I have a 1988 IROC with the TBI fuel system. The car originally had a 305ci engine and I installed a 350ci crate engine for the same year of camaro. I recently got it running, but I'm having problems with the fuel system. I installed a new fuel pump and fuel filter and I'm getting 13 psi teed in to the fuel line with the engine running. The timing is correct at 0 degrees with the set timing connector removed. It runs good up until about 2500-2800 rpms and then it simply won't rev any higher than that. I suspected that it wasn't getting enough fuel, so I opened the throttle all the way and added fuel to the top of the TBI and it reved higher than previously mentioned. Could someone tell me what I can do to cure this? Are the stock injectors big enough to support the 350ci engine? Would building the adjustable regulator as mentioned in the tech articles be beneficial? Please help.

 

I would say to definitely modify your fuel pressure regulator to be adjustable and you most likely need to get bigger injectors for it, the stock ones are only like 40 pph. What exactly are the specs on the engine, we can help you figure out what injectors and what kind of tuning you're looking at if you tell us the specs on it.

 

Its a stock 1988 350 that is bored out 0.040". Everything else is stock 350 demensions and has factory intake and exhaust manifolds.

 

Yes, tell me what injectors you have. If they are the stock 305's and you are using the same ecm chip for the 305, your engine is probably running very lean. Hope you haven't toasted it.
Let us know your injector size and if you have done any chip mods.
Also, any error codes?

I'd plan to get bigger injectors and do some chip mods.

S-D

 

if your engine simply wont go past 2800 rpm then there is something wrong / broken.. etc

Its not because they are too small or any of that sillyness. It should run fine as is.

maybe you have an ignition problem or maybe you have a faulty injector.. something like that. How does the injector spray cone look like at that rpm

 

I have the original 305 fuel injectors, which I assume are the 40# models. I have installed the hypertech ECM chip also. The pattern is a good atomized cone spray. I'm pretty sure nothing is broken on the engine keeping it from reving correctly, because when I add additional fuel to the TBI at wide open throttle the engine will rev normal. I hear that the 5.7 liter trucks run 55# injectors and I'm considering that route. Thanks for the replies.

 

Have you tried putting the old chip in and using that?
Also am still interested to hear if you're getting any error codes or an SES light when this condition is present.

Keep us posted-
Best-
S-D



"Silliness".......... What a lame *** attempt at acting like a condescending pimpledick. By the way, "Silliness" is the proper way to spell it.

 

Yes, I have tried the stock chip and there is no difference in operation. I've even tried another PCM with both chips and still no luck. No codes are present other than the ESC code that will set whenever I time the engine. I clear that one each time as well.
I'm not trying to be arrogant, but I'm not new to working on cars. I'm currently graduating PSU in the automotive service tech program, but I am new to major engine modifications to electronically controlled vehicles. I also know that nothing beats experience in the field and that this is the best site for reaching knowledgeable people about 3rd gen. Camaros. I'm thinking that someone has done this same modification before and has ran into the same problem. I also know what an engine sounds like when its starving for fuel. Thanks for everybodys help.

P.S.
I like the reply to the silliness comment

 

If you are saying the engine won't free rev past 2800 without help from you, then you have a MAJOR problem. I'd look elsewhere than injectors. Do you have any idea what your AFR is to cause the engine to not be able to rev past 2800 with no load on it? You must be in the 20s (to one). I know you're "not new to cars," but I'd advise to stop doing that...take a look at the fuel pressure when it won't rev any higher than 2800 (ok, so do it once more). You probably have a serious blockage somewhere, or the pump is bad (I know it's new).

 

the lo3 has 50 lb/hr injectors
the lo5 has 55 lb/hr injectors

the 454 uses 74 lb/hr injectors

a buddy of mine done a 383 with a 305 tb in a caddy seamed to run ok
made just over 225 hp with 256 gears

 

L03's are "supposed" to have 40 lb/hr injectors. However, I looked at a Caprice L03 bin and the BPW constant works out to exactly 55 lb/hr injectors (BPW of 132). IMO, there is no definitive answer as of yet. I know the formula works because my car had a BPW of 122, and that's not far off the calculated BPW of 120 for 68 lb/hr injectors (I'm "supposed" to have 68 lb/hr injectors).

 

TJM-
I don't know if you've checked you air-fuel ratio yet- If you do not have the excellent WinALDL program, cable and a laptop, here is a quick and dirty way (I pulled this from a previous post- all responders agreed with the following):

"Anyone ever hear of this. i read about this mode in a camaro repair manaul. it says you can use your SES light as an air/fuel ratio gauge. this is what is says:if ALDL B is grounded to terminal A with the engine running, the system enters field service mode. in this mode, the dash warning lamp will indicate wheather the system is operating in open or closed loop. If working in open loop, the warning light will flash rapidily 2 1/2 times per second. in closed loop, the flash rate will slow to once per second. Additionally, if the system is running lean in closed loop, the lamp will be off most of the cycle. A rich condtion in closed loop will cause the SES light to remain lit for most of the 1 second cycle."

You may use this to get an indication of your afr.

Are all your other sensors hooked up and working properly?

Sorry to hear of your troubles- I'm sure you want to drive it. I guess we keep going at it until it works right.
S-D