What could be going on here? Now when I turn the key on to prime the fuel pressure, it jumps up to the normal 40 psi then quickly dies off. Just before the install, with the old injectors the pressure stayed at 40psi even after the fuel pump was shut off. Is this normal after a new injector install? There is no way it's fuel pressure regulator because as I said earlier, it was fine before the injector install. Could there be an injector that is "stuck" open allowing the fuel to just dump in the chamber? If so, what sorta problem is that going to cause? Is my oil going to now be contamianted??

Also, it now backfires. I double checked the spark plug wires. They are fine. I'm thinking I installed the injector wires in the wrong spots because stupid me I didn't mark them before I removed them. Would installing the injector wires wrong give the same affect as installing the plug wires wrong? Is that what's causing it to backfire? If so, how in the world am I going to figure out which wire goes to which injector??

Help guys, I'm desperate here!! Thanks

 

Makes no difference on the injector wires.

You should hold pressure.

Recheck the plug wires again (why did you remove them anyway?)


It is not good to have fuel dump into the crankcase(if in fact it is)...if an injector is open when priming, it'll always be open when running the engine.

 

are u sure that the pressure is dropping. on my car when i changed the injectors a couple of weeks ago i didnt get some of the bolts tight enough and it made a a big vacuum leak and it was chugging and backfiring and didnt want to run i went back and tightenend every thing up again and didnt have any more problems.

 

First, it is normal for the pressure to drop a few pounds when the pump goes off (5 or 6, but not like 10 or 20). It should stay at that level though and not continue dropping right away.

Also make sure you got the fuel rail down good on all the injectors, and the injectors all got seated properly in the holes on the intake. I usually use some vaseline or motor oil lightly on the O-rings to make sure they go in and don't tear.

Hope this helps, but regardless, Good Luck!



- Vern

 

dbassett74


STUPID QUESTION
I got the same injectors as you did from fiveomotorsports..just wanted to ask, on the end that goes into the manifold (red caps), do those red caps stay there or do they need to be removed...they sorta look like protective caps but I installed the fuel rail with them on last night and the injectors seem to fit good with them on.

Let me know if you removed them...

Thanks.

 

I didn't remove them. I too thought they were protective caps because they looked a lot different than the OEM ones. But as long as there is a hole in the bottom of them can you can see the tiny silver screen in there, you're okay.

 

Now I may be way off base here having not seen these injectors (can you post a pic of one?), but I'm betting those plastic caps you're talking about should have been removed before installing them. That could also explain why they didn't apprear shorter like you were originally told they would be......



- Vern

 

Yes, the screen is visible in the center.
Here is a pic I got from the tech article on this site...the cap isn't red in this pic but you can see what I'm talking about...
Does that cap stay on? I'm thinking it's part of the injector.

 

I didn't remove mine and the car seems to run fine. But you're right, that could explain why they weren't any shorter than the OEMs. I will call Bruce to see what's up...

 

Just left him a voice mail. I'll let you know what he says. But, it really seemed like those caps where integral to the injector. I even tried to remove one of them thinking it was a temporary cap and it wouldn't budge. I really just think it's a different design than the stock Multec units. Again, I left mine on and the car runs great.

 

Just heard back from him. He said they are part of the injector, DO NOT REMOVE THEM!!! Good luck!

 

Great! Thanks for calling. I bolted down the fuel rail last night with the caps left intact and supplied pressure...no leaks!! phew, I really didn't want to take it off again.

Did you notice that your manifold bolts were really loose? At least half of mine were finger tight!!! I torqued them all to 25, and then to 45ftbs.

 

Glad you found out for sure. Sorry if I raised a false red flag. My apologies, but at least now we all know for sure!!!!

Have a Great Day!!!



- Vern

 

ok guys i am trying to figure out whether or not i have a leaking injector or fuel rail or what here. i am noticing it is always wet on the passenger side of the engine so i inspect everything it looks fine. i took it apart to to see if one of the injectors was stuck open (my car runs way to rich with loads of new parts this is the last thing i need to replace maybe) now i turn the acc on with the injector wires unplugged no leaks from the injectors no leaks int he fuel rail and the fuel pressure goes up to 43 then quickly drops to 20 after pump shuts off.. now do i have to plug the injector wires in to see if an injector is leaky?? and why does my pressure drop to much i saw you guys said it is only supposed ot drop 5-6 psi... not good for me. i have an 87 gta 350 with cold start injector also. any ideas???? help asap cuz car wont pass emmisions for long time now cant drive..

 

No, you don't have to have the injector wiring harness plugged in to see if one is leaking. All you're trying to do is fire up the fuel pump and pressurize the fuel rail. That big a pressure drop still seems like a bad sign to me. But yet you didn't see any leaking. What happens if you wiggle each injector a bit? You did this test with the fuel rail not bolted down to the intake but held up where you could see the bottom of each injector, right? Also, what do you mean by "it is always wet on the passenger side of the engine"? And if it is, does it appear to be oil, gas, or antifreeze/coolant? Be sure to check all the lower o-rings on the injectors. Might be a good idea to replace them when you bolt the fuel rail back down. BE SURE TO PUT SOME MOTOR OIL OR VASELINE ON THE O-RINGS BEFORE YOU PRESS THE INJECTORS INTO THE INTAKE MANIFOLD! This helps them seal and helps prevent them from tearing when you push the injectors in.

Let us know how this works...

 

hey guys. none of my injectors leak and no spots ont he fuel rail either. i switched to a different fuel pressure regulator of of an 89 350tpi and it now holds pressure. it will hit 43 then the fuel pump will shut off and it will drop to like 40 and stay there.. so i put her all back together and now when i start the car and let it run the psi is at 36 at idle with vaccum tubes on. when i take the vaccum tubes off it hits 43 again and stays. the car still seems to run very rich at idle. what is the psi at idle supposed to be with the vaccum tubes on? and with them off? thank you for all your help