EFI TROUBLE! ED W. All Cooters, Help!!

[Bobby Fazio]

Originally Posted by J.R. Haddad

Alan, oil was Mobil 5-30 and stock filter G.M. A.C. Delco before and after,
no changes on either. I try not to introduce any variables unless I'm at
the track while I'm sorting out this new to me combo. J.R. Ed, Datalogger
is an Accel Gen.7. I am able to download it, but cannot get graphs
lately. J.R.

Email me your downloaded runs and I can try to graph them for you and also look to see if anything is funky between a good run and bad run. Bobby.fazio@gmail.com Also make sure no tunes were uploaded in between or anything else was changed. Check your timing on the wheel vs what the computer reads to make sure they are on same page.

[west coast]

Check engine to drive shaft ratio on your data logger it should tell you if it is a converter.

[ALMACK]

Originally Posted by Pedigo Perf

Did you measure the amount of oil you drained out? Maybe it is carrying more now,

If it has the same RPM but lost 8 MPH then it about has to be in the converter.

^^ That 8 mph difference is what stood out to me.

[D.Johns]

I've seen where a two-step would intermittently come off and on during a run as the car vibrations made the switch connections. Picked it up on the data logger for the ECU.

Also seen where the O2 sensor has went bad threw the computer into safe mode since when the sensor fails it fails lean.

Check TPS and throttle opening 100% physically.

Could be a valve hanging open at the top of the rev range or ring flutter also.

Lots of possibilities just have to start the process of elimination with any data you have.

[Alan Roehrich]

A lot of your information points directly at the torque converter.

You should absolutely verify the correct tune is loaded in the ECM, as well as verifying that the timing and fuel pressure are actually correct as read by gauges and a timing light. If all of that is correct, then look at the converter.

Mike is correct about filters. The only short AC Delco filter you can trust is PF2232, the Duramax filter, which does work on the small block and big block, at least for me. Other than those, I now use Wix Racing filtrs.

[Tim Lisson]

Find a convertor.

[Tim Lisson]

Oh, one other potential, remove all of your injectors and spray carb cleaner in screens and blow compressed air to dry. Reassemble. With batch fire your o2 will not show a dead hole on one side.

[Tony Goodman]

Turbo 200 trans, possibly broken stator support in the trans. Had that happen before, thought it was the ecu also.

[Ed Wright]

Not sure why you want to graph your air/fuel or timing. Not much use there. numbers versus RPM are all you need.
I think it's your converter as well.

[Mark Yacavone]

I doubt it's the converter.Of course I know why it always gets blamed. Black Magic.
So JR changed the engine oil and all of a sudden the converter doesn't work?
If the sprag all of a sudden decided to slip, the lower numbers would be down, but the MPH would be the same ..within reason.
Going the other way, if all of a sudden the vanes in the pump decided to fly off , the stall would be way high, and the low numbers would be off, but the rpm in the lights would be sky high. In this case ,it would last about one run, and the trans would be full of metal..
Back to the EFI guys...