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Re: Just a question... Posted by Ari [Email]  (#2847) [Profile/Gallery]
(more from Ari) on Tue, 17 Sep 2002 16:46:08
In Reply to: Re: Just a question..., Evan, Tue, 17 Sep 2002 14:04:41 Members do not see ads below this line. - Help Keep This Site Online - Signup |
You mentioned that they 'replaced the fuel filter and tested the fuel pump, both of which did nothing'. I assume that means that a new fuel filter was no help, and that the fuel pump worked.
First, I wouldn't rule out the DI. It almost seems like if you let it warm up, the problem goes away. DI problems can be very tricky. If there is a bad connection on the DI, it may very well clean up once things get warm and expand.
When I hear an engine sputtering, I think fuel or ignition. Yes, the ECU controls this, but it's a pretty expensive piece of machinery to shotgun. Here's a few questions -
When the engine sputters, what does the tachometer do? Does it fluctuate around, or does it dive for zero and then come back up, very quickly? If it dives, almost as if the tach wire were being connected and disconnected, I would think about the hall effect sensor, AKA Crank Sensor. It tells the ignition (DI) when to fire, and also tells the fuel pump to be on - the fuel pump runs only when the engine is turning. An intermittent crank sensor could give you fits.
I assume you keep the tank fairly well full. The fuel pump is two-stage; one stage fills a bowl when the tank is less than half-full. If the booster pump is weak, you could have fuel delivery problems at around a half tank.
Try very hard to borrow a known good DI cassette, and see if that works. That's the best way to tell if the DI is bad. Alternatively, remove the DI, and flip it over. There is a plastic cover held on with some screws. Remove them and the plastic cover. Does the circuit board look nice and clean? No burned marks? If so, good. Flip the DI back over, and sight into the four coils. You should see fluid (oil) in each. The coils should be around 3/4 or more full. No signs of fluid leaking. A cracked and leaking coil is the sign of a DI on the way out. Visual inspection of the DI isn't a perfect test, as a bad DI can look good. But a bad-looking DI is usually a bad DI.
A minor sensor problem or minor vacuum leak will result in a poor idle. A bad AIC will give a lumpy idle, but probably not a sputter, and won't do anything if the engine is at speed. I almost have the feeling that your sputtering is a much bigger, more aggressive issue. Look for big things. Crank sensor, DI, no fuel. As to the ECU, instead of replacing it, why not simply reseat the electrical connector? A bad connection could be giving you problems.
You may replace the ECU and all will be well. That's a great approach of you can get one dirt cheap. But ECU's rarely fail, or fail much less often than the DI, crank sensor, or just having a bad connection.
posted by 192.249.4...
, Tue, 17 Sep 2002 12:35:22, Tue, 17 Sep 2002 16:46:08 <-- Viewing This Message
, Mon, 16 Sep 2002 20:40:18
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