I'm having fuel issues with my 89. At about 2800 rpm, the motor begins to break up and run really bad, so I put a pressure gage on the fuel rail. Ignition on, not running, 40 psi. Motor running, drops to a little over 30. At high rpm when it starts to run bad, the pressure drops to under 20. When I shut the engine off, pressure drops to zero like a rock. I changed the fuel filter and added a check valve right at the tank, same thing, but takes 5 seconds to drop to zero. Next I pulled the return line off the tank and deadhead it into the gage. I get 50 psi running. I did not take it for a drive, I know I should have, but no way to watch the gage. Next, I took a long screwdriver to the body of each injector to see it one wasn't firing. On the driver's side, each injector gave me a solid TACK TACK TACK, while the injectors on the passenger side went tick tick tick. With the screwdriver right on the manifold, I got the same sounds. Interestingly, when I put the screwdriver on the #1 injector, it touched both the body and the manifold and sparked. The VOM verified 12v between the injector body and manifold.

So... I need injectors. I believe these to be original, with probaly 100k on them. The FIC website says they are sold out, does anyone have a suggestion on another reputable supplier? For a stock engine I need 22lb injectors? I figure I'll do the regulator while I'm in there.

:edit: The pump is about two years old, and I eliminated the pulsator. I failed to mention the wild fluctuations I sometimes got on the gage, so one of the things I am going to do is pull the pump and check that all my connections are solid, both fluid and electrical.

 

Seems to me also have a fuel volume issue.

 

Thats pretty obvious, but I have an injector that reads 12v on the body, so i want to replace all eight. Do you have a recommendation for someone who would have them in stock?

 

Call up FIC, I think he can also rebuild yours.

 

FIC is where I purchased mine, there is another joint others use and their name slips my mind currently. Sorry. Both seem fine. My car did similar with fast pressure bleed off, belched black smoke, stalling, etc. Once the cats lit off with good mixture, big time smoke show!

What pump did you pick up? I did a Walbro 255, way too big for my bolt on L98 but Summit carried a drop in and has been working fine. Cost was about $100 I believe, TI Automotive makes them. 100% smart to do the FPR while in there and if you do not want EGR, prime time to block that off also...oh and pick up a fuel rail oring kit. Felpro gaskets are adequate and available at Autozone and such.

 

The pump was in a box of parts that came with the car. I believe it was a Delco, and new.

 

Tl;dr. When I installed a new fuel pump last year, I replaced the pulsator with fuel hose, and the supplied plastic clamps weren't holding the pressure. I replaced them with stainless hose clamps and the problem is gone.


An update for anyone with a similar issue. I replaced my injectors because one had an internal short, and I think one was leaking. I also added an adjustable FPR because I didn't know if the old one was original and getting weak, etc. Neither of those fixed the issue, so checked the check valve I installed, and found it was blown out of position and not doing squat. I dis have pressure in the line still, so it seemed the internal check valve was ok. I checked my in tank wiring, all that was good, so I checked the little piece of fuel hose that replaced the pulsator. It was ok, but I wondered if those plastic squeeze clamps were tight enough... the steel line the hose attaches to necks down where the hose goes and the hose doesn't fit that tightly, so I put some stainless screw clamps on, and now it runs strong, fuel pressure is great.

 

You don't want to rebuild them, you really can't actually rebuild them. You can clean them and install new filters and cups but if you have a bad or shorted coil that one is junk. You can get the new Bosch style injector from Holley, they should have them in stock and it is a direct replacement.

 

First of all, there’s a fuel pump relay and a long wire going out to the fuel pump, this can break down and cause high resistance, and can heat up when the car is running further reducing fuel pump productivity. Then the fuel pump itself and can be an issue.

I’m re-doing my whole fuel system for 3X capacity of OEM so I’m removing some parts that can be useful to you perhaps?

I’ve got a set of new LS1 injectors never installed, which are known to drop in and behave close to the stock ones. Also have the fuel lines to the fitting on the back of the fuel filter wick is also fairly new, have a new never installed fuel pump, have a set of injector rails with almost new FP regulator, and all new o-rings. Let me know if you need any of it.