I'm trying to figure out a problem with my engine. I was having leakdown and other injector problems, so I got some Ford 24lb injectors and a crane AFPR. After I put the new injectors in, I went for a ride and the engine feels like it's fighting itself. It reminds me of the feeling when the catalytic converters are clogged, but I don't have any!

I have adjusted my fuel pressure and injector constant and I'm now getting 128 BLM readings at idle.

Anyone have any ideas?

Thanks!
-dperk

 

im not sure about the 128 blm readings, i suggest post this on the prom board if thats the problem. but what i would think is that you are running too rich or to lean if the only things you altered in this time period where the injectors and afpr. check your fuel pressure. post the info on your car 5.7 or 5.0 any modifications?

 

128 blm is perfect. Is this constant all the time? What size injectors were in before? Different flow rate?

 

I had the stock 22lb injectors before. This is a stock L98 engine except it has headers on it and now Ford 24 injectors.

 

Is the 128 blm present above idle? What is int doing? With the headers are you using a heated o2 sensor in the collector?

 

I have to datalog it on the road. My laptop battery only runs for aobut 2 mins!

The blm's stay at 128 when I rev up in the garage. I'll get a datalog on the road when I rebuild another laptop.


I am not using a heated O2. I have a pair of shorty headers and I welded the bung intot he header before the collector, so it's pretty close to the engine.

 

It would be very rare for the blm to stay at 128 in closed loop without any chip tuning. It would however stay at 128 in open loop, o2 sensor not outputing voltage, too cold maybe.

 

Right - if you can datalog (apparently you can since you're seeing BLM values), look at the O2 voltages and make sure you're going into closed loop. Chances are you need a 3 wire heated O2 sensor....

 

TunerRT shows that i'm in closed mode. Can it be that it's coming out? What values should I be seeing, or looking for? I've watched the O2 crosses and it fluctuates pretty good. I could always try a heated O2 I guess.

I was hoping someone would say "it sounds like your coil is bad" or "maybe you have a vacuum leak" or something like that.

 

It could be...
Weak coil
Worn plugs (check gap and plug color)
Weak/worn plug wires
Carbon built up in cap/rotor
Vacuum leak
Wrong fuel pressure
Wrong injector constant

Check ignition and plugs, they will tell you a lot. That will let you know if you're running rich or lean. Does the computer keep cutting the spark advance? Are you detecting and knock?

What fuel pressure do you have everything set to? You set the injector constant to 24? Did you make sure to plug the vacuum line back in to the fuel pressure regulator? Check connections on plenum.

 

I have all new plugs/wires/cap/rotor/pickup coil/ignition module...

I am afraid that I got a crappy coil from autozone. I didn't know if that can cause this symptom or not.

I didn't plug the vacuum line when setting the fuel pressure. I left it all connected and set the pressure to 40lbs when at idle. I did change the injector constant to 24. I tried it at 22 and 25.5, but right at 24 was what gave me the 128 blm at idle.

When I watch the spark advance, it does jump around a little. It's not real steady at all. I graph the advance relative to TDC or Reference pluse and they both have little bumps in the graph. It's not smooth like a flatline.

 

Spark advance will always be jumping around with the esc connected, computer controlling. You need to log some data. You should be able to check the coil with an ohm meter for resistance on primary and secondary windings.
If it ran fine before the injector change I would look in that direction but it sounds like many things were changed at the same time, yes?

 

I'm going to post this as new under the prom section, but in case you want to see my datalog from today...

http://www.ubertux.net/ecu/