Ford vs Chevy Build-up

Tony Corley · 04-30-2015, 08:27 AM

First step will be to connect the regulator correctly, as shown in the 2nd drawing you made. Then you can adjust fuel pressure.

SSGT Mustang · 04-30-2015, 08:57 AM

Check the connection to O2 sensors. There's a connection from the harness near the passenger side strut tower. Disconnect it, clean the inside well, make sure the connectors clamp tightly and reconnect using dielectric grease. Do the same where the wires terminate at each O2 sensor.

I have a convertible street car with heads, cam, etc. I had the same problem that you are describing. By chance, some kid told me about those connectors and that it's not uncommon for them to get corroded, preventing the O2's from looping back to the computer. I cleaned them up, put in the dielectric grease and the problem went away.

I use a moates quarterhorse to tune the engine. When you programmed the computer, did you change the variable for injector size to 24 lbs.?

Tony Corley · 04-30-2015, 09:19 AM

As long as the Mass Air Flow is correctly calibrated for 24 lb injectors, there is no tuning change required to make it run. Fine tuning, however is a different story. Checking the connectors, and all of the grounds is always a good idea, if still needed after fuel lines are corrected.

HandOverFist · 04-30-2015, 09:47 AM

Thanks to all for the replies!

First off, the Aeromotive recommended fuel diagram. I have seen it and it would be a horrendous maze to plumb...I can however easily modify to the second diagram I posted if it would be preferred to my current plumbing.

O2 sensors - I have the factory O2 sensor connected on the passenger side and a aftermarket wide band on the driver side. By not having the other narrow band connected is that causing a problem?

I think I know what the "Baro" is and it is located in about the stock location on the firewall...yes it is still hooked up. I think it is what you can see in the upper right corner in the image here...

TP voltage is correct. Not completely familiar yet with all the efi terminology...ECT and IAT? (Ok, IAT = intake air temp)

I had a damaged injector harness originally and bought a good used harness. I guess it could happen and I will re-check, but it appears near impossible to get the wiring wrong due to the length of the injector connector pigtails. I'll go back today and check again on all these tips and make needed changes.

Here is a link to the PMS controller if anyone cares to look at it... http://www.mediafire.com/view/u2ptoj..._IV_7-2004.pdf

Tony Corley · 04-30-2015, 10:17 AM

ECT= Engine Coolant Temp. Connectors only plug one way on Ford harnesses. Hook up both o2 sensors and move the wideband to a new location. The 2nd diagram you made will work. Fuel from pump to rails, from rails to inlet on regulator, bypass from regulator to tank. Once you get fuel pressure to where you can adjust it, you can drop it a couple of pounds. Car should run fairly clean without the PMS if everything else is correct. As stated earlier, the factory ECM on a Fox Mustang is fairly adaptable on it's own. The PMS just allows for fine tuning and raising the rpm limit.

HandOverFist · 04-30-2015, 10:27 AM

Quote:

Originally Posted by Tony Corley

ECT= Engine Coolant Temp. Connectors only plug one way on Ford harnesses. Hook up both o2 sensors and move the wideband to a new location. The 2nd diagram you made will work. Fuel from pump to rails, from rails to inlet on regulator, bypass from regulator to tank. Once you get fuel pressure to where you can adjust it, you can drop it a couple of pounds. Car should run fairly clean without the PMS if everything else is correct. As stated earlier, the factory ECM on a Fox Mustang is fairly adaptable on it's own. The PMS just allows for fine tuning and raising the rpm limit.

ECT - I assume that would require a sensor which is no longer on the engine lol. I'm betting it screwed into a port in the lower intake on the driver side...you saying I must have it for the engine to run properly? Is this the sensor here? Can it be installed in the intake instead of that tubing?

Not having both factory O2 sensors hooked up is causing problems I am experiencing? I guess my basic question now is what is the minimum amount of changes I can get away with right now. The PMS can control everything over 2000rpm...all I need is to get it to run/idle cleanly atm.

west coast · 04-30-2015, 10:52 AM

Rich looks like you created some of your own problems should be easy to fix with some time. I believe you o2 sensors are daisy chained together in the wiring so if one is not plugged in the other one will not work. Some of the years of cars are wired differently on this circuit. if you are missing the engine coolant sensor you will have problems, your after start enrichment table is like a choke will not change your fuel going to the motor as it warms up. Have not used the system you are working with just the stock computer with a chip. hope this helps. good luck

black88coupe · 04-30-2015, 11:01 AM

Quote:

Originally Posted by HandOverFist

ECT - I assume that would require a sensor which is no longer on the engine lol. I'm betting it screwed into a port in the lower intake on the driver side...you saying I must have it for the engine to run properly? Is this the sensor here? Can it be installed in the intake instead of that tubing?

That sensor in the pic is the coolant temp sensor for the computer. There is a second temp sensor that is for the gauge in the dash (normally goes in the drivers side front of the intake and has a small "stud" sticking out of the top for the gauge hookup). You can eliminate that coolant tube if you like and put the sensor right into the intake.

Tony Corley · 04-30-2015, 11:01 AM

Put the ECT sensor in the intake where the heater tube came out of. The o2 sensors are not causing the current issue by themselves, but will cause tons of other tuning issues.
So,
Reroute fuel
Add ECT sensor
Add o2 sensor

Should correct the issues, possibly have to lower fuel pressure a little, but maybe not, every engine is different.

black88coupe · 04-30-2015, 11:04 AM

Quote:

Originally Posted by HandOverFist

Not having both factory O2 sensors hooked up is causing problems I am experiencing?

