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Steve4012

Fuel pump problems 85 turbo

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Thought as much, thanks Andy.

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I'd run the whole circuit cleaning every single connection and socket for corrosion or loose fits. Full voltage disconnected / low voltage under load is classic for a high resistance connection somewhere.  

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7 hours ago, Steve4012 said:

Maybe I need to re-examine the earth at the pump? 

Or the earth strap fuel tank to chassis.

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I would disconnect the pump outlet side and see if it pumps fuel into a container from the tank.

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2 minutes ago, Steve V8 said:

Or the earth strap fuel tank to chassis.

I've checked these are tight Steve but even so is it significant for fuel pump earth? I didn't mention but I added a second earth from pump to chassis which had no effect. Snowrx, couldn't agree more but it's literally ignition to inertia to fuel pump on the positive and an earth at the pump to chassis. Worryingly, both my old units started up fine during my failed test with the fuel cans and sounded perfect even with no fuel passing through. On the car both just thudded once and wouldn't buzz continuously. I'm missing something and even though I've ordered yet another pump I know this is unlikely to solve anything.

1 minute ago, Andyww said:

I would disconnect the pump outlet side and see if it pumps fuel into a container from the tank.

Tried that Andy, the new pump is not pumping anything through. Loads of fuel in tanks and when removing inlet to pump literally pours out like a hose pipe.

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4 hours ago, Steve V8 said:

Or the earth strap fuel tank to chassis.

Ah in line pump..tank strap superfluous, 

So scavenge from LH tank, pump, filter, PRV return to RH tank.

I know FA about the Turbo Esprit, so just putting this out there.

Is sufficient fuel returning to LH tank via the balance pipe? (blocked or kinked breather pipes could cause vacuum and imbalance starving pump of fuel, killing pump) try running with fuel caps off.

Air leak above fuel level in fuel pipe LH tank to pump.

Though I did once have three toilet pans from B&Q that leaked, I don't think it possible to have three faulty fuel pumps so I'd be looking at the PRV before buying another, or finding out why they are failing before destroying another. 

Do these pumps run constantly? If not surely there's a relay of some description that's shutting down the pump and failing to restart.

 

 

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8 hours ago, Steve4012 said:

I've checked these are tight Steve but even so is it significant for fuel pump earth? I didn't mention but I added a second earth from pump to chassis which had no effect. Snowrx, couldn't agree more but it's literally ignition to inertia to fuel pump on the positive and an earth at the pump to chassis. Worryingly, both my old units started up fine during my failed test with the fuel cans and sounded perfect even with no fuel passing through. On the car both just thudded once and wouldn't buzz continuously. I'm missing something and even though I've ordered yet another pump I know this is unlikely to solve anything.

Tried that Andy, the new pump is not pumping anything through. Loads of fuel in tanks and when removing inlet to pump literally pours out like a hose pipe.

If there is electrical resistance along the electrical supply line, the voltage would drop when an electrical load is applied. Weak links would be corroded fuses, dirty (arced) switches etc.

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£20 - £100 ish   There are loads of clones, copies and branded versions on the market.  I agree that is beyond statistical likelyhood to have 3 failures in a row even with a £20 pump.   Surely the smoking gun is a mechanical issue, e.g. somat in the tank?

Could also perform a post mortem on a proven failed pump?

 

Edited by 910Esprit

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7 hours ago, Steve V8 said:

So scavenge from LH tank, pump, filter, PRV return to RH tank

Correct. 

7 hours ago, Steve V8 said:

Do these pumps run constantly? If not surely there's a relay of some description that's shutting down the pump and failing to restart.

 

 

I've been wondering this too as both the originals seem to work now off the car whilst just a single thump when on it and nothing more. I'll try and rig something up off the car to see if they actually pump fuel. 

I use the Sytec OTP17 on my other car which runs perfectly so bought the same for this. They are £45 off Ebay from Matt Lewis Racing. I'll not put it on straight away though until the problem has been found. 

2 wires, fuel in and out, It really should be simpler than this! 

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My old pump died on my car.

AA man confirmed we had fuel and the pump was trying but did not have enough umph to raise the fuel to the correct pressure.

I had a bit of trouble when I tried to buy a replacement. There seems to be many repro ones but I bought a really good one but many do not deliver the fuel at a high enough pressure. I had to send one back and buy a correct one which was quite a bit more than others which look the same. I think I bought mine from SJ. Been no probs with that since then.

Hope you can figure out your issue.

 

buddsy

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12 hours ago, Steve4012 said:

 

Tried that Andy, the new pump is not pumping anything through. Loads of fuel in tanks and when removing inlet to pump literally pours out like a hose pipe.

So, plenty of fuel getting to the pump, the pump is running and making the right sound, but if outlet is disconnected no fuel is pumped out? This almost sounds impossible. The pumps are so simple inside. It must be blocked surely? Was the tank definitely clear and free of crud? 

