Current Voltage to Fuel Injectors

[3.8L Strong]

Can someone look at these voltage readings to my fuel injectors and tell me what you think? The engine is a 3.8 V6 from a 98 Camaro.

While cranking over the engine:

These are the highest readings from the voltmeter. The voltage was fluctuating up and down.
Current Battery voltage at 12.20 volts
# 1 injector 5.80 volts
# 2 injector 5.19 volts
# 3 injector 4.70 volts
# 4 injector 5.50 volts
# 5 injector 5.72 volts
# 6 injector 4.45 volts

With key on, no cranking of the engine:

These are the highest readings from the voltmeter.
Current Battery voltage at 12.0 volts
# 1 injector 6.22 volts
# 2 injector 6.20 volts
# 3 injector 8.95 volts
# 4 injector 6.22 volts
# 5 injector 7.75 volts
# 6 injector 6.23 volts

Would this indicate possible problems with the PCM? I have checked out each wire from the wire connectors back to the PCM. They all ring out OK. I have read that the voltage to the injectors should not drop more than .2 volts or (2/10ths) volts lower than the Battery voltage. In this case, every reading is far below the required voltage value. What is your opinion? Let me know. Thank you, Tommy.

[slow6]

Re: Current Voltage to Fuel Injectors

Are you having problems? Got a dtc code? SES light?

You should check the resistance of the wires and injectors!
Hows Hawaii weather?

[3.8L Strong]

Re: Current Voltage to Fuel Injectors

Yes, I'm getting a P0300B code setting with the mil light blinking. What kind of resistance should I be looking for? The injectors are brand new. I tested them out with battery voltage before I installed them. The weather here in Hawaii is awesome! I really feel sorry for those who are living in those area's where it is snowing really bad. Thank you for your support, Tommy.

[smithtim]

Re: Current Voltage to Fuel Injectors

Yes, I'm getting a P0300B code setting with the mil light blinking. What kind of resistance should I be looking for? The injectors are brand new. I tested them out with battery voltage before I installed them. The weather here in Hawaii is awesome! I really feel sorry for those who are living in those area's where it is snowing really bad. Thank you for your support, Tommy.

anybody know what the b is for in P0300B?? as I know that if it is just P0300 then it is a random misfire or if it is P030# then it is a misfire specific to cylinder # .... and the flashing means catlyst damging

are you sure that the misfire is due to the injectors? you said that they are brand new injectors.. did the car have a misfire beofre you put in the new injectors? if it did it before then I would start looking at other stuff (plugs, wires, compression etc.,) or if it did not do it before then most likely just a bad injector and I would be taking them back to the parts house

not sure of the exact details of what voltage you need but should be listed in CHiltons or whatever.. also this link looked like it had some info about the 3.8

http://www.lindertech.com/fuelguru.htm

and I have found tons of usefull info from

http://shbox.com/1/how_tos.html

but keep in mind the shbox link is designed for the LT1 V8 firebird so not all specs are the same but still is very usefull

[3.8L Strong]

Re: Current Voltage to Fuel Injectors

anybody know what the b is for in P0300B?? as I know that if it is just P0300 then it is a random misfire or if it is P030# then it is a misfire specific to cylinder # .... and the flashing means catlyst damging

are you sure that the misfire is due to the injectors? you said that they are brand new injectors.. did the car have a misfire beofre you put in the new injectors? if it did it before then I would start looking at other stuff (plugs, wires, compression etc.,) or if it did not do it before then most likely just a bad injector and I would be taking them back to the parts house

not sure of the exact details of what voltage you need but should be listed in CHiltons or whatever.. also this link looked like it had some info about the 3.8

http://www.lindertech.com/fuelguru.htm

and I have found tons of usefull info from

http://shbox.com/1/how_tos.html

but keep in mind the shbox link is designed for the LT1 V8 firebird so not all specs are the same but still is very usefull

I'm not sure if the injectors are causing the misfires. The injectors are brand new. What I'm trying to find out is what is the voltage suppose to be at each injector wire connecter with the engine cranking over, or with the key on and engine off? This is a new engine installation. I have installed a 3.8 V-6 from a 98 Camaro into my 2002 PT Cruiser. The engine harness was fabricated specifically for my application. The plugs are new, the plug wires are new, the coil packs are new, the ignition control module is new, the 02 sensors are new, the crankshaft sensor and camshaft sensors are new, the throttle body and all the sensors on it are new. I was just told by someone that I should see at least 10 volts at each injector. The question is, why is the voltage so low? Thank you for your support, Tommy.

[slow6]

Re: Current Voltage to Fuel Injectors

I dont think the voltage has to be a specific value with the key in the run position (engine off). I just found out that pulsewidth with the key in the run position (engine off) doesnt matter.
The ECM has to be given information for it to calculate load, and with more load it will generate more volts for the injectors.

