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

Took my car, '92 Camaro J/SA, out to our local track on Aug.2, ran 11.54 and 11.52 @ 114.00. Air 2400 ft. Density 28.97 Humidity 55%.
Go to the same track on Aug.16, 2400 ft. Density 29.03 Humidity 77%,
and car goes 11.84, and 11.82 @ 106.00. Changed nothing but the oil.
Leaked it yesterday, perfect! RPM @ the finish line the same and A/F
Ratio @ the finish line the same. I am lost. All help welcome. J.R.

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

Why are you assuming it is an EFI problem?

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

Alan, you're right, I should not have jumped to that conclusion. It's just
that I'm a Quadrajet and sometimes Holley guy, and the EFI and this problem have me baffled. J.R.

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

I would be surprised if it's an EFI problem.
What system do you have?
Using a data logger?

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

I'd check the rubber brake line hose at the rear end housing.I've had 2 that all of a sudden would let fluid through under pressure but internally had collapsed and wouldn't let the pressure release. Same symptoms on our car as yours.Hope you get it fixed fast without a lot of trouble.

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

Compare incrementals and see where you are off.

If your A/F ratio and RPM are the same, odds are your timing is as well.

If your RPM is the same, but your MPH is low..................

The humidity is 22% higher on the slower pass.

What change did you make with the oil (and filter)?

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

Incrementals- 60- 1.48-1.53
594-6.75-6.92
660-7.24-7.42
1000-9.55-9.79
1320-11.52-11.82
The 330's were not working either day. Thanks so far guys, J.R.

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

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.

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

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.

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

I would shy away from any AC Delco filters. I had several collapse due to plastic internals. Cost me an engine. Check the filter it could be collapsed. Now I run a System One reusable filter. No more passenger car filters or oil.

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

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.

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

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

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

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

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

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.

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

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.

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

Find a convertor.

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

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.

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

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

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

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.

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

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...

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

Ya, probably the u-joints slipping.

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

Carson, thank goodness your humour is back!! Your Kyle sheep jokes
kept me going one very cold winter! So, I'll order the new u-joints in
the morning! J.R.