The pumps should run continuously, no relay.

Assume the pump is the correct one?

The pumps are fuel injection pumps as they pump into the pressure regulator. A pump designed for carbs wont work. Must be a pump for injection as the fuel system on the Turbo is  a recirculating pressure-regulated system.

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12 minutes ago, 910Esprit said:

 Surely the smoking gun is a mechanical issue, e.g. somat in the tank?

 

Tanks, balance pipe have been out and verified good. I've spent a lot of time under lh side of car, will check out fuel return and  balance pipe other side also. 

4 minutes ago, Andyww said:

So, plenty of fuel getting to the pump, the pump is running and making the right sound, but if outlet is disconnected no fuel is pumped out? This almost sounds impossible. The pumps are so simple inside. It must be blocked surely? Was the tank definitely clear and free of crud? 

The pumps should run continuously, no relay.

All correct above Andy apart from the sound of the pump is different to my other car. Attached pic of inside of fuel tank and they are both the same. They look fine to me... 

rps20190521_073039.jpg

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The pumps have an anti-flowback valve so this would need to be overcome to be able to pump any fuel out, but I think you did mention you have tried a direct 12V feed and it is actually measuring 12V when pumping so that rules out voltage drop causing low pressure.

If all else fails, maybe even open one of the failed ones up if its not under warranty and have a butchers inside?

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1 hour ago, Andyww said:

The pumps have an anti-flowback valve so this would need to be overcome to be able to pump any fuel out, but I think you did mention you have tried a direct 12V feed and it is actually measuring 12V when pumping so that rules out voltage drop causing low pressure.

This is what it feels like. Similar to trying to start a car with a flat battery. It does something but then falls flat on its face, same as the fuel pump although now I have a constant buzz but no fuel output. The car cranks easily so certainly should run a fuel pump. Frustratingly I left my good multimeter at work over the weekend so only had an analogue one yesterday. I'll check exact voltages when I get home tonight. 

Thanks all for your input. 

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Update: 

11.5v into fuel pump from ignition. Battery is similar from yesterday's messing around. Put charger onto fuel pump terminals and confirmed at 12v. 

Pump buzzes but no fuel out and confirmed fuel available on inlet. 

Rigged the below pic up to test old pumps. No fuel out on either and voltage at charger crocodile clips/ pump terminals dropped to 8.5v on one pump and 7.9v on the other. I would have thought this means they are both knackered. Will remove new pump and conduct same test. The pumps themselves as @Andyww suggested are obviously the cause of the voltage drop. At present I can't see past having 3 bad pumps?! 

 

rps20190521_182420.jpg

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Update 2:

New pump tested in same way. No fuel output and pump terminals read 13.9v! Confirmed charger output is exactly 12v.🤨

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Just noticed something on the spec of the pump in the link above. This is an 8 bar pump. Thats over 100 PSI! The fuel pressure regulator limits the pressure to 4 PSI. So the pump will be strangled, trying to pump far more than needed, and use a high current causing it to fail.

That would likely be the cause of failure. pump too high spec. Were all 3 pumps this spec? Did the supplier specify for the Esprit because if they did, they are liable for the failures.

The correct pump should be 2 bar or so.

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The first two failures were the original pump to this car and the one off my dry sump which I replaced during its mechanical restoration with a Sytec the same as I've just bought again for this car. The Sytec pump on my dry sump has been fine so far (about 500 miles). Both the original pumps off both cars were bosch 0580464014. The ad states that the Sytec pump is a direct replacement for that Bosch unit. 

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OK so in that case I would suspect the fuel pressure is adjusted too low, so the pump is having to pump against too much of a restriction. Same result different cause.

Yes I know you have not adjusted it, but the setting can go out.

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Good call, thanks. Another pump is on its way and the first thing I'll do is check the fuel pressure at the fpr. Many thanks for all the input. 

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Thinking about this some more, I still reckon that pump is wrong. Too high max pressure. It could have been working marginally on the other car owing to a higher fuel pressure reg setting but still running hot and drawing high current.

They seem to have listed it as an equivalent to every Bosch pump there is. A normal EFI system would have its pressure reg running at 30-50 PSI and the pump would be fine for this use but might be struggling at a limit of 4 PSI. Why not use one which is proven to work on the Esprit such as the one SJ sells?

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Hi Andy, I've now done exactly that and ordered one from SJ and will return the Sytec. I was concerned I hadn't actually found the problem causing the failure of the pumps but I've now exhausted all possibilities. The voltage supply is correct, the bad pumps made it look faulty. The fuel system is spotless and I've been out before work this morning to verify the fuel return is clear which it is. I'll put the sj pump on, check the fuel pressure and if that pump fails I'm screwed! 🙂

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