Stroker novice, injection upgrade and map ??s

[Jeepin89701]

So then 24.38lbs at 43.5psi would be what at 39psi would be my question? My math brain is sleeping 3:40 am here, and thanks for your input!

[Jeepin89701]

SO go advise if at all dirty however the TPS, IAC, MAP and Throttle body all have about 35 miles on them from new. Possibly just needs more miles on pcm to adjust?? Maybe need to reset pcm and start adjustment period over.

Yeah, I think that may be all you'll need to do. I find it takes about 100 miles for the ECU to complete its adaptive learning.
FWIW i'm running Ford Racing 24lb injectors (rated at 39psi) with the stock 39psi regulator on the front of the injector rail.
Note that the injector flow rate is proportionate to the square root of the fuel pressure at the rail, so a 20% increase in fuel pressure will increase injector flow rate by 9.5%.

Is the stock PSI on OBD1 is 30 or 39 at idle? Also I thought that the standard flow rate test is 43.5lbshr, So if there 24# injectors they were tested at 43.5PSI. I could be wrong on all of this. There seems to be a lot of misinformation out there. My brother had a spare (new) stock regulator that I will grab from him this weekend and put in mine, reset the CPM and put the old TPS back in it and see if I get any better results...

[Cheromaniac]

So then 24.38lbs at 43.5psi would be what at 39psi would be my question?

The answer is 23.08lb/hr.

Is the stock PSI on OBD1 is 30 or 39 at idle? Also I thought that the standard flow rate test is 43.5psi

It's 30psi with the vacuum attached to the regulator, and 39psi with the vacuum disconnected (effectively what you'd have at WOT).
Many injectors are indeed flow tested at an industry standard 43.5psi (3 bar) but some aren't so you have to check with the manufacturers or vendors.

[Jeepin89701]

So then 24.38lbs at 43.5psi would be what at 39psi would be my question?

The answer is 23.08lb/hr.

Is the stock PSI on OBD1 is 30 or 39 at idle? Also I thought that the standard flow rate test is 43.5psi

It's 30psi with the vacuum attached to the regulator, and 39psi with the vacuum disconnected (effectively what you'd have at WOT).
Many injectors are indeed flow tested at an industry standard 43.5psi (3 bar) but some aren't so you have to check with the manufacturers or vendors.

Based on these calculations, if I'm understanding correctly my injectors could be my issue @23.08lb/hr. I have Denso F55E-A2E rated at 24.38lb/[email protected], might why I'm being told to run @ higher pressure? Think I'm becoming more confused!

[Jeepin89701]

So then 24.38lbs at 43.5psi would be what at 39psi would be my question?

The answer is 23.08lb/hr.

Is the stock PSI on OBD1 is 30 or 39 at idle? Also I thought that the standard flow rate test is 43.5psi

It's 30psi with the vacuum attached to the regulator, and 39psi with the vacuum disconnected (effectively what you'd have at WOT).
Many injectors are indeed flow tested at an industry standard 43.5psi (3 bar) but some aren't so you have to check with the manufacturers or vendors.

Based on these calculations, if I'm understanding correctly my injectors could be my issue @23.08lb/hr. I have Denso F55E-A2E rated at 24.38lb/[email protected], might why I'm being told to run @ higher pressure? Think I'm becoming more confused!

So your 24# @ 39psi is your @ wot.. In order for my injectors to have 24 # at wot they would need 42psi so I would be looking for 33 to 35 psi with vacuum attached and 41 to 42 with vacuum disconnected/ or I need to pick up some different injectors do you have a part # for the ford racing injectors that you are running, or am I overthinking this?

[jsawduste]

You guys have beaten the injector sizing and flow rates to death.

FWIW my OBD1 (now OBD2) ran 24 lb Accels at 41 psi. A 2 psi bump would show on the WB AFR but also the smell of the exhaust. With the OBD2 I now run 46 psi through the same injectors but with a different cal. The difference is the ECM calibration of the MAP sensor tables and short term fuel trims.

The TPS can be checked with a volt meter and there are plenty of web sites that show how. Highly doubt that`s your problem.

I would be looking at the vacuum numbers at idle to see it the MAP sensor is dumping fuel due to a low vacuum signal.

Don`t go playing with FP values much. 40-44 psi is where you want to be. You don't have a WB AFR to see what your AFR`s are and it`s a distinct possibility that taking to much pressure out could cause the engine to go lean in open loop.

[Cheromaniac]

I have Denso F55E-A2E rated at 24.38lb/[email protected], might why I'm being told to run @ higher pressure?

Those injectors originally came in the '96-'98 Mustang Cobra & Lincoln Mark VIII 4.6 4V engine and flow 262cc/min or 25.0lb/hr @ 43.5psi (3.0 bar).



A fuel pressure of 44psi should be close enough for you but you'll need a wideband O2 sensor to monitor the AFR and tell you if you need to make any adjustments.

[jsawduste]

Couple of other points.

Is the ECM seeing a VSS signal ? On decel the ECM leans the AFR to avoid the engine loading up.

