'97 Vortec 7.4....need some help to diagnose fuel

[DEMON44]

Sorry for the cross post, but I just noticed this injection forum, so this is my first time in here

OK have '97 CC dually with Vortec 454 and NV4500 stick. Need help to diagnose. Been having an engine vibration since I got it.

first plug wires were rotted out and arcing. so changed them out. helped some. Now still have engine vibration. and just got CEL, said bank #2 running lean. So shot manifolds with temp gun. driver side all got to 300* quick and even.....

but passengerside
ambient 32*

#2 virtually no temp increase ~43* maybe just from compressing air

#4 slight temp increase 67*

#6 got to 200*

#8 virtually no temp increase.



.........so why? all injectors on 2 bank bad? is there separate drivers for each bank? got one bad? I did run an injector cleaner cycle after changing the plug wires........not a bottle in the fuel tank kind but a real hook up to the test port on the fuel rail, disable the pump, and close off return line. run off a pressurized bottle and regulator. no real change.



any ideas? I'm not sharp with gas engines.


thanks guys.

 

[Thunder]

The most common problem with Bank 1 or 2 running lean is the MAF sensor. Try cleaning it with some some electrical cleaner or rubbing alcohol in a spray bottle. Sometimes that fixes it.
Check for vaccum leaks
Possibly could be a stuck EGR valve also.

 

[DEMON44]

Thanks. had a go at it tonight. think its fixed itself up. pulled the MAF and clean...was dirty. had sporatic spark on #2 as well. pulled cap. cleaned. put noid tester on #2....cause thats the only one we could get without pulling the upper intake. was firing just fine. reinstalled cap.....in a more straight manner that it was/ might have had #2 arcing on the head even with the new plug wires. as it was touching the intake.

anyways runs 100% better now......cleared CEL. will have to wait and see now.

Thanks again.

 

[oldtoyboyd]

If it has the flat style dist cap they are known for arching out. Only replace with a delco as others seem too missfire soon afterwards. Most 1 tons do not have missfire monitors. It will not set a missfire code but it will show missfires under scantool data.

 

[DEMON44]

ok its been a few days now, there is still a small slight miss. but power is up and fuel ecomony is way up, smoothness is way up. but that tiny miss still.

So you say Delco cap 'eh. we had the cap off and it looked ok cleaned it up a bit but what about the rotor? just replace the cap you think? It is a flat style, with 4 out the driverside and 5 out the passengerside. we had a snap-on scantool hooked up during the whole deal too. there were 3 o2 sensor code on the bank 2 before we cleaned it up. now there hasn't been any codes since. just the small miss. maybe a new cap is the ticket. the injectors are all giving fuel. the cylinder temps all came up fast after messing with the cap and wires again.

thanks for the help, its getting there.

 

[oldtoyboyd]

Go ahead and replace cap and rotor. Go under missfire data on the snapon scanner and you will see what cyl are missing on the history counters.

 

[DEMON44]

Its prett much smooth out now. I will still recap and rotor it.

thatnks for all the info.