CIS: Fuel pump relay, and then some...WUR?
10-07-2008, 05:20 AM
#1
Rennlist Member
Thread Starter
CIS: Fuel pump relay, and then some...WUR? - SOLVED! (sort of)
Hi, what a great day... (I woke up from a call from the missus saying that somebody had broken in to the Citroen during the night. Great. A key to the house MIGHT be missing, so I need to change all the locks. Great)
I decided to take the kids to school in the Porsche. After dropping them off and driving for a few minutes, the car started hesitating, and finally died. Just like it was out of gas. (it has half a tank of gas in it...)
A fellow rennlister lives near by, and he offered to tow the car back to my place. I jumped the fuel pump relay, and the car started, but would still not run properly. It will not idle properly, but it revs almost normally. It hesitates and sputters when I hit the trottle from idle. It has never been like that before, and was running perfect this morning also, until it stopped.
It seems like the fuel pump relay died, but why the poor running with the jumper in there?
PS: CIS aka K-Jetronic.
I decided to take the kids to school in the Porsche. After dropping them off and driving for a few minutes, the car started hesitating, and finally died. Just like it was out of gas. (it has half a tank of gas in it...)
A fellow rennlister lives near by, and he offered to tow the car back to my place. I jumped the fuel pump relay, and the car started, but would still not run properly. It will not idle properly, but it revs almost normally. It hesitates and sputters when I hit the trottle from idle. It has never been like that before, and was running perfect this morning also, until it stopped.
It seems like the fuel pump relay died, but why the poor running with the jumper in there?
PS: CIS aka K-Jetronic.
Last edited by gruffalo; 10-18-2008 at 09:04 AM.
10-07-2008, 09:15 AM
#2
Check the easy stuff first like the fuel filter (old?), fuse to the fuel pump (corroded?), in tank pump (blocking fuel path?), corroded connections on the resistor pack that feed the coil, just to name a few. Also, a lot of crud, dirt, oil on the air sensor plate can cause poor idle and low rpm hessitation.
Dennis
Dennis
10-07-2008, 09:23 AM
#3
Rennlist Member
Thread Starter
I also remember the car was running @1600 rpm idle when cold today. Never seen that before. Perhaps I'm running on the WUR only?
The car has been running without a single hickup for the last 5 seasons, these problems appeared suddenly, it hasn't gradually become worse or anything like that.
The car has been running without a single hickup for the last 5 seasons, these problems appeared suddenly, it hasn't gradually become worse or anything like that.
10-07-2008, 09:49 AM
#4
If it revs almost normal it isn't just running on the CSV. If the CSV isn't shutting off, it could be causing the problem. Might try unplugging it to see if the problem goes away.
Dennis
Dennis
10-07-2008, 10:19 AM
#5
Rennlist Member
Thread Starter
what's the electrical connector on the WUR for?
Since my problem appeared suddenly and included a problem with the fuel pump relay, could the general cause be of an electrical nature?
Since my problem appeared suddenly and included a problem with the fuel pump relay, could the general cause be of an electrical nature?
10-07-2008, 10:32 AM
#6
Instructor
Once the engine is started, cold start enrichment needs to be reduced before the WUR warms up from heat from the block alone. The electrical connector on the WUR supplies current to heat the bimetallic strip directly.
10-07-2008, 11:09 AM
#7
Instructor
The fast idle sounds like a vacuum leak, and the hesitation when you hit the throttle from idle also sounds as though it's running very lean. Given the suddenness of the symptoms, my wild guess is that your intake plenum chamber ("spider body") may be loose on the throttle body.
When the engine is cold, the warm-up regulator reduces the control pressure acting on the control plunger in the fuel distributor, which allows it to lift higher, exposing more of the metering slits and enriching the mixture. As the engine warms, a bimetallic strip acts to increase the control pressure and lean the mixture back to that for the engine at operating temperature.
With age, the bimetallic strip tends not to bend enough to enrich the mixture fully for a cold start. This sometimes is compensated for by enriching the mixture via the mixure control screw, which leaves the mixture a little too lean for cold running and rich for normal running. When cold and with the mixture lean, the engine will hesitate when you hit the throttle, and may backfire through the intake. Eventually, the bimetallic strip will fail in the full lean position, and you will not be able to start the car at all when the engine is cold.
The cold start injector is controlled by the thermo-time switch in the water bridge. When the engine is cold, this switch fires the cold start injector for additional enrichment, for a maximum of about ten seconds.
If you have had trouble starting the car, especially in cold weather, and it hesitates on acceleration when cold, your WUR may have been failing. It doesn't sound like it, from what you've said; and, once the engine is started, it gradually runs better as less enrichment is required.
Another sudden onset problem may be the little green wire which runs between the electronic ignition module and the distributor, but (as far as I know) that wouldn't make the engine idle fast.
When the engine is cold, the warm-up regulator reduces the control pressure acting on the control plunger in the fuel distributor, which allows it to lift higher, exposing more of the metering slits and enriching the mixture. As the engine warms, a bimetallic strip acts to increase the control pressure and lean the mixture back to that for the engine at operating temperature.
