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V8 Fuel Pressure testing valve... Shrader?


cweeden

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  • Gold FFM

Hi All,

I am trying to test the fuel pressure in the fuel rails of the V8 and bought a testing kit designed for Shrader valves however it doesn't appear to fit the Esprit.

Is the valve a Shrader valve?

When I take the dust cap off there is what looks like a rubber bung sitting there. I can twist this but it doesn't seem to want to come out easily and I don't want to pull too hard and break something. Should I just pull a bit harder?

Any suggestions welcome. :-)

Thanks

-Chris

 

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I tested mine and it is a standard Schrader valve. I just screwed it on very tight and that was it. I want to say I had about 55 to 57 lbs or 4 bar pressure. Typically, the injectors operate at about 43lbs / square inch or 3 bar.  Some injectors, mine were locking up at the higher pressure. I changed out my injectors with new ones. Lots of work as I tried to clean the originals, bought a machine etc. Reinstalled them and they were locking up. The new ones , cheap work perfect and really made a great difference. Use the stock ng plugs. Don't use Imodium plugs mine would not run right with the iridiums. Thanks Mark

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  • Gold FFM

Thanks Mark,

Late last night I also found it mentioned in the service notes so it is definitely a Shrader (or Shraeder as Lotus refer to it). I guess I just need to pull out the small rubber bung that must be additional dust protection. There is no way it will operate normally with that in place, since the valve centre cannot be depressed by the gauge attachment and it prevents the attachment from reaching the threads.

cheers

-Chris

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  • Gold FFM

OK, so quite a bit of progress today and she runs........ but only briefly. The primary pumps seems to have failed (fuses are fine and swapped relays), the secondary pump runs during cranking which is enough to fire her up but stops a few seconds after cranking (as per design) causing the engine to stall.

Anyone taken the pumps out of the tank with the tank in situ? Any advice on how to undo the retaining ring without the special tool or is that a must? I'm off to check Alan's parts cross reference now for the primary pump and maybe a new secondary, it seems daft not to replace them both while its all apart.

BTW the rubber bit in the Shrader valve above was an additional dust cover and just needed a firm hand to remove it. 🙂

cheers

-Chris

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I have quite a bit od items that i have talked with the forums help and kind much smarter people on here , but never replacing the pumps in the tank. Ask me about coils, wires, injectors and everything else under the plenum and I could probably answer. ??? I believe you can remove the pumps without removing the tank, but it is definetly tight quarters. Mark

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I remember reading a similar problem on here-there are two 5 spade-connected relays, in the fuel system, which do different things.

Have a look for that post to clarify, or just ensure the relays are the correct part number (not just that they have five connectors!)

good luck, and "Don't use Imodium plugs" is sound advice!

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Yes, the pumps can be removed in place.

First depressurize system!!!  Remove the fuel filler cap(s). Use a rag and make sure no pressure at the Schrader valve on the rail.

Disconnect the fuel lines at the pump.

Spray some lube like WD-40 on the locking ring prior to attempting to unlock it. Use a non-sparking brass drift and a hammer to gently tap it around counter-clockwise.

I like to coat the new o-ring with some silicone grease before replacement. Prevents the o-ring from bunching or getting cut, and keeps it from drying out over the years.

Travis

Vulcan Grey 89SE

My Lotus Photo and Projects Album

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  • Gold FFM

Thanks for the advice guys. I thought it might be time to provide a little more info to what I have been doing. I have owned the car for many years now and know the relays etc are correct since it all used to work just fine. It just hasn't appreciated being sat for 6 years or so with the injectors out, not running. I was working on it but lost enthusiasm and bought an Evora instead, a middle finger to the Esprit if you like. 🙂

I sold the Evora late last year, never really falling in love with it and the kids were getting a little too big to enjoy the back seat fully.

So I picked up working on the  Esprit a couple of weeks ago and here's the story so far.

I have tested all of the primary injectors with a scruffy but workable rig I knocked up from some copper pipe and my airline for pressure. I had a cheap Chinese injector driver to provide the signal. It proved that they all work and since they were cleaned and flow tested 6 years ago I have assumed that is going to be good enough. I just didn't want to put any back that were sticking, new Viton o-rings before being popped back into place.

I drained about 21 L of fuel that smelt nasty but was at least flowing and not a jelly mess. I removed the hose from the link pipe and caught the fall out in a large plastic tray, not a fun job with fuel running up to my shoulder in defiance. I disposed of it at a friendly garage after the local tip refused to take it (along with most things I try to dump it seems, rubble for example!), glad my tax is paying for a useful service. Grrrr.

After pulling the fuel pump relays and new battery installed, the electrical systems fired up without a hitch, the headlights blinked and even the key fobs both work. I removed the plugs and put a tiny amount of Redex into the bores and turned the engine over carefully on the starter. Just a little at first and eventually turning enough to build oil pressure.

Tested compression and all within a couple of psi of each other. The gauge was showing about 130 psi which would be low but it only cost £13 so I suspect it's not well calibrated. Happy enough with that.

