Chevrolet Repair Questions? Ask a Chevy Mechanic for Answers ASAP
My name is ***** ***** I am a licenced diagnostic technician with over 20 years experience.
I will do my best to help you with your automotive problem. Please remember, I cannot see, hear or feel your vehicle which can make diagnosing very complicated and some vehicle require extensive diagnotics that require certain diagnostics computers that can not be done over a computer or phone.Please be patient as I am not online 24 hours a day, as I do work, but I do check my page every day.A positive rating is always appreciated for my time and knowledge to help you with your problem.
Did you notice if you had injector pulse when cranking? that will determine if we are into a secondary ignition problem or signal reference problem.
Also do you have access to a scanner to pull a data stream? id like to know if you have a rpm reference when cranking.
There is a good chance that it is the coil and module assembly, but you are probably sick of just putting parts in by now.
LEt me know on those things and ill help you out the best i can!
did you check every fuse in the vehicle? both underhood and interior fuse blocks?
the ecm communication problem is where we should be looking i think.
Im going to have a look at the diagram
Im going to send you the pcm wiring diagrams, there are 4 of them.
print them off and we will check a few things
IF the powers and grounds are good for the pcm, than it probably is. so pop the pcm out and back probe the terminals and lets make sure that all the 12v feeds and grounds are good..
IF one are missing than we will have to chase that.
give me a few mins and ill upload them for you
im kind of hoping is a connection or a wire under the fuse block asssembly
1 and 2
3 and 4.
let me know what you find.
Also please check for 12 at the injectors and 5v reference at the sensors
also, do you have a test light?
you can use that as a noid to check for pulse at the injectors too.
Im sending the data link connector diagram too to check for power and grounds to.
ill be online on and off tonight, and im off this weekend so ill be checking my pages all weekend. hopfully we can get your van gointhis weekend
ok. let me know how it goes.
tommorow, check the pcm powers and grounds, 12v at the injectors, 5v ref at sensors and pulse at injectors and well go from there.
no, the ecu body should never be powered. it should always be open, but securley attached to the body ground. IF the actual ecu housing is 12v than something is not right there. I dont think i have ever seen a computer casing powered. that would be something internal in the ecu if you have the 12v at the ecu assembly (unbolted and not touching the body) IF you have any 12v at any ground point, that would indicate a ground. this will require some searching.
also check every ground from the body to the engine, frame and body.
i can send you power distribution and ground distribution if you need. please let me know any additional diagrams you might need. I wish there was a simple answer to this, but this will involve more of a hands on approach. ITs good that you are familiar with this stuff, and it might be a good idea to have a friend that might be able to help you along.
This is one of those times i whish i could pop my head through the computer.
let me know if you need anythiung at all i i will do my best.
Again, vehicle grounds, fuse block powers, ecm powers and grounds.
Hi there I'm just finishing work soon.
When I get home I'll give you a message
hi sorry for the delay,
the passkey will not affect the fuel gauge issue. and you should still be able to access your pcm and it only effects the starter.
the concern i have is when you said that the pcm housing was 12v. thats either the computer or a ground is missing.
every pcm power and ground needs to be verified. IF all grounds and powers are present, and the dlc connector has its powers and grounds than we either have a bad pcm or a major vehicle ground is missing.
give me a minute and ill upload the bcm diagram.
I think if we can get this communicating, this will be our starting problem.
regarding the key, ya ive seen some of these have some pretty rough keys and not have starting issues. Even with a bad key, we should still be able to comunicate with the pcm
i might arrange to talk to you tommorow sometime.
I normally charge for this, but im really curious on this one so id like to go through a few things with you, so id call you at no charge.
let me know if you have some time tommorow night (around 9ish?) its 10:38 where i am now
ok, ill be back on tommorow night between 8 and 9 , ill see if your online. let me know how you did and if your up for a call.
hi again, can i get your number?
i think one of your modules has locked up the entire system so i have to tell you how to bypass them all and pinpoint which module is failing. it is easier on the phone
i have to go out and do a little running around. i was hoping you were online a little early to talk before i had to go out again.
No problem though, leave your number for me and ill call you when i get back if thats ok.
It should be around 9:30. i hope thats not too late.
ok, im home. let me know when u have a few minutes