Well my 85 2.5 pulls a code 45.

The rich exhaust is extremely noticeable! When the car is running it stinks of gasoline (not black smoke).

I looked in the book and followed the diagnostic steps, ruled out a faulty ECM.

So i did the recommended labor to try to fix it.

it is NOT a leaking fuel injector..
It is NOT the MAP sensor.
NOT the TPS..
No excess fuel in the cannister..
It is running in an open loop...

IDK what else the problem can be. I fixed up some ground wires today, and even fixed an exhaust leak where the manifold hits the downpipe...

Any suggestions? im really stumped...

EDIT: fuel injector is basically brand new...
99% syre i dont have a fuel leak... but given a good suggestion i would look into it.
On a cold day engine starts at about 2k RPM then lowers to 1k after a while.

[This message has been edited by JZeFF (edited 01-06-2009).]

and a side question..

in this Topic...
https://www.fiero.nl/forum/A...060206-2-065518.html

Does this apply for a 4cyl or just the 6?
And is that terminal under the battery??

Lets see - open loop- rich exhaust - hmmmmm sounds like your O2 sensor might not be doing it's thing

See.... in the Haynes manual for the car it says code 45 will not be caused by a faulty oxygen sensor.

Could it be bad anyways?

The only reason i diddnt think it was supect was because the book specifically said that.

And is there a way to tell if its faulty?

[This message has been edited by JZeFF (edited 01-06-2009).]

From the FACTORY 1985 Fiero service manual:

Diagnostic aids; A code 45 will not be caused by a faulty O2 sensor, diagnosis should begin with these items

Fuel pressure-system will be rich if pressure is too high this is accompanied by rich black smoke

Leaking fuel injector-symptoms will be similar to high fuel pressure

HEI shielding-and open ground CKT 453 may result in EMI, or induced electrical "noise". The ECM sees this noise as distributor pulses which results in higher than actual engine speed signal. The ECM delivers too much fuel, causing system to go rich. Engine tach will read higher than actual engine speed which can help in diagnosing this problem.

Canister purge-check for saturation.

Coolant sensor intermittent open-this will cause higher than normal fuel delivery in the time the sensor is open. A coolant sensor code will not set until it is open for 1 minute, therefore intermittent open could cause code 45.

MAP sensor-This will cause the ECM to sense a higher than normal manifold pressure (low vacuum) causing the system to go rich. Unplug the MAP sensor which allows the ECM to use a fixed value for MAP, if the rich condition is gone when the sensor is unplugged, replace the sensor.

TPS-an intermittent TPS output will cause the system to go rich due to false indication that the engine is accelerating.

Hope this helps.

-Joe

the 2krpm starting is just the idle choke. it runs u high at start to warm the engine up faster, which gives u lower fuel economy at first, but then again engine is warm faster. point is thats not part of the problem, its normal.

I have found with my car, a 86 v6 that initially with an exhaust leak you may or may not get a lean code just depends on how you drive it. now with the exhaust leak was fooling the o2 sensor into telling the ecm to add gas especially at high rpms due to outside air being pulled into the system. then when the rpms go down the the air going into the systems slows and then the code 45 pops since there is too much gas now in the system.

I was screwing around with a lean and a rich codes for months, o2 senors, spark, map, throttle, iac. then one day i notice some black around on one of my header to y manifold connectors. took the manifolds a part realigned them and put it back together. replaced the o2 senor again since it was fouled up again, and cleared the ecm. I haven't had a code problem again and the exhaust fumes have cleared up as well.

quote Originally posted by joesfiero: From the FACTORY 1985 Fiero service manual: Diagnostic aids; A code 45 will not be caused by a faulty O2 sensor, diagnosis should begin with these items Fuel pressure-system will be rich if pressure is too high this is accompanied by rich black smoke Leaking fuel injector-symptoms will be similar to high fuel pressure HEI shielding-and open ground CKT 453 may result in EMI, or induced electrical "noise". The ECM sees this noise as distributor pulses which results in higher than actual engine speed signal. The ECM delivers too much fuel, causing system to go rich. Engine tach will read higher than actual engine speed which can help in diagnosing this problem. Canister purge-check for saturation. Coolant sensor intermittent open-this will cause higher than normal fuel delivery in the time the sensor is open. A coolant sensor code will not set until it is open for 1 minute, therefore intermittent open could cause code 45. MAP sensor-This will cause the ECM to sense a higher than normal manifold pressure (low vacuum) causing the system to go rich. Unplug the MAP sensor which allows the ECM to use a fixed value for MAP, if the rich condition is gone when the sensor is unplugged, replace the sensor. TPS-an intermittent TPS output will cause the system to go rich due to false indication that the engine is accelerating. Hope this helps. -Joe

Well.. this must be the manual i have.. haha

I checked all of them except the HEI one, and the Coolant one.

