Big Problem Help!!!

[maldrake20]

guys i was driving down the freeway the other day not thrashing the car or anything doing aroun 120km/h and put my foot down in 5th to overtake slow car in front and all i got was this whomp whomp whomp through the exhaust but no compression revs up to 2500rpm nothing past there I had to putt putt all the way to nth syd from gosford at 70-80km/h and not got past 2500rpm or the whole car would shudder and now tonight I had to drive it back home and even worse getting less and less compression taking it to the mechanic in the morning but I need to ask you any ideas!!?? Just so the bugger can't rip me off!

I turn the car off and back on and it is ok as soon as I get going same thing happens again?

Also what is the HICAS light and will that have anything to do with it?...

Please help guys!

[JimX]

If the car starts and idles ok then it's probably your AFM. Check for a loose plug for a start, that is hopefully all it is. I had the same symptoms when I accidentally yanked out my S-AFC wiring loom, thus causing the AFM to become disconnected.

Not sure if the HICAS has anything to do with it, mine never came on when I had this problem.

[maldrake20]

I had a search through the threads last night and it sounds exactly like this except mine shudders and ****ters when i put my fot down

"HELP !- losing a cylinder in the rain

As topic states:

losing cylinder(s) when parked outside in the current Sydney weather for 6 hours on an otherwise stock ECR33. after a while (quite a while) & some heat it comes good. The plugs are newish and the Datto has never missed a beat.

Are S1 RB25's prone to this ??

has anyone else experienced this ??

It's kinda spooked me... "

Yup, adam's spot on. it'll sound like a WRX just off idle & runs about as bad as an engine can without stalling !

Swapping the pos of the coils on the alloy mount... well I'm dead certain the moisture was between the coil & mount and that by simply removing/inspecting/cleaning/silicone spraying/replacing (with sighted good ones) the known faulty ones came good !!

Also I eyeballed the sus coils arcing (up to 12mm !!) to the alloy mount from their bases which was a bit of a giveaway.

I reckon seeing is believing, & there's been a lot of threads about coil pack testing involving swapping coils and tossing the failing ones. So how many perfectly good ones get tossed !!

Using the "Crank & Eyeball" test, if the coil is good you should see a spark, but NOT necessarily at the plug electrode !

If no spark do the GraemeW test. Many have questioned the validity of this test, but if it fails it's well & truly dead. I know from searching these forums that other members coils' have passed the resistance test but got binned anyway, consequently the rumour exists that this test is unreliable - methinks not !!

P.S. I gapped the plugs to .75mm and no more miss under load @4500rpm above 8-9 PSI with stock ECU. Jay95 posted about this in another thread & I give it the full thumbs up.. gap 'em down with confidence.

so do you think it could be the coil packs?

[JimX]

Yep definitely could be coil packs, it's just hard to understand exactly what the problem is going off a written description which is why I suggested AFM. Also I just noticed you said it's getting worse, if it's AFM then it's all or nothing (ie it won't get any worse). Check your coil packs too.

Worst case it's your rings or something, in which case you should probably look at your state of tune because they probably shouldn't just go like that with regular driving.

[Steve]

Well, if it all happens at 2500rpm, I am tending to agree with JimX's first impression - AFM.

Generally the cut is at 2500rpm from limp home mode.

Check for loose wires and try giving the AFM a clean, but first, have you tried doing an ECU diagnostics?

Like all things car though, you can never be 100% certain what it is until you have tried eliminating the possibilities:)

[maldrake20]

Sorry mate extreme newbie here as far as maintaining the car myself always goto a mechaninc... AFM? Air Fuel Meter? and how would i try doing any ECU diagnostics?

I took it too the mechanics today left it there all day and the bloody thing did not play up once and he can not see anything wrong I drove it home and around the coast for bout 1hr and no probs... could it have something to do with the rain i was driving in?... I don't see how has never been a prob b4.

What loose wires would i be looking for? thanks for your suggestions so far guys please help me out more if you can! thanks!!!

[JimX]

If the problem has fixed itself then your engine is definitely fine It sounds like an intermittent contact in your AFM (Air Flow Meter). This is the thing just behind your air box, it measures how much air is going into your engine. Unplug the small wiring connectors and spray with some electrical contact cleaner (get it from Jaycar), plug it back in and try again. Also spray the AFM filament with the contact cleaner. Do a search on cleaning the AFM for more detailed instructions.

[hippy]

sounds like a dry joint somewherw in the elctronics ...??

[GTRgeoff]

I got a bit enthusiastic cleaning the engine bay and a day later the barge started dropping cylinders under load. Fine off boost and stumbling at idle so I whipped out the coil packs and water had filled in 3 of the plug wells and was seeping past the rubber weather seals. Even so the damage was done and a serious coating of baked on crap is right up the ceramic insulator on a few of the plugs. I tried to clean most of it off but was still dropping a cylinder so a new set of 7 heat range standard plugs gapped to 0.8mm has solved the problem and it's delivering more power than ever. And I was worryng it would be a coil pack.

I leave the plug cover off with the copper plugs so i can clean and gap them every time it starts to get rough under load....about 5000km but the power is better than the platinums.

Sounds like [some of] your plugs got water around them and were not firing in some cylinders. After 18 years of racing cars, swinging spanners for a living and getting a mechanical engineering degree I still find that plugs are the number one culprit for lost power and misfires.

[Steve]

I agree hippy, probably a dry contact. Often I have found that plugs are the main culprit - over years of vibration and heat cycles they can play up.

I hope it is that anyway, cos I rember the dramas enrico went through when he was having the same problems.