Ok guys, any and all help will be much appreciated. I have a 96 F150 extended cab orignally a 5.0 with a 4R70W tranny. I have swapped in a 351W stroked to 393 ci. The truck operated ok for a couple of months with the CEL coming on once in a while for the system tool lean bank 2 code. I'd disconnect the battery to erase the code and it would be ok for a couple of weeks or so. Well, the problem has become progressively worse over time to the point of the truck sputtering under acceleration/load and the CEL light comes back on immediately after attempting to erase the code. I am in the middle of the diagnostics of the problem. But I have a question or two about the differences of the fuel injection and electronics between the 5.0 and 5.8. What size injectors did Ford use on the 5.8 from the factory? I know that the 5.0 has 19 lb. injectors. Does the 5.8 use the same size? Are there any other differences in the rest of the fuel injection system?

My plan is to make sure the factory electronics/injection system is working properly and then investing in a computer chip/programmer. I just wonder if I should/need to upgrade to 24 lb injectors and a properly tuned MAF sensor before the chip/programmer.

Balboyford
97 EB Explorer 5.0 AWD
96 F150 393 4X4

 

my 96 f150 302 had the same trouble code about a week ago. all i had to do was tighten all the clamps on my intake and it ran fine. the check engine light never came back on after i erased the code. i've heard it can alsp indicate a dirty MAF sensor too. hopefully that helps.

 

Wow, you are running a 393 on 19lbs injectors? You should be running probably 30lbs injectors with a MAF tuned for them...........

 

+1, 393ci is alot to be running stock 19lbs injectors. I would upgrade the cam lifters rockers and injectors and MAF then I would invest in some Long tube headers and a true dual exhaust. Then take it to a REPUTABLE DYNO and have it tuned. MPG may improve as well.

Good Luck!!

 

How could you swap a motor and not know what injectors are in it?
What computer is running the motor?
What parts are in the stroker.. cam? heads?
Who told you this would work with a stock computer?

 

I know what injectors are in the motor right now, I just don't know what Ford put in the 5.8 from the factory. I have the stock 19 lb. injectors from the 5.0 in it right now. The stock 96 computer is running the engine and transmission. The stroker is a mild stroker with mild pocket ported E7 stock truck heads and the cam is a custom grind flat tappet with 280 duration and 440 lift. The block is from a mid 80s van and I swapped on the fuel injection intake and the E7 heads. I have been running this stroker with a 92 Mustang computer in an 84 truck for approx. 2 years and just this past November, I bought my current 96 F150 and swapped in the engine and used the 96 stock electronics because of the 4R70W transmission and emissions. It has been running ok since then besides the intermittent system too lean on bank 2 code. That problem has gotten progressively worse though. As I said, I am in the middle of diagnosing that problem and I am narrowing it down to the injectors or possibly an intake gasket leak. Another question: I have heard from two different people two different explanations for bank 2. Is bank 2 cylinders 5-8 or is it the monitor O2 sensor after the cat? As I'm sure many or all of you know, 96 was, I believe, the first year for OBDII, hence the monitoring O2 sensor after the cat.

Sorry Conanski, I should have included all of that info in the initial post.

I didn't think about going as high as 30 lb injectors. I was stuck on 24 lb in my head, I'll have to find a tuner to take the truck to. I'm in NE OH, anybody know of a good reputable tuner in that area? Thanks for the input guys, I'll let you know what I find. If you think of anything else please let me know.

Baldboyford
97 EB Explorer 5.0 AWD
96 F150 393 4X4

 

OK. thanks for the additional info.. it's hard to know where to start without the basics. The MAF 5.0 computers can run this motor.. it's requirements are probably not too far beyond the fuel limits of the 19lb injectors, though it will be stretching the computers learning limits at part throttle operation for sure. The learning ability of the computer is also the reason why the motor "appears" to run OK for a while after you disconnect the battery.. you are just erasing everything it has learned, that's all. The code you are seeing may be the computer telling you it has reached it's adjustment limits at some point in the fuel map. What you could try is install an adjustable fuel pressure regulator and boost it to 50psi with no vacuum. Reset the computer and drive it for a while to see if the code comes back. In effect this will make the injectors perform like larger injectors, and it may be enough to cover the lean area in the fuel map. If you do decide to use larger injectors on this motor I highly recomend you get a tuner than can correct for them and not try to trick the computer with a "calibrated" MAF meter. The fuel requirements on a larger displacement motor are much different than the stock 5.0 requirements, and you'll get better performance from remapping the computer than feeding it lies.

P.S. Both windsor motors used 19lb injectors.

 

Thanks for the info, Conanski. I was considering going to an adjustable fuel pressure regulator; this helps to make up my mind. Thanks for the advice on the differences of a "calibrated" MAF meter and having a tuner remap the computer. I've done a couple of fuel injection engine swaps in a variety of vehicles, but everything has used stock electronics with stock engines up until now. Tuning is uncharted territory for me. I'll let you know what happens with the truck. One question still remains though. Do you know what the code reader is referring too by bank 2? As I stated in an earlier post, I have heard from two different people two different explanations for bank 2. Is bank 2 cylinders 5-8 or is it the monitor O2 sensor after the cat?

