[GF8 Hesitation at 4k]

1 hour ago, evowrx said:

Have you tried switching out atm? 

AFM? I have cleaned it and it cleared the code. I haven't been able to find one at a wreckers that matches mine and neither do the ones on Trademe. Someone has attempted a repair on mine at some point and has gooed it up, so I cant read the numbers off it, and the plug is long and skinny rather than a shorter stacked one. 

Electrics aren't really my specialty so I dont know if its wise/possible to rewire the plug for a different AFM model, or if that will even work. 

If the AFM was faulty, wouldn't the diagnostics have picked that up?

As a list of things I have done:

• O2 Sensor
• Knock Sensor then Knock Sensor Delete
• AFM Service (this may not have fixed problem???)
• Coil pack (brand new OEM from Subaru)
• Leads (in good nick, from Axel).
• Timing is fine (checked when I did crank seal)
• No Vac Leaks (all checked by mechanics)
• No Codes
• Diagnostics show no issues

 

To do: 

Plugs
Crank Angle Sensor??? (This would throw a code though, wouldn't it?)
AFM???
 

[GF8 Hesitation at 4k]

So I have just bought a brand new coil pack, to be sure, from Subaru.

 

The problem still persists. 

 

Will do an ECU reset. The plugs aren't that old which is why I havent replaced them. FARK i am over this car, I just cannot get it running right.

[GF8 Hesitation at 4k]

Alright then so I have swapped the coil and leads! Immediately, things were better. The massive, jerky hesitation was gone, however above 4k the car was still feeling sluggish - felt to me like it was missing a cylinder. 

 

I took it for a big drive and gave it a bit of a spanking, and the hesitation has crept back. It's nowhere near as bad, but its there. 

 

So, would I be right in assuming that maybe the coil that @axle117 extremely generously donated is on the fritz too, and as the car/coil got hot, it started to fail (how i'd expect a coil to fail normally)? I wondered if perhaps the plugs might have been a little glazed after all of the prior misfires, but since the failure appears to have come back a little, i'm guessing coil fault. Would that mirror everyone's thoughts?

Ill order a new one from my friends at Subaru Lower Hutt tomorrow if so - I REALLY appreciate everyones input on this. I'm so infuriated that the problem I initially thought it was on day one, that I've spent 6 months trying to diagnose, is the fault after all. You guys are absolute legends. 

 

[GF8 Hesitation at 4k]

15 hours ago, slystiguy said:

Check codes weekly.

 

Before shelling out on $$ I'd check resistance in spark leads and coil pack and check against factory tolerances... Only say that because you have some pretty janky looking spark plug lead setup? And it does work on finding dead ones..  Also check all the wiring to and from coil pack make sure nothing is loose. Be easy enough to swap coil out and test tho if someone will lend one to you locally for a couple hours. 

 

 

 

Thanks man. Axle is hooking me up with leads and coil, so I will test that and see how I get on.

 

[GF8 Hesitation at 4k]

15 hours ago, boostin said:

Axle, yours should work. Just slightly different design. Speedy, yours has inbuilt igniter and definitely won't work.

 

I wouldn't be too concerned about that corrosion. 

Cheers mate, I may as well give it a hoon anyway and see if it helps.
 

18 hours ago, SpeedySub said:

Sorry mine is different

This is my one

[pic]

 

It does look like there has been some arcing between them

If you can make my one work you can have it for the price of postage

(or if anyone wants it I will do for the price of postage)

Cheers mate, as mentioned yours has igniter so ill leave it, but thank you
 

18 hours ago, axle117 said:

Mine looks different too


Sent from my iPhone using Tapatalk

Will send you a PM mate. 

[GF8 Hesitation at 4k]

On 9/3/2017 at 7:59 PM, evowrx said:

Sometimes the specialists are the better choice as even though the hourly is higher if they are what theyre meant to be it takes less time and less trial and error to diagnose and fix the issue.

I know I know I know. The car was at the mechanics that looked at it, for a WOF and TBH I didn't actually expect them to go as indepth as they did. 

 

On 9/3/2017 at 11:34 PM, boostin said:

If it's missing under no load too like you say, check dumb things like cambelt timing and injectors correctly connected, ie wires to 1 and 3 swapped, 2 and 4 swapped. 

This is what concerns me the most. I have been on the receiving end of coil failure before, and this doesn't feel like it. It happens hot or cold. It happens under load or not. 

Cambelt timing is spot on, as I've already checked it. Injectors haven't been touched since I own it and bear in mind, it ran absolutely SWEET for over a year.

Here's a pic of the coil @axle117 @SpeedySub

Fark, now I'm looking at it, there is clearly corrosion between the two parts of the coil... looks like it might even have been arcing out. 

Had never noticed until I uploaded that pic now. Shiiiiet. 

[GF8 Hesitation at 4k]

On 02/09/2017 at 10:57 AM, slystiguy said:

+1 for coil pack, hesitation and back firing is almost always coil pack related IME. You can test resistance in coil packs and sometimes it will find a dud but isn't always that accurate. 

