91 Diablo won't start

After a long winter sleep my diablo won't fire up. I change the cap, rotor and new plugs to get it ready for the summer fun. The engine turns over but won't fire up. I checked the spark and it seems fine. I don't hear any fuel pumps prime when you put the key in the on position. I don't remember if they did. I never payed any attention to them. Any body have any other ideas.

 

Thanks

Relay for the fuel pumps is behind passenger seat under rear storage unit.(Easlily removed with two screws at very bottom) When you turn the key you shouild hear the relay click and the pumps should activate.

Found the relay. When I turn the key to the on position it clicks but I don't hear any fuel pump action am I suppose to?

Was it running properly BEFORE you changed wires, cap and wires?

Good question

 

Staccato, where are you located?

Check fuses for fuel pumps...the relay is clicking, so that is making the circuit to the pumps live. Also remove relay...get electral tester....one of the circuits in the MALE RECIEVER should be at 12 volts when the key is turned on. The relay , when activated makes the connection from this 12 volt circuit to the pumps. Later today, I'll pull the relay and tell you exactly which pole on the relay should have 12 volts at all times. Don't panic, we wwill figure it out..if it was running fine before storage, its something simple.

Hi guys thanks for the help.

 

andrew I live in Windsor, Ontaro, Canada.

 

The mistake I made was I didn't start it before I changed everything, I just thought it would be easier to work on a nice cool engine for a change. I put new plugs, cap, roter, changed the oil and drained the coolant and refiled her up fresh. I looked at all the fuses behind the passanger foot kick plate and the ones behind the seat by the relay and they all look fine.

 

I just bought the tec. manual last night from the quy on e-bay. I thought this would be a good place to start and understand my car if I want to start doing all my own repairs.

 

Checked the relay power and this is what I have

 

Key off there is power from 86 to 30 - 12 V

Key on there is power from 86 to both 87 - 87 terminals - 12 V

Nothing on 85 terminal ?

When 12v is present to 87 with key on, and not present with key off, means the relay is working.

Staccato, how far are you from Detroit? (guessing you are less than an hour from me)

 

Like Lambo128 said, you should hear the fuel pump.... but I am guessing something more simple if you put it away working... I would triple check everything you touched while working on the car..

Terminals 85 and 86 activate the relay...if it is clicking they are working. They CONNECT terminals 30 to terminals 87. you should have 12v at terminal 30

when you check for voltage go from each terminal to GROUND , not to any other terminals on the relay.When you turn on the key either terminals 87 (2 of them) or 30 should have 12v to ground. Remember fuel pumps will only go on momenteraly untill they reach presure.

Hi andrew I live about 15-20 minutes from the tunel of Detroit

 

Lambo128 I have 12V at terminal 30 with the key off and 12V at 30 and 86 with the key on.

 

Can the fuel pumps be seen or are they in the gas tank? I was going to disconnect the fuel lines from fuel filters and run a spare line to a pale and see what happens.

 

I looked around and don't see anything that I might have disconnected.

 

Does any have a layout of the distributor cap wiring I just want to check to see that I didn't screw that up. I no the firing order just want to make sure I put all the wires back in the correct spots. Which one is #1. The cap is labled 1A 1B and so on.

12v on #30 is fine with either key on or off. Thats good. Fuel pumps located under passenger side rear fender under a cover. Kepp in mind, that if you did not get #1 cylinder wire on the right spot on the Distributer cap car will not run.If you want to do a quick check, just loosen bolt that connects fuel line to fuel rail, turn key as to start and see if any gas comes out.

#1 Cylinder 2nd Terminal left of screw..

Thanks Lambo128

 

Looks like I have the #1 correct. Can you tell me from there clockwise what the wire numbers on the cap are just to double check. I will also losen the fuel rail lines to see if any gas is getting there. Thanks for all your help.

 

This is what I have and it looks to be right with the firing order.

 

1-12-4-9-2-11-6-7-3-10-5-8

 

Have to keep ducking in and out of the garage with nobody noticing me leaving my easter dinner party.

Thanks Lambo128

 

Looks like I have the #1 correct. Can you tell me from there clockwise what the wire numbers on the cap are just to double check. I will also losen the fuel rail lines to see if any gas is getting there. Thanks for all your help.

 

This is what I have and it looks to be right with the firing order.

 

1-12-4-9-2-11-6-7-3-10-5-8

 

Have to keep ducking in and out of the garage with nobody noticing me leaving my easter dinner party.

Have someone crank the car at the same time you hit the bottom of the fuel tank with a rubber mallet This might get the brushes in the pump to make contact and it could start. If it starts I would say You sould put in a fuel pump. At least this is something to try, good luck

The fuel pumps are on the right side. There is a panel you remove to get to them. 2 external pumps. That firing order doesn't look right. I'll check.

I think the #'s you are refering to are the #'s around the cap.

 

I believe the firing order is 1-12-4-9-2-11-6-7-3-10-5-8.

 

FRONT OF CAR

 

Drivers side 12 passenger side 1

11 2

10 3

9 4

8 5

7 6

 

REAR OF CAR

 

I got this from another site. I hope it helps.

 

( It is different than the Countach firing order)

Sorry that looks different from how I set it up on the computer.

 

I'll try this again.

 

......................front of car.........................

 

left side................12...right side...............1

left side................11...right side...............2

left side................10...right side...............3

left side................09...right side...............4

left side................08...right side...............5

left side................07...right side...............6

 

 

......................rear of car...........................

FWIW, it would be exceedingly rare to have a fuel pump go bad. It will be an electrical issue. Do not forget to check the coils.

Another quick test....take relay out...run a jumper wire in the relay holder from terminal # 30 to terminal # 87. Just do it for a second, you are now bypassing the relay and putting power to the pumps directly. If you hear the pumps come on, then the relay is bad. If pumps don't come on there is a problem with the wiring from the relay to the fuel pumps...it is unlikely that BOTH pumps would be bad. Remember this is IF you have 12 volts from relay post # 30 to a ground point before you start.

All good info. I will try again once I get home from work today.

 

The numbers I posted are the wires on the cap starting at one and going clockwise.

 

The firing order marked on the car is 1-7-4-10-2-8-6-12-3-9-5-11

 

I'll keep posting what I find.

 

Thanks

have you checked to see if you are getting a spark?

loosen the fuel line and turn key on and see if fuel sprays out

Hi guys.

Just undid the fittings at the end of the fuel rail and turned the key and no gas came out. So I think I have a fuel pump issue.

 

So I will start down that road and let you know what I find.