Help understadning my CJ7 SBC datalog

[Dlxman]

I have posted this under Unhappy CJ7, but would like to re-iterate my help needed. History - 70s 350 with TBI installed in 2014. .195 intake heads, 30 over pistons, mainly stock, but whole assembly balanced with TH400. Ran great, but now lacking power under acceleration. I got the Tunerpro so I can read more than a key turn for the OBDI. I attached a log file. Idled, went down the road with mild accelerations, WOT a couple times to feel/show the stutter. Idled at a turn, geared down and WOT through 1-3. Once home, I put it in park, and idle went through the roof!

Any help of what to look at, or try next, my wife and I would really appreciate it. We love driving this Jeep, but have not been able to enjoy it for most of the summer.

Diagnosing by wallet, and some manual reading diagnosis has not panned out. I'm savvy with engines, some electronics. New to the Tunerpro, I am asking for support! Moral support if any.

Thank you for your time!!

[dave w]

Is the data log for the 1227747 ECM?

dave w

[Dlxman]

Hi Dave, My apologies for not noting this. You are correct

[dave w]

Are the BPW and SA Hacks setup in the .bin file? ---- BPW and SA data are very useful.

Knock Accumulations are unusual. --- Maybe experiment with temporarily disabling knock? Monitors show a saw tooth, normally flat line with an occasional spike.

Mostly running rich. ---- Maybe an injector is dripping? Check injectors with a timing light to verify spray pattern.

dave w

[Dlxman]

I do not have the .bin file installed at this time. I only did the .adx so I can log some data. One thing I did not do was increase the latency in the USB to 1msec. Once I do this, I can re-log data (maybe it can smooth out the charts). I rebuilt the TBI, and did see a nice spray pattern about 1 month ago, but can check again. I am unfamiliar with the BPW and SA Hacks.

[tayto]

I have posted this under Unhappy CJ7, but would like to re-iterate my help needed. History - 70s 350 with TBI installed in 2014. .195 intake heads, 30 over pistons, mainly stock, but whole assembly balanced with TH400. Ran great, but now lacking power under acceleration. I got the Tunerpro so I can read more than a key turn for the OBDI. I attached a log file. Idled, went down the road with mild accelerations, WOT a couple times to feel/show the stutter. Idled at a turn, geared down and WOT through 1-3. Once home, I put it in park, and idle went through the roof!

if it ran good before and now doesn't it's time to go back to the basics, fuel delivery & spark. spark plugs, cap & rotor look good? what's your fuel pressure? have you verified your base timing? not saying scanning won't help but there are basics you should check especially if you haven't touched anything since you got it running 8 years ago.

on the note of "rebuilding the tbi". i don't like this term as it usually entails replacing a few orings and cleaning the unit. hardly a rebuild. did you check the throttle shaft for play? i haven't seen one in the last 10 years that couldn't use throttle shaft bushings. i recently am a BIG fan of taking the injectors to a professional shop that has an injector cleaner (ultrasonic) & test machine . getting a flow report is an excellent bonus as well. i don't guess at this stuff any more this is my recipe for a "rebuilt" TBI

[Dlxman]

Hi Tato, thank you for your input. All the basics have been checked as good or new. Cap and rotor were replaced last year with a bad connection to the ignition on module under the GM HEI cap. I have completed vacuum leak tests on all areas including the throttle shaft to end up clean! Which is good. As Steveo had mentioned, originally the injector spray pattern was good after the "cleaning and gasketing" of the TBI.
I checked it this evening, and behold the right (passenger side) put out no fuel. This was after warm up and closed loop. The left side had a cone, but seemed a little wet, not a fine(ish) mist. I did swap the RH to LH connectors to see if it was in the wireing, but no difference. Not sure if this was the right way or not. Regardless, I am going to pull the injectors and either clean or replace them.

I will let you know by this time next week if it was successful, as it will take time to get it done, and be abck in town to try it out.

[tayto]

good stuff! i just ran into this with a set of recently cleaned injectors. if injector is not spraying take a small hammer and tap the injector pod repeatedly while the engine is running. have brought 2 injectors back to life this way. i recommend finding a set of factory injectors and getting them cleaned, i have heard new injectors are made differently and can affect the tune/require further tuning

[Dlxman]

Hi Tato, thank you for your input. All the basics have been checked as good or new. Cap and rotor were replaced last year with a bad connection to the ignition module under the GM HEI cap. I have completed vacuum leak tests on all areas including the throttle shaft to end up clean! Which is good. As Steveo had mentioned, originally the injector spray pattern was good after the "cleaning and gasketing" of the TBI.
I checked it this evening, and behold the right (passenger side) put out no fuel. This was after warm up and closed loop. The left side had a cone, but seemed a little wet, not a fine(ish) mist. I did swap the RH to LH connectors to see if it was in the wireing, but no difference. Not sure if this was the right way or not. Regardless, I am going to pull the injectors and either clean or replace them.

I will let you know by this time next week if it was successful, as it will take time to get it done, and be back in town to try it out.

How do I know which injectors I have? No markings....??? TBI #17089018 3459 JWZ

[tayto]

that # appears to be the number stamped on the TBI unit itself. if the injectors have no number etched in the top or paint markings the only way to determine what they are is to get them flow tested @ 13 or 14 psi

http://www.gearhead-efi.com/Fuel-Inj...d-part-numbers

[dave w]

Perhaps a picture of the EXTREMELY UNUSUAL Knock (sawtooth pattern) will be helpful?

dave w

Knock.jpg

[dave w]

Perhaps a picture of the EXTREMELY UNUSUAL Knock Accumulation will be helpful?

dave w

Knock.AccumulatorJPG.JPG