another misfire thread...

[black91turbo]

Well as I previoulsy posted I just got my motor done.....I put in the Lex AFM and the PTE 550's with a AFPR. Before when i would start the car the idle would sputter and go in and out b/w 1000 and 1200 until normal operating temperature and then would go away and idle normally at about 650. Now it is sputtering all the time. It is sputtering through the gears (the first 3 anyways) so I am thinking it is a misfire. I have no codes, running 36 psi of fuel at idle, and my wideband is reading about 15.9-16.2 during the sputter at idle but every once in a while will suddenly jump to above 17. Ignition timing is set to 12 degrees and the cam timing is dead on. I don't know where to go from here so any input would be appreciated...Thanks guys!

 

[jdub]

Drop your fuel pressure to 28-30 psi at idle w/ the vac line connected to the AFPR.

You also might want to check your spark plugs and wires. What plugs are you using?

 

[black91turbo]

Well when i drop the fuel pressure my AFRs go to 17.8 at start up and then flat line (18 or over) at idle.....do you think my sensor is FUBARED? I am using the DENSO Iridium Spark plugs from Toyota.....and my plug wires have about 1000 miles on them. Thanks for your input by the way JDUB...I was hoping you or someone with lots experience would hep me out!
Another thing...how much vacuum am i supposed to see my FPR gain after i give it some throttle? because right now I am pulling in 5 psi from 36 to about 41...

 

[jdub]

Those AFR's are very lean for idle...it should be in the 14.5-15.5 range. Did you reset the ECU by pulling the EFI fuse after you installed the Lex/550 combo? When you drop AFPR pressure, did the sputter go away or at least get better?

Doesn't appear the plugs/wires are the problem. Did you check the gap on the plugs?

Set your timing to the stock 10 deg BTDC with the diag block jumped per the TSRM.

The AFPR should increase FP 1:1 with boost...that is what you look at. Manifold vacuum wise, this is a good guide:
http://www.cygnusx1.net/supra/TechTips/vacuum_gauge_readings.aspx

 

[black91turbo]

Those AFR's are very lean for idle...it should be in the 14.5-15.5 range. Did you reset the ECU by pulling the EFI fuse after you installed the Lex/550 combo? When you drop AFPR pressure, did the sputter go away or at least get better?

Doesn't appear the plugs/wires are the problem. Did you check the gap on the plugs?

Set your timing to the stock 10 deg BTDC with the diag block jumped per the TSRM.

The AFPR should increase FP 1:1 with boost...that is what you look at. Manifold vacuum wise, this is a good guide:
http://www.cygnusx1.net/supra/TechTips/vacuum_gauge_readings.aspx

When I drop the fuel pressure the sputter stays the same just idles down a bit. I did not check the gap on the plugs because I was told that the toyota plugs come pregapped!? Yeah when i get home I will set the timing to 10 degrees. Thanks for your help JDUB! I will update this tonight

 

[jdub]

Based on a stock CT-26, gap them at .030".

Might want to put a multimeter on your coils and test per the TSRM.

 

[black91turbo]

Based on a stock CT-26, gap them at .030".

Might want to put a multimeter on your coils and test per the TSRM.

I swapped the AFM housing from the LEX to stock and it fired right up with perfect AFRs. It sputtered for a little bit but then I gave it throttle to about 3000rpms and the sputter went away. I took it out and it was smooth as it gets through the gears....Still kind of puzzled though because looking at my mods i should be running rich with a LEX and not lean. Anycase, it runs great now. I still need to check on those coils like you said. Oh and the fuel is at 29 psi with 14.8-15.1 AFR (on the stock AFM) What do you think? ::shrug::

 

[jdub]

A Lex AFM allows more air through (~25% more)...with 440 injectors you can run lean. That's why you use the 550 injectors...they counter balance the additional air with 25% more fuel. You're running a stock AFM with 550 injectors, you're correct...it should be rich, but your FP and AFR is good. That's kinda puzzling.

Did you drill out the J-tube return line?

Is the accordion hose in good shape (no leaks) and the hose connectors tight?
(i.e. no unmetered air is getting past the AFM)

 

[black91turbo]

A Lex AFM allows more air through (~25% more)...with 440 injectors you can run lean. That's why you use the 550 injectors...they counter balance the additional air with 25% more fuel. You're running a stock AFM with 550 injectors, you're correct...it should be rich, but your FP and AFR is good. That's kinda puzzling.

Did you drill out the J-tube return line?

Is the accordion hose in good shape (no leaks) and the hose connectors tight?
(i.e. no unmetered air is getting past the AFM)

I actually bypassed the j tube so that really can't be the issue...as far no unmetered air getting in, i have checked all of my hoses (they are all new from toyota) to make sure they are nice and tight and they were. I guess i need to check for vacuum leaks in th emanifold area...I drove it today all day and put about 100 miles on the new motor and my AFR were dead on at 14.8-15.2 the whole time at idle and about 14.6-15.1 just cruising in gear. At boost they get really rich..as rich as 10:aigo: But i am sure that has something to do with the BOV and me not recirculating to the intake... BTW i did flow test my injectors before install too at cleaninjectors .com and they came back great...all that does is complicate things even more

 

[jdub]

That's what you would expect to see with the Lex AND 550's installed :dunno:

Did you use the same electronics on both housings?

Any codes?

 

[black91turbo]

That's what you would expect to see with the Lex AND 550's installed :dunno:

Did you use the same electronics on both housings?

Any codes?

Same electronics...no codes. I am posting a link of the engine bay...maybe I hooked something up wrong

http://i230.photobucket.com/albums/ee37/black87turbo/101_3286.jpg

discard the date because I just took the pic

 

[jdub]

Take a look at this diagram:
http://www.cygnusx1.net/supra/TechTips/graphics/vacuum_2h.gif

Make sure your AFPR vac line is to the correct fitting and check the line orientation of the VSV (#17650) is correct. If you are not getting boost pressure to the AFPR, fuel pressure will not rise on the 1:1 ratio as designed. This could be it (crosses fingers)...at least for the lean AFR's with the Lex. Are you seeing any change in FP when you disconnect the vac line from the AFPR?

I can see you have the BVSV line misrouted...it should be connected from the hardline in front of the 3000 pipe to the fitting on top of the TB. It looks like you have eliminated the EGR...is the other fitting on top of the TB capped off?

The routing for your catch can is a bit off too. The T-fitting from the TB should be in the line going to the accordion hose...the NA PCV hardline should be straight to the catch can.

 

[black91turbo]

Take a look at this diagram:
http://www.cygnusx1.net/supra/TechTips/graphics/vacuum_2h.gif

Make sure your AFPR vac line is to the correct fitting and check the line orientation of the VSV (#17650) is correct. If you are not getting boost pressure to the AFPR, fuel pressure will not rise on the 1:1 ratio as designed. This could be it (crosses fingers)...at least for the lean AFR's with the Lex. Are you seeing any change in FP when you disconnect the vac line from the AFPR?

I can see you have the BVSV line misrouted...it should be connected from the hardline in front of the 3000 pipe to the fitting on top of the TB. It looks like you have eliminated the EGR...is the other fitting on top of the TB capped off?

The routing for your catch can is a bit off too. The T-fitting from the TB should be in the line going to the accordion hose...the NA PCV hardline should be straight to the catch can.

I am going to double check if the FP changes when the vac line from the regulator is disconnected....

I actually capped off both fittings on top of the throttle body because when i had them on there it sounded like they were producing a leak for some reason and now i am not hearing that leak...I routed the vac line from the hardline by the coil pack straight to the hardline by the intake manifold...does the throttle body need vacuum?

When i was doing the catch can i read the tech section and the guy had the TB port capped off, so i kept reading and found that i need to T it but to the hose that is going to the catch can..... I think you may have actualy posted that he needs to T it to hose #4 (on his pic) which was the hose going to the catch can...I must have interpreted that wrong...I thought that the guys setup was kind of confusing with him using the stock PCV hardline..

 

[jdub]

The T from the TB needs to be in the hose from the accordion to the catch can. If you think about it, the catch can needs vac...the TB produces the best source 90% of the time when the motor is not in boost. Under boost, the accordian produces a weak vac.

The TB produces vac...the BVSV needs a vac source to function properly.

 

[black91turbo]

The T from the TB needs to be in the hose from the accordion to the catch can. If you think about it, the catch can needs vac...the TB produces the best source 90% of the time when the motor is not in boost. Under boost, the accordian produces a weak vac.

The TB produces vac...the BVSV needs a vac source to function properly.

ok i will reroute everything tommorow...maybe that will solve my mysterious lean AFRs with the LEX...Thanks for all of your help jdub! I will update this tommorow night!

 

[black91turbo]

Well I rerouted the vacuum going to the PCV....It did not do anything for my AFRs on the stock AFM....they pretty much stayed the same. Double checked the FPR when i take that vacuum line off of it, the FP goes up instantly. Still perfect AFRs through the gears (except very rich under boost)Come to think of it, i was at about 12.6-13.4 AFR under boost with the LEX but normal driving they went as high as 17.1.

http://i230.photobucket.com/albums/ee37/black87turbo/101_3287.jpg

http://i230.photobucket.com/albums/ee37/black87turbo/101_3289.jpg

BTW I am getting great voltage to ecu from all 6 injectors....Don't know how that helps but I checked it just in case