2003 RD688S no power on a hot day

[03' Big Red]

hey guys

i need some help here. i have a 2003 RD688S with the AI 350, i had a problem with poor throttle response and no power after 1800 RPM,

i had a local shop check fuel pres, it was low so they put a new pump on and they also adjusted the valves. the truck ran much better for a bit. the last couple of days though it's been a real dog, at 1800RPM it's flat..no power at all but after a storm rolled through today and cooled things off the truck run's 100% better, it would pull through 2100RPM. all the filters are new and the engine speed sensor has been replaced. it seems to me that there is bad sensor somewhere. the electronic malfunction light comes on very sporadically, maybe once a month, more or less. i haven't had the codes scannned thought. is there a way for me to scan the codes without a scanner ?

i now know that air tempature makes a huge difference on performance.

thanks for any input.

Edited July 27, 2012 by 03' Big Red

[mathura]

hey guys

i need some help here. i have a 2003 RD688S with the AI 350, i had a problem with poor throttle response and no power after 1800 RPM,

i had a local shop check fuel pres, it was low so they put a new pump on and they also adjusted the valves. the truck ran much better for a bit. the last couple of days though it's been a real dog, at 1800RPM it's flat..no power at all but after a storm rolled through today and cooled things off the truck run's 100% better, it would pull through 2100RPM. all the filters are new and the engine speed sensor has been replaced. it seems to me that there is bad sensor somewhere. the electronic malfunction light comes on very sporadically, maybe once a month, more or less. i haven't had the codes scannned thought. is there a way for me to scan the codes without a scanner ?

i now know that air tempature makes a huge difference on performance.

thanks for any input.

You could pull codes from diagnostic switch on dash board. If the dash is digital then there are two push switches at the side or you could use the cruise control set resuume switch to display the codes.

[03' Big Red]

i have read about using the cruise control switches, what is the process for that ?

[mathura]

i have read about using the cruise control switches, what is the process for that ?

Here is the procedure

BLINK CODE METHOD

The V-MAC III system is capable of flashing a

two digit blink code for each detectable active

fault in the V-MAC III system. These codes are

displayed on the Electronic Malfunction Lamp

(EML) which is located on the dashboard. The

primary reason for the blink code is to allow quick

diagnosis of active faults in the system without

requiring an expensive troubleshooting tool.

To properly activate and use the blink codes,

follow the steps listed below.

1. Turn the key ON and wait until the Electronic

Malfunction Lamp’s two second power-up

test is finished.

2. There must be an active fault for the lamp to

remain ON after the two second power-up

test.

3. With the Speed Control ON/OFF Switch in

the OFF position, press and hold the

SET/DECEL Switch until the malfunction

lamp goes OFF.

4. The malfunction lamp will remain OFF for

approximately one second.

5. Immediately after the wait time, the Vehicle

Electronic Control Unit (VECU) will begin to

flash a two digit blink code. The two digits of

the code will be separated by a one second

idle time (malfunction lamp OFF).

6. Each digit of the blink code may consist of

up to nine ON/OFF flashes. The ON and

OFF time between each flash will be one second.

7. The ON flashes of the malfunction lamp

must be counted in order to determine the

two digit blink code.

8. Only one active fault will be blinked per

request. There must be a separate request

for each active fault, where there are

multiple active faults present in the system.

To request another fault be displayed, hold in

the SET/DECEL Switch until the malfunction

lamp goes OFF. The blinking sequence will

begin again after a one second delay.

9. If a fault blinking request is made while the

Vehicle Electronic Control Unit (VECU) is in

the process of blinking an active fault, that

sequence will stop and the next active fault

will be blinked.

10. If an active fault is cleared while the Vehicle

Control Unit (VECU) is blinking that fault, the

procedure will not stop.

11. After every complete blinking sequence, the

malfunction lamp will return to normal. It will

remain ON for active faults and OFF for

inactive faults.

12. The Vehicle Electronic Control Unit (VECU)

will provide blink codes for active faults

registered by both the Vehicle Electronic

Control Unit (VECU) and Engine Electronic

Control Unit (EECU).