QuestionQUESTION: Hi Mike, I've had a recurring problem with the fuel injector clogging in my 95 Blazer. At least, I believe that's the problem. Occasionally the car will start, run for about 5-10 minutes then shut off again. It will restart and shut off again right away. After 2-3 times it won't start at all. I've changed the Crank sensor, Cam sensor, Fuel pump (3 times), Fuel regulator (twice), Electronic Ignition module, EGR Valve, MAP sensor, and the Ignition Coil. I did a full tune-up on it and the PCM was flashed (twice). I've drained and filtered the gas and added injector cleaner, but still having the problem. This is the third time in a year and a half. Please help!
ANSWER: Very common problem with these engines is the CFI system that GM used. It was cheaper than a port injection system and, when new, worked just as well. The problem is that it is dependent on a snake-like bundle of plastic tubes delivering the fuel to the injection points from a central distribution point. Actually, if you are familiar with the fuel injection used on aircraft engines, or on early Mercedes with fuel injection, it will look very similar. Now those systems worked great and lasted forever, why doesn't GM's? the problem lies in that word I used earlier to describe the system: plastic. Over time, the plastic becomes more and more brittle, eventually cracking and creating leaks. GM stuck this whole mess down inside the intake manifold, so when it leaks fuel, it leaks it into the manifold. This causes the mixture to be too rich, and kills the engine after a short interval of running. Fortunately, it can be fixed easily, if not cheaply, by replacing the injector assembly. And it should be the whole injector assembly, not some attempt to repair it. The assembly can be bought for a little over three hundred if you buy it yourself, expect to pay around five hundred from a shop if they supply it. The labor is involved and not cheap, but it should only have to be done once, the truck will head to the wrecking yard before it goes bad the second time.
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QUESTION: Funny about the truck heading to the wrecking yard!! lol
I have already replaced the injector twice in a year and it may be clogged again. I talked to a company that specializes in fuel injectors and they said it doesn't sound like it's the injector at all. The main code that keeps coming up is P0441...Evaporative Emissions Control System Leak Detector (Small Leak). I'm not sure what else to check from there. One O2 sensor was replaced and the CAT was pulled and checked. Any other ideas?
(Also, thanks for getting back to me so quickly!)
Answer Oh, boy. that code could be for anything from a bad gas cap to a disconnected or rotted piece of hose in the evap emissions system. The system is designed to route any excess gas fumes into a charcoal canister and then burn them in the engine rather than vent them into the atmosphere. It is controlled by a series of vacuum solenoids, which are controlled by switches. One of those switches is probably bad. This can sometimes be the result of overfilling the gas tank, which overworks the system (I have a hard time with this, too, but when the pump clicks off, you have to take it out and hang it up, not sneak a little more into the tank). You can check the function of these components with a hand-held VOM, or look at most of them with a proper full-function real-time scan of the ECM. Good luck.
