Will missing engine throw CEL???

[Ru Dawg]

Just wondering if the DIS sends inputs to ECU... another words like my subject, will missing plugs or wires cause a check engine light?

 

[Alec]

It can, at least with my OBD2. I've gotten misfire codes which the computer attributes to an ignition problem.

 

[Ru Dawg]

woops, can someone move this to the GENERAL forum?

 

[MrShorty]

I'm currently running on four of six cylinders with no CEL, no KOEO, nor KOER codes ('92). Most '95's are still running OBD-1/EEC-IV. It appears that, in '92, the computer can't tell if a cylinder missfires, but, by '96, it can. Do you suspect a missfire? Here's what I did on mine, when I suspected a misfire. With the engine idling, pull each spark plug wire off the spark plug one at a time (you could also pull the injector plugs. spark plugs wires are easier to get to). If the cylinder is functioning as it should, the engine will bog down. A misfiring cylinder will not affect the idle.

 

[Jefe]

With OBD-II, yes. (not sure when Ex's switched to OBD-II) Once it reaches one of two categories a CEL will come on; a 30%(?) misfire in one cylinder, or a certain count of times any cylinders have misfired.

 

[Glacier991]

Yes OBD-II can detect engine misfires. Has to do with timing from the crankshaft position sensor believe it or not.

Happy exploring

Chris

 

[boominXplorer]

96 and later have OBD II
95 and earlier have OBD I

 

[PunkChild]

Just for reference it's MIL (Malfunction Indicator Lamp) not CEL. Not trying to be an ass but it bugs me since I'm an auto tech.

 

[Glacier991]

Punkchild you are correct of course. However Ford Service writers were having trouble communicating with customers who saw the words "Check engine" on a light, and not understanding when the service writer asked if they got a "Malfuntion Indicator Light". Ultimately in the wearly days even Ford service writers came to call it the Check engine light. Later the "Service Engine" light. I first saw it abbreviated CEL and SEL on the internet, but it does the same thing. Different strokes for different folks.

I think if you ask a Ford service writer they'll tell you depending in the year they use ONE name with the customer, and another with the mechanics.


Happy Exploring

Chris

 

[Paul Gagnon]

Originally posted by Ru Dawg
woops, can someone move this to the GENERAL forum?

It's fine, here is the best place for it actually.

 

[dogfriend]

I know this is an old thread, but I thought that I would add some pertient info:

Even with OBD-II, it is possible to have a misfire without generating a code or CEL (MIL).

I found this out today as I was trying to diagnose what I thought might be a transmission problem. I recently got a scanner (Diagtek) and ran KOEO , KOER and stored code tests without any results. So I hooked up the scanner and tried to repeat the problem under the conditions where it was happening (60+ mph, uphill or heavy acceleration). Bingo, when set to monitor for "Engine Currently Misfiring" it would briefly switch from "No (false)" to "Yes (true)" just after the jerking that I thought was the trans.

It still hasn't set a CEL (MIL) even though I repeatedly made it misfire by pushing it hard uphill just to make sure that was the problem.