7 PSI for my EFI fuel pressure!!!

[gtzero]

Originally Posted by kevinfier Manny, I think Paul is talking about the screen in an Ascona/Manta. You have a GT dont you?

Yes, I have a GT. So the procedure described by Paul won't work for a GT?

[gtzero]

Originally Posted by Travis This is easy to test without replacing. Turn the ignition on, open the flapper in the air flow meter with your fingers and read the pressure. If you get ~40 psi, you'll know the regulator is good. -Travis

Travis,

I noticed that I don't hear anything from the fuel pump when I turn on the ignition. Is the pump not working until the engine is started? Is this normal behaviour? Will this affect the test you described above?

I know some makes of cars have the electric fuel pump turn on before the engine turns over.

[Travis]

Originally Posted by gtzero Travis, I noticed that I don't hear anything from the fuel pump when I turn on the ignition. Is the pump not working until the engine is started? Is this normal behaviour? Will this affect the test you described above? I know some makes of cars have the electric fuel pump turn on before the engine turns over.

The pump turns on when the flapper in the AFM opens a bit.

-Travis

[David McCollam]

Gtzero,

Take it from me, you'll definitely be replacing parts one at a time going that route. I did and ended up with a couple of NOS fuel pressure regulators. I still had the original unit in place and working fine when I sold the car. Those things rarely go bad. Mine ran under 100 PSI for quite a while and was fine once I figured out the root cause of the problem.

Mine was actually two pronged. One, the original tank had been replaced by a '74 carburated Manta/Ascona tank. Usable, but not optimal. That tank was full of sediment and the fuel sock was clogged. I replaced the tank with the '75 Manta/Ascona tank. Proble solved, right. Wrong!

Unknown to me, the tank I replaced the other with had been sitting with gas and sediment in it until the fuel evaporated, leaving the sediment behind. The tank must have been open as well to allow as much in as there ended up being. Anyway, I began to experience fuel leaks at the fuel rail connections and stumbling. I tried new hose, new clamps, cleaning the injectors, changing the fuel pressure regulator and thought about replacing the throttle body.

After several months of head scratching, suggestions, reading Bosch factory publications on the L-Jet system and looking for a new pressure regulator I stumbled into a Porsche racing shop (forgive the moment of weakness, i was desperate). The guys there told me I'd never diagnose the problem without testing the fuel delivery pressure. They were right.

I put a fuel pressure gauge on per factory service manual directions and discovered that the pressure at the fuel rail was 100 PSI. Twice the maximum factory specs! Hence the fuel leaks. I was extremely fortunate that there was not an engine fire!

To get to the heart of the problem, I quickly shut down the engine and realized there was a blockage in the return line. No gas was actually ever making it back to the tank. This caused two problems, high pressure and fuel starvation when the return cup in the '75 tank was pumped low.

The fuel return line ended up being full of sediment and I had to use a piece of piano wire on a variable speed drill to clean it out. I then had to replace the tank fuel filter because the sediment went into the tank and covered it when there was a demand placed on it. I eventually went to the Manta B external prefilter between the tank and fuel pump.

Once that was in place, no more problem. The car ran like a champ. :-) Wish I still had it. :-(

Good luck on the fix!

[namba209]

Manny, run a search for fuel tank sock, I think Otto had a solution to remove the sock without taking out the fuel tank float level plate. HTH

[gtzero]

Originally Posted by David McCollam Gtzero, Take it from me, you'll definitely be replacing parts one at a time going that route. I did and ended up with a couple of NOS fuel pressure regulators. I still had the original unit in place and working fine when I sold the car. Those things rarely go bad. Mine ran under 100 PSI for quite a while and was fine once I figured out the root cause of the problem. Mine was actually two pronged. One, the original tank had been replaced by a '74 carburated Manta/Ascona tank. Usable, but not optimal. That tank was full of sediment and the fuel sock was clogged. I replaced the tank with the '75 Manta/Ascona tank. Proble solved, right. Wrong! Unknown to me, the tank I replaced the other with had been sitting with gas and sediment in it until the fuel evaporated, leaving the sediment behind. The tank must have been open as well to allow as much in as there ended up being. Anyway, I began to experience fuel leaks at the fuel rail connections and stumbling. I tried new hose, new clamps, cleaning the injectors, changing the fuel pressure regulator and thought about replacing the throttle body. After several months of head scratching, suggestions, reading Bosch factory publications on the L-Jet system and looking for a new pressure regulator I stumbled into a Porsche racing shop (forgive the moment of weakness, i was desperate). The guys there told me I'd never diagnose the problem without testing the fuel delivery pressure. They were right. I put a fuel pressure gauge on per factory service manual directions and discovered that the pressure at the fuel rail was 100 PSI. Twice the maximum factory specs! Hence the fuel leaks. I was extremely fortunate that there was not an engine fire! To get to the heart of the problem, I quickly shut down the engine and realized there was a blockage in the return line. No gas was actually ever making it back to the tank. This caused two problems, high pressure and fuel starvation when the return cup in the '75 tank was pumped low. The fuel return line ended up being full of sediment and I had to use a piece of piano wire on a variable speed drill to clean it out. I then had to replace the tank fuel filter because the sediment went into the tank and covered it when there was a demand placed on it. I eventually went to the Manta B external prefilter between the tank and fuel pump. Once that was in place, no more problem. The car ran like a champ. :-) Wish I still had it. :-( Good luck on the fix!

