Engine running rich, stumbling, rough idle after motor swap - Page 2 - Toyota GR86, 86, FR-S and Subaru BRZ Forum & Owners Community

toyubie · 08-04-2017, 04:18 PM

I found my old port injectors (on the left), they look very different from the ones I just pulled from the motor (right).

Although I forgot fuel pressure was a thing and sprayed gasoline directly over the engine disconnect plug so I'm waiting for it to evaporate before I start her up.

You guys have been incredibly helpful, I can't thank you enough for staring at my shitty data logs! Hopefully putting my old port injectors in will solve this. I'll keep you guys updated.

toyubie · 08-04-2017, 05:20 PM

Engine started right up, no pump of the pedal needed. Went right to cold start RPMs, dropped smoothly to idle. No check engine light. No stumble/hesitation at 3k.

http://www.datazap.me/u/toyubie/brz-...ata=2-3-7-9-10

Data looks much more stable although the fuel trims are not what I expected to see. I suppose that could just be the ECU learning. I'll be driving to work in about an hour so we'll see how she does.

EDIT: Also I'm sure there's a lot of gunk built up from running so shitty the past few months. Could take some time to burn off.

Gords_zenith · 08-04-2017, 11:45 PM

Do you know why the injectors were different?

steve99 · 08-05-2017, 02:51 AM

ok sounds good i suspect you have found the cause.

I think that dude you bought the motor off might have been "spinning a yarn" as my old man used to say.

If that motor had different (larger flow) injectors then it was almost certianly running forced induction . You dont need larger port injectors on Naturally aspirated motors even to run E85.

The fuel trims will be a bit erratic for 100km or so till the ecu gathers and interprets some average fueling data.

toyubie · 08-05-2017, 08:46 AM

Quote:

Originally Posted by steve99

I think that dude you bought the motor off might have been "spinning a yarn" as my old man used to say.

If that motor had different (larger flow) injectors then it was almost certianly running forced induction . You dont need larger port injectors on Naturally aspirated motors even to run E85.

Quote:

Originally Posted by Gords_zenith

Do you know why the injectors were different?

I was able to find my messages to the seller in a backup and he does actually say he was running E85, but nothing about changed injectors. I bet he was tuned for them, didn't pull them out, and forgot about them.

Quote:

Originally Posted by steve99

The fuel trims will be a bit erratic for 100km or so till the ecu gathers and interprets some average fueling data.

Already seems to be leveling out during partial throttle pulls! It feels brand new, awesome!! Can't believe I didn't check them sooner.

Dru670 · 04-07-2018, 01:11 PM

Did you figure out the problem and is it fixed?

08-04-2017, 04:18 PM	#15
toyubie Member Join Date: Apr 2016 Drives: none Location: none Posts: 41 Thanks: 4 Thanked 15 Times in 10 Posts Mentioned: 0 Post(s) Tagged: 0 Thread(s)	I found my old port injectors (on the left), they look very different from the ones I just pulled from the motor (right). Although I forgot fuel pressure was a thing and sprayed gasoline directly over the engine disconnect plug so I'm waiting for it to evaporate before I start her up. You guys have been incredibly helpful, I can't thank you enough for staring at my shitty data logs! Hopefully putting my old port injectors in will solve this. I'll keep you guys updated. Last edited by toyubie; 08-05-2017 at 08:39 AM. Reason: Fixed image quality

08-04-2017, 05:20 PM	#16
toyubie Member Join Date: Apr 2016 Drives: none Location: none Posts: 41 Thanks: 4 Thanked 15 Times in 10 Posts Mentioned: 0 Post(s) Tagged: 0 Thread(s)	Engine started right up, no pump of the pedal needed. Went right to cold start RPMs, dropped smoothly to idle. No check engine light. No stumble/hesitation at 3k. http://www.datazap.me/u/toyubie/brz-...ata=2-3-7-9-10 Data looks much more stable although the fuel trims are not what I expected to see. I suppose that could just be the ECU learning. I'll be driving to work in about an hour so we'll see how she does. EDIT: Also I'm sure there's a lot of gunk built up from running so shitty the past few months. Could take some time to burn off. Last edited by toyubie; 08-04-2017 at 05:38 PM.

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08-04-2017, 11:45 PM	#17
Gords_zenith Senior Member Join Date: Nov 2012 Drives: WRB BRZ Sport Tech Location: Durham, Canada Posts: 354 Thanks: 178 Thanked 110 Times in 64 Posts Mentioned: 3 Post(s) Tagged: 0 Thread(s)	Do you know why the injectors were different?

08-05-2017, 02:51 AM	#18
steve99 Banned Join Date: Dec 2013 Drives: FT86 Location: Australia Posts: 7,996 Thanks: 1,035 Thanked 4,994 Times in 2,984 Posts Mentioned: 598 Post(s) Tagged: 2 Thread(s)	ok sounds good i suspect you have found the cause. I think that dude you bought the motor off might have been "spinning a yarn" as my old man used to say. If that motor had different (larger flow) injectors then it was almost certianly running forced induction . You dont need larger port injectors on Naturally aspirated motors even to run E85. The fuel trims will be a bit erratic for 100km or so till the ecu gathers and interprets some average fueling data.

04-07-2018, 01:11 PM	#20
Dru670 Senior Member Join Date: Oct 2015 Drives: 2016 Scion FR-S Location: Las Vegas Posts: 155 Thanks: 11 Thanked 8 Times in 8 Posts Mentioned: 1 Post(s) Tagged: 0 Thread(s)	Did you figure out the problem and is it fixed?

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