I did not check those two because i was not sure how...
Any advice on this?

Shows how much I know

hey.. any effort is better than no effort =] still a plus from me


Anyone got any other pointers for me?

quote Code 45 - O2 Rich Trouble Code 45 indicates that the O2 sensor is showing a persistently low exhaust oxygen content (rich), despite the efforts of the ECM to decrease injector on-time (thus decreasing fuel delivered). Integrator and BLM numbers may indicate < 128 by a substantial margin. The conditions for setting this code are: No Code 34 or Code 35 (MAF error) present, and The O2 sensor voltage remains above 752 mV, and The ECM is in Closed Loop control, and Throttle position is < 2 percent or > 20 percent, and the above conditions exist for more than 20 seconds. Typical causes for this code include: O2 sensor defective or contaminated (if incorrect RTV sealant or too much RTV is used, this may happen) Faulty EPROM calibration Leaking fuel injectors Fuel pressure too high EMI interference from poor plug wires Evaporative Emission system defect TPS and/or EGR problem MAF sensor reading higher airflow than is actually present

[This message has been edited by DIY_Stu (edited 01-07-2009).]

quote Originally posted by DIY_Stu:

im not exactly a mechanic.. but based on stu's list..

Code 34 or 35 is not pulled..
idk how to check o2 voltage...
ECM running in open loop..

NO clue how to see if o2 sensor is bad.. (not new)
Idk anything about EPROM calculation... but i know in the diagnostics i did i ruled out a faulty ECM.
Fuel Injector did not leak when the plug was disconnected, diagnostic terminals were grounded, and engine was cranked.
How do i check for high fuel pressure?
Plug wires are less than 6 months old.
I already have a plate made to remove the EGR from the system... should i do it?
Where is the MAF located.. does the 2.5 have one? If its the little blue thing in the air filter housing, that was recently replaced

I would check the coolant temp sensor if the ecm thinks that its cold, open on them is-40, it will spray more fuel trying to warm the engine up. like a choke on a carb, also it won't go into closed loop until the engine reaches operating temp once again if the sensor is no good you get no closed loop
Ant

ok.. standing looking at the engine from the rear of the car... left hand side is the coolant pressure release cap. where is the sensor?
Is it towards the bottom of that tube?

I hate not knowing as much as u guys... but im trying. haha

Yes, I believe the one on the thermostat housing below the cap is the sensor that feeds the ECM. There is another one that feeds the gauge, but dont worry about that for now. Did you check to see if the RPMs were higher than normal? Also, being intermittent as described in the manual, testing the coolant sensor might not help that much because you could get a good reading. I would test everything else first and if you still have the problem, try replacing the sensor.

For the 1985 4 cylinder, the factory manual clearly states that a bad O2 sensor will not set this code. Im not sure why, but to double check I went and got out my factory 1988 Fiero manual. The duke was changed around quite a bit in 1988 so this shouldnt apply, but the code 45 for 88 says that an O2 sensor can cause it. However, it says to pull the O2 out and check if there is a lot of white powder on it which would cause it to read rich. It says the sensor itself being bad will not cause the code, just the contamination.

To check for high fuel pressure would be hard because it would most likely be from the pressure regulator which is on the Throttle body itself. I cant help in that area I guess because I dont have my manual in front of me right now.

Youll get through this, its just a minor problem so dont get discouraged. Take it as a learning experience, this is the best way to learn anyway.

-Joe

The CTS is the one on the thermostat housing. The gauge and overheat light sensor is the one on the head.

well i went and purchased a CTS, i will put it in as soon as the car cools down. hopefully it makes a difference...

The guy at the parts store told me that on older cars looking at the o2 sensor to see if it has white powder on it will do absolutely nothing. Something about a crystal in it? or lack of one?

I've just skimmed through this thread... and if you haven't yet managed to test your O2 sensor, you might find this guide from Michigan Fieros helpful. Here's the link

http://www.michiganfieroclub.com/files/o2test.pdf

Best of luck

br1anstorm