1998 Bravada Starting problem

[willyman82]

Hi,

I have this problem nailed to the wall of success in my garage. It drove me nuts for almost a whole year. It is a multi-faceted, VERY hard to track down problem. For me the problem seemed only to happen if it was A: Cold, or B: sitting for more than 2 days. At the time it had 150K miles.

First what happens is the stock injectors start to leak because of poor design. http://www.lindertech.com/reconinj.htm These guys have a replacement fuel injector assembly for $300 (bottom of that page) that fixes the problem and is a different design, unless you are in California. In CA the typical type of injectors in the 4.3L Vortec are not allowed because of this failure mechanism.

If this problem has been going unchecked for a while your cats may be clogged as mine were. That was the original symptom that I started chasing to find this problem. The post-cat is only a few hundred, but the pre-cat is $1100 from GM. I still havent replaced mine because of the cost and have been using a clamped in pipe in place of the pre-cat. This does not set any codes as long as the post-cat is still in place...its just not so good for the environment. Also, my O2 sensors were fouled.

After the post-cat and O2 sensors, I found shorly after that my plugs were badly fouled. I replaced them, which is a huge pain in these cars. Then I found they were fouled a second time about a month later. This time I replaced the whole ignition system (coil to plugs). Fortunately, I kept the old stuff and now I have spares for everything, because that wasnt why my plugs were fouling.

Finally I took apart the manifold on a hunch and it was soaked inside with gas. Replacing the CSFI module under the intake cover FINALLY fixed my problem. Now I am just saving up for that damn pre-cat. One final tip...Dont use platnum plugs in this engine. I get better milage with the cheepies and my mechanic friend (who was equally stumped by my problem) advised me that the platnum plugs foul faster than regular ones in engines that tend to run a bit rich.

I have 181K on the vehicle now. Good luck!

[vando002]

what is and where is the CSFI module?

[old_master]

The "CSFI module" is actually the housing that the 6 mini fuel injectors are in, commonly referred to as the injector assembly. It's located under the upper intake manifold.