Twistedframe

Hi all! I recently added a complete performance package that included, a new Throttle Body, Intake Manifold, Cam, Head and fuel system upgrades... Ever since, I have had really odd problems with the idle and shoddy performance due to the system being too rich. .... Still, the problem continues to get worse.

First off, I'll share some info on what I have done to the engine, and then fill you in on the problem and what I have found out, and then ask a question or two that may be able to help me get this taken care of???

This is a 1997 Honda Accord LX 2.2L nonVtec (F22B2)


Mod List:

Cold Air Intake
4-2-1 Header
Catback System
8mm Sparkplug Wires
ECU Upgrade
MSD SCI Ignition
MSD Blaster Cap
MSD Blaster SS Coil
Iridium Spark Plugs
Adjustable Cam Gear
Race Cam
160° Thermostat
VENOM Performance Control Module
Bullfrog Throttle Body
Port/Polished Intake Manifold
Port/Polished Head w/Racing Valve Grind and High Compression Chambers
1" Throttle Body Spacer
Walbro 255 Lph Fuel Pump
Adjustable Fuel Pressure Regulator @ 38-40psi
High Flow Fuel Rail
- 260cc Fuel Injectors (Not Yet Installed)
- AEM Fuel Filter (Not Yet Installed)

PROBLEM:
The car exhibits a very erratic idle constantly bouncing from 500 to 1700 rpm after it gets to a normal operating temp. After it has warmed up and you come to a stop, and it is in neutral, the rpm’s will drop drastically to around 200 or lower. Most of the time it will do this and correct itself back to 1200, and then fall again.. After it does this a couple of times, it now has a 50% chance of dying or sustaining the 200 rpm idle.

When driving, if you are at a constant cruise speed or even under a very light acceleration, the car wants to surge pretty badly. (It feels like the old V8’s that would “miss” due to spark distribution problems) If you gently “roll” on the gas, and take it up through the rpm band slowly, you can feel the engine unloading itself from the seriously rich fuel trim. It will sort of hit spots where it finally burns off the excess and runs normally.. I feels as if the fuel curve were stair-stepped, if that makes any sense.

I have gotten a Check Engine Light 4 times in the past month (every time in the morning on the way to work), and it is always the same. SYSTEM TOO RICH (BANK 1)


DIAGNOSIS: (From Honda Dealer)
Inspected and found that car has aftermarket throttle body. The O/E TPS sensor returns .31 volts at closed, it should be .49 -.50 volts. Tried to adjust TPS sensor, but O/E has no adjustment, need to reinstall O/E throttle body or buy an adjustable TPS sensor. Also, vacuum is very low – should return 1.00 volts at idle – It is 1.40 – This may be related to bad TPS reading or improper cam timing. Car does have aftermarket camshaft and gear, CAR WILL NOT GO INTO CLOSED LOOP AT IDLE, also fuel trim ratios are way off, this will also cause a fuel trim code in the near future.


MY 2 CENTS:
After speaking with the owner of the place that supplied the head package, I found out that there is no such thing as an “aftermarket adjustable TPS sensor”. I was informed that my O/E sensor COULD be adjusted, seeing as how they adjust them all the time for performance/economy driving. --I tested this, and found that it actually does, in fact work. You can adjust it one way to make the throttle snappier, or the opposite way to make it more docile for the ease of street driving.

The part about the vacuum being low is correct. The camshaft is the culprit of the low pressure. However, the cam gear is at 0 right now, and does not seem to make any kind of difference when adjusted, except for when adjusted too far to either way, then it’s a noticeable loss in power.

As for the fuel trim ratios, well, when I had the car tested, it had the stock ECU in it. Now, the ECU has been reprogrammed and the problem has steadily gotten worse, due to the aggressive fuel curve that has been introduced.

I have researched this closed loop issue (for those of you who don’t know), and have found that what that means is basically, when you start your engine, the O2 starts doing its’ thing. It sends signals to the ECU to tell it whether it is running too rich or too lean. The ECU then tells the fuel injectors to add or decrease the amount of fuel, in order for it to run at its’ most efficient, fuel economy, with the least amount of harmful exhaust gasses. This is what’s known as “closed loop”, or economy mode

When you press the gas pedal to 80% or more, the ECU picks up on this and immediately switches to “OPEN LOOP”, where it no longer listens to or even cares about the O2 sensor. It is in “race mode” now, if you will. The ECU now uses the advanced fuel curves that are programmed into it, and allows the injectors to DUMP massive amounts of fuel into the engine for maximum performance. As soon as you let off the pedal, below 80%, it switches back into Closed Loop operation.

MY CAR WILL NOT GO INTO CLOSED LOOP!!!!!!!!!!!! It *thinks* that I have 80% throttle in it ALL THE TIME apparently. It also stinks REALLY bad. It smells as if I have no cat on it. (A direct link to being way too rich)

MY QUESTIONS:

1. What could cause an engine to NOT go into Closed Loop mode?

2. Are there ANY suggestions that you may have or does any of this sound familiar or similar to problems you may have encountered in the past?

2 MORE CENTS:
I still have some more tests to run, but this sounds like an electrical problem to me??? The tests that are in line will be to, check the Air Intake Charge sensor, Idle Air Control Valve, and EGR return plate.. I will also be putting a new fuel filter in it as soon as it arrives, and I imagine that will clear up quite a bit of the low-end sluggishness that comes from 91k miles worth of garbage in the original filter! I also have 260cc injectors that need to be put in, that at this point, are completely pointless. If the engine is getting too much fuel from stock injectors, getting BIGGER ones will surely do no good right now.


Sorry for the long-*** explanation, but this is a big-*** problem.

Thanks Guys!!



Modified by Twistedframe at 3:56 AM 2/4/2004

Twistedframe

are there any more sensors worth checking to correct this??

hondatim

check coolant level to make sure it is full when at operating temp. If coolant level is low, could cause some of you idle 'hunt' issues. As for low vacuum, did you just install TB, intake manifold, etc.? If so, are you sure that you may not have a vacuum leak.

Also, what camshaft is installed.

what spec did you adjust your valves to, if intake valves were adjusted too tight, would cause intake valves to be slightly open and cause low vacuum, erratic idle, low idle and a lot of the other issues you are describing, including running rich.

Just a couple of things to check.

One other thing, what ECU are you running in car now?

Just curious...

I may be able to help a little more with some more info...

Twistedframe

Well, the coolant level is monitored and maintained <U>very</U> regularly, so that's one to scratch of the laundry list of things to check..

I installed a Bullfrog BigBore TB, ported/polished intake manifold, Stinger Cam, ported/polished head with a racing valve grind, and milled to have high compression chambers. -And I do know that the vacuum is low, but not sho about a leak.

The valves are a bit tight on the intake side; 6 thousandths I believe, and 8 on the exhaust.. Gude told me that it was a bit tight too, so I have plans to change that hopefully this weekend if I have time!!

Sweet man!! That would kick so much *** if that works ) haha damn! it's been this way and steadily getting worse for as long as I can remember!

BTW, I am using a JetECU.

Thanks!!!!