I have 6 cylinder ford falcon BA factory fitted LPG version. I put in all six spark plugs and coils 5 months ago. When I started car yesterday, it was vibrating badly at idle position and low rpm.
It looks like one cylinder is misfiring. Any idea on what could have gone wrong?
Car misfiring only at idle and low rpm but not while driving/high rpm, right? Could be a lot of things. First thing I would check is pull off the spark plugs leads and look into the holes (where the spark plugs are) checking for any liquid. It should be dry. 1) Sometimes, if the engine was cleaned, water enters a hole/s, or 2) Sometimes, the rocker cover seal/gasket fails and engine oil enters a hole. This liquid causes the spark plug to earth leading to a misfire (electricity takes the path of least resistance), usually at low rpm. Be careful pulling off the leads - a slightly broken lead could also be the problem and pulling off the lead may cause the lead to fully break leaving you stranded (without a lead).
I bought car few months ago so I was not sure how long the plugs and coil were change prior to purchase and therefore I changed them while doing car service.
Are you saying it is because of faulty plug or coil?
Not enough electrical grease between the plugs and coils, try reapplying it.
it's 6 cylinders I don't think you would notice the misfire while running at higher rpm
did you space the plugs, pull out the plugs and have a look at them to check if there's anything that might be concerning or irregular
My experience with V6 commodores tells me you'll notice a misfire even at high RPMs.
I had this problem in another car and it was actually the ECU sending faulty messages to one coil pack. It always fouled the plug and kept having spark blow out.
I am getting it checked on Thursday. It seems like there is something which I can't figure out myself.
have you swapped around plugs and coils from other cylinders to isolate the issue?
also, spray some aerostart around the manifold. see if it picks up on the revs. could be a manifold gasket.
Any updates? My money is on bad coils (aftermarket ones can be a bit iffy) or a vacuum leak (namely in intake manifold gasket)
I had a great time with an AUII, 6 cylinders and LPG, backfiring, and blowing off the airfilter.
I replaced copper leads with carbon leads under wise advice from one mechanic, then put the copper back myself. I have to admit mechanics have been using the same line about one being better than the other for decades. In between , I had to replace the coil twice, and at huge cost (different cylinders blown). I fixed it by selling it. You can find heaps of stories AU LPG on the internet, and none of them are worth reading.
An old interstate friend later told me it was all about a different spark plug gap for Falcon LPG, but I'll never know
I end up changing all coils again. It worked fine for one week and it is now giving cranking noise at start however when it is started and gets heated, it is running smoothly.
It looks like I am having trouble with starter motor now which I changed when put in new coils last week.
FML!
Why did you replace the spark plugs and coils five months ago? Could be that it looked like you'd fixed whatever problem that you were trying to fix back then, but didn't and that same problem is back. Or it could be that one of the plugs or coils that you replaced is now faulty. Or it might be a whole new fault. Diagnosis is a little tough in a forum.