7.4L Injector #/hr constant in bin file

[kevinvinv]

Hi,

I am looking at a bin BHDH for a 94 7.4L truck- and the injector #/Hr constant is 67.9 #/Hr.

This isn't right... is it? I thought these injectors were something like 80 or 90 #/Hr?

This is the "higher fuel pressure" system from 94 I think.

Comments?

[1project2many]

That's a correct number. Injector flow is about 74 lbs/hr @ 30 psi. Big change from the early engines' 80 lbs/hr @13 psi.

Hopefully I'll have additional BCC's for you this evening.

[kevinvinv]

Thanks man. You can abort the BCC search. I went with the BHDH from 94 and got everything copied into 0D. It didn't take 5 hours but it did take quite a long time!

The scalers were probably the worst. I wish that Tuner Pro had a little bit better way to cut/paste Scalers :)

There were a LOT of very significant number changes between my original 5.7L cal and the 7.4L BHDH. I was a little surprised in fact. So far it seems to run though...

[1project2many]

No problem.

Congrats on getting the swap done. Now to get on with tuning...

[kevinvinv]

I have some pinging going on when the engine is lugging. I first of all don't get what the knock sensor is good for if it doesnt stop the knock but anyway... what is the best way to address knock? Should I be retarding the timing or adding fuel or is it not that straightforward?

[1project2many]

OEM tune is very conservative in BBC. Increasing elevation should decrease the tendency for knock although fuel quality can always be suspect. Sensor is a microphone only. Continued PCM detection of voltage on signal line causes increasing reduction of timing based on calibrated values to maximum reduction level. If programmed reduction is insufficient then knock continues. Confirm the scantool is actually showing knock. PCM can't fix what it can't hear, and not all noise heard by human ear is knock. Since O2 level decreases as elevation increases, I would expect the pcm to be reducing delivered fuel already so any changes to cure real knock should be in timing area.

Is distributor installed correctly at base timing?