Re: Fuel mixture

"Ray O" <rokigawaATtristarassociatesDOTcom> wrote in message news:...[color=blue]
>
> "Nobby" <nobbyondanet@ntlworld.com> wrote in message
> news:L0N_g.36126$Or2.2341@newsfe7-gui.ntli.net...
> Basically it's pinging and quite flat on performance since I have put a
> cold air intake and a straight through performance exhaust system on. I
> have turned the timing back 3 degrees to try and stop the pinging but
> according to a emissions test it is showing around 0.4% and it has 200215
> miles on the clock and sounds like new with no smoke or rattle/rumble
> what's so ever.
>[/color]

I've been thinking a little more about the symptoms and have more questions.

You mention that the emissions test is showing around 0.4%. Is this CO %?

In the U.S. 0.4% is right around the allowable limit, and would indicate a
rich air/fuel mixture, so making the mixture richer would make the problem
worse, not better.

You mention that the problems started when you installed the cold air intake
and straight through exhaust system on.

Does the cold air intake use the type of air filter that is oiled? If so,
the oil may have contaminated the MAF sensor. Also, check to make sure
there are no holes or cracks in the intake snorkel between the MAF sensor
and the throttle body. Check to make sure there are no vacuum leaks by
measuring manifold vacuum.

When the aftermarket exhaust was installed, was the #1 O2 sensor installed
properly and its operation checked? Are you sure that there are no exhaust
leaks?

Problems with the cold air intake and #1 O2 sensor could cause the symptoms.
--

Ray O
(correct punctuation to reply)

Yes defiantly the CO2 reading, as the maximum allowed with no catalytic converter is 3.5% in the UK and Gary said he was surprised is was even running so low as the mixture usually needs turning up to run smooth at that many miles on the clock. He's had an MOT bay for donkeys years now, and says he's never seen a Celica come in with this engine configuration and didn't like to mess to much. He has owned 2 Celica's over the years and says the block and head is the same as most up to the latest shape but the manifold set-up is something new to him...

--
Nobby

Never let the bastards grind you down...
Think positive and get even!!!


"Ray O" <rokigawaATtristarassociatesDOTcom> wrote in message news:d510a$453be80b$180ffe52$26200@msgid.meganewsservers.com...

"Ray O" <rokigawaATtristarassociatesDOTcom> wrote in message news:...[color=blue]
>
> "Nobby" <nobbyondanet@ntlworld.com> wrote in message
> news:L0N_g.36126$Or2.2341@newsfe7-gui.ntli.net...
> Basically it's pinging and quite flat on performance since I have put a
> cold air intake and a straight through performance exhaust system on. I
> have turned the timing back 3 degrees to try and stop the pinging but
> according to a emissions test it is showing around 0.4% and it has 200215
> miles on the clock and sounds like new with no smoke or rattle/rumble
> what's so ever.
>[/color]

I've been thinking a little more about the symptoms and have more questions.

You mention that the emissions test is showing around 0.4%. Is this CO %?

In the U.S. 0.4% is right around the allowable limit, and would indicate a
rich air/fuel mixture, so making the mixture richer would make the problem
worse, not better.

You mention that the problems started when you installed the cold air intake
and straight through exhaust system on.

Does the cold air intake use the type of air filter that is oiled? If so,
the oil may have contaminated the MAF sensor. Also, check to make sure
there are no holes or cracks in the intake snorkel between the MAF sensor
and the throttle body. Check to make sure there are no vacuum leaks by
measuring manifold vacuum.

When the aftermarket exhaust was installed, was the #1 O2 sensor installed
properly and its operation checked? Are you sure that there are no exhaust
leaks?

Problems with the cold air intake and #1 O2 sensor could cause the symptoms.
--

Ray O
(correct punctuation to reply)

Nobby wrote:[color=blue]
> Yes defiantly the CO2 reading, as the maximum allowed with no catalytic converter is 3.5% in the UK[/color]

Defiantly? Why is it difiant?

3.5% CO2 is very, very low, but 3.5% CO is very high.
[color=blue]
> Basically it's pinging and quite flat on performance since I have put a cold air
> intake and a straight through performance exhaust system on. I[/color]

I believe you caused an air leak when you installed the cold air intake
or the exhaust system.