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Esprit V8 starts and refuses to run


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My 98 Esprit, 60k miles, starts and dies after 8 - 12 sec.

A former topic, I know.

After a 9 month rest at my warmed garage (due to a disease) I recently tried to wake the car up. Put a new battery in, pulled the plugs, injected some oil in the cilinders and cranked it over without relays installed for fuel pumps and ignition, till oil pressure came up. After installing the relays the engine started immediately. But, just for a few seconds - and stopped by lack of fuel.(clearly)

I’ve read all the former cases in this forum for this issue so I checked “all” the mentioned causes.

I already had renewed the fuel pumps. The contacts of the primary pump relay were somewhat burned so I replaced it too.

The issue is that the engine refuses to run normal. The start procedure is in accordance with Lotus ; secondary pump runs for 5 sec during start, primary relay(pump) comes in and at the point where the secondary pump (relay) drops out, the engine dies after some seconds.

The primary relay is still on and shuts off because of no ignition signal from the crankshaft sensor.(ECM controlled)

I checked the functionality of both pumps with the OBD tool from Peter Meears by activating them both, and individually on and off.

If I manually hold the secondary relay the engine runs (poorly), as soon as I release the relay the engine dies. If I manually hold the primary relay, the engine dies after the secondary drops out.

All negative contacts checked and are present. Positive on contact 30 on both relays is present.

My conclusion would be that the (my) secondary relais influences the power supply to the primary relay - how?  Studying the circuit diagrams the ECM controls these …

And all this after 9 months in a warmed garage??

Anyone suggestions? I would be very pleased to hear!

Regards Ruud.

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Hi Mike, I disassembled the fuel pumps and found out that the fuel lines were not tight enough and to my opnion unable to keep the fuel pressure optimal. Temporary I added extra clamps to be "sure" th

Hi Chris thank you for warning, I have installed Cohen submersible hoses. cheers Ruud.

suspecting a ruptured fuel line in the tank after both the pumps merge. I ordered a replacement piece of in-tank fuel line from gates, it's a specific part number and you get like 12" of line. I can d

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Do you have access to another ECU so that you can discount that as an issue?

1996 Esprit V8, 1998 Esprit V8 GT, 1999 Esprit S350 #002 (Esprit GT1 replica project), 1996 Esprit V8 GT1 (chassis 114-001), 1992 Lotus Omega (927E), 1999 Esprit V8SE, 1999 Esprit S350 #032, 1995 Esprit S4s, 1999 Esprit V8 GT (ex-5th Gear project), 1999 Esprit V8SE ('02 rear)

1999 S350 #002 Esprit GT1 replica

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  • Gold FFM

It really does sound like you are not getting fuel from the primary pump and only running on pressure from the short period the secondary is running. 

I'm wondering if you can test the fuel pressure with the secondary pump disabled? 

I'm not sure if OBDII will show that the pump works or just that the ECU has asked it to work.

My guess is you are unlucky and may need to replace the primary pump again or a component controlling it.

cheers

-Chris

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Hi Chris, I will test the fuel pressure with the secondary pump disabled.

If I test the pumps with OBDII I can hear the difference between the two pumps;

not that the primary rotates slower, just you can hear the sound from deeper out of the tank.

I surely will check the pressure and keep you posted!

Thanks for your suggestion.

cheers

Ruud.

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I bought a kit like this one from Amazon, it worked for a short time (long enough to test the pressure) but started leaking so I sent it back for a refund. 😇

https://www.amazon.co.uk/gp/product/B00DQS1Y12/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1&fpw=alm

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Hi Freek, thank you for your reply, do you know the shraeder valve has the same thread dimension and pitch on the V8 in comparison to 4 cylinder? I hope it does...

Thanks, bedankt,

Ruud.

Hi Chris, the kit is no longer available from Amazon probably due to quality....

Quote

 

I bought a kit like this one from Amazon, it worked for a short time (long enough to test the pressure) but started leaking so I sent it back for a refund. 

https://www.amazon.co.uk/gp/product/B00DQS1Y12/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1&fpw=alm

 

 

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suspecting a ruptured fuel line in the tank after both the pumps merge. I ordered a replacement piece of in-tank fuel line from gates, it's a specific part number and you get like 12" of line. I can dig up the info. 

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1 minute ago, v8GTmac1 said:

suspecting a ruptured fuel line in the tank after both the pumps merge. I ordered a replacement piece of in-tank fuel line from gates, it's a specific part number and you get like 12" of line. I can dig up the info. 

That's a good point, the hoses in the tank do perish and crack. You need hose that is suitable to be submerged in fuel, not any old fuel line. 👍

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  • 2 weeks later...

Dear Michael and Chris, thank you both for your participation in my problem. I have taken the pumps out and the fuel lines are still "soft" and not ruptured. On the bench both pumps are running well (by ear), also the connectors on the pumps and at the top of the tank closure (the yellow one) look like new. I still haven't found out the type thread of the connection of the Shraeder valve to check the fuel pressure. 

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15 hours ago, Ruud Hensbergen said:

Dear Michael and Chris, thank you both for your participation in my problem. I have taken the pumps out and the fuel lines are still "soft" and not ruptured. On the bench both pumps are running well (by ear), also the connectors on the pumps and at the top of the tank closure (the yellow one) look like new. I still haven't found out the type thread of the connection of the Shraeder valve to check the fuel pressure. 

