Tinoco17

Okay I have a 91 z28 with a 350 swapped t5. Old owner put in some ford 19lb injectors.fuel pressure is bumped up to 54 psi I'm running rich or maybe lean cause there's a strong gas smell coming out of the exhaust failed smog. Also on a cold start it doesn't idle high or fast just idles at 650 with a slight surge. Also going 15 miles it jerks.higher speeds it runs good. What could cause it not to idle high on cold starts all my other camaros did it also my buddies z28 does it but this won't doesnt idle high on cold starts any help would be great

Tinoco17

I put on new wires, spark plugs and coil also has a new distributor new cts a month old 02 sensor

Tinoco17

Switched iac with my buddies still no change. Also switched tps with him same thing

Tinoco17

Switched computers with him also no change

vetteoz

iTrader: (13)

Is the memcal ( chip ) in the computer for a 350 or a 305?
Have you pulled the codes to see if the computer is showing any faults?

Tinoco17

Both computers are for a 350 the car is a stock 350 car just the tranny and injectors are different. Yes no code. Well when I drove it back from a 3 hour trip the check engine light came on after I shut the car off and turned it on but went off after a couple of miles it was for the egr but the egr and solenoid are brand new the ses light hasn't came on anymore

Guest

Wrong injectors and to much fuel pressure...

formula_novice

iTrader: (1)

I agree. Get the correct fuel injectors in there and lower the fuel pressure to about 43psi. Pull the battery to reset the computer, plug it back in, and then see how it behaves. You shouldn't start with something messed up and try and to compensate for it.

Tinoco17

I've searched on this forum and seen people running 19lb ford yellow top injectors with high fuel pressure. Something about those injectors tested at lower pressure I think it was 37 or 38 and gm is at 43.5

formula_novice

iTrader: (1)

What is the duty cycle of your 19lb injectors running at 54psi?

Tinoco17

At 54 psi they're running at 22 lb.

rgarcia63

Ford & GM PCM fuel programming is not the same, couple that with how they rate injector flow @ 85% duty cycle at different psi and you'll see why it necessary to raise/lower the pressure, but that can affect other things such as spray pattern.

VincentZ28

iTrader: (2)

Install the 22lbs injectors. Get a chip for the 350 with the torque converter lockup turned off. This is the right way to go without trying to short cut it. Its searching for an automatic trans.. Make sure the knock sensor and EGR are for 90-92 TPI.

What year of car did the engine come out of?

Tinoco17

It's the stock engine only thing that was changed was the fuel injectors and the automatic transmission was swapped for a stick

ninetyone

iTrader: (2)

The Ford injectors are rated the same as the GM, I have been through this many,many times. I know for a fact my Ford 24lb blue injectors are TRUE 24lb/hr just like GM. He needs a chip for a 350 with a five speed conversion. The injector size can be adjusted in the chip. The timing tables are also different between auto and stick, many differences there.

ninetyone

iTrader: (2)

Thats not true.

ninetyone

iTrader: (2)

your running lean,but ecm is holding injectors open longer in an attempt to richen things up. I bet your fuel trims are through the roof! So, even though its injecting tons of fuel,in reality you are "running lean"

VincentZ28

iTrader: (2)

Since you live in California like I do, do it right so you can pass smog..