So I have a problem. I’m sure if Fuel or Vacuum or what?

[JSzabo]

I just finished a major maintenance to my Delorean.

Put new spark plugs, all fuel lines replaced.
New updated fuel pump and controller.
New water pump, thermostat.
Belts, pulley bearings.
Oil, oil filter.
Gaskets, o-rings.
Cleaned air manifold, all new bolts and plugs for it.
Rebuilt kjet/fuel system (DMC rebuilt). Fuel manifold cleaned and ungunged.
New clutch line, master clutch cylinder , and slave clutch cylinder.

So we put it back together. Connected all vacuum lines fuel lines.
First we didn’t have the air clearer box on. And it would start then die. Thinking there was still air in the fuel lines. We kept starting and it fired up. Then died. Then fired up then would die. My mechanic friend had me start the car and he pressed down on the fuel pendulum and it would keep running.
Thinking it needed the air cleaner box for better air pressure. We put the the air cleaner box back on. And it would do the same thing start up run for a sec then die. Would do that fine about two more times then wouldn’t even start again. Until we waited about a min and would do the same cycle again.

I believe we have all vacuum lines attached we checked the vacuum canister there was one plug that was kinda rotted away so we plugged it with a new rubber plug and still the same thing.
Not that I believe it has anything to do with it but the bumper is not on.


Any ideas?

[David T]

Sounds like the fuel mixture is too lean. It starts and runs for a moment because of the cold start valve. Once it uses up that fuel it doesn't have enough to run unless you press the plate down. Is the frequency valve buzzing?

[DMC5180]

Well, it’s firing on the initial burst of cold start injection fuel only. It only opens the CSV while the key is in the start position. Considering,the shotgun approach to everything you’ve done to the fuel system. You’ll to verify all the bits are installed correctly. Seems like at this point you need to put a pressure gauge in the fuel system to verify pressures. You replaced the fuel pump. Confirm the lines are correct and the external check valve flow arrow is oriented from the pump. One thing you could try just to confirm fuel pump is flowing enough fuel, is the WUR plug swap to the CSV trick. This is a work around for a bad accumulator HOT Start condition. It will keep the CSV open when you release the key. The engine should stay running but may load up and die. This should allow the all the injector lines to purge. Alternatively you could bypass the the RPM relay, jump the brown and White/Purple wires. The pump will run and you can check fuel pressure resistance on the Air metering flap.

Has the CO screw been touched?

Ha ha, this is my the long winded version of what David T. Stated in basic form.

[JSzabo]

Sounds like the fuel mixture is too lean. It starts and runs for a moment because of the cold start valve. Once it uses up that fuel it doesn't have enough to run unless you press the plate down. Is the frequency valve buzzing?

Yes I believe it is. Me and Brother in law where wondering about that.

[JSzabo]

Well, it’s firing on the initial burst of cold start injection fuel only. It only opens the CSV while the key is in the start position. Considering,the shotgun approach to everything you’ve done to the fuel system. You’ll to verify all the bits are installed correctly. Seems like at this point you need to put a pressure gauge in the fuel system to verify pressures. You replaced the fuel pump. Confirm the lines are correct and the external check valve flow arrow is oriented from the pump. One thing you could try just to confirm fuel pump is flowing enough fuel, is the WUR plug swap to the CSV trick. This is a work around for a bad accumulator HOT Start condition. It will keep the CSV open when you release the key. The engine should stay running but may load up and die. This should allow the all the injector lines to purge. Alternatively you could bypass the the RPM relay, jump the brown and White/Purple wires. The pump will run and you can check fuel pressure resistance on the Air metering flap.

Has the CO screw been touched?

Ha ha, this is my the long winded version of what David T. Stated in basic form.

No, Thank you for all that. I’m getting this all together for things to check. My Brother-In-Law works on Semi Trucks and cars and his and my friend is a great mechanic but we all have never worked on a Volvo engine before. So we are kinda behind the ball with this.

[Bitsyncmaster]

Does it die when you let off the key? That can happen if the white wire on the resistors falls off.

[SS Spoiler]

bet your fuel lines are reversed at the pump....

[JSzabo]

Does it die when you let off the key? That can happen if the white wire on the resistors falls off.

Ya basically. Where would I have to look for that white wire/resistors?

[JSzabo]

bet your fuel lines are reversed at the pump....

Even if the car stays running if we press down on the fuel/air Pendulum?

[Bitsyncmaster]

Even if the car stays running if we press down on the fuel/air Pendulum?

Well if it runs like that it is not the white wire problem.