I have a '95 Diablo with a R check engine light. When key on/off trick it blinked twice (weak feul mixture). I swaped o2 sensors and the opposite check engine light came on. Ha Ha easy fix right, WRONGO I replaced both o2 sensors with oem sensors, cleared the check engine light and went for a drive. The car had a smoother idel but here's the bad part. After about 20 minutes of driving not only one but yes folks, BOTH check engine lights came on. Key on/off again both blinks twice again. If anyone has had this happen please help, I did read that unhooking the battery in conjunction with clearing the code is important I can try that. If anyone can help me I would be greatfull.

Could it be that you have bad fuel, causing one then both [new] lambda sensors to fail ?

I would first put a multimeter across the connectors to each Lambda sensor to confirm that the voltage is actually indicating a poor mixture.

In the case of two flashes / poor mixture error code, the manual i have indicates to check as follows:

1. Check proper operation of fuel pump, fuel level, electrical supply to fuel pumps

2. check ignition system, poer module, coils, high voltage wire, distributor, spark plugs

3.check fuel pressure regulators

4. check exhaust system, air infiltrations before the lambda probe

5. Check electric and vacum connections to the intake plenum, of the absolute air pressure sensor

6. Check lambda probe wiring


I hope this is of some help, and that someone else will chime in and help.

Please post the feedback, its always much appreciated.

Regards

how about checking your alternator's output, is it starting to fail? (and check battery voltage)

if the alternator starts to fail you can get all sorts of weird problems

Thanks alot guys, I will go through the following, may take me some time but I'll keep you posted. I do have receipts that the previous owner had a new distrubuter, cap, rotor and an alternator rebuild by the dealer as well. I really appriciate the quick response. Thank you.

Thanks alot for the quick responce guys, I have receipts showing the previous owner had a dealer replace the battery, distributer, cap, rotor and an alternator rebuild, it might take me some time but I'll go through everything. If anyone has specs on what proper voltage readings are on some of these items along with the pressure of the fuel pressure regulators that would be helpfull. All I have is a parts manuel to work off of. Much thanks to all.

by disconecting the battery will not clear the codes.on my 94 vt to clear codes you need the tool that plugs into the comp and than you turn the key on and than it clears the codes.its like a 10 dollar part from lambo to get the tool to clear codes.if it was a 96 you would need a scanner.

Thanks for the info, I allready have the tool and it does clear the code but the lights come back on. I had read another post stating that you needed to do both clear the code and disconnect the battery. I don't really know but it's worth a shot. Thanks for the responce I appreciate that.

Adam,

I also have a 94 VT and both engine lights came on. What type of tools? cable? where to get it? lambostuff?

Thanks,

Tony

I will tell you, I sold my Diablo a few weeks ago because of these reasons.
On any OBDI system you have to have a special scanner/computer to read whatis going on with your car. There are only a handful of places in the US that have these. I have heard it over and over, if the car runs good and you watch the gauges don't mind the check engine lights. I thought for a car with an original price tag of 250K you shouldn't ever have these issues.
I am fixing my problem for good. I just picked up a Diablo that had an engine fire so there is no motor or trans. I plan on dropping a LS3 with a Porsche G-50 trans in it. No more Lambo computer problems, expensive bills and if any of the running gear breaks down while on a road trip I don't have to have my car shipped to a dealer that could be 8-12 hours away.
When I had my car I wanted to drive it all the time, I loved it. When I was
trying to sell is I quit driving it as much to keep the miles down because possible buyers was always crying about the milage. Seems that most people looking for one of these cars thought 24K miles on a Lambo was too high, It's all a bunch of bull. Now I won't have to WORRY about putting a ton of miles on the car. I have learned, there is alot to factor in when buying a diablo. I wish you the best with your car, If I were to have taken mine anywhere for repair it would have been Steve at Driven Exotics or Al Bertoni.
They are both located in California.

Take Care
Benj

Maybe you won't have "no more Lambo problems", but you won't have a Lambo either. Better to learn what's causing it and fix it. It ain't that hard. A CEL is about the most innocent of problems there is and happens on allot of cars, certainly no reason to get rid of it. I could never live the BIG LIE after having owned the real thing.

Wait till you try and sell the "thing" your building. Hope your ready to take a beating.