Hello all , so I put a new intake manifold and runners on my 87 gta 5.7 . I also put a new ac delco fuel pressure regulator (internals) . Didn’t run worth a crap after I started it . Done some poking around and the passenger side is dead . Fire is there but that side is dumping fuel bad. Key on fp goes to around 50 then drops off fairly quick. I tapped injectors and now the pressure holds around 30 key off . When I tap the injectors the pressure falls off with each tap . So stuck injectors or did i do something wrong with the regulator possibly? The car sat for around 10 years before I got it but ran fine before I put the manifold on. Thoughts ? Thanks

 

Sounds like you need to retrace your steps. Unless the manifold job took you months to complete it seems very unlikely the injectors all suddenly started sticking.

Why did you put a new manifold and runners on? Are they actually "new", or 35+ year old "new" parts.

 

Hi , thanks for the reply. Yes it an old accel intake and edelbrock runners . Yeah it’s odd one side is stuck open. I guess I could put a Noid light on and see if they are getting the proper command from the ecm , I’d imagine if they were electrically open the light would stay on and not pulse . Short of that I guess I’ll have to take it back off. Thanks for the advice sir .

 

So key on not cracking the Noid light has nothing I unplugged all the injectors on that side and they still leak down . For my dim mind would that not rule out an electric issue on the car side ? The ecm provides ground for them to open? With them unpugged and still leaking that would rule that out would it not? They all ohmed out fine . Thanks

 

Why?

Did you have a problem that led to them being replaced?

 

Just a aftermarket accel piece not wrong with the stocker

 

With key on, not cranking, I do not believe the ECM will pulse the injectors. The ECM needs to see a distributor reference pulse before the injectors will fire. You need to crank the engine. If the noid light fires, you could still have injectors stuck open. That is because the pintel would be stuck inside the injector even with the ECM pulsing it.

Fred

 

Yeah , I am going to pull it apart tonight and have a look. I’ll let you know when I find.

 

I would suggest going with a set of Bosch 3's from Southbay. You may have heard that after installing Bosch 3's the BLM gets pegged at 160. That is what happened to me. After some web research, I found a data sheet for battery voltage offset's. I edited the bin with the offsets and that helped to correct the BLMs. I think Southbay also has the Multecs.

Hope this helps,

Fred

 

Hey Fred SS thank you for the referral. Just to clarify....we do not carry the multecs. Never did never will....lol
The injectors you may see on our website are delphi's. They look like the multecs but they are not. Actually they are brand new and we receive great feedback on them for the people that want to go for the additional cost

 

I pulled them last night I didn’t see anything wrong with them but I have a local injector place here cleaning them and they will test them too . So I guess I’ll see what’s what later on today or tomorrow. $25 to clean and test them I figured was worth a try and at least hopefully I can say hey that’s what caused it to dump fuel .

 

Keep us posted

 

3 of 8 are Stuck open. That would do it .

 

Damn...looks like you need new injectors!

 

Yup , so guys the car was originally a 305 but now has a 350 . The injectors I pulled are from a 305 according to the p/n . If I were to put the proper 22 lb injectors in there do I need to retune the car or Should just stick with the 19’s . Car is fairly stock other than intake manifold and exhaust. Thanks

 

might as well do it right

 

I agree, can a guy just put them in or will I need to retune it ? I apologize I am not really up on the Tpi stuff. All the other cars I had were either carb or obd2 stuff.

 

A constant flow of 19#hr in the tune with larger than 19#hr it will run rich.
My guess it was running lean before but a datalog wideband o2 or a plug read would be the only way to tell. But might be to late for that.

 

Thanks for the help ,I’ll put the 22’s in there . I do have a aem wide band setup from from a past car I can put in there I guess and see what it’s doing after I get it running and deal with it then if needed. Thanks all

 

https://www.ebay.com/itm/11607235497...mis&media=COPY

if you got Delphi 22#hr and this chip it might run better. I’ve seen the addition of high flow base and runners cause slight lean conditions. A later year custom tune could be better but this option might be close.

 

My car is a 5 speed I see that chip is for an automatic. Probably better off to wait and see what it’s doing with the a/f gauge and go from there. Thanks

 

It would need a custom tune an automatic transmission tune would correct for fueling . Apyp Vette based with recurved timing would be a good start if you get into diy.