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2004 IS300 Manual Swapped
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Discussion Starter #1
Hi everyone, hoping to get some advice. Just finished the install on my BC 264 cams along with the whole timing belt service, did an engine break in per Crower of 20 minutes at 1500-2000 rpm with an engine break in oil. Started right up and ran great, no issues at all. Drained the oil and refilled for a test drive, and got a CEL/flashing TRAC light almost immediately. Got it scanned and codes were for Cyl #1 misfire and random misfire. It idles fine, runs fine, and doesn't seem like there's any misfire at all (my Civic had a misfire issue back in the day and was nothing like this). I replaced the plugs but did not do the wires, and the connectors for the coil packs were fairly brittle. First step is new wires and connectors, but figured I would ask if anything else could be causing my CEL. Thanks for any advice!
 

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Discussion Starter #2
Oh, and I did check valve clearances. All were in spec on the tighter side, except two exhaust valves I measured at 0.009”. Not sure if that would be a big enough issue to cause a misfire code, especially since I read that the BC spec is 0.006-0.008”.
 

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Discussion Starter #4
Recheck your connections at the coils and plug wires. Also check your reluctor on the crank.
Tried spraying some electrical connector cleaner in the coil connectors and made sure wires were tight, also ordered a set of connectors and wires to install tomorrow anyways. Since mine were rough. There was lots of oil in the spark plug valley (cleaned out during rebuild) so wondering if there was possible coil damage, will check that tomorrow too.
What is the reluctor and how would I check it?
 

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Often people forget to remove the retainer (red arrow) when doing the timing belt and crank seals and damage the reluctor or whatever you call the sprocket wheel (green arrow) at the back of the pulley. The teeth spin past a sensor telling the ECU where the crank is and when to fire, if its damaged you get a misfire.

137232
 

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Discussion Starter #6
Often people forget to remove the retainer (red arrow) when doing the timing belt and crank seals and damage the reluctor or whatever you call the sprocket wheel (green arrow) at the back of the pulley. The teeth spin past a sensor telling the ECU where the crank is and when to fire, if its damaged you get a misfire.

View attachment 137232
Dang, was hoping it wasn’t the trigger wheel haha. I did remove the retainer before pulling the trigger wheel and didn’t notice any damage when re-installing.
 

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Discussion Starter #7
New plug wires and connectors are in, CEL is still on but I want to get it cleared then see if it comes back. I drove around for 10-20 minutes and it ran great, didn’t seem to be any issues. That said, I didn’t go above 3/4 throttle or 4K rpm since I want to be gentle with the new cams for a little bit. Will update tomorrow once I get the CEL cleared.
Oh, and all 3 coils tested OK.
 

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Discussion Starter #8
So neither of the stores I went to had code readers that would clear my CEL, finally decided to just pull the negative lead on the battery and wipe the ECU. While I was waiting I also cleaned the connector for the crank sensor. Started it back up, no CEL and ran great. Idle was low and felt like it might die at first, but I think the ECU figured it out because idle is fine now. Fingers crossed I’m good from here on out!
Also, in a moment of frustration I took it to redline in 1st leaving autozone, HOLY COW it feels awesome with the cams!!! Gonna put a couple hundred more miles on before playing with the cam gear.
 

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Discussion Starter #9
CEL is back on after 30 miles, pulled plug #1 to see what’s going on and despite being a little oily it looks fine. Any chance not using an iridium plug is giving me issues? I’m using NGK V-Power plugs, here’s a comparison of the old and new plugs.
 

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Discussion Starter #10
Pulled the plug boot and injector plug on cyl 1 to see if it’s actually been misfiring without me noticing, and it definitely ran worse when pulling each so I think I’m right in saying it hasn’t been misfiring significantly to this point. Still at a bit of a loss at this point, really don’t want to pull the crank pulley off to inspect the trigger wheel but getting to the point where I can’t think of what else to look at. I did confirm that cam timing is still good.
While idling I did notice there was a mechanical clunk coming from the throttle body, not sure if this is normal or causing problems but figured I’d point it out. Thanks for any advice!
 

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Could try cleaning the MAF and maybe the idle holes under the plate on top of the throttle body. Im grasping at straws here but who knows.
 

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Discussion Starter #13
Quick update, I reset the ecu again Sunday morning to head to a Cars & Coffee event and ended up putting around 60 miles on the car with no CEL. I left the HVAC on so the idle never dropped too low, so I’m wondering if the slightly choppier idle from the cams is either causing a misfire at low idle or making the ecu think there is one. I’ll continue to put some miles on the car and order an OBD2 scanner that can do real time data to see.
 

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If you have a adjustable cam gear you could try moving that a degree or 2 either way to see if it helps, assuming it is the lumpy idle.
 

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Discussion Starter #15
If you have a adjustable cam gear you could try moving that a degree or 2 either way to see if it helps, assuming it is the lumpy idle.
I have the cam gear set at 0 right now, was originally planning on going to -3 after putting some miles on. Does retarding the timing make idle worse though? Also need to call Titan and confirm how many degrees each tick mark is.
 

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It can change the idle. I don't know any specifics with those particular cams, but as they are a fair bit more aggressive than standard you might find it gets worse as you dial it back. I seem to remember reading that those cams were on the limit of what the standard ECU can handle, you can search around for the threads on them and what others are running.
 
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