 

I wouldn't bother changing pod filter if it's installed properly, won't be hurting anything and doesn't hurt the tune.. I'd be checking that bov isn't leaking. If it's hunting it's most likely a vacuum leak somewhere. Common places are the plastic turbo pipes on intake and intercooler. 

 

p.s sounds like you need to find a subaru mechanic that is confident with the early model stuff, they're pretty simple so if they can't work it out don't go back.

To be fair these guys are great mechanics, but yeah perhaps Suby is not really their forte. I am deeply suspicious of mechanics and do most of the work myself, but this car i've barely had to touch other than oil change etc, since I've had it so I haven't really needed to consult a mechanic. I was weary of a specialist because $$$$ and like I say, I just cant justify spending a grand fixing a three grand car haha.
 

On 02/09/2017 at 11:13 AM, axle117 said:

All good bud.

Send me a pm and we can sort it out.

Will do, ill make sure I have the pic of the coil pack first.
 

On 01/09/2017 at 3:28 PM, boon said:

I could be talking out my arse on this one but I seem to recall an issue where the coil packs crack, then when they get hot they short to the manifold so you lose spark on intermittent cylinders at random.

 

EDIT: Misfire and blowing heaps of smoke, to me, is probably a spark issue. If it was a fuel issue (other than maybe way too much fuel?) it wouldn't smoke.

Appreciate all the feedback. I really hope it is just the coil pack. I will take a photo of the coil pack tonight/tomorrow (well, the numbers on it) and see if either of you above have the correct part. Would LOVE to get this sorted. 
 

[GF8 Hesitation at 4k]

2 minutes ago, axle117 said:

Where are you mate? If you're in Auckland, I have a coil pack and leads that you can use for troubleshooting and if it fixes the problem you can have for a box of beer. 

I'm in Wellington boss, but if you want I'd still be happy to buy em off you if you aren't in need of them and dont mind sending them down? That's really kind of you.

Also, thanks everyone who took the time to offer suggestions, I really appreciate it. The car has been like this for months. I need to do a cambelt soon anyway, so i figure ill try and fix this as well if I have the front off the car (when I was thinking it might be sensor related). 

[GF8 Hesitation at 4k]

I spoke to Subaru about a coil pack a while ago, as mine is older and just has the straight pack mounted on the intake manifold, and it was surprisingly cheap from Subaru. About $150 excl from memory. Ill give the coil a swap and see if I can ditch the pod. Haven't done the plugs, in the past when plugs have been failing for me, it hasn't felt anything like the hesitation I'm experiencing. In fact I'm still really unconvinced it's spark related, but I hope to be proven wrong. 

Whenever I've had spark issues in the past its always a lot more minor - this hesitation is virtually like a key-off as opposed to subtle misfire. 

On 8/28/2017 at 4:25 PM, boon said:

I still think coil. Sounds like a spark issue to me. A triggering problem would cause a CEL.

How exactly did you determine the spark is good? A shitty spark that works just fine at idle will quickly get blown out at 1 bar of boost.

 

The mechanics who had the car for the day told me they said it was holding great spark and rock solid fuel pressure, so I just took their advice on that. 

[GF8 Hesitation at 4k]

Hey everyone,

I understand this is a well documented issue with EJs and I've done considerable reading on this all over the past 6 months, but I'm still coming up flummoxed. 

'98 GF8. Basically stock as a rock apart from a BOV (booooo) and a Pod. Idle has been hunting a little (maybe 100-150rpm fluctuation). When I'm driving it, when I get above 4,000 RPM, if I'm at anything above about 1/8th throttle, it will start to jerk and hesitate quite nastily. It blows a bit of smoke too when it starts misfiring. I can get it to above 4k to red line if i'm just crawling up in revs. 

Ran Diagnostics and it threw Oxy Sensor, AFM and Knock sensor. Replaced all three still the misfire persists. Gearbox has done 255km but the motor only 150km so I also ran a knock sensor delete as apparently the knock sensors can get interference from noisey gearboxes? Problem still persisted.

Took it to mechanics to put on a proper diagnostics computer: no codes, nothing out of the ordinary. They checked the whole engine for vac leaks and found nothing. Strong spark. Strong Fuel pressure. They could not find a fault and they had it for a whole day. Car has a relatively new fuel pump too. The engine will misfire even if it's not under load above 4k (i.e. just free revving at a standstill). It does not drop boost, or have boost spikes. Holds firm.

The car cost me very little and for well over a year, ran perfectly. I'm trying to avoid spending thousands on it as it's only worth 2-3k anyway, so just trying to chip away at what the issue might be. It's not my daily so I don't care if it takes me a couple of months to rectify. 

I'm thinking of doing a crank sensor next? Maybe Camshaft sensors? I'm reluctant to do the coil pack as spark is good. Any other suggestions?

TIA