

the shop told me its a burned out wiring harness....gonna switch to test but thats the verdict as of now...will keep you up to date and thanks again for the help!!

[j cAT]

Originally Posted by TheRealPistolP

the shop told me its a burned out wiring harness....gonna switch to test but thats the verdict as of now...will keep you up to date and thanks again for the help!!

the wiring harness/connector that is on top of the intake manifold that feeds the opti distributor with power etc has been know to failure.. I have never seen this but it has been found by others..this is a good possibility...

[TheRealPistolP]

yes!! my beast is back. they replaced the wiring harness and he riding solid as ever. feeling real husky right now. thanks again for all the help. hopefully we stay that way. Caprice for life!

[j cAT]

Originally Posted by TheRealPistolP

yes!! my beast is back. they replaced the wiring harness and he riding solid as ever. feeling real husky right now. thanks again for all the help. hopefully we stay that way. Caprice for life!

thanks for the reply ..

can you give details on how/why this failed ?

good luck..