75 1.8 garage find won't start Options

[jhelgesen]

(IMG:http://i184.photobucket.com/albums/x311/jhelgesen/75%20914/DSCN5132.jpg)

I'm trying to resurrect a 75 1.8 thats been sitting for 15 years. (she was hiding in a basement next to the furnace for all that time). Pretty darn rust free as far as 914's go. She got parked for FI issues.

(IMG:http://i184.photobucket.com/albums/x311/jhelgesen/75%20914/DSCN5141.jpg)

I'm trying to get her running again. I've got the tank clean. The fuel pump was cleaned and runs. The fuel injectors have been cleaned and checked, click well. Dual relay clicks when attempting to start. She turns over, but I'm not getting power to the fuel injectors. What to I try next?

Thanks,

[ClayPerrine]

Clay...info I got was from a Porsche mechanic who helped me get my 75 l-jet sorted. The AFM completed the circuit (according to him) and it needs to open just enough to allow the pump to run (relays, afm etc are all in the loop). He was dead on as the test we did with him there was open it alittle and behold..the pump started. His explanation was porsche did this so as not to have fuel being dumped in without air. I'm no expert here but this came right from a Porsche mechanic and he demonstrated the fuel pump not running when cranking and the flap close...and the fuel pump ran when opening it slightly. I saw it with my own eyes. Maybe the 75's are different but that is what I saw.

I have been doing this (and living with a L-Jet equipped 914) for 24 years, and I had factory training from VW on the L-Jet system. Your mechanic is partially right. The air flow through the air flow meter should trigger the fuel pump. But when you are trying to start the car, there is not enough air to consistently trigger the fuel pump. So they have the circuit tied to the starter circuit that causes the pump to run when the engine is cranking. It does not run when the key is in the on position, only when it is in the start position. If you don't believe me, take the yellow wire off your starter and see if the pump runs when the key is turned to the start position.

Also check the 2 fuses on the relay panel. I believe one of those is for the power to the relay's and the other for the fuel pump? Since they are exposed they get corroded very easily.

The fuses on the relay board are not used for the injection on an L-Jet car. You do not need either the fuses or the relays on the relay board.

[computers4kids]

Clay...info I got was from a Porsche mechanic who helped me get my 75 l-jet sorted. The AFM completed the circuit (according to him) and it needs to open just enough to allow the pump to run (relays, afm etc are all in the loop). He was dead on as the test we did with him there was open it alittle and behold..the pump started. His explanation was porsche did this so as not to have fuel being dumped in without air. I'm no expert here but this came right from a Porsche mechanic and he demonstrated the fuel pump not running when cranking and the flap close...and the fuel pump ran when opening it slightly. I saw it with my own eyes. Maybe the 75's are different but that is what I saw.

I have been doing this (and living with a L-Jet equipped 914) for 24 years, and I had factory training from VW on the L-Jet system. Your mechanic is partially right. The air flow through the air flow meter should trigger the fuel pump. But when you are trying to start the car, there is not enough air to consistently trigger the fuel pump. So they have the circuit tied to the starter circuit that causes the pump to run when the engine is cranking. It does not run when the key is in the on position, only when it is in the start position. If you don't believe me, take the yellow wire off your starter and see if the pump runs when the key is turned to the start position.

Also check the 2 fuses on the relay panel. I believe one of those is for the power to the relay's and the other for the fuel pump? Since they are exposed they get corroded very easily.

The fuses on the relay board are not used for the injection on an L-Jet car. You do not need either the fuses or the relays on the relay board.

Are you sure about the relays on the board? I too had an Ljet that had been parked for a year because it wouldn't start. I went ahead and cleaned the blue 25 amp fuse closest to the firewall (didn't help), the other fuse is for the rear glass defogger if equipped.

However, the last relay (closest to the firewall) is part of the equation. When I changed mine out with a known good one the car fired to life instantly.

[ClayPerrine]

Clay...info I got was from a Porsche mechanic who helped me get my 75 l-jet sorted. The AFM completed the circuit (according to him) and it needs to open just enough to allow the pump to run (relays, afm etc are all in the loop). He was dead on as the test we did with him there was open it alittle and behold..the pump started. His explanation was porsche did this so as not to have fuel being dumped in without air. I'm no expert here but this came right from a Porsche mechanic and he demonstrated the fuel pump not running when cranking and the flap close...and the fuel pump ran when opening it slightly. I saw it with my own eyes. Maybe the 75's are different but that is what I saw.

I have been doing this (and living with a L-Jet equipped 914) for 24 years, and I had factory training from VW on the L-Jet system. Your mechanic is partially right. The air flow through the air flow meter should trigger the fuel pump. But when you are trying to start the car, there is not enough air to consistently trigger the fuel pump. So they have the circuit tied to the starter circuit that causes the pump to run when the engine is cranking. It does not run when the key is in the on position, only when it is in the start position. If you don't believe me, take the yellow wire off your starter and see if the pump runs when the key is turned to the start position.

Also check the 2 fuses on the relay panel. I believe one of those is for the power to the relay's and the other for the fuel pump? Since they are exposed they get corroded very easily.

The fuses on the relay board are not used for the injection on an L-Jet car. You do not need either the fuses or the relays on the relay board.

Are you sure about the relays on the board? I too had an Ljet that had been parked for a year because it wouldn't start. I went ahead and cleaned the blue 25 amp fuse closest to the firewall (didn't help), the other fuse is for the rear glass defogger if equipped.

However, the last relay (closest to the firewall) is part of the equation. When I changed mine out with a known good one the car fired to life instantly.

Sounds like pure coincidence to me.

I am 100% positive about this. Betty's 914 has not had a relay on the relay board for years. She doesn't have a heater hooked up, no heated rear window, and no D-Jet. And it runs just fine.

The relay boards for all years of 914/4 cars were functionally identical. I assume there were manufacturing changes because there are no electrical changes to the board.