At idle use a business card in the TB to partially block off the air feed for the IAC. If the engine stumbles with minimal blockage you may need to add an air bleed to the throttle plate itself. I start with a .09 wire drill and slowly move up to find the sweet spot. Usually around a 1075/1097 diameter.

[Jeepin89701]

Couple of other points.

Is the ECM seeing a VSS signal ? On decel the ECM leans the AFR to avoid the engine loading up.

At idle use a business card in the TB to partially block off the air feed for the IAC. If the engine stumbles with minimal blockage you may need to add an air bleed to the throttle plate itself. I start with a .09 wire drill and slowly move up to find the sweet spot. Usually around a 1075/1097 diameter.

I watched a video on the card blocking the IAC test last night, seems like a test I will be doing this weekend. I'm being educated on this subject at a rapid pace and do appreciate it. I will have to find some instruction on air bleeding at throttle plate, I'm sure there is a video out there somewhere.

[Jeepin89701]

You guys have beaten the injector sizing and flow rates to death.

FWIW my OBD1 (now OBD2) ran 24 lb Accels at 41 psi. A 2 psi bump would show on the WB AFR but also the smell of the exhaust. With the OBD2 I now run 46 psi through the same injectors but with a different cal. The difference is the ECM calibration of the MAP sensor tables and short term fuel trims.

The TPS can be checked with a volt meter and there are plenty of web sites that show how. Highly doubt that`s your problem.

I would be looking at the vacuum numbers at idle to see it the MAP sensor is dumping fuel due to a low vacuum signal.

Don`t go playing with FP values much. 40-44 psi is where you want to be. You don't have a WB AFR to see what your AFR`s are and it`s a distinct possibility that taking to much pressure out could cause the engine to go lean in open loop.

And the OBD1 does a less of a job with map sensor calibration, so I my need a map adjuster? and a WB 02 sensor.. The beating the injector size and flow rates did help in my understanding of them, I attempting to be a sponge for this know how. Information gold!!!

[Jeepin89701]

I have Denso F55E-A2E rated at 24.38lb/[email protected], might why I'm being told to run @ higher pressure?

Those injectors originally came in the '96-'98 Mustang Cobra & Lincoln Mark VIII 4.6 4V engine and flow 262cc/min or 25.0lb/hr @ 43.5psi (3.0 bar).



A fuel pressure of 44psi should be close enough for you but you'll need a wideband O2 sensor to monitor the AFR and tell you if you need to make any adjustments.

So I myself had these tested @43.5psi and they got 260cc/24.38lbshr(@3 bar), will look into my options for a WB 02 sensor. Any recommendations?

[Jeepin89701]

oops, a vss signal??? help me out here!

[jsawduste]

And the OBD1 does a less of a job with map sensor calibration, so I my need a map adjuster? and a WB 02 sensor.. The beating the injector size and flow rates did help in my understanding of them, I attempting to be a sponge for this know how. Information gold!!!

Brief non tech description, overly simplified.

The MAP sensor is one of the inputs that the ECM uses to adjust the AFR. As the engine coolant warms the ECM shifts from Open Loop (where it ignores the O2 sensor and runs on the built in calibration) to Closed Loop where it reads all the inputs and adjusts the AFR based on those sensor inputs.

***Below approx. 73% throttle the engine continues to run in CL. Once you get above 73% the system reverts back to OL. It is again ignoring the O2 sensor and is relying on the MAP sensor voltage and the built in cal within the ECM to adjust the AFR and timing.

An adjustable MAP sensor only works in OPEN LOOP. It does so by changing the output voltage to the ECM. The ECM interprets that voltage and adjusts the AFR and the ignition timing. Again in OPEN LOOP only.

In your case the adjustable MAP sensor shouldn`t even be in your vocabulary. Sooner you forget about it the better off you will be.

The ECM reads the amount of air within the exhaust with a narrow band O2 sensor. A WB O2 sensor does the same thing but in a little slower pace. It normally sends it`s readings to a gage where we can watch what our AFR`s are.

This is a WB O2 http://www.autometer.com/2-1-16-wideban ... antom.html

Again, this is an overly simplified explanation and there are other factors involved. Lets not take to big a bite at once.

[jsawduste]

VSS signal..........

Vehicle Speed Sensor. The ECM looks at the TPS voltage and the VSS voltage as well as the MAP sensor vacuum and leans the fuel mixture for coast down conditions. If the ECM see`s no VSS signal then it will continue to dump fuel into the engine as it approaches idle. Hence it loads up and stalls.

[Jeepin89701]

OK I have changed the gear for the VSS(never seen the acronym), Time to jack stand the jeep and break out the volt/ohm meter for the VSS. Thanks for the link to the wideband 02, and the simple technical break down on the MAP sensor and how it factors into the equation as well(Have forgotten about adjustable map). Looks like I have a lot to go over, readings to take and miles to drive. With 35 to 50 miles on this new motor I know the pcm needs time to adjust/adapt as well. The good news here is this post has gone over a lot of information, very helpful for me and my understanding of where and what to look at and possible causes for the variety of issues that could be related to AFR problems. The fixes for alot of these issues have also been gone over and I have many directions to go for possible issue solutions. Thank all of you for sharing your knowledge!!!!