No injector pulse!!! update

[turbocrazy]

So I rebuilt my 7mgte and I can't get it to fire after a lot of testing if figured I have no injector Pulse i know the ecu supply's the negative current to make the injectors open but I'm not getting it im showing hot on both sides of my injector clip what could be wrong I've checked everything I can think of am about to say my ecu died

 

[hvyman]

The ecu's rarely go bad and its usually from user error.

The ecu is more likely not receiving the necessary inputs to send the outputs for the injectors.

Start with checking for codes.

 

[turbocrazy]

Checked for codes all I got was one it was 52 I think or 51 had to do with a/c and WOT. But im hot on both sids and not getting a negative from the computer is there another relay thAt might controll that the one near the battery is good

 

[Nick M]

When are you testing for ground? The ECU only supplies the ground with spark confirmation or STA signal.

 

[supraguy@aol]

I'm gonna vote for dodgy CPS.
But that's because I'm feeling crazy this Monday.

 

[turbocrazy]

We checked the cps and it seemed to be working and it's sending signal to everything and I'm pretty sure the cold start injector is firing and why would the computer send hot to the negative side of the injector clip?

 

[jetjock]

It's not. It just appears that way. Think about it.

 

[turbocrazy]

What am I thinking about? Both sides of the inector clip has 12v and from the readings we got with the noid light no negative. Now the weird part is we did get injector pulse for a min but as soon as we plugged them back in to fire it up it lost it again??

 

[hvyman]

Have you checked for spark?
Does your tach move when cranking?

 

[jetjock]

... Now the weird part is we did get injector pulse for a min but as soon as we plugged them back in to fire it up it lost it again??

Not weird. It's actually very telling. And remember, you can always spin the CPS manually...

 

[turbocrazy]

Ya I get spark and if I remember my tach moves and we turned the cps manuel and still get spark when we spin it Manuely and we still get no pulse

 

[turbocrazy]

ok so i have a update on my issue i had to fix my connector on my cps and while trying to diagnose my problem i left the key on and noticed when i move my cps wires (car harness) i could hear a relay tic so i figured i had a broken or dirty wire which would get continuity but not send the correct signal so i tryed to fix it and by re wiring the connector on the car harness and still get the relay tick so im guessing somewhere in the harness is a break/short so im gonna try strait wires from ecu to the cps connector to eliminate the short. from the look of the wire diagram the cps goes strait to the ecu anyway (am i correct?) so this should hopefully fix the problem and also at the other question i know for sure my rpm gauge is not moving at all so let me know if what im gonna do sounds like a good idea and possible fix

 

[supraguy@aol]

Boom. I was half-right.

 

[hvyman]

The cps wires are shielded. usually it takes the most abuse right around the connector so your problem is likely there.

 

[supraguy@aol]

Werd. Of course, the cps wires have to travel all the way around the block to get back to the firewall. I've seen many occasions reported on here,
where the harness rests against the egr valve, and melts slightly. Any number of symptoms could manifest in such a case. Make sure your harness isn't in trouble back there, while you're looking at things.

 

[turbocrazy]

If fixed Both sides of the cps connector and got the dryed out cracked wires I was hoping that's where the fault was but it seems to be deeper in the harness and my engine has had the egr deletes since I've had it but if a strait shot to the ecu down the passenger side doesn't cure it I'll just have to tare into the engine harness and investigate more

 

[super51fan]

The engine main harness have problems around the #6 intake runner. Sometimes you can push and pull gently on harness and the problem goes away for a short bit. If so you have narrowed down your problem.

Supraguy said the same thing. This is where I would look first.

 

[turbocrazy]

ok so i re did my whole cps wiring to the ecu and still no go... still have not injector pulse and still no movement form the tach i was looking up the ig- wire to see if maby that was the problem but that seems to just lead to the diagnostic block, right? i guess ill try and get the harness out and look back where the egr stuff use to be and see if i can find anything in the harness but i have found out that relay ive been hearing clicking is the brown vacuum thing not sure what its called but there is one for the egr vacuum and the fuel seems like the egr one is the one ticking when i wiggle the wires. anyone else have any clues while i go check the harness??? could use any useful info to track this PITA down!!!

 

[turbocrazy]

could the AFM cause this issue if the wires were messed up??

 

[jetjock]

^ No. And if you had spark it was never CPS related.