RE: IML: 81 Imperial changeover

Well, your pressure is low, but that would not cause the flooding you are experiencing. We can fix the low pressure with a replacement pump (as I recall, you?ve already done the filters, right?)

But before you spend money to replace the in-tank pump, If you would stay with us a little bit longer, I?d like to know the pressure at the output of the Control Fuel Pump ? that?s the one that is plumbed over to the nozzles. Measure it under the same conditions as you measured the 10 PSI.

When the engine is idling, I?d expect to see around 20 PSI there. If your pressure is way too high there, that explains the fuel flowing from all the nozzles and supplying too much fuel.

The cause of that would likely be a failed power module, and the thing to test there is the voltage being supplied to the control fuel pump. If it is getting 12 volts, or near that, the power module is screwing up badly.

Of course it is your car, and you may well decide to give up on the original EFI system at this point, I won?t try to argue you out of it. To me, this would be a shame because you will get a bad feeling about the system, as many other folks have, and miss the fact that when these cars are right, they are both delightful to drive and very durable and reliable.

I have to point out also, these systems seem to be very sensitive to the exhaust system ? people have reported lots of problems in going away from the factory system. None of these events has been carefully documented, so I?m shooting in the dark a bit here, but if it still has the original 3 cats on it, and all the plumbing, I don?t think it is causing your present trouble. If the exhaust system has been modified, I can?t guess what if any effect this is having on the problem. Out here in CA, we don?t dare modify anything in the exhaust system, because of our smog rules ? now back to 1974 cars, and probably going to stay there.

Dick Benjamin

From: mailing-list-owner@xxxxxxxxxxxxxxxx [mailto:mailing-list-owner@xxxxxxxxxxxxxxxx] On Behalf Of arbie104@xxxxxxxxxxx
Sent: Monday, February 20, 2006 6:47 PM
To: mailing-list@xxxxxxxxxxxxxxxx
Subject: RE: IML: 81 Imperial changeover

I just checked the pressure at the fuel filters. Only getting 10 psi on starting and running! Where do we go from here, or is it time to put on a carburator and scrap the FI? Also have several holes blown out in the "Y" pipe. I planned to just use the band style muffler clamps that summit sells to cover the holes for now. I see a complete "Y" pipe with cats on each side on e-bay for @$250 with free shipping. If I go the carb route I can get a whole dual exhaust system for less than $250. I'll be ok with that in PA because it is 25 years old and I will be putting antique plates on it...no inspection required!

-------------- Original message --------------
From: "Dick Benjamin" <dickb@xxxxxxxxx>

New fuel pumps are available, and that would be the way I?d go.

If yours is putting out too much pressure, it has probably been replaced with an incorrect pump ? there was an incorrect number floating around on the IML a year or so ago and I was guilty of forwarding it on to some other members.

Hopefully, my correction got noticed by all who pay attention to these cars, but if it turns out that you have too high pressure, I will dig out my notes and repost the correct replacement pump.

I bought one of the incorrect pumps from NAPA but it turned out that their catalog was in error, stating that it was the correct pressure; it turned out to be 42 PSI instead of 13!

Guess what, my symptoms were exactly what you are seeing!

I quickly checked the pressure, and took it back to NAPA ? where I have a very good relationship.

They apologized profusely, and pointed out that their catalog is not always accurate! After all that work (dropping the tank, modifying the fuel pickup sock etc.) I had the pleasure of doing it all over again with the right pump! However, I?ve driven the car on quite a few long trips since, and it is such a pleasure to drive that I?ve forgiven everyone. We toured Canada in it last fall, and it was superbly comfortable, very fast, and averaged over 24 MPG for the trip!

Dick Benjamin

From: mailing-list-owner@xxxxxxxxxxxxxxxx [mailto:mailing-list-owner@xxxxxxxxxxxxxxxx] On Behalf Of arbie104@xxxxxxxxxxx
Sent: Sunday, February 19, 2006 12:25 PM
To: mailing-list@xxxxxxxxxxxxxxxx
Subject: RE: IML: 81 Imperial changeover

Have not done that. If it's over 13 psi, would it be best to replace the fuel pump (assuming I can get a replacement) or would putting a regulator inline to cut down the pressure be a good fix. Thanks for the heads up!

-------------- Original message --------------
From: "Dick Benjamin" <dickb@xxxxxxxxx>

Have you measured the pressure at the fuel filter outlets? This symptom is typical of an in-tank pump putting out way too much pressure. It should only be generating 13 PSI.

Dick Benjamin