Another Rb25 Misfire Topic

[fmlycar]

Should have mentioned it's a auto converted to manual so I think timing is supposed to be 20 deg btdc. That's what it was set at and tuned at anyway.

Is there any way to check the resistance for the CAS to check if it's faulty?

TPS values are 0.42v idle with engine off and 4.06v wot engine off.

[fmlycar]

Tried a different cas and made no difference.

Adjusted tps to 0.45v closed and 4.10 wot and no change

Running out of ideas

Edited July 21, 2015 by fmlycar

[fmlycar]

Checked fuel pressure and is 38psi at idle and free reving without load it goes over 50psi. would it be worth while trying another set of coil packs?

[fmlycar]

Checked TPS again and adjusted to 0.5v closed but only got 3.30v at WOT with a multimeter. This was tested with engine off and ignition on. While running I had very similar result. It's conflicting values with what the power FC was reading this morning. I had 0.49v at idle (car running) and 4.11v WOT. What are the acceptable values for the TPS? This could be my problem if it uses tps feedback for fuelling maps and it's reading low.

[fmlycar]

Miss has now gotten worse. O2 sensor isn't showing voltage on the power fc. What else can I do? Its a 1500km trip to the closest dyno and it's my daily so I'm getting desperate

[Ben C34]

Coils.

[Hadouken]

road trip?

I cant remember if we covered this,

what gap is your spark plugs?

have you tried to gap them down further to see if the miss goes away?

Have you lowered the boost to see if the miss goes away?

[fmlycar]

Tried a different set of coil packs (splitfires) and didn't improve. So I put my splitfires back in with a plug gap of 0.55 and still no improvement. Don't know if there is another car in town I can lend coil packs off. Only a couple imports here and even less are modified.

Boost won't go over 0.95 bar atm. As soon as it tries to build boost it coughs and hesitates, pops and backfires then will clear up and pull but is now breaking down above 12psi once it finally gets there.

My coil packs look to be in newish condition. Don't want to go throwing 600 at new coil packs if I don't have to or if it's not the problem.

Edited July 24, 2015 by fmlycar

[fmlycar]

Checked all earth's. Cleaned aacv while I was at it.

Is there any way to check coil packs with a multi meter? I tried checking between + and - on the coil pack but couldn't get a resistance reading at all. Also tried from the spring in the bottom to every pin and nothing came up on my multi meter. Have I missed something there?

[fmlycar]

Checked solder joints for afm, all ok. Checked continuity for coil pack loom and all good. Applied dielectric grease to coil pack boots with no improvement.

[Ben C34]

You can't check coils with a meter.

You've given it a red hot go. Due to the distance of a Dyno perhaps buying a wideband gauge would be wise.

[fmlycar]

Yeah thinking that's the next step. Seems like a solid investment and could save me a lot of time and money. And recommendations on what's good to run all the time?

[iruvyouskyrine]

Innovative MTX-L

[XRATED]

Sounds like a leak under vacuum.

Injector caps, injector manifold seals, Tb shaft seal.

Stuck, busted nrv on the brake booster or pcv valve.

Been loosing any coolant?

Is the keyway flogged out in the CAS/ camshaft drive?

Does the Toyota dealership still have a Dyno?

Pfc's are prone to dry sockets on the boards, can throw up similar issues.... usually more consistent.

Edited July 27, 2015 by XRATED

[fmlycar]

No Coolant loss, keyway on cas/camshaft is perfect, no leaks from injector caps or manifold seals. Haven't check TB shaft seal but have sprayed that area fairly liberally with carby cleaner with no change in idle. Not sure if Toyota still have a dyno.

Coated the coil packs in urethane seal coat and regapped the plugs at 0.7 and I did notice a slight improvement initially but still breaking down under heavy load/boost. I think the coil packs are the culprit in this case. I was in denial as they're splitfires and looked to be in good condition, however that couldn't mean there isn't anything wrong with them. Especially since the ignitor is built into each coil pack. Guess all I can do is order some new one's and see how I go. Bit of a roll of the dice but don't have many other options.

[scotty nm35]

If the coils aren't getting enough voltage they will give a low output spark. Tried a temporary decent power feed?

You could buy a set of coils then realize it's the PFC that needs changing, it's more likely if it's older than the coils.

[XRATED]

If you've tried other sets of coils with no result then, a new set is unlikely to fix your issue. As Scotty has said, power supply and ground for the coils make an amazing difference.

Your comments about issue improving post coating the coil pack boots.......... I'd try a new coil pack loom, clean your grounding points and/or add an additional ground cable from the back of the head to the battery and add a larger (fused) power wire directly from the battery to the new loom. Clean or swap the ignitor module.

It is odd, spark will usually blow out under peak load and get worse with more throttle and boost.

Leaking fuel injector or poor throttle/accel pump tune or damaged fpr ? Could be flooding to the point of misfire during vac and transition to boost.

I lived and worked in Alice many years ago (had an hr31), so I can empathise. Back then, the local Toyota dealership had a dyno and would tune (mostly Finke buggy's etc) performance cars/buggy's etc.

[fmlycar]

Power fc is a gtt model and about the same age as the coil packs if not newer (I can dig out the receipt to check). I've checked voltage at the coil packs at idle and they're all getting 14.19v after taking it for a drive last night it is missing at idle and generally running rough.

Will get some new coils packs, plugs and fuel filter and hope like hell that fixes my issue. I could always try my coils in another car and see if it makes theirs run like ass too.

[Ben C34]

So all started after an overbooost?

I'd do a comp check before spending cash.

[fmlycar]

Already done a comp test and was 150psi on all 6