    Here you go https://www.glowshiftdirect.com/fuel-rail-thread-adapter-for-chevrolet-gm-ls-engines/     -4an. 

you dont need to buy from them, find the -4an adapter to whatever your guage has anywhere on the internet.

Edited by v8GTmac1
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and are you sure you want to leave those old hoses in the tank? They are kinda known for deteriorating due to the fact that these cars sit around a lot. 

This is what I ordered but i've yet to install it, I actually used a temporary hose for the time being and soon after found this part number online. 

 Gates hose

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Most pumps have a non-return valve (check valve) in them which can fail. So the pump runs and generates pressure which quickly bleeds away when it stops. They may be able to hold a very low pressure, so enough to start the engine but not enough for it to run (or it may run badly). When you connect the pressure guage you wlll see the system pressurise when you turn on the ignition, but the pressure will quickly drop  when it switches off. (the same symptom as a leaking in-tank hose). The only solution is to change the pump.

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Hi Micheal, thank you for your hint for  the -4an adapter! I will find a supplier in the Netherlands. I will replace the "old" hoses when I have to take the pumps out again.

Dave, I am not sure if there are non-return valves fitted. As soon as I get the -4an adapter I will know a lot more and let you know.

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On 26/12/2020 at 09:20, dclare said:

Most pumps have a non-return valve (check valve) in them which can fail. So the pump runs and generates pressure which quickly bleeds away when it stops. They may be able to hold a very low pressure, so enough to start the engine but not enough for it to run (or it may run badly). When you connect the pressure guage you wlll see the system pressurise when you turn on the ignition, but the pressure will quickly drop  when it switches off. (the same symptom as a leaking in-tank hose). The only solution is to change the pump.

i did read somewhere on this forum that our pumps do need to hold some kind of pressure. 

I made some videos a year ago when i was dealing with this. 

 

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On 27/12/2020 at 13:54, Ruud Hensbergen said:

Dave, I am not sure if there are non-return valves fitted. As soon as I get the -4an adapter I will know a lot more and let you know.

Hi, Im pretty sure they do, otherwise how would the system retain pressure after the pump is turned off? There is no separate check valve on an Esprit v8.

To test if this is the problem you can buy a stand-alone in-line valve for a few pounds from ebay (https://www.ebay.co.uk/itm/352823213738 - good quality but there are much cheaper ones if you want to risk it) and make up a temporary feed hose with a length of fuel hose, jubilee clips and a few cheap fittings. Make up the pipe to the fuel rail (make sure the check valve is the right way round to stop the fuel flowing back to the pumps) and fit it between the fuel rail and the existing feed pipe - if the engine then runs you know the pump's valve is faulty. If you don't want to grub around in the tank changing the pumps (horrible job) you could even keep the stand-alone check valve/hose in place if you make it well, rather than make a quick test hose.......

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Thanks Ruud.

Despite all my previous comments I do feel that your most likely cause is a failed primary pump. Your engine only runs on the pressure created while the secondary pump runs briefly when you  turn the ignition on. As soon as that that pressure is used to run the engine for a few seconds the engine dies because it isn't getting its main (primary pump) fuel supply......

Although the primary pump runs when its out of the tank that's no guarantee it can generate any pressure.

This fuel pressure test kit has all you need (although it is £60) - https://www.amazon.co.uk/dp/B0727NDK81/ref=pe_3187911_185740111_TE_item

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  • Gold FFM

I agree with Dave and was the issue I had too.

I suspect this cheaper kit from Amazon would also do the job since the schaeder valve on the fuel rail doesn't seem to be unusual.

https://www.amazon.co.uk/449855-Injection-Pressure-Gasoline-Tools/dp/B00TT6YJUI/ref=sr_1_5?crid=86SO0ANCLRXI&dchild=1&keywords=fuel+pressure+tester&qid=1609772429&s=automotive&sprefix=fuel+pre%2Cautomotive%2C149&sr=1-5

I don't think the thread is -4an though, having said that I am no expert.

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Hi Dave and Chris, this weekend I was able to measure the fuel pressure. Contact on, secondary pump running; 30psi. When starting (included primary pump) 40psi. Then after 5sec. engine cuts off - fuel pressure is at that point still there(!). Engine is off and the pressure falls directly. Also when I put contact on (in ignition position - so secondary pump runs) and turn it off - the fuel pressure immediately is gone. So my assumption is: there are no non return valve(s). Or fails? 

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Do you have the Service Notes Section EMM (for ECM and Fuel Injection?

It seems that your fuel pressure after initial pump priming is low (should be closer to 50psi). The pressure drop after the pump stops after priming is typically between 6 ->12psi.  If you don't have the Notes, I can let you have image copies.

You may want to check your fuel pressure regulator..

1996 Esprit V8, 1998 Esprit V8 GT, 1999 Esprit S350 #002 (Esprit GT1 replica project), 1996 Esprit V8 GT1 (chassis 114-001), 1992 Lotus Omega (927E), 1999 Esprit V8SE, 1999 Esprit S350 #032, 1995 Esprit S4s, 1999 Esprit V8 GT (ex-5th Gear project), 1999 Esprit V8SE ('02 rear)

1999 S350 #002 Esprit GT1 replica

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Mike thank you very much for your remark. In the service Notes Section EMM.2 is noted that the fuel pressure should be between 45 - 73 psi depending on operation conditions. So the fuel pressure in my car is too low. I will check the fuel pressure regulator and keep you informed...

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