You could try checking their volts with the engine running, but that probably wont tell you much.

PLEASE correct me if I'm wrong! Hope an ASE certified Guru will chime in here!! :)
Sorry I cant help more

[3.8L Strong]

Re: Current Voltage to Fuel Injectors

OK, I just took another reading. This time I went straight to the negative side of the battery terminal for the ground source. Here is what I got:

Current battery voltage: 12.05 volts
With the key on and engine off:

# 1 injector - 11.67 volts
# 2 injector - 11.69 volts
# 3 injector - 11.68 volts
# 4 injector - 11.69 volts
# 5 injector - 11.69 volts
# 6 injector - 11.69 volts

So, what does this suggest? Does it look like I have a ground problem somewhere? How can I resolve this problem? Can I run another ground wire somewhere? Or could it be the PCM. Thank you, Tommy.

[iGoRa]

Re: Current Voltage to Fuel Injectors

this looks good, as far as I know they are ~12v pulses , so its hard to read with regular voltmeter.

You gonna rock in your PT.
RWD?

[smithtim]

Re: Current Voltage to Fuel Injectors

OK, I just took another reading. This time I went straight to the negative side of the battery terminal for the ground source.

Current battery voltage: 12.05 volts
With the key on and engine off:

# 6 injector - 11.69 volts

So, what does this suggest? Does it look like I have a ground problem somewhere.

this readings look Ok as you expect a little voltage drop.. not an expert with this but I would expect that the wiring is OK... easy way to check it is to visually inspect everything for any damage that may have been caused during the installation as if everything was fine before why should it be any diffrent now ( I am assuming here that you pulled eveything from the camero and just kept as is... if you mixed and matched parts then it might well be a compatiability issue??)

sorry I couldn't be of more help


p.s. I just reread this and you said these readings are with the voltmeter reading ground directly to the battery and the eariler readings were with voltmter reading ground to the injector.. so there is something going on there but from your later post I think that has been already sorted out

[3.8L Strong]

Re: Current Voltage to Fuel Injectors

this readings look Ok as you expect a little voltage drop.. not an expert with this but I would expect that the wiring is OK... easy way to check it is to visually inspect everything for any damage that may have been caused during the installation as if everything was fine before why should it be any diffrent now ( I am assuming here that you pulled eveything from the camero and just kept as is... if you mixed and matched parts then it might well be a compatiability issue??)

sorry I couldn't be of more help

Actually, the parts are from various Camaro's. The PCM is used from one Camaro. The engine harness is from another Camaro and so on. I sent the Camaro computer and engine harness as well as the Chrysler computer and engine harness to a fuel injection company. They
re-programmed the two computers and then fabricated one engine harness from the two engine harnesses I sent to them. So, now I have one modified engine harness which I have one GM computer and one Chrysler computer plugged into. Alot of thought went into the concept to make it work. There were a few wires that were crossed which I corrected. My thought is because I'm using a used GM computer, it may have already been damaged when I purchased it from a seller on Ebay. Unfortunately there is no why to find out if there is a short somewhere within the computer. At least I don't know of a way. Does anyone know of a way to check for a short in the computer? Thank you for your support.

[smithtim]

Re: Current Voltage to Fuel Injectors

Actually, the parts are from various Camaro's. The PCM is used from one Camaro. The engine harness is from another Camaro and so on. I sent the Camaro computer and engine harness as well as the Chrysler computer and engine harness to a fuel injection company. They
re-programmed the two computers and then fabricated one engine harness from the two engine harnesses I sent to them. So, now I have one modified engine harness which I have one GM computer and one Chrysler computer plugged into. Alot of thought went into the concept to make it work. There were a few wires that were crossed which I corrected. My thought is because I'm using a used GM computer, it may have already been damaged when I purchased it from a seller on Ebay. Unfortunately there is no why to find out if there is a short somewhere within the computer. At least I don't know of a way. Does anyone know of a way to check for a short in the computer? Thank you for your support.

other than testing a wire from the computer to the injector for continiiuty (which I think you said you already did) I can't think of a way to actaully test the computer itself ... but if you had professionals do the programing etc., I would see if they put any kind of warnatty on it or if they know of a way to check that it is out for you.. alot of the time if they have already done work for you they will do stuff like that for free to keep a good name...

sounds like a neat project and will rock when it is done

good luck

[3.8L Strong]

Re: Current Voltage to Fuel Injectors

Yes, I sent the PCM back to them to have it checked out. They reprogrammed it and sent it back to me. I'm getting the same response. They said they had no way to test for shorts in the PCM. I may have to purchase a new PCM and have it programmed for my application. Thanks for your support, Tommy.