With age, the bimetallic strip tends not to bend enough to enrich the mixture fully for a cold start. This sometimes is compensated for by enriching the mixture via the mixure control screw, which leaves the mixture a little too lean for cold running and rich for normal running. When cold and with the mixture lean, the engine will hesitate when you hit the throttle, and may backfire through the intake. Eventually, the bimetallic strip will fail in the full lean position, and you will not be able to start the car at all when the engine is cold.
The cold start injector is controlled by the thermo-time switch in the water bridge. When the engine is cold, this switch fires the cold start injector for additional enrichment, for a maximum of about ten seconds.
If you have had trouble starting the car, especially in cold weather, and it hesitates on acceleration when cold, your WUR may have been failing. It doesn't sound like it, from what you've said; and, once the engine is started, it gradually runs better as less enrichment is required.
Another sudden onset problem may be the little green wire which runs between the electronic ignition module and the distributor, but (as far as I know) that wouldn't make the engine idle fast.
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10-07-2008, 11:30 AM
#8
Rennlist Member
Thread Starter
To summarize:
The car has been running very strong, always, cold/hot, with no hesitation, never. Until today.
High idle on startup, drove for approx 2 miles, suddev violent hesitation on acceleration, then just idle for a minute or so, then dead. I was able to restart it again, but it died when I tried to get going. I felt 100% like lack of fuel (starvation).
Ambient temperature 5 degrees C.
Had it towed to my house, jumped the fuel pump relay, and it started (this was approx 30 mins later). It ran a lot better, but still like crap. Hesitation and poor idle. Hard to get it rolling without killing the engine.
Maybe the somewhat improved running was due to the engine cooling down?
Where do I go from here debugging this?
The car has been running very strong, always, cold/hot, with no hesitation, never. Until today.
High idle on startup, drove for approx 2 miles, suddev violent hesitation on acceleration, then just idle for a minute or so, then dead. I was able to restart it again, but it died when I tried to get going. I felt 100% like lack of fuel (starvation).
Ambient temperature 5 degrees C.
Had it towed to my house, jumped the fuel pump relay, and it started (this was approx 30 mins later). It ran a lot better, but still like crap. Hesitation and poor idle. Hard to get it rolling without killing the engine.
Maybe the somewhat improved running was due to the engine cooling down?
Where do I go from here debugging this?
10-07-2008, 11:52 AM
#9
Instructor
Just to be clear, I suspect that your fuel pump relay is not the problem, otherwise the symptoms would not have continued when you jumped the relay sockets. Neither should a pump or relay fault make the engine idle fast. Did you check that the fuel pump wasn't operating before you pulled the relay? To do so, turn the key momentarily to the start position and release it before the engines starts. The fuel pump should run for a couple of seconds, then stop.
When you jump the relay sockets 30 and 87, the pump should run continuously. If it seems to run OK, and isn't rumbling (which indicates that something is fouling the rotor and that it may soon sieze), it may be dying and not able to deliver the flow the engine and injection system requires.
If the wild guess of the loose spider body is wrong, the fuel pump delivery rate should be measured. To do this, the return line in the engine bay needs to be disconnected and the flow rate measured. It should be about 1350cc per 30 seconds.
Should the flow rate be significantly lower, either the fuel pump is weak, the fuel filter could be blocked or the fuel distributor has a partial blockage. In this case, I suggest conducting the test again, but on the delivery line ie taking the fuel distributor out of the circuit. If the flow rate is still low, the pump is bad or the filter is blocked; if the flow rate is OK, the fuel distributor has a blockage and probably needs to be rebuilt.
For the test, the fuel pump relay must be removed and sockets 30 and 87 bridged, very preferably with a switch on a lead. The tester needs either an assistant to operate the fuel pump or a lead long enough to be operated when the tester is in position to conduct the delivery rate test. I clamp a hose to the fuel return line and direct it into a graduated container beside the car. Trying to do it directly from the fuel line in the engine bay seems to me to be a recipe to spill fuel.
This test has the potential to spill a lot of fuel. You need a fire extinguisher beside you. If you are not confident that you can conduct the test safely, get a mechanic to do it.
When you jump the relay sockets 30 and 87, the pump should run continuously. If it seems to run OK, and isn't rumbling (which indicates that something is fouling the rotor and that it may soon sieze), it may be dying and not able to deliver the flow the engine and injection system requires.
If the wild guess of the loose spider body is wrong, the fuel pump delivery rate should be measured. To do this, the return line in the engine bay needs to be disconnected and the flow rate measured. It should be about 1350cc per 30 seconds.
Should the flow rate be significantly lower, either the fuel pump is weak, the fuel filter could be blocked or the fuel distributor has a partial blockage. In this case, I suggest conducting the test again, but on the delivery line ie taking the fuel distributor out of the circuit. If the flow rate is still low, the pump is bad or the filter is blocked; if the flow rate is OK, the fuel distributor has a blockage and probably needs to be rebuilt.
For the test, the fuel pump relay must be removed and sockets 30 and 87 bridged, very preferably with a switch on a lead. The tester needs either an assistant to operate the fuel pump or a lead long enough to be operated when the tester is in position to conduct the delivery rate test. I clamp a hose to the fuel return line and direct it into a graduated container beside the car. Trying to do it directly from the fuel line in the engine bay seems to me to be a recipe to spill fuel.
