'93 Bravada Injection Issue

Hey all,

I'm having an issue with my Bravada. Been chasing it for quit a while and still havne't gotten it right. I've seen in a few other threads a similar problem and think that's what's going on with mine. It starts hard, smells like gas, runs really rough at idle and when you first take off, got gas in the oil and the mileage is terrible. I've seen that people point to the fuel pressure regulator and the hoses right at the injectors themselves and in that area. I cetainly need to check that out and that's most likely it with everything else that I've done. What I want to know is are the hoses in the "nut kit" that I've heard about, or what's in that? Is there a new gasket in there for the plenum? I've also seen in a couple places people talking about a special bolt that requires a special tool, what's the story with that? Am I better off replacing the injection unit instead of just the pressure regulator? And overall how hard of a job is this? What do I really need to buy? I'm pretty good with basics but I fear this may be better suited for the pros, but then I don't want to spend the $ if it's really not that tough. I've looked in my Hayes and they talk about removing the throttle linkage and a bunch of other things. What's the easiest and best way to do it? Any help or suggestions you might be able to give me are greatly appreciated.

I'd check the Jimmy and Blazer forums...

There's lots of real good and detailed info about that exact problem with the fuel injection system.

J-Ray

The CPI replacement is straightforward, disconnect your negative battery cable…remove plastic cover that says Vortec, the wiring connectors to the MAP sensor, throttle position sensor, idle air control valve and intake tuning valve, the rubber & plastic duct and vacuum hose on the throttle plate, 10 10mm bolts…2 are holding the ignition coil , 1 is holding the throttle cable bracket then remove the small vacuum line at the rear of the intake manifold/passenger side.
Gently lift the manifold top and flip it over to the left and let it lay on the side.

Now at this point you can look for a cleaned area inside the manifold as it will normally be completely grungy inside. Spraying gasoline cleans the area of the leak. If it’s real clean near the CPI middle to the passenger side, your CPI is bad. If it’s clean around the drivers side, you have a fuel supply line leak.
If the CPI is leaking, replace the fuel supply lines also.

To replace the CPI, inside the intake, disconnect the CPI electrical connector, pull the injector poppets from their holes and pull the CPI injector unit out.

The internal fuel line replacement is a fairly difficult job due to the little special Allen head screw that holds the fuel line bracket to the back of the intake between the motor and the firewall…drivers side. AFTER you get the replacement fuel line w/the replacement Allen screw included, get a tool that fits the new screw EXACTLY because the original screw has a little tit inside the Allen hole and is loctited(thread sealer/locker) in place and won't come out easy. Get comfortable and take your time removing the screw so everything else will go easy.
Disconnect the fuel line fittings at the rear of the intake next to the firewall and remove the special allen head screw to release the fuel line bracket then pull the fuel line out through the inside of the intake manifold.
Before you install the new screw, clean off the thread sealant with a wire brush because there will be plenty of residual loctite in the screw hole.

Says Jim in Phoenix:”
The part number for the fuel line kit is 17112705, and GM calls it NUT KIT, dealer cost $69.70(the allen screw was not part of the kit). gmpartsdirect.com quotes $34.85, so anyone who has NEVER replaced this hose kit in the intake manifold should order one to have on hand--there WILL come a time. With the intake cover off, this is a good time to pull the EGR valve, clean it, and put the fine mesh screen over the exhaust port feeding the EGR. I use the stainless steel fine mesh screen from a sink faucet aerator and a drop of blue rtv to hold it in place. When I did the hoses, I inspected my EGR, which has worked perfect for 10 months and about 14,000 miles. There was a small pile of carbon laying at the bottom of the screen, prooving the need for same.”

Chris,

Thanks for the reply. Do you know if the "nut kit" comes with the lines that go to the injectors too, or do those not go bad and shouldn't need to be replaced? Instead of replacing the CPI can I replace the fuel pressure regulator, or is it just a matter of time before the CPI needs replaced too?

The poppet valve injector lines are attached to the CPI and are not included with the "nut kit". I don't know of any poppet valve problems on Bravada's through the years...maybe someone else knows of some on other cars.
I've read where people have replaced the regulator on the CPI and did fine. If you was sure the regulator was the problem, it would likely be OK and probably be worth the risk. The leak at the front/passenger side of the CPI is where the regulator is located.