Plenum replaced and plumbed in, fresh fuel installed, gapped plugs and relays re-inserted, fuel pressure gauge plugged into the Shrader test port (after removing puzzling extra dust cover) and now getting closer to the magic moment. Obviously I noticed the primary pump didn't fire when the ignition was turned on but I decided to crank the engine since I had the fuel feed line to the fuel rails disconnected and ready to pump some fuel into a container flushing out the pump and filter of old fuel. The secondary pump kicked in and I collected about 1 L of fuel, still not the best colour, probably some rust in the tanks but free from any obvious debris and smelt fine, so decided to push on. I will replace the fuel filter after some more fuel has been pushed through it. 

Reconnected the fuel feed and cranked the engine with the throttle mashed to the floor. The ECU won't trigger the injectors when 100% TPS is registered, so I could build pressure using the secondary pump without the risk of it starting. Pressure looked good so I took my foot off the throttle and cranked again. Fired up almost straight away and ran for a few seconds before the fuel pressure dropped when the fuel pump stopped (as designed) and it died. Quite a result even if it did sound a bit tappety but that is too be expected until the oil has a chance to really get around.

I connected my laptop and ran the very helpful tool from Peter England to check a few things. I could manually trigger the pumps one at a time allowing me to swap relays etc to make sure the issue is with the pump. Nice also to see my TPS giving the full 0% to 100% range.

So now I am making a special tool to mimic the Lotus fuel pump removal tool, I'll let you know how that goes. I have no idea how you manage to get a hammer into that space (I am trying to avoid removing the ECU) and I don't want to risk damaging the retaining ring, it seems to be obsolete. I've ordered a new pump from SJ Sportscars (£71) and it's now a race to see if I can remove the old one before it arrives.

Once the fuel is pumping properly and the engine runs for a little longer I will check more of the ECU parameters and make arrangements for new belts (they are new but 6 years old, the problem with losing enthusiasm at the wrong time) and all of the fluids. The oil and coolant is 'new' but again 6 years old now, the coolant system is the one I am most worried about. I then expect a good number of other gremlins to show themselves but I'll have a good game of Whack-a-Mole with them until it is all sorted. 🙂

I'll let you know how it goes.

cheers

-Chris

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Wow, A very detailed progress.  I doubt that the oil and coolant needs replaceing.  Oil is inexpensive enough and filter also, so hey it couldnt hurt.  Might suggest a 10w50 Mobil One Synthetic,  I did use a Mobil 1 - 204 filter and cut it open to look at it and was pleasantly suprised at how well made it was. I am not sure the cam belts would need to be changed as the onl;y real worry is possibly a flat spot on them since they havent been exercised.  There are certainly wiser people on here than myself in those regards.  I would of course keep the rpms low initially once it is started and I would also check the oil lines at the filter and also at the oil coolers in the front of the car to make sure that the clamps have not loosened up.  I recently had one come off and fortunately all ended well, but well you know.  My Esprit has cat delete pipes (Off road use only) and it really sounds great and the turbos definetly spool up quicker.  That is my only real mod.  I also tried to clean my original injectors when I changed coils, and plugs and wires, and thermostat (Big Help), but the injectors were locking up and the car would not run right and I also changed to NGK Iridium plugs and it would not run right, so back to the original plugs and it runs like a champ.   What software are you using on the laptop?  Sorry to "Ramble On" as Zeppelin would say?  Thanks Mark

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  • Gold FFM

So good news, the retaining ring is off, however the tool I made wasn't able to budge it, so I reverted to the hammer approach and used a long shaft (about the thickness of a strong screwdriver), I cut a groove into it so that it could locate itself on the lip of the retaining ring to minimise the risk of it slipping off and doing some damage. Shame about the tool, it would have been a lovely little victory. Oh well. :getmecoat:

@Vulcan Grey did you have to remove the seat belt reel in order to extract the pumps or will they come out with careful wiggling?

@Espritv8black the OBDII Scan tool is by Peter Maeers (not Peter England as previously stated, sorry @peter_england99 ). It is a bloody excellent tool and I really appreciate Peter making it available. You can follow the link below to grab a copy. 

 

 

cheers

-Chris

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On my 89SE (not a V8, of course but similar) I only removed the ECU. Done this pump removal a few times over 18 years.

The V8 pump opening might be closer to the belt reel, so remove if necessary. It's not a big problem, jut make sure you always keep a bunch of slack so it doesn't suck the belt up too far and lock the inertia reel.

 

Travis

Vulcan Grey 89SE

My Lotus Photo and Projects Album

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Thanks Travis, I decided to stop being lazy and move the ECU out of the way, I only needed to take the cover off the seat belt and then I was able to wriggle to pump assembly free. 🙂

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Chris,  Would you like to Holiday in America............at my house................there are few projects that await you..................on my Lotus.  Good opportunity to get away from the Brats.....I mean Kids!!!

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