This test has the potential to spill a lot of fuel. You need a fire extinguisher beside you. If you are not confident that you can conduct the test safely, get a mechanic to do it.
10-07-2008, 12:03 PM
#10
Team Owner
is it possible that the fuel has been contaminated? was the fuel caqp locked? is it still locked have you opend the cap to see if there are any debris left in the cap area.
Sorry to hear that your Car was vandalized
Sorry to hear that your Car was vandalized
10-07-2008, 12:04 PM
#11
Instructor
Sorry, gruffalo; I didn't realise that you replied so quickly to my previous post. Get someone to start the car while you are at the back listening to the fuel pump. You really need to establish whether it is working or not.
If you can hear only the sound of silence, remove the cover plate and tap the pump with a hammer or spanner while the engine is being cranked. If that makes the pump run momentarily, something is fouling the pump rotor (probably the pump internals disintegrating). This means that you need a new pump (though I do know one keen guy who got into his pump and removed whatever was fouling it; dunno how long it lasted after that).
If you can hear only the sound of silence, remove the cover plate and tap the pump with a hammer or spanner while the engine is being cranked. If that makes the pump run momentarily, something is fouling the pump rotor (probably the pump internals disintegrating). This means that you need a new pump (though I do know one keen guy who got into his pump and removed whatever was fouling it; dunno how long it lasted after that).
10-07-2008, 02:48 PM
#12
Rennlist Member
I had a similar symptom recently -- I even called AAA to bring out some fuel, and the symptom persisted. Turned out the problem was vac leaks. Disconnect the aux air line at the cold start valve, tape over the fitting and cork the line. Check the vac line to the EGR valve.
Ultimately, the problems in my case were a combination of a leaking vac line to the EGR valve(primary cause), cracked plastic fitting at the cold start valve, plus the vacuum limiter had failed in two different ways; the diaphragm had ruptured and the valve itself was not closing properly. The aux air line leak can affect mixture, the vac limiter would not allow unmetered air into the system but it wasn't right so I fixed it anyway.
I replaced all of the vac lines in the engine bay for good measure and the car runs fantastic now.
Ultimately, the problems in my case were a combination of a leaking vac line to the EGR valve(primary cause), cracked plastic fitting at the cold start valve, plus the vacuum limiter had failed in two different ways; the diaphragm had ruptured and the valve itself was not closing properly. The aux air line leak can affect mixture, the vac limiter would not allow unmetered air into the system but it wasn't right so I fixed it anyway.
I replaced all of the vac lines in the engine bay for good measure and the car runs fantastic now.
10-07-2008, 05:18 PM
#13
Rennlist Member
Thread Starter
back from the lab (garage)
Forget the relay, it works .
It's running rich, I suspect. It runs normally when cold, but as it warms up, things are getting gradually worse. I drove it a couple of miles, and in the end it would idle, but not accelerate. If I ease the throttle on, it wil run smoothly at e.g. 3k rpm. If I hit the throttle agressively, it will cough, hesitate violently, and entertain the neighborhood with loud bangs and flashing from the rear silencer. That spells rich in my book...
It needs to be rich when cold, so that explains the smooth running when cold. But it obviously stays rich as it warms up.
Why?
WUR stuck on, or any other suggestions?
I have a complete spare engine, so I can easily swap parts, but need help to narrow down my options.
Forget the relay, it works .
It's running rich, I suspect. It runs normally when cold, but as it warms up, things are getting gradually worse. I drove it a couple of miles, and in the end it would idle, but not accelerate. If I ease the throttle on, it wil run smoothly at e.g. 3k rpm. If I hit the throttle agressively, it will cough, hesitate violently, and entertain the neighborhood with loud bangs and flashing from the rear silencer. That spells rich in my book...
It needs to be rich when cold, so that explains the smooth running when cold. But it obviously stays rich as it warms up.
Why?
WUR stuck on, or any other suggestions?
I have a complete spare engine, so I can easily swap parts, but need help to narrow down my options.
10-07-2008, 05:29 PM
#14
Are you getting black smoke? If so try unplugging the cold start valve when warm. If it improves or eliminates the bad running either the csv is leaking or the thermotime switch is bad. If that doesn't help, you will need to get a CIS tester and check the control and system pressures.
If no black smoke, check your timing (valve then ignition), voltages to the coil and condition of your distributor cap and rotor to name a few.
Dennis
Dennis
If no black smoke, check your timing (valve then ignition), voltages to the coil and condition of your distributor cap and rotor to name a few.
Dennis
Dennis
10-07-2008, 05:48 PM
#15
Team Owner
dont hit the fuel pump with anything metal, if you hit it hard enough you will crack the permanent magnets that are pressed down the inside of the blue can, same goes fo,r dont drop the fuel pump, if you buy a new one these same instructions are usually included in the box.
About the only thing you can do with fuel pump are listen to it and run it backwards
About the only thing you can do with fuel pump are listen to it and run it backwards