Thanks again,
Baldboyford
97 EB Explorer 5.0 AWD
96 F150 393 4X4

 

Bank 2 is the drivers side of the motor, the sensor after the cat just monitors cat performance and has no effect on engine operation.. it's an OBD2 emissions thing.

 

Thanks again, I really appreciate the help.

 

Ok, First Update. During my diagnosing of the problem, I found (of all things) the cyl. 2 (Bank 1) spark plug wire loose, barely connecting to the spark plug. I pulled the wire and inspected the boot and wire connector inside the boot, reinstalled the wire ensuring a positive mechanical connection. I then reset the computer and took it for a test drive (approx. 15 miles) and the cel has not come back on yet. I don't know if the no. 2 plug wire was always on the edge of loosing connection since the engine swap or not, causing the intermittent code of system too lean bank 2. I was told by a good service manager friend that a rich condition on one bank can cause the computer to think that the opposite bank is running lean, so I won't know for sure for a couple more rides in the truck for sure, but it was very possibly the problem.

By the way, I am still going to look into finding a tuner to help me get the engine running at its optimum. Again, thanks for all the input and I'll keep you updated on the progress.

Baldboyford
97 EB Explorer 5.0 AWD
96 F150 393 4X4

 

Second Update, the bad news, the cel came on after about week and a half. Went to an Advance Auto to have them read the code and it came up the same code, system too lean bank 2.

The good news, I've met with a local tuner that is a dealer for SCT. On my first visit with him today he plugged into my OBDII port with a diagnostic computer that can read the ECM realtime and bank 2 was running at 23% while bank 1 was at 6% during idle indicating that the ECM was trying to make up for a lean condition on bank 2. I've already unplugged the injectors one at a time on bank 2 and they all produced the same slight stumble at idle when unplugged. I'm thinking the injectors are ok other than being too small. I'm leaning towards an intake gasket leak for the lean condition. Another possibility is a wonky O2 sensor. I just replaced the O2 sensors during the engine swap, but they aren't from a Ford dealer. I've heard of people having problems with O2 sensors especially that weren't from a dealer.

The other good news is after I have this problem chased down, I'll have this tuner flash my ECM for optimum performance along with a new set of 24lb. injectors at minimum of parts added.

Balboyford
97 EB Explorer 5.0 AWD
96 F150 393 4X4

 

Yeah there's no substitute for a realtime analysis, I just started using a TweecerRT on my truck, it will display all the sensor outputs realtime on a computer. I quickly noticed how hard my injectors are working, duty cycle was at 80% at only 4000rpm on my motor.. a warmed over 351, so I can't see a 393 running up to potential on them. The first thing I did with the tuner was enter the correct engine displacement and MAF transfer function, and right away the engine idles smoother and responds better. The Tweecer allows you to save 4 different calibrations and switch between them on the fly, and switching back and forth between this first calibration and no calibration the difference is obvious. Everything the experienced tuners are saying is true, the motor runs better when the computer has accurate numbers to work with.

You very likely have an air leak somewhere on bank 2, these motors typically run pretty lean at idle and should only require very small injector duty cycles, so 23% is WAY too high. The computer is attempting to compensate and when it reaches it's adjustment limit it throws a code. The leak could be in the intake but could also be the exhaust manifold or air injection system.. basically anywhere upstream of the O2 sensor where extra air could get in.

 

The tuner I am working with also mentioned the possiblility of an exhaust leak. I never really thought about it, but that does make sense to me. Since this is a swap, the O2 sensor is approx. 6-10 inches down the y pipe from the header/y pipe connection so it could have a leak at the head or between the header and y pipe (shorty headers).

Thanks for the input. Your TweecerRT sounds like a handy tool to have. Who makes it? I am probably going with the SCT Xcal 2. They have an Xcal 3 out now, but my tuner says they are still working some bugs out of it.

Baldboyford
97 EB Explorer 5.0 AWD
96 F150 393 4X4

 

I think you guys have the problem(s) figured out, but I figured I would add a similiar diagnostic problem I had. About a year ago I picked up my truck that I was storying at a friends house and it ran really rough when it first started up, coughing and spitting out black smoke. I have a few gauges in the cab that monitor various engine sensors, and the most valuable one of them all is the Air/Fuel ratio sensor. When it runs properly I can see it running a bit rich for the first minute or so and then I can see the computer cycling it back and fourth making adjustments trying to keep in right in that desired ratio of 14.7, or something close to that. Well, when the truck was having issues when I picked it up I noticed that it would behave normally for the first 10 or 15 minutes and then slowly lean out to where it was so lean it was beyond the meter. After each start it got worse and worse until it basically always stayed lean. I started replacing various parts that I thought would be causing this problem and then after a while I decided to replace the O2 Sensor. As soon as I replaced the O2 Sensor the truck ran good as new. I don't know if it was the O2 sensor the entire time, or if some other problems caused the O2 sensor to fail. If a truck does run too lean it will run so hot that it can definately burn out an O2 sensor, so don't always trust them. As conanski as stated, there is no substitue for real time data for analysis. Best of luck.