|
|
|
Help?? My nephew's 1991 740 with Regina is hesistating upon accleration. changed out a bad frayed crank sensor but problem still exists. I've been searching but can't find any concrete failure modes. Was thinking it might be a bad MAP sensor. Idea's???
|
|
-
|
|
|
Thanks again for all the responses and an update on the problem.
It turns out that it was the fuel pump like suspected. I offered to help my nephew change it but he has a busy schedule and deceided to take it to a local garage.
|
|
-
|
|
|
Hi Al
this has come in handy a few times.
i had the guage on the shelf. a hydrolic hose store had the tee and made the hose. total cost was about 20 bucks.
our regina pump went bad, worked sometimes but not others and the fuel guage confirmed low pressure.
if you have one made get the hose made longer so you can see guage when driving.
a rap on the gas tank will kick start a dying pump sometimes, but it wont last long.
good luck
Mike
|
|
-
|
|
Based on age, I'd suspect the fuel pump, if original. Art Benstein replaced one on a relative's '92 a couple of years ago. It's tricky to get a gauge in the fuel rail schraeder valve, but Art managed with a tire gauge -- enough to see low pressure. Should be about 36 at idle, going to 45 with the FPR vac hose removed and plugged.
You could also check the pump current draw at the 4-pin plug (pink wire) in the left rear "wheel housing" after removing the panel cover. Should be at least 7 or 8 amps. I recall Art saying he saw a low and fluctuating current on the pump he replaced.
|
|
-
|
|
|
I have an 89'&went through a lot of problems last summer,Did you pull any codes???Maybe knock sensor,,,or clogged sock onthe fuel pump,in tank.,or frayed wire thru pump sender housing,,vacum leak on line to map sensor.another prob maybe base of the ign.coil maybe wearing out.It controls injectors opening&closing.&would prevent fuel from getting to injectors.
GREAT car,,,lot of fun to drive,,now I just need a job to pay for more parts!!
|
|
-
|
|
|
What symptoms did you have and what was the problem? I checked the line to the MAP and it looked ok.
|
|
-
|
|
|
Hi Bruce,
Found Art's detailed write up on changing the fuel pump. http://cleanflametrap.com/ReginaFuelPump/ I should make that current measurement first seeing this looks like an involved jog. Any links on how this is best done.
Thanks,
Yama
|
|
-
|
|
|
"I should make that current measurement first seeing this looks like an involved jog. Any links on how this is best done."
I did it by making a fuse extender (with 2 open ends) for fuse 11, then connecting the ammeter across the extended fuse wires.
But later I realised that by opening the 4-pin plug I mentioned above, the meter could be inserted between (in series with) the pink wire terminal in each half of the disconnected plug.
[The other 2 wires are just for the fuel sender, so no problem with them being temporarily disconnected.]
BTW, the ignition coil and/or power amp have absolutely nothing to do with "firing the injectors".
|
|
-
|
|
|
I'm measuring 3.8A at fuse 11. Is this a good reading?
|
|
-
|
|
Hi Al,
3.8A does seem low