- This topic has 15 replies, 4 voices, and was last updated 7 years, 8 months ago by
.
-
Topic
-
-
Replies
-
Could a bad ignition switch keep power from getting to the fuel pump? I have no power to the fuel pump, but there is power going to the fuel gauge!
A bad ignition switch is a common cause of a non-running fuel pump, as also is a blown fuse or bad fuel pump relay. But before we go down that road, I would like to explore a different route first. It could be as simple as a blown fuse. Have you checked ALL of the fuses? The fuel pump and the engine computer share a fuse, ECM-B, located just to the left of the fuel pump relay. Is your 5-speed the original transmission? and/or Is your PCM (engine computer) the original one? Here’s why I ask: If the ECM-B fuse is bad, it will cause malfunction of the engine computer and prevent the fuel pump from energizing. If the fuse is good, then how about this: That particular set of codes, except for the EGR code (P0405), occurs together when one of two conditions happen. 1) The factory installed automatic transmission was swapped out for the manual transmission, which is very common for these trucks, but the PCM was never reflashed afterward. 2) The engine computer was replaced. They are, by default, programmed for automatic transmissions and need to be reprogrammed for manual transmissions. If those situations do not apply, then it could also mean that the engine computer has become faulty. It could be as simple as reflashing the software, or it could mean replacement of the PCM if the re-flash doesn’t work.
I’m not sure if the ecm is the original but probably is. I’m Gonna say the 5 spd is factory. All the fuses is good relays too. But I traced the fuel pump problem down to a faulty plug. Replaced the plug and that now works. But with that fix came new problems. And I did replace the ignition switch cuz someone hacked the other one up. The problem now is the truck starts up but runs like crap. I’m getting EGR solenoid code now. I know theres vacuum leaks but in the beginning it would start and run good. But while it’s running the truck is shacking spitting sputtering the moment you give it some gas it chokes the engine.
Maybe this will help:
https://www.obd-codes.com/p0405
The first thing I would do personally though is pull the EGR off and make sure the pintle is clean and clear. Reinstall, clear the code and retest.
This truck doesn’t have the egr I just watched Eric replace the motor in that sonoma and the place that it goes is blocked off
Well that explains the code then. Ok, so the next step would be to take it to a dealer shop or an independent shop with the proper gear to reflash the computer to delete the EGR and the auto trans. Once the computer is correctly programmed, then you’ll be able to get reliable data from it for the other issues you have. Right now the data is unreliable, and the computer itself could be causing the performance problems from having the incorrect programming for the current configuration of the truck..
If reprogramming COM does not work.
Please take off clean and inspect all sensors. Inspect all harnesses. Check all fuses. If you have a multimeter resistance test all sensors compare to specs.
Post results. Thank you.
Thanks for all the comments I did replace the fuel filter and it will now ideal but now it’s flooding and when you press the accelerator it chokes itself out
Please explain “now it will ideal”. Please post results of your findings after inspection and testing. Did you have PCM reprogrammed?
Haven’t done anything to the comouter yet. The Motor would start up then act like it was running out of gas. I saw the fuel was dirty when I tested the fuel pump so I changed the filter. So now it will idle. It will idle good then start dying out. The idle is all over the place. But when it does idle and you give it some gas it will immediately die
[quote=”forbiddenfantasy99″ post=186747] It will idle good then start dying out. The idle is all over the place. But when it does idle and you give it some gas it will immediately die[/quote]
The computer could really be causing a lot of this if it is not programmed properly for your vehicle. Aside from that, if the gas was really very dirty, there could be injector issues. There could also be vacuum and air leaks. You need to hook up a scan tool and look at the live data stream and check the fuel trims and such. If you don’t have one, you can usually get a cheap universal one that can display on your smartphone or computer for around $20 at Amazon. Those will let you read codes, view live data, and erase codes, and not much else, but nowadays scanners are essential for properly diagnosing problems.
- You must be logged in to reply to this topic.