David,

Thank you very much for sharing your experiences. I think I'm going to try Travis' suggestion first since that will be a really easy test of the regulator.

Thanks again to everyone,

Manny

[gtzero]

Originally Posted by Travis This is easy to test without replacing. Turn the ignition on, open the flapper in the air flow meter with your fingers and read the pressure. If you get ~40 psi, you'll know the regulator is good. -Travis

Hi Travis,

I tried your suggestion and got nada. I didn't hear the pump. I didn't get any pressure reading.

I spoke with Gil and he informs me that I have an LE2 jetronic system. All these designations are pretty much Greek to me. But I described to him what I just tried and he said that he believes that my system needs one more signal in order for the pump to operate. Maybe a tach signal.

Anyways, I thank you for the suggestion. It was a very quick test. I've gone ahead and ordered the regulator from Gil. Hopefully, it will be here on Saturday.

Manny

[David McCollam]

Good luck with that. Let me ask a couple of questions in closing my effort of contribute. Gil and Dennis installed the system on your car or just sold you the system? The system operated initially and now gives you problems after sitting idle for a period of time? You have a Bosch LE Jetronic injection system in an Opel GT, using an adapted GT tank?

Just wanting to make certain that I understand all the facts of the situation.

Thanks.

[gtzero]

Originally Posted by David McCollam Good luck with that. Let me ask a couple of questions in closing my effort of contribute. Gil and Dennis installed the system on your car or just sold you the system? The system operated initially and now gives you problems after sitting idle for a period of time? You have a Bosch LE Jetronic injection system in an Opel GT, using an adapted GT tank? Just wanting to make certain that I understand all the facts of the situation. Thanks.

Hi David,

At the time, it was only Gil. And I basically had him build the car. So I really can't remember what all went into my GT. All I remember saying to Gil was I wanted to stay Opel with more power and as up to date mechanically as possible. He said a 2.4 FI engine. And I said plus 5 speed and disc brakes. The manifolds were extrudehoned and ported by Roger Wilson. And a set of headers were put onto the exhaust. All heat wrapped.

Until recently, I wasn't aware that a special tank was needed. But that's not to say I didn't get one. I suspect that Gil did it right. The car ran beautifully for years. It's been 10yrs since the conversion.

I was told by Gil this morning that I have an LE-2 Jetronic injection system. The only thing that I know about this is that Travis's suggestion of checking the fuel pressure regulator doesn't work on this type of injection system.

In all this time, I haven't had to do anything to the fuel system. I don't drive the car every day. It shares duty with 3 other vehicles. And I stored the car for a year with someone starting the car every couple of weeks. Not until recently have I started using the GT on a more daily basis. So I guess it's about time to address some aging systems.

Manny

[David McCollam]

Hi Manny,

If replacing the fuel pressure regulator brings no specific relief, I would then strongly suggest, removal and cleaning of the fuel tank and fuel pick up. With the age of the tank and the symptoms it demonstrates, it certainly sounds like a contributor to the problem at the least. It wouldn't hurt to do it and would be a relaively simple and inexpensive process. It would also eliminate the potential for a problem in the future.

Good luck.

