Turbo - Stock Fueling, etc. (1 Viewer)

[Cruiserhead05]

Hey guys,

Looking for a few opinions here.

So my current setup is a '97 LX with a 62-1 Turbonetics turbo. Intercooled, with full 3" exhaust. Tranny is stock with upgraded valve body. Fueling is stock with cleaned injectors and factory HG replacement it OE parts. Spark plugs and wires were replaced 15k miles ago and we used MR2 Turbo plugs.
Produces 7-9lbs of boost easily.

At the time of install, we did install a wide band and fuel/air was all happy at full throttle. Because of space limitations, this was removed since everything was initially 'kosher".

I've now put 10k+ miles on the setup with no issues.

During a 700 mile roundtrip over the weekend, I decided to push things on the highway. After several second of 7+ lbs of boost, I noticed a subtle "jerking" or "bucking" from the trip. I immediately let off the gas and given that I was in the middle of nowhere at night, didn't try it again.

Does this sound like a fueling issue, spark issue, tranny slipping, etc.?

 

[scottryana]

Really hard to say with this much info, any noise, did you have a scan gauge on it, what were the IAT's?

Did it feel like fuel cut? I don't think you will have any spark blow out issues at 7lbs. How is the driveability since? Notice any transmission slipping?

 

[Wheelingnoob]

What fuel pump?

The only times I have had issues like that on boosted cars was when I had fouled plugs and or loss of fuel pressure causing a lean miss.

 

[Cruiserhead05]

I do have a scangauge. IAT's were at about 85F.

It did feel more like fuel cut, as the tranny has had no issue before or prior.

Fuel pump is stock and original. Truck has 181kmiles. Maybe it's time for a Supra TT pump?

 

[scottryana]

New fuel filter and pump certainly wouldn't hurt.

 

[Wheelingnoob]

I do have a scangauge. IAT's were at about 85F.

It did feel more like fuel cut, as the tranny has had no issue before or prior.

Fuel pump is stock and original. Truck has 181kmiles. Maybe it's time for a Supra TT pump?

IAT's sound fine.

Its really hard to know what is could have been with out having more data (AFR's and so on). I would start with the cheap things first and work from there. When was the fuel filter last changed?

I would do in this order:

Check all hoses (vac and otherwise)
Change spark plugs (My 1jz would foul plugs like they where going out of style felt like a studder under boost)
Fuel pump

 

[Wheelingnoob]

New fuel filter and pump certainly wouldn't hurt.

lol beat me by 5 sec.

 

[Cruiserhead05]

Thanks for the feedback guys. I'll check the plugs this weekend and also look at reinstalling the wideband permanently. All vac hoses are good to go.


The fuel filter was replaced at 150k when the head gasket was replaced.

I know there are threads around here on upgrading the pump so I'll research before asking in this thread.

 

[scottryana]

Yes some ran the supra pump, about the same flow at low voltage, but increased flow at higher voltage. I will get you the part number when I get home

 

[Wheelingnoob]

Yes some ran the supra pump, about the same flow at low voltage, but increased flow at higher voltage. I will get you the part number when I get home

Hmm interesting thought, what if the relay is not switching from low voltage to high?

 

[bsmart82]

Inspect spark plugs first, and I would reinstall wideband to monitor a/f ratio.

 

[scottryana]

23221-46110 Supra pump assembly

Might have given you the wrong impression, at low normal voltage the Supra pump will pump the same volume as the LC pump, but as the voltage goes up it actually has more volume.

 

[Wheelingnoob]

Just a heads up bad spark plugs will show as lean condition on your wide band so in this case it may not help too much.

Scott I understood what you where saying. My thought was what if the relay that switches from 9V to 12V is not working and its stuck at 9V, it would only manifest under situations like he had. Longer periods of boost (load) where the demand for fuel is at its greatest.

 

[Cruiserhead05]

Thanks.


Definitely going to check and possibly replace plugs before I work on reinstalling the wide band.

It looks like the bung for the wide band is probably rusted at this pointed so it'll require a little work.

I've been searching around but can't find the threads showing the guys that swapped in supra pump. If memory serves me correct, it's not a direct fitment.

 

[akarilo]

look at reinstalling the wideband permanently.

Above all else for sure! Let us know what you find out.

 

[Wheelingnoob]

Above all else for sure! Let us know what you find out.

Again just to be clear, if the spark plugs are the issue a loss of spark on a cylinder/s will show as a flash of lean on the wide band AFR. So may be confusing and send you in the direction of a fuel supply problem when its not.

I would install the wide band and replace the plugs first thus cheaply eliminating that variable.

 

[CCC TT]

Sorry, a little off topic but how do you like driving a boosted truck? How's gas mileage around town and at what rpms are you starting to see boost?

 

[Cruiserhead05]

Boosted truck is awesome. I forgot what a stock 1fz was like and a few weeks ago road in one. Huge difference but would still like to ride in a 2uz powered 80 for comparison.

My setup begins to build boost around 2k rpms.

Mileage is around 11-12 and pure highway I can do 14-15. I'm sure though, that with 315's my highway mileage should go up a little; currently running 295's.

 

[airsix]

When you say the wide-band showed good A/F ratios, what exactly were the ratios under load/boost?

Ben

 

[Cruiserhead05]

Don't remember off the top of my head but I think 14.1. I could be wrong though. Going to reinstall and go from there, as well as check plugs this weekend.