TOO RICH????!!!!

rideapony · Sep 3, 2007

Hi all, Finally I'm driving my new rebuilt 306. It runs fine but I noticed my fuel economy is really bad (or maybe not?). I'm on the final stages of breaking in the engine and the clutch so haven't push it too hard and my fuel economy is between 12.5 and 14 MPG mostly city, is it bad???

Please can someone help me with this issue? how to better my MPG? perhaps timing, and or 195* stat? or maybe a faulty sensor? Please where can I start? or is that mileage normal????

A new problem I experienced resently is a throttle response delay only when cold. That is, I hit the gas and it doesn't want to go until some elapsed time I can feel the sudden acceleration, once it warms up it runs fine, what could that be?

Here are some of the engine and drivetrain specs: Tricflow heads, U/L intakes, and stage 1 cam. 65mm FMS throttle, 110 lph fuel pump, 19 lb injectors, BBK Ceramic shorties, T5 WC tranny, Spec stage 2 clutch, and 3.55 gears. 180* Mr Gasket balanced stat, Taurus electric fan, and I just installed a new Griffin rad.

All your suggestions and ideas will be greatly appreciated

Nick C.

jrichker · Sep 3, 2007

Dump the codes and see what the computer says is wrong…Codes may be present in the computer even if the Check Engine light isn’t on.

Here's the link to dump the computer codes with only a jumper wire or paper clip and the check engine light, or test light or voltmeter. I’ve used it for years, and it works great. You watch the flashing test lamp or Check Engine Light and count the flashes.

See http://www.troublecodes.net/Ford/

IF your car is an 86-88 stang, you'll have to use the test lamp or voltmeter method. There is no functional check engine light on the 86-88's except possibly the Cali Mass Air cars.

89 through 95 cars have a working Check Engine light. Watch it instead of using a test lamp.

Codes have different answers if the engine is running from the answers that it has when the engine isn't running. It helps a lot to know if you had the engine running when you ran the test.

Trouble codes are either 2 digit or 3 digit, there are no cars that use both 2 digit codes and 3 digit codes.

For those who are intimidated by all the wires & connections, see http://www.actron.com/product_detail.php?pid=16153 for what a typical hand scanner looks like. Normal retail price is about $30 or so at AutoZone or Wal-Mart.

Or for a nicer scanner see http://www.midwayautosupply.com/pc-7208-90-equus-digital-ford-code-reader-3145.aspx – It has a 3 digit LCD display so that you don’t have to count flashes or beeps.. Cost is $30.

rideapony · Sep 3, 2007

Thank you Jrichker for your prompt reply, I just pulled the codes using KOEO mode and found codes 67 and 95. As I read before I'm not too worry about code 95 but what about 67? There are basically two potential failures that trigger this code: NEUTRAL/DRIVE SWITH OPEN OR AC ON and CLUTCH SWITCH CIRCUIT FAILURE. What to do next?

Also would you be concerned about code 95? (Fuel pump secondary circuit failure-ECA to ground) and if so how to fix it?

Thank you buddy, Nick

rideapony · Sep 3, 2007

Jrichker, surfing some of your thread replies specifically the one on 07-08-07, 12:42 PM I found some answers to those codes. Code 67 probably came on while I open the switch for the test while the AC was ON. Code 95 probably came on because I have a hidden fuel pump cuttoff switch that I usually turn OFF to dissable the pump and was off while I ran the test. Thank you for those valuable entries.

But do you have any ideas about the two main issues I'm having? Poor mileage and delayed throttle response while cold?

Thank you for all your help and if someone else can help will be great.

Nick

BigHairyMonkey · Sep 4, 2007

poor driveability before a car is warmed up can attest to a crummed up ECT sensor. Replace it, its cheap.

86bluecobra · Sep 4, 2007

I just had an issuewith my 302 running very rich. two main culpruts could be ECT or ICT. my ECT was the issue. Look at my thread entitled starting blues there is info in there how to test that sensor.

rideapony · Sep 4, 2007

Ok guys thanks a lot for the ideas I'm at work right now but as soon as I get home I'll start inspecting those sensors. I'll post the results.

I don't think there should be any other potential causes for those two poor performance conditions but if someone else has any other ideas please bring them on.

One more thing have anyone uses those E3 plugs advertised on the summit catalog? They have some new plugs that have some sort of triangular shape at the electrode end. They claim better ignition, lower emisions, and better fuel economy. Right now I'm using NGK-V's. Anyone?

Thank you all, Nick

ninety15.0 · Sep 4, 2007

How many miles do you have on the motor? Also you said that most of the driving you do is in the city. What kind of driving are we talking about? 30-40mph cruise...or stop light to stop light kinda stuff. Because honesltly...14 isnt horrible for all city driving.

rideapony · Sep 4, 2007

Well my engine has about 1200 miles and my driving is kind of mixed, some 30-40 city and some 60-75 Hwy. If I drive mostly city speeds then I'll get slightly over 12 mpg. So I guess it might be normal.

To tell you the truth I sort of expected to have a small hit on my mileage but got confused when I read some threads from guys that claim better mileage with freshly rebuilt engines.

I'm going to test those sensors anyway to eliminate potential rich condition just to feel more confortable. Should I check both 02 sensors too? What are typical signs of a rich condition, perhaps plugs color? or an air/fuel gauge will help to determinate that? I heard horrors about how to interpretate those gauges but what do I know!!!???

Thank you, Nick

86bluecobra · Sep 4, 2007

Usally the o2 sensors from what I gather are the idle control for air fuel mixture. Have you checked your fuel pressure regulator? perhaps it is set to high if it is an aftermarket piece or if it is still stock it could be gone aswell.

rideapony · Sep 4, 2007

I read the Starting Blues and will check the ECT and ACT following those values charts. As for the O2 sensors I heard that if bad they induce to either lean or rich conditions.

I have the stock FPR and checked the pressure on it which is normal ( 40 psi). I'll let you guys know what I find regarding those sensors and or if I solved my problems.

Nick

rideapony · Sep 4, 2007

Ok here is what I found: I checked the voltage of the ECT and found that it had too much resistance I measured like over 7 volts I unplugged the sensor and measure the resistance at the sensor terminals and it was right where it supposed to be. Then I cleanned the terminals and squeezed the terminals at the connector and re-measured and it was good (0.88 v. at 188* F.) WTF!!!!

I think there is the possibility that the sensor might be failing intermitently, so I'll go to the dealer and buy a new one. I just don't trust the cheap plastic ones from kragen. By the way mine is a brass one but I think it could be going bad.

I then measured the ACT and it was right where it supposed to be (0.90 v at 155*F). I will see how she runs tomorrow and let you all know about the results.

So anyone using E3's DiamondFire spark plugs? are they good? will they fit my TFS twisted wedge heads? they are advertised on the newest summit catalog page 84.

Thank you all, Nick

86bluecobra · Sep 4, 2007

definetally don't get the plastic one. I used it for a year and it failed now I have a ford one back in there. Much better.

speedytang · Sep 4, 2007

Forget those plugs you gain nothing but wasting your cash.
Stick with a standard Copper plug.

rideapony · Sep 5, 2007

Good call I'll disregard those plugs. Today I felt some progress on my engine's performance. The throttle response got better but I think for what I heard that the computer must be reset after any electrical repairs. It makes sense but I missed to do that when I "fixed" the ECT connection, and definitelly I think I'm going to replace the sensor with a new one from the dealer.

I pulled the codes again and there was none. I also think that if the rich condition problem is solved by fixing or replacing the ECT my mileage will automatically improve (at least that is my theory, and I hope so!!!) I will find out soon and report to all of you.

Thank all of you for your ideas and suggestions, Nick

86bluecobra · Sep 5, 2007

Np sir.

rideapony · Sep 9, 2007

Ok guys, I just came back from a trip to Sacramento and calculated my mileage per gallon. It came to ~20 MPG Highway driving and hitting it somewhat good. would this sound typical considering using a 306 engine T5 tranny and 3.55 gears?

Now, regarding the Trottle body response delay when cold still there and have no idea on how to fix that.

As I just replaced my almost new stock radiator with a new Griffin aluminum one I bought for $176.00 from Summit, I saw to my delight that the temperature stays at 180*. BUT here is a question I have regarding operating temperature:

Obviously staying at or under 180* the computer senses that low temperature and enriches the air/fuel mixture, but reading other articles I learned that the optimum coolant temp for the best performance is between 195* and 200*. Wouldn't be good to operate the engine at those temperatures?

Please forgive me if I ask all of those questions but just want to learn and get the best of both scenarios (Fuel economy and performance) So please don't get too hard on me about all of those ??'s.

Thank you a lot for all the help, Nick

speedytang · Sep 10, 2007

After the car has run its start up time you can drop temperature below your example of 180 degrees and it will not increase the fuel because of the lower temperature until you restart the car or reset the computer.

86bluecobra · Sep 10, 2007

It wouldn't hurt to install a 195 degree thermostat and try it. For what they cost peace of mind is well worth it.

rideapony · Sep 10, 2007

Thank you guys, I think I'll install a 195* MrGasket stat but I have to change my elect. fan thermal switch, right now I have a 180* stat and 195* ON 185* OFF thermal switch. I remember some time ago I installed a 190* stat and stayed with the same switch and the fan was ON almost all the time, so I'll have to thread a 200* ON 195* OFF Hypertech switch. Hopefully she won't run too hot.

Thank you all, Nick

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