You need both hooked up for the factory EEC. Not sure on the aftermarket setups.

04-30-2015, 08:27 AM	#1
Tony Corley Member Join Date: Nov 2011 Posts: 264 Likes: 42 Liked 61 Times in 25 Posts	Re: Ford vs Chevy Build-up First step will be to connect the regulator correctly, as shown in the 2nd drawing you made. Then you can adjust fuel pressure.

04-30-2015, 08:57 AM	#2
SSGT Mustang Member Join Date: Mar 2005 Location: Jersey Posts: 359 Likes: 35 Liked 204 Times in 54 Posts	Re: Ford vs Chevy Build-up Check the connection to O2 sensors. There's a connection from the harness near the passenger side strut tower. Disconnect it, clean the inside well, make sure the connectors clamp tightly and reconnect using dielectric grease. Do the same where the wires terminate at each O2 sensor. I have a convertible street car with heads, cam, etc. I had the same problem that you are describing. By chance, some kid told me about those connectors and that it's not uncommon for them to get corroded, preventing the O2's from looping back to the computer. I cleaned them up, put in the dielectric grease and the problem went away. I use a moates quarterhorse to tune the engine. When you programmed the computer, did you change the variable for injector size to 24 lbs.?

04-30-2015, 09:19 AM	#3
Tony Corley Member Join Date: Nov 2011 Posts: 264 Likes: 42 Liked 61 Times in 25 Posts	Re: Ford vs Chevy Build-up As long as the Mass Air Flow is correctly calibrated for 24 lb injectors, there is no tuning change required to make it run. Fine tuning, however is a different story. Checking the connectors, and all of the grounds is always a good idea, if still needed after fuel lines are corrected.

04-30-2015, 09:47 AM	#4
HandOverFist VIP Member Join Date: Oct 2013 Location: Gulf Breeze, FL Posts: 1,651 Likes: 8 Liked 33 Times in 16 Posts	Re: Ford vs Chevy Build-up Thanks to all for the replies! First off, the Aeromotive recommended fuel diagram. I have seen it and it would be a horrendous maze to plumb...I can however easily modify to the second diagram I posted if it would be preferred to my current plumbing. O2 sensors - I have the factory O2 sensor connected on the passenger side and a aftermarket wide band on the driver side. By not having the other narrow band connected is that causing a problem? I think I know what the "Baro" is and it is located in about the stock location on the firewall...yes it is still hooked up. I think it is what you can see in the upper right corner in the image here... TP voltage is correct. Not completely familiar yet with all the efi terminology...ECT and IAT? (Ok, IAT = intake air temp) I had a damaged injector harness originally and bought a good used harness. I guess it could happen and I will re-check, but it appears near impossible to get the wiring wrong due to the length of the injector connector pigtails. I'll go back today and check again on all these tips and make needed changes. Here is a link to the PMS controller if anyone cares to look at it... http://www.mediafire.com/view/u2ptoj..._IV_7-2004.pdf __________________ Rich Taylor I/SA - 321 Last edited by HandOverFist; 04-30-2015 at 10:00 AM.

04-30-2015, 10:17 AM	#5
Tony Corley Member Join Date: Nov 2011 Posts: 264 Likes: 42 Liked 61 Times in 25 Posts	Re: Ford vs Chevy Build-up ECT= Engine Coolant Temp. Connectors only plug one way on Ford harnesses. Hook up both o2 sensors and move the wideband to a new location. The 2nd diagram you made will work. Fuel from pump to rails, from rails to inlet on regulator, bypass from regulator to tank. Once you get fuel pressure to where you can adjust it, you can drop it a couple of pounds. Car should run fairly clean without the PMS if everything else is correct. As stated earlier, the factory ECM on a Fox Mustang is fairly adaptable on it's own. The PMS just allows for fine tuning and raising the rpm limit. Last edited by Tony Corley; 04-30-2015 at 10:20 AM.

04-30-2015, 10:52 AM	#7
west coast Senior Member Join Date: Dec 2008 Location: Rainy Washington Posts: 610 Likes: 12 Liked 227 Times in 74 Posts	Re: Ford vs Chevy Build-up Rich looks like you created some of your own problems should be easy to fix with some time. I believe you o2 sensors are daisy chained together in the wiring so if one is not plugged in the other one will not work. Some of the years of cars are wired differently on this circuit. if you are missing the engine coolant sensor you will have problems, your after start enrichment table is like a choke will not change your fuel going to the motor as it warms up. Have not used the system you are working with just the stock computer with a chip. hope this helps. good luck __________________ James Boyce 6052 K/SA Stock National record holder 2015,2018,2 times in 2022,2023

04-30-2015, 11:01 AM	#9
Tony Corley Member Join Date: Nov 2011 Posts: 264 Likes: 42 Liked 61 Times in 25 Posts	Re: Ford vs Chevy Build-up Put the ECT sensor in the intake where the heater tube came out of. The o2 sensors are not causing the current issue by themselves, but will cause tons of other tuning issues. So, Reroute fuel Add ECT sensor Add o2 sensor Should correct the issues, possibly have to lower fuel pressure a little, but maybe not, every engine is different. Last edited by Tony Corley; 04-30-2015 at 11:09 AM.