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1970-1995 Range Rover Classic
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Discussion Starter #1
93 RRC SWB fuel pump replaced - starts but won't stay running

Hello fellow RRC road warriors - I am in dire need of guidance and direction.

I just replaced the fuel pump (only the pump, not the entire assy) on my 93 Classic with an aftermarket part that *should* be compatible with the truck and strong enough to produce the needed pressure to run it.

First, yes, my old fuel pump was tested before removal and found to be not working - test: checked that I was getting 12.0V at the pump plug when I had someone turn the key on, but pump would not run.

Link to the aftermarket part: http://treperformance.com/FuelPumps/TREReplacementFuelPumps.html#366

The pump fit very well into the pump assy and I had only to modify the elect connections a bit to get it back together.

I put the assy back into the tank and reconnected everything - except the "send" hose and had the wife turn the key on for 1 sec at which time, copious amounts of gas came barreling out - WORKS!

Reconnected the send hose and tried to crank the truck - fired nicely and appeared fine for a few seconds, then RPM's dropped and it eventually stalled after 6 or 7 seconds.

Then I turned the key on and off a few times to prime the fuel rail/system - and cranked again - same thing but not as strong of a start - and, got weaker each time.

I pulled the *return* fuel line off at the plenum and turned the key on - no gas is coming out (this is a test I performed in the weeks leading up the the failure of the old fuel pump and gas always came out of the nipple). I know gas is being sent up to the rail - but for some reason it's not cycling through the rail and coming out the returned line?

So, I am now stumped - read every post I could fine on this forum and don't find any dealing with this specific scenario.

At this time: when I crank the truck - it fires runs briefly every time and then dies. No gas pedal input affects it - if I press on the accelerator, it does not help the truck to stay running or increase the RPM's.

Thanks in advance - SMD
 

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1995-2002 Range Rover P38A
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Re: 93 RRC SWB fuel pump replaced - starts but won't stay running

Nothing on the return and dying after a few seconds suggests not enough fuel pressure from the pump. Not being familiar with any of the vehicles in the list that the pump is suitable for I wouldn't know but they are all pretty old motors. You haven't fitted a pump for a carb equipped car have you? A pump intended for use with carbs will run at 4-6 psi, a pump for an EFi system needs to produce around 10 times that pressure.
 

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Discussion Starter #3
Re: 93 RRC SWB fuel pump replaced - starts but won't stay running

Hello Gilbertd - thanks for the response - so, I hear what you are saying - and it makes sense. The fellows that I purchased the pump from listed it on Ebay - and that is where I bought it - in the auction, they specifically state that it's compatible with 93 RRC 3.9 EFI - but, that may not be true. I also went to the website today (to get that URL/link that I posted earlier) and I noted that among the list of vehicles on that page......the 93 RRC is *not* among them.......??.........so, perhaps that is the problem and they have sold me a pump that will not work on my RRC.

I pulled and cleaned the IAC valve with brake cleaner - sprayed it good and reinstalled it - I cannot really tell if it has failed until I can get the darn truck to RUN for a few mins. No help there.

I disconnected the battery for about a minute to let the ECU reset itself, re-connected and tried to start - no change: it fires, runs anywhere from 1-4 seconds then dies.
 

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1970-1995 Range Rover Classic
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1970-1995 Range Rover Classic
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Discussion Starter #5
Re: 93 RRC SWB fuel pump replaced - starts but won't stay running

Thanks for chiming in and offering this advice. Without a tool to do this check the scientific way, I removed the *incoming* fuel line at the rail put a few paper towels around it and turned on the key - a STRONG stream of fuel shot out of the fuel line in just a second or two before I turned off the key.......it shot over the paper towels and soaked the plenum.......I am thinking because of this that there is no problem with fuel delivery? Of course, I have no idea what the true PSI of the fuel is, but is sure looks good and strong.

Based on everything I am reading, I am beginning to suspect that it may be the fuel pressure regulator? Or, is it possible that there is air trapped in the system that is causing the injectors to not get fuel?

As I said, the truck starts, runs briefly and then dies.......since ZERO gas will come out of the *return* fuel line when I test by turning the key to ON, it just seems that there is truly some type of blockage - not likely I know, but that is how it seems............lots of fuel being sent in, none coming out???????

I am going to look into seeing if I can get a fuel pressure tester from an auto parts store.........I have every confidence from what I'm seeing that the pressure will be in the norm range.

SMD
 

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1995-2002 Range Rover P38A
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Re: 93 RRC SWB fuel pump replaced - starts but won't stay running

Just because you've got a lot of fuel, doesn't mean it is at the pressure it needs to be. Later Classics and the P38 have a Schrader valve in the fuel rail so the easiest way of checking fuel pressure is with a tyre pressure gauge. According to RAVE, on earlier ones without this, it should be checked at the output of the filter. The fact that the engine dies and there's no fuel returned to the tank says to me that the pump isn't giving enough pressure for the regulator to open and send any back. It should be at 2.0-2.5 bar (30-38 psi) from the pump, any less and that is the problem. I looked at the site you linked to for the pump but they don't appear to give any useful data such as working pressure and flow rate just what cars they will fit.
 

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Discussion Starter #7
Re: 93 RRC SWB fuel pump replaced - starts but won't stay running

Yep - I agree - I have to do a real PSI test. I am going out to obtain a fuel pressure testing kit.

Will advise once complete.

SMD
 

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Re: 93 RRC SWB fuel pump replaced - starts but won't stay running

Coincidentally I'm having the same exact problem today - truck was running fine then just stalled out, like it was out of gas. I can get her started again, but she dies again soon after. I haven't tested/changed my fuel pump yet.
 

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Re: 93 RRC SWB fuel pump replaced - starts but won't stay running

So I messed around with my truck this afternoon, new gas, cleaned IAC and TPS - and was finally able to get her to run long enough to get her up the driveway and parked for the night. This weekend I plan to run through the same tests as Revo. Speaking of...Revo, I don't mean to hi-jack your thread.. Just figured we might be able to help one another out here. I was lucky to stumble across this on my first search. :)


Sent from AutoGuide.com Free App
 

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Re: 93 RRC SWB fuel pump replaced - starts but won't stay running

revoR, I replaced my IAC valve with a part 21738 (it's $50.00 :neutral: ) from Advance Auto today at lunch. Truck started up, and then died again. However, I've been going down to the garage periodically and starting her. Each time she ran longer than the last. At this point she's running and holding idle. Maybe the ECU needed to adjust.. I don't know. I'm still going to test the fuel pump this weekend as I think there may still be an underlying problem as the idle doesn't appear as smooth anymore. Anyway just wanted to pass info along... hope your making out okay.
 

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Discussion Starter #11
Re: 93 RRC SWB fuel pump replaced - starts but won't stay running

sfgraham2 - sorry to not have seen your posts sooner - thanks for chiming in and no worries about "hijacking my post"......all of your comments, experiences and feedback are most welcome.

I also pulled the IAC and sprayed it down really well with brake cleaner - stuck a rag soaked with it into the hole and cleaned out some some gunk - no help at all there.

I picked up a fuel pressure test kit at Harbor Freight for $20 bucks last Thursday and just have not gotten around to doing the test.

The thing with that is, the only pressure I could possibly test is the pressure when I turn the key on and the pump pushes fuel up to the rail to prime it for about 2-3 seconds........since my truck will not run, I won't be able to get a reading on the pressure when it's idling.....and I think that is where the problem is.......the fuel system primes the rail and the truck starts, but dies immediately. So, presumably, the pressure is not enough for the EFI system to keep the truck running/idling.

However, in the diagnostic test shown in the RAVE manual, it does prescribe this test and the expected pressure when the pump kicks in to prime and also, how long it takes for the pressure to drop after the pump finishes prime and shuts off:


Insert the pressure gauge in the fuel feed line immediately after the fuel line filter. The filter is located beneath the right hand rear wheel arch attached to the chassis.

Turn ignition on (fuel pump primes fuel rail).
Expected reading 2,4-2,6 kg/cm2 (34.0-37.0 p.s.i.)

Turn ignition off (fuel pump off).
Pressure drop-max 0.7 kg/cm2 (10 p.s.i.) in one minute.



I guess this test will prove if there is an issue with pressure..........and then, I think it point either to the new aftermarket pump I installed OR the fuel pressure regulator...........incidentally: was pricing the regulator......OMG - $150 - 200 or there is on Flea-Bay for $80, used (can't imagine I'd want to install a used Regulator though.....sigh).

That's all the news from Lake Woebegone.

Hope your truck runs soon - I will post again once I have some more data.

SMD
 

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1995-2002 Range Rover P38A
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Re: 93 RRC SWB fuel pump replaced - starts but won't stay running

I have had a bit of this problem - I think there is a learning function in the ECU - you can reset it by disconnecting the power for ten seconds but I found that taking it for a drive fixed the problem.
 

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Discussion Starter #13
Re: 93 RRC SWB fuel pump replaced - starts but won't stay running

Hello Johnno - Thanks for chiming in........in an earlier post, I indicated that I'd disconnected the battery for about a minute - and I did this to reset the ECU......does that in fact reset the ECU? Or do I need to pull the ECU plug to reset it? I assumed that disconnecting the battery would result in a reset of the ECU - but maybe that is not truly the case?
 

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Re: 93 RRC SWB fuel pump replaced - starts but won't stay running

Should be the same thing - I've disconnected the plug on the ECU but it is a bit of a pain to get to. Seriously, if it starts up, try taking it for a drive and see if it eventually settles down (I'm assuming it will run at higher revs - above an idle).
 

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Re: 93 RRC SWB fuel pump replaced - starts but won't stay running

Hang on, isn't everyone over thinking this? It ran all right and then stopped because the fuel pump died. A new fuel pump was fitted and it runs but not properly. If the fuel pump that had been fitted was up to the job, it should run just as it did before the old one died. Fit the correct pump not some crappy aftermarket junk......

No, the 14CUX controller isn't clever enough to have any adapation for the fuel pressure, it simply turns the pump on when needed.
 

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Re: 93 RRC SWB fuel pump replaced - starts but won't stay running

there is an adaptive function around the TPS and it seems to affect the idler valve as well. At any rate I've sorted out idling problems by taking it for a drive so something is going on.
The ECU doesn't talk to the pump. Usually it would have a pressure shut off but I'm not sure on the range rover set up.
I've assumed he has an idle problem i.e. starts and runs but doesn't idle.
 

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Re: 93 RRC SWB fuel pump replaced - starts but won't stay running

Bit of a back pedal here - I went and read the original post. What the ECU does is run the pump for a few seconds when the ignition is turned on and then it waits until it gets an engine speed signal before turning the pump back on. It gets the engine speed signal from the coil negative but I don't have the book handy so I don't know what pin it is. If you find the pin and test it to earth you should get 4-5 volts (I think there is a resistor in there somewhere). The wire goes from the coil negative into the loom that runs from the MAF sensor and then into the ECU plug if you want to inspect it.
Just looked it up (in the online ecumate manual) because I don't have a life - it's pin 39 second from the right on the bottom looking at the back of the plug and the resistor is 6.8V.

Yours in range rovering
 

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Discussion Starter #18
Re: 93 RRC SWB fuel pump replaced - starts but won't stay running

Wanted to give an update on this. I was not able to get the Classic to run using the 1st pump I purchased on ebay:

http://www.ebay.com/itm/320635611199?_trksid=p2059210.m2749.l2649&ssPageName=STRK%3AMEBIDX%3AIT

I tried to determine why it would not run - I only replaced the pump portion of the assembly with the above part. Nothing I tried worked - there seemed to be no other issue except it seems that in the end, this pump, that the seller said would work on a 93 RRC did not work.

So, being the cheap-skate that I am - I went BACK out to Ebay and found a complete fuel pump assembly - the whole enchilada for $105.00:

http://www.ebay.com/itm/140724028322?_trksid=p2059210.m2749.l2649&ssPageName=STRK%3AMEBIDX%3AIT

When I dropped this assembly into the RRC and tried to start it, it would not start at first……pump ran briefly….then stopped running…..and would not run, even to prime…...I nearly went berserk and was contemplating setting the truck on fire at this point……but, instead, I went and pulled every fuse associated with spark and fuel including the relays and then I unplugged the ECU and next time I tried to start it, it fired right up, ran perfectly and has not shown any indication of any issue with fuel flow.

Based on my experience, it seems that the above part works with the 93 RRC - it had the correct/round plug, but it did NOT come with the fuel line fittings nor the rubber ring or the plastic screw on ring.

It's good to have the truck up and running again.

SMD
 

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Re: 93 RRC SWB fuel pump replaced - starts but won't stay running

Just an update - I've had a similar problem over the last few days (starting and stalling turning into randomly not starting and then randomly starting). Seemed to be the fuel pump working intermittently (in my experience a common failure when they are on the way out) so I swapped it with a spare I had. Still had the same problem so I swapped out the fuel pump relay and it seems to have fixed it. Time will tell.
 

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Re: 93 RRC SWB fuel pump replaced - starts but won't stay running

That's a funny link, Revor. "LWB electric fuel pump" maybe it's stronger than a SWB fuel pump? LOL

I've used the Airtex aftermarket pump from Autozone(just the pump) for years and it's worked fine.


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