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no start, no fuel


gfallon

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I am working on a friends 1986 lotus esprit turbo with the bosch injection.

I started working on his car due to a poor cold warm up issue,  it sounded to me like it was too lean when cold. I rebuilt the warm up regulator  2 years ago and remembered how to change the fuel mixture and was able to get it running rather good. but decided to do a smoke test on the intake system and found the injectors all leaking air. so I replaced the O-rings on all the injectors.

NOW IT WILL NOT START!  I can get it to run on starting fuel so I am confident it is a fuel delivery problem

I took off the fuel line to one injector and I have no fuel going to it when trying to start.

I thought maybe something was wrong with the fuel distributor so I got a rebuild kit and everything look good in there but some tired o-rings

but it changed nothing, still no start. 

I checked the fuel pumps for pressure and they tested 100psi so I am sure they are good and the fuel filter has a new lotus sticker on it so it has been changed not too long ago

 

anyone have an idea of what could be going on with this?  or an idea of what else to check?

it will fire on the cold start injector for a few seconds but will only do it once. I would think it should fire every time I try to start as long as its cold.  any thoughts on that?

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5 hours ago, gfallon said:

I can get it to run on starting fuel

Hi Brian,

Is your starting fuel an aerosol like "Easy Start" ?

5 hours ago, gfallon said:

it will fire on the cold start injector for a few seconds but will only do it once

When you say it will only does it once, what do you have to do to repeat the fire.

If you have 100psi of fuel at the fuel distributor but no fuel at the injectors during cranking, the only things I can think of at present are air sensor plate issue or warm up regulator issue.

Is the sensor plate action smooth and free?

I haven't worked on these early Bosch systems for decades so can only offer these basics.

Andy.

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5 hours ago, AndyPG said:

Is the sensor plate action smooth and free?

That is the first check. Also, work that 'metering vane' up & down. Should be relatively smooth.

 

Do you hear the fuel pumps run at Key On Engine Off? Have you replaced the battery?

I'll send you a PM too.

Edited by CarBuff

Atwell Haines

'88 Esprit

Succasunna, NJ USA

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yes,  starting fuel is a spray can.  so starting spray 

so the first time I start the car it will run for about 6 seconds which is the cold start injector, and then dies.  the next time you try to start it nothing. so its like the cold start injector will only fire that one time and no more. I would think if the engine is cold it should fire every time you try to start it, not just one time.

I rebuilt the warm up regulator 2 years ago and it has been running fine till now,  but will check anyway.

the air sensor plate moves freely (if that is what I think you are talking about, or the metering vain should also be the same thing.)

I don't remember if I heard the fuel pumps key on and engine off but I hot wired them to by pass that and still nothing  

I tested the fuel pumps themselves 100psi each ( did try to test at the distributor but got different readings each time and they never were what the book called for. not sure if it was the way I tested it of if the fuel press gauges I barrowed from the parts store was not working correct.  (the first one I barrowed was broken and missing parts so took it back and got another from a different place)

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Are you positive that the fuel pumps run when you are trying to start the engine? (I'm not talking about the initial KOEO pressurization I mentioned)

 

Once the engine starts cranking, the RPM relays will not energize the fuel pumps unless they 'sense' ignition pulses.  Often, the capacitors in those 'analogue' RPM relays fail after many years. So you get that initial 5 second run until the pressure bleeds down.

 

Unplug the RPM relays, give them a gentle shake. You should NOT hear any internal rattling! (Crude troubleshooting method, but effective, LOL)

 

Don't ever swap the RPM relays.🙄  If you think they could have been switched inadvertently, verify correct position by looking up the part numbers.

The Cold Start Injector is only momentary at normal  room temp.  I bet that the symptoms remain the same even if you unplug it.

 

 

Atwell Haines

'88 Esprit

Succasunna, NJ USA

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  • 1 month later...

SO, I have been able to get it to start and run by bleeding the air out of the system and giving a gap at the plunger.  but it stumbles with light throttle inputs and only under 2,000 rpm.  

any ideas at what may be causing this issue?

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Assume that when you say

3 hours ago, gfallon said:

giving a gap at the plunger

you mean applying fuel by pressing down a bit on the accelerator when cranking?

 

That is normal starting procedure (mentioned in the Owners Manual) since there MUST be airflow pushing on the metering vane to dispense fuel to the injectors. The engine will not start if the throttles are closed.

 

Bosch FI is critically dependent on a 'tight' intake system. Are any gaskets missing or poorly sealed? Could there be any cracked or loose vacuum lines?  (I know you said it was a Friend's car, wink wink)🥴

Atwell Haines

'88 Esprit

Succasunna, NJ USA

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the plunger in the fuel distribution assembly. 

I think I may have to much fuel pressure to the top center line on the fuel distributor ( line going from warm up regulator to dis) the plunger is not moving with light throttle inputs and if you push on it it takes more pressure than you would think to push it down yourself.  I will need to barrow a fuel presser tester and see how much I have there, 

so the question then is how to adjust the warm up regulator?  I know about the "pin"  but does it need to go down or up to lower the pressure 

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