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Re: engine miss and CEL (long) Posted by Ari [Email]  (#2847) [Profile/Gallery]
(more from Ari) on Wed, 28 Mar 2007 07:30:19
In Reply to: Re: engine miss and CEL (long), Roger Hyman, Wed, 28 Mar 2007 06:05:47 Members do not see ads below this line. - Help Keep This Site Online - Signup |
It may seem strange, but the best sort of failures are complete and total. Something doesn't work at all, repeatably. You are stuck in the situation where something either fails intermittently, or is just far enough out of whack to occasionally cross the line into engine misfire. Short of replacing every part, wiring harnesses included, they're a pain to find. Mechanics hate them.
A partially bad CPS is hard to troubleshoot without special equipment. That's why some folks might just swap it out. That can be pricey,unless you've got a particularly nice mechanic that can temporarily swap in a known good one. But this kind of fault can be very tricky - is it a bad sensor, or a bad wire? This could be a poor ground from the engine to chassis. The trick with this sort of problem is to balance throwing parts at the problem, hoping it's the part and not a harness, against troubleshooting, which takes time and expertise.
Sorry if that dashed what remained of any glimmer of hope you once had. I guess my job is done. In a case like this, the best place to start is to make sure the basics are sound. Make sure the grounding from engine to chassis is good. Make sure ALL grounding is good. Reseat the connector on the ECU. Inspect cables for wear, kinks, and any other sign of distress. Track down even more vacuum leaks. Yes, you may have found one. But like mice and spiders, there are always more. Pull the right front turn signal off and make sure the hose to the charcoal canister is on OK. Could that be it? Not likely, but it is easy to check. Replace all the plugs, assuming you haven't already, with the exact right NGKs. Make sure they are gapped properly. I like to err on the tight side of the gap, as (1) a wider gap is more likely to misfire under boost/high compression conditions, and (2) gaps widen with time.
After that, I think of CPS and MAP. Misfire is usually ignition, which is why I think CPS, assuming the DI has been ruled out. But that's why new plugs is good. And make sure the DI cable is properly grounded.
posted by 192.249....
, Wed, 28 Mar 2007 05:26:30, Wed, 28 Mar 2007 07:30:19 <-- Viewing This Message
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