chicken lingo

I have a '93 del sol with a d15 shooting me a code 43.
When I bought the car it had a blown HG, not sure if relative, besides the fact it would shoot coolant straight out the muffler.
Needless to say, swapped HG, new fuel filter, and put a new o2 sensor in.
And I made sure to check the injector O rings.
From the get-go I've had a code 43 after 5-10 minutes of driving when I hit around 2.5-3k rpm.
My MPG is shot down to around 25, and this is driving me nuts.
Any ideas?

NotARaCist

iTrader: (1)

Replace your fuel filter, and test (or just replace, it's cheap) your fuel pressure regulator.

Former User

Any performance issues?

chicken lingo

None that I can tell.
I mean, i know the d15 is a slow engine,
But the car doesn't really noticeably bog after the CEL comes on.
I'm just getting really bad MPG, and I've gotten comments that my car smells like gas.

Former User

Sound like an O2 sensor issue. Is the exhaust manifold cracked? Exhaust leak near O2 sensor?

chicken lingo

I checked around the manifold for cracks, when I took the head off, and I couldn't see any.
The previous o2 sensor I took out did not have anti-seize on it, when I changed it, so the threads were stripped, and rusted.
I was able to get the new sensor in there, and applied the provided anti seize.
Could stripped threads cause issues to this degree?

Former User

If the O2 sensor fit does not completely seal off the inside exhaust from the outside air, that could be your problem.

chicken lingo

Would I have to purchase a entirely new manifold to fix my issue?
Or is there a temporary fix I can use to test to see if this is the issue in it's entirety?
And thank you so much,
I muchly appreciate your help!

Former User

Replacing the manifold is one way to fix, but others may know whether the sensor bung in the manifold can be modified to seal properly.

TomCat39

Is your exhaust manifold stock and for a D15B7?

If it is, there isn't any kind of sealer that will last at the temps the header gets and the O2 sensor I know is barely past head level on the very short 4-1 stock header.

Research shows temps can easily reach over 1000* F. Permatex Copper High Temp is only good to 700* F and I don't know the pressure rating it has. The loctite I like to use has the pressure rating but only is good for intermittant up to 600* F.

It's either a different/new header. Or a timesert might work. It realy depends on how thick the bung is if there is enough material for the timesert.

One thing that comes to mind on the timesert or helicoil is I'm not sure the material of either, it would have to be iron or steel I would think for the temps it will be exposed to.

Maybe someone else knows of something better.

chicken lingo

Hey, thanks for your help!
I went ahead and snagged this off amazon. along with an o2 adapter bung. I couldn't find any parted sols near me, so I'm hoping this'll work.

TomCat39

I have that exact header and the collector output OD is 2.0 inches as it needs the walker 31357 flex gasket which is for a 2001 DX/LX.

I'm not sure if the stock catalytic converter will fit to that header as the stock collector size is a fair bit smaller than that.

chicken lingo

it fits, but the problem is it's about 2 inches short of the exhaust system.
Any type of extension out there/ a way to pull the system forward?

chicken lingo

welp, CEL came back on, even after resetting the ECU.
I'm going to replace the FPR, and see what comes up.
If it's still on, I'll check the resistance of the wiring.
If that doesn't work, then I'm at a loss.

NotARaCist

iTrader: (1)

Common causes of the code are a failing FPR, a clogged fuel filter, or a failing O2 sensor. When you replaced the fuel filter, did you use OEM, or something else?

chicken lingo

Denso o2, brand new.
New OEM filter.
New Exhaust header. I fixed the issue with the length by pulling the system forward, applying copper gasket and flex flange.
Wiring on O2 is spliced, but OK. I made sure to re-strip wire, cut off and wrap.
I'm going to grab a FPR tomorrow at work, and will update.

NotARaCist

iTrader: (1)

And do you still have the OEM fuel injectors? Have they ever been serviced?

chicken lingo

OEM injectors. 196k miles. Never been serviced.

NotARaCist

iTrader: (1)

Give the replacement FPR a shot, and if that doesn't help, give these guys a call, and see about getting your injectors serviced. It's reasonably priced, and will noticeably increase your gas mileage, responsiveness, and engine health.

Also, just to be sure...you're resetting your ECU after each fix to see if the code comes back, right? The code won't just go away on it's own in short order - it takes quite a few "OK" cycles for the CEL to actually turn off.

chicken lingo

appreciate it.
I'll keep the thread updated.

chicken lingo

The FPR did nothing. Reset the ECU twice.
I'm going to try re-wiring the harness above the o2 sensor, to eradicate the splice for resistance.
if this doesn't work, I'll be cleaning the injectors.
Do you happen to know the resistance/volts off-hand?

Former User

What's the update on the header install? You mentioned a fitment issue.

chicken lingo

I was able to pull the cat forward and align it.
I used the dorman flex gasket, and copper gasket spray.
No issues with leaks/etc.
Albeit, the header had a hole in the weld upon initial inspection.
Typical for ebay/amazon, but nothing muffler putty couldn't fix.

chicken lingo

Well, guys, think I figured the issue.
I pulled the o2 wire apart and started looking.
There's oil in the connector.
It starts at the cam shaft adjuster and drips down the harness.
Going to pack it with dieletric grease, tomorrow,
and clean off the harness.
Will update.
Thank you everyone for your help.

chicken lingo

Cleaned off with electric spray, packed with dielectric grease, re-wrapped connector.
nada.
I feel as if I'm grasping at strings here.