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

J.R. Haddad · 08-18-2015, 07:06 PM

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.

Alan Roehrich · 08-18-2015, 08:40 PM

Why are you assuming it is an EFI problem?

J.R. Haddad · 08-18-2015, 08:52 PM

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.

Ed Wright · 08-18-2015, 09:46 PM

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

Bill Bogues · 08-18-2015, 10:12 PM

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.

Alan Roehrich · 08-18-2015, 10:12 PM

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)?

J.R. Haddad · 08-19-2015, 12:25 AM

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.

J.R. Haddad · 08-19-2015, 12:36 AM

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.

Pedigo Perf · 08-19-2015, 06:39 AM

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.

Mike Pearson · 08-19-2015, 08:53 AM

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.

08-18-2015, 07:06 PM	#1
J.R. Haddad Senior Member Join Date: Jun 2012 Posts: 784 Likes: 936 Liked 1,464 Times in 307 Posts	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.

08-18-2015, 08:40 PM	#2
Alan Roehrich Veteran Member Join Date: May 2006 Location: Murfreesboro TN Posts: 5,111 Likes: 1,570 Liked 1,814 Times in 413 Posts	Re: EFI TROUBLE! ED W. All Cooters, Help!! Why are you assuming it is an EFI problem? __________________ Alan Roehrich 212A G/S

08-18-2015, 08:52 PM	#3
J.R. Haddad Senior Member Join Date: Jun 2012 Posts: 784 Likes: 936 Liked 1,464 Times in 307 Posts	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.

08-18-2015, 09:46 PM	#4
Ed Wright Veteran Member Join Date: Mar 2005 Location: Sand Springs, OK Posts: 8,132 Likes: 896 Liked 390 Times in 170 Posts	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? __________________ Ed Wright 4156 SS/JA

08-18-2015, 10:12 PM	#5
Bill Bogues Member Join Date: Apr 2005 Location: Bethany La. Posts: 323 Likes: 96 Liked 169 Times in 53 Posts	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. __________________ Bill Bogues 4696 STK

08-19-2015, 12:25 AM	#7
J.R. Haddad Senior Member Join Date: Jun 2012 Posts: 784 Likes: 936 Liked 1,464 Times in 307 Posts	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.

08-19-2015, 12:36 AM	#8
J.R. Haddad Senior Member Join Date: Jun 2012 Posts: 784 Likes: 936 Liked 1,464 Times in 307 Posts	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.

08-19-2015, 06:39 AM	#9
Pedigo Perf Member Join Date: Feb 2008 Location: Wichita Ks Posts: 383 Likes: 70 Liked 30 Times in 17 Posts	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.

08-19-2015, 08:53 AM	#10
Mike Pearson VIP Member Join Date: Mar 2007 Posts: 2,446 Likes: 614 Liked 1,919 Times in 576 Posts	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. __________________ Mike Pearson 2485 SS