Okay prior info regarding start injector not injecting. Sent it to get repaired and got it back and same thing. But why? Did they not correct the issue or what am I doing wrong??? Since as before I have a ground on one of the wires and when I crank the engine I do get voltage on the injector. However I took a little closer look at things this time and see that yes I get voltage but it is only 9 volts rather than 12v. Is this the problem?
It takes about 15 seconds of cranking to get the rail pressure up to 25 lbs. Been told that I should have like 35 lbs. Is this the problem? And then instead of staying there for an hour perhaps, it goes back to 0 pressure in about the same time of 15 secs. Seems like the pressure should stay longer than that and wondering what could cause the pressure to leak down when I have no fuel leaks.
15 seconds of cranking alone is quite a lot of cranking. That is quite a long time before the igniter would even have the proper fuel pressure etc to start the engine. I understand that some Jags, corrected this issue in some way. On this model the MAF flap has to be open by actual cranking before the pump will run. Since my pressure will not hold is there any way to improve on this. It would be nice if I could bring the rail up to pressure before unnecessary cranking. I may have more than one problem but right now I am kind of in the dark. Can you Doug or anyone straighten me out on what I might be overlooking. Seems like the start igniter should spray but doesn’t. I must be overlooking something.
Lee
Hmmm. Mulling needed. As I recall the cold start injector should get a full 12 volts. But…it may work fine on just 9 volts.
Unless you’re in a very cold environment the cold start injector won’t make much difference. The engine will start but with a little additional cranking. Maybe 3 or 4 seconds.
The pump should recharge the fuel rail in just a few seconds. Maybe 3-5 seconds at the most; certainly not 15. And 25 psi is too low, for sure. You want to see about 36 psi.
I wonder if the fuel pump is weak? Or the filter clogged?
There is an anti-drain valve in the fuel line. It’s in the trunk, attached to that odd Air Bleed Valve. It must’ve failed. As far as I know it is NLA from jaguar but a generic check valve could be easily plumbed into the system
Cheers
DD
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Depends on where you measured it, Lee - the injectors are powered through the injector resistor pack. With current flowing the voltage over the injectors drops to some 4,5V, and the injectors will operate at 3V…
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Sure is, as Doug says; check pump performance. Connect the pressure gauge to the fuel rail inlet hose to measure ‘raw’ pump pressure - it should read 100+ psi, ex factory, less than 40 psi will not run the the engine. And pressure should reach maximum within 2 seconds; low pressure is a bad pump, slow build-up is clogged pump feed. And regulated fuel pressure should be 36 psi, give or take a tad without the engine running…
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You have - but the leaks may be internal. There is a hexagonal one-way valve between the pump and the filter; with the pump running the valve opens to the filter. When the pump stops, the residual fuel rail pressure closes the valve - retaining rail pressure. A rapid leak-down implies that the valve has failed - though in principle leaking injectors (end external leaks) will also bleed off rail pressure, but usually at a very slow rate. Working properly; rail pressure is maintained ‘indefinitely’, but some leakdown is to be expected - but immaterial. The pump, working properly, will raise fuel rail pressure to spec within a couple of seconds…
In a couple of instances, the plunger inside the valve has revolved - which partially blocks fuel flow. Which may explain the slow build-up of pressure - but not necessarily the low pressure obtained; this is a pump problem…
To test; connect the pump directly to the the filter - bypassing the non-return valve and check pressures and/or run the engine (leakdown will be instant with this set-up).
The ‘3rd’ hose on the non-return valve connects to the return hoses for pump venting - it should be clamped for this testing.
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Negative; the the fuel relay is activated by two circuits in all EI versions. One is the ‘crank’ (white/yellow) will run the pump with ign in ‘crank’. The other circuit is indeed operated by a reed switch in the AFM - triggering the relay as the flap opens. Both circuits may operate during cranking if the cranking rpms are high enough.
To test, place gear lever in ‘D’ (to prevent actual cranking - you should hear the pump running in ‘crank’. Then remove the air filter and prop open the AFM flap - the pump should run with ignition ‘on’. And with ign ‘on’ the the pump should run if the AFM flap is moved fractionally (1/4"?)…
The most likely fault is a defective pump, but the one-way valve, or indeed blocked pump feed lines/changeover valve may be involved as well…
Frank
xj6 85 Sov Europe (UK/NZ)
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Frank I was going to answer you in the Forums but it will not let me log
in again. Why am I having so much trouble logging in?? Sure would like
to get that problem solved also. Who can I call or whatever to kind of
fix this problem.
Anyway back to the Jag. Well I checked out the pump. You say it is
suppose to be putting out aprox 100psi! I checked right at the pump
outlet and it is only putting out about 30psi. It is running but not
building up the pressure. What could be wrong with the pump? It is
relatively new. Can it be partially plugged up with gasoline gum? The
auto has been sitting for awhile and you know what happens to the
gasoline we get now. Do you think there is any way I can run some fuel
gum-cleaner through it to perhaps to perhaps make it work again since
the motor is still turning. There are a lot of fuel line cleaners on the
shelves to purchase. Wonder if it is worth a try? Got any ideas? Fuel
pumps are not cheap thus wondering.
Lee Noga
P.S. Okay sending again. I noticed from my email I sent it to the NO
REPLY thus no answer from you. Wanted to correspond but cannot log into
the site for some reason. I logged in the other day and posted my
message so don’t know?
Anyway Frank I did what I was thinking and run gasoline and some
cleaner additive that I purchased, and recirculated it in a one gallon
container. After running it for 1/2 hour the outlet pressure went from
30psi to 60psi thus the cleaning is working somewhat. I am going to let
it run for a couple of hours and see what I get for pressure at the end
of that time. Maybe I can save this pump.
Okay I finally got logged in again and see my message is appearing. You haven’t had time to read it yet Frank no doubt. But will let everyone know if I was successful to get this pump to regain the pressure it should have. Bad fuel will cause molasses type deposits in the pump. I am hoping that this cleaner will do the job and bring this pump back to where it should be again. It is lucky that the pump did not completely stall out. I have drained out both tanks and replaced with non-alcohol fuel. Costs a lot more but worth it!
The pump can put out 100 psi if it is deadheaded. If it’s feeding into a FPR, though, the pressure in the line is controlled by the FPR.
If the pump only delivers 30 psi at the fuel rail inlet hose(!), raw pump pressure, Lee – the pump cannot sustain the engine. At your 60 psi, after cleaning it, may – try it? While a brand new pump will deliver 100+ psi, wear will drop, but the pump may still deliver enough to supply the engine. Below some level, guestimated 40 psi, the pump will not, and should be changed. That the pump is relatively new does not guarantee its function. However, 60 psi will likely work – but it is not in prime condition…?
I think I replied to your post on the forum only – since the e-mails usually refers to both. That you cannot log in to the forum…it has happened to me, but the administrator fixed it – though why was not clarified…
Frank
Well thought everything was going in the right direction. The pump was initially putting out 30psi. Running cleaner through the pump raised in to 60psi after a half hour. Thus thought I would let it run for about an hour. When I came back the pump had failed and was not running. The back of the pump was eaten out and not sure if the fuel cleaner was the culprit or if the pump failed electrically and partially burned the end where the connectors were. This brings up a point. With 12v going to brushes and always some sparking going on with brushes, what prevents a fire??? Anyway now to order a new pump. And here I am confused also. I got on Ebay and noticed that there is an assortment of pumps which range in price from $30 to over $200.00. They all claim they are for a 1987 Jaguar XJ6. Which one to get???
Lee
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The most likely explanation is that liquid petrol is not flammable, Lee - and oxygen is required for ignition anyway.
The price range you quote is a bit excessive; and the old adage is still valid: “It is not the brand that guarantees the quality - it’s the quality that guarantees the brand”. Must be something special about the 200 dollar one - but any of them is likely to work, and better than none…
Frank
xj6 85 Sov Europe (UK/NZ)
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This should do the trick.
Google “CBC5657 Jaguar” and you’ll find the right one.
The same basic pump was used on many cars. Present day replacements might be semi-generic and require changing the wiring connectors…which are typically included in the package. No big deal.
Cheers
DD
Not too hep on the internals of the fuel pump but from what I see, this could have been disastrous. I will try and take a picture of it to show you. Maybe one or some of you could explain why this happened? In this case you say liquid petrol is not flammable. How can you say that? Just throw some on some leaves or something and then throw a match to it. It will virtually explode. The fuel pump did have oxygen when the plastic burned a hole in it on the end. I am a little concerned about having sparking electrical contacts next to fuel. In a normal mechanical pump there is no electrical involved to ever start a serious fire.
Lee!
Its just my thought, could it be a problem with the
pressure regulators in the fuel in the trunk etc.
Walter
Liquid petrol in the open is certainly highly flammable. As Frank pointed out, oxugen is needed. Readily available in the atmosphere.
But, in a closed space entirely filled with petrol, no oxygen availble No fire, even if a spark takes place.
Now, in the combustion chamber. Air with oxygen and petrol present. Add a spark and get a boom… Fire and exposion are mates…
No pcture seen tosee the guts of your failed pump. I suspect two chambers. One with an impeller and fuel. The other connected,but sealed. Small electric motor here.
One way to clear a 'dirty" pump is to introdue a liquid and reverse the conections so the motor runs in reverse. So the fuel flow is reversed.
Knocking on wood, the orogonal pump in my lump worl perfect;y on locl fuel. I’ll not go further on the fuel thing…
So, if you can get a reasonable pressure to flow, it oughta run.
Carl
Here is a picture of the plastic end of the furl pump that failed on me. If one looks inside you can see the brushes. Don’t know what happened internally but there obviously was a short and it burned out a hole in the plastic. To me this is a very big concern since the obvious short or burning of the plastic could easily start a huge fire and being next to the fuel tank could be a complete catastrophe. Has there been any XJ6 fires caused by this area?? Is the fuel completely separated somehow from the brush area to prevent a fire?
Lee
That’s scary indeed…
Did you run the pump for an hour dry?
Never heard or seen something like this before.
There must have been a short somewhere as it’s only on one side, maybe e piece of metal that lodged itself in the wrong place?
For new pump, I would suggest you get a Bosch, and now they are Turbine type pumps. They are also Ethanol compatible.
Had two el-cheapo variants and they didn’t last long.
The likely reason is pump clogging up with tank debris, Lee - or bearing wear just stalled the pump, burning up the electrics. Remember that you nagged the pump for considerable time to try and clear it - and the lack of pressure may just have been caused by slow rotation caused by plain friction. And a stalled electric motor will overheat rapidly…
Your concern about fire is understandable, but there are no reports or expressed regulatory concern about fuel pumps causing fire. And electric fuel pumps are used by the millions, if not billions…
Even your actions caused no fire - and it put extreme conditions on the set-up. Not to underplay the risks of petrol fires, they are common enough - but they follow fuel spills, evaporation and ignition with oxygen present…
Frank
xj6 85 Sov Europe (UK/NZ)
Well you have to admit, the scenario is rather scary! Seems to me the possibilities are very present. Yes you can prejudge the reason my pump failed like it did, but with the bad alcohol fuel that we are forced to use now, causes this molasses type of deposits to form. With a very hard working pump trying to work in this condition is what you see apparently. Yes a normal situation is an auto driven every day to prevent the fuel from going bad and forming the molasses type deposits. Remember alcohol in fuel is derived from several sources such as sugar cane etc, same stuff that molasses comes from. Unfortunately this auto was not used regularly enough. My fault. I guess I should either drive the auto more or sell it.
Lee
aye, fire is very much on my mind. In my formewr profession, I dealt with the consequences, many times. Some just property, others critters, Ouch.
I germany my MG had an engine fire. A quick thinking gas attenmdant quenched it fast enough so that no real damage toiok plade. close though!!! it was at one of the SU carbs…
Not ot overly alarm you. My 94 Jeep Grand Cherokee. has a module inserted in to it’s plastic tank. Teh module is a fuel pump and the fuel guage sensor. Not an common thing.
The extra’s that came with the engine and transmission for my car included a similar module, but for a Cadillac Fleetwood Brougham. When the one in my Jeep failed, i forgot about it and did not compare them…
Or merely add the two prepump filters as
Aristides and many others have.
No comment on Ethanol by me.
Cut the impeller chamber open and see what is in it!! Jusat for your satisfaction and enhancement of the archives.
I do not dreive my cars a lot any more. but, i do crank them up just to keep them limber…
And,in our state, EVACUATION!!! FIRE SEASON…
Carl
Waiting for new fuel pump! Will seen how things all work after that. I still suspect that I have a start igniter problem.