93 bravada run problem

[rustylane]

I have a 93 bravada that is hard to start. The fuel pump at turn on is at 60 psi for 2 sec as needed then falls to 0. Once started the fuel stays at 60 psiand it will idle fine for about 30 secs and then stumble and allmost stall. It then will rev up to 1000 rpm and idle fine for a few secs and do it again. The idle sensor was changed as well as cap and rotor, new distributor,and the fuel pump relay. If you get to driving at speed it will run ok untill you come to a stop and it stumbles and stalls. Its still hard to start. Could it be the cmfi unit doing this. I hope not its costly.I was thinking it the fuel pressure regulator, but am unsure. Could it be the egr valve? Please responed to [email protected] or post. Thank you

[Chris Stewart]

The first thing to check is what the computer thinks is wrong.
Here's how to check a '91-'94 Bravada for trouble codes:
Jumper the 2 top right hand holes on the assembly line diagnostic link(ALDL)under the steering column-lower dash area then turn on the ignition switch and count the check engine light flashes. You'll get a single then double flash...1-2 or code 12 three times which means the computer is saying "Ok Pal, I'm gonna tell ya any trouble codes stored". Any codes stored will flash 3 times.After all the codes stored are shown you'll get another set of code 12's which let's you know "that's all folks" unless you want to see again which it'll then just keep reporting the stored codes. When you get through, just cut the ignition switch off and pull your jumper wires. To reset the check engine light, disconnect either battery cable for 15 to 20 seconds. Let us know what codes are stored and we'll discuss what's the problem.

[rustylane]

I did that and all I get is code 12 on it. The puter is stating that all well.

[Chris Stewart]

It sounds like the idle air control valve(IAC) is sticking. It's mounted just above the throttle. Remove it and clean the plug valve, spring and spray some carb cleaner in the intake manifold where the IAC is mounted. This should let the IAC function normally.

[ericn1300]

try changing the PCV valve first, that seems to have fixed mine, cost under 3 bucks and takes maybe 5 mins to change

[rustylane]

I changed the pvc and changed the Idle valve. It looks like its the injector unit doing it. It does hold pressure in fuel when running but it falls to 0 after key turn on and the two seconds. So Im replacing that item also.

[Chris Stewart]

CPI fuel line replacement, thanks Barrett & Jim in Phoenix (Post #1)
I thought I'd paste this post from VMag Bravada before they burn out altogether.

Re: CPI fuel line replacement for '91 to '94 Bravada ...Hey Barret
: Yes, there will come a time, when I replaced my CPI, the incoming fuel line snapped off when I pulled it out of the old CPI b/c it was so brittle. Glad I had a new kit there. The screw that holds that plate to the intake is tricky, I agree as well! Mine was a little bit difficult to get both of the fittings inside the wall of the intake all the way, guess it was machined just a very tiny bit small. : Are you putting that screen on the intake side or the EGR side of the gasket? Just curious, I think I will try that as well, I am getting a little bit of a rough idle and I haven't cleaned the EGR since December.I suspect he's putting the screen on without loosening the gasket so if the gasket is stuck to the intake the screen will go between the EGR valve and the gasket. If the gasket is loose then whatever you choose will be ok. Because we're dealing with soot, it'll seal itself is there's a fair seal to begin with...I'm waiting for mine to fail so I can use the faucet screen too.: : I just did the fuel lines on my 94 and you got it right Chris, that clamp screw is tricky. The part number for the fuel line kit is 17112705, and GM calls it NUT KIT,T 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.: : Finally, before you put the intake cover on, anytime, you should run the fuel pump to check for leaks--there is a single black wire on the firewall which you can jump directly to the battery for the fuel pump.: : Jim in Phoenix: : :

The Trouble Code 45 is Oxygen Sensor sensing RICH condition. That confirms the fuel leak inside the intake plenum. When the motor is cold it can use the extra fuel but after it warms up and sits long enough to leak out that 50+ psi fuel, it puddles and goes real rich when you restart. : : : I guess a fuel line replacement is in your future.: : : It's 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. 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. 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.: : : note: Any additional info gratefully accepted.

[rustylane]

Thanks ill keep all this in mind. Just as soon as it stops snowing here ill start. I do thank all for the advice and if I can help you in any way let me know. I have all the codes for most cars in my book including some of the dealers codes.