[baz]

manny before you go stripping the car to bits may i just say it would be a good idea to unhook the fuel line working back from the reg 1 joint at a time to see where you have flow and where you dont
(btw from what you said in an earlier post i would be wondering why the pump dont prime the system when you turn on the ignition )
if you get fuel out next to the reg then change the reg if not then go back to the filter and see if it comes out of the pipe before the filter from the pump ,if not go to the input side of the tank and run a fuel line to it and see if it will run the engine ,
this way you will know from end to end where the system is working but make sure the pump runs first so you know it should have pressure if the pump runs

[gtzero]

Originally Posted by baz manny before you go stripping the car to bits may i just say it would be a good idea to unhook the fuel line working back from the reg 1 joint at a time to see where you have flow and where you dont (btw from what you said in an earlier post i would be wondering why the pump dont prime the system when you turn on the ignition ) if you get fuel out next to the reg then change the reg if not then go back to the filter and see if it comes out of the pipe before the filter from the pump ,if not go to the input side of the tank and run a fuel line to it and see if it will run the engine , this way you will know from end to end where the system is working but make sure the pump runs first so you know it should have pressure if the pump runs

Baz,

In answer to your question as to why the pump doesn't prime the system with the ignition on, it appears from all the response that I've gathered that the LE2 Jetronic system requires at least 2 signals before it activates the pump. Gil Wesson seems to think that it might require a signal from the tach. Which would mean the engine needs to be running. Or at least turning over.

I was also thinking of doing a systematic check of each component. But I just don't have the time right now. Just too many things on my plate.

Manny

[gtzero]

Hi All,

I got the new fuel pressure regulator from Gil and put it on tonight. It just registered 36.5 psi at idle and revving the engine registered 44 psi. I think my problem is solved. I hope. I'll road test the car just as soon as I put on the new rear shocks but I feel pretty confident.

Thanks all for all the help,

Manny

[gtzero]

WOW! The engine totally feels different. I only went around the block but she felt really nice.

Thanks everyone for your help,

Manny

[Keegann]

Since there are a few FI experts on this thread I thought I'd ask a question or two.
I just picked up a complete Fuel injection system pulled off of a Manta about 20 yrs ago (according to the seller). It is all there, but before I start investing in modifications for my GT, I thought I would inquire about injection reliability.

The side draft I'm using now works just fine, but I think injection is good looking and sounds trick. Injection won't be cheap to retro-fit and I'm used to carbs. So someone please let me know: what am I getting into? Are the Bosch injection sets as reliable as most modern multiport setups? Flawless cold starts, low, smooth idles, precise throttle response? Would I be better to stick with the webber on my daily driver 1.9L GT?

I appreciate any input you have.

[namba209]

I haven't done the FI on my GT, but have seen a few and there are modifications that need to be made in the heater box, wiper well and areas just in front of the windshield. You may want to check a few pics in the gallery, just to get an idea what's involved.

[tekenaar]

Originally Posted by baz manny before you go stripping the car to bits may i just say it would be a good idea to unhook the fuel line working back from the reg 1 joint at a time to see where you have flow and where you dont (btw from what you said in an earlier post i would be wondering why the pump dont prime the system when you turn on the ignition ) if you get fuel out next to the reg then change the reg if not then go back to the filter and see if it comes out of the pipe before the filter from the pump ,if not go to the input side of the tank and run a fuel line to it and see if it will run the engine , this way you will know from end to end where the system is working but make sure the pump runs first so you know it should have pressure if the pump runs Originally Posted by gtzero Baz, In answer to your question as to why the pump doesn't prime the system with the ignition on, it appears from all the response that I've gathered that the LE2 Jetronic system requires at least 2 signals before it activates the pump. Gil Wesson seems to think that it might require a signal from the tach. Which would mean the engine needs to be running. Or at least turning over. I was also thinking of doing a systematic check of each component. But I just don't have the time right now. Just too many things on my plate. Manny

NO Bosch L-series FI 'primes the fuel system', i.e. powers the fuel pump, without either the engine running or the ignition switch in the "Start" position! They are specifically designed to operate that way for safety reasons. If the engine stops running for any reason, so does the fuel pump . . . even with the ignition key still in the "On" position.

In the L-Jetronic (the first 'air meter' version), the ignition "Start" position picks the 'fuel pump' relay in the "Dual Relay" to start the pump and, once the engine is running, air flow opens the air meter flap sufficiently to close a set of fuel pump contacts to keep it running. If the engine stops for any reason, there's no air flow to hold the FP contacts closed and the pump stops.

In the LE-Jetronic (later 'air meter' version), a single stage "Main Relay" is used which 'senses' ignition pulses to both start the pump and power the injectors during the "Start" phase of the engine and continuing to power both as long as the engine runs because ignition pulses are present. Again, if engine stops, no more ignition pulses and power is removed from both pump and injectors.

In either system, even if left sitting for a long time so that the fuel rail pressure drops to zero, the electric pump will pressurize the fuel rail to its maximum regulated pressure within ~2 seconds after turning the ignition key to the "Start" position, i.e. trying to start the engine. As soon as the engine starts, vacuum at the FP regulator drops fuel pressure to a lower regulated "idle" pressure.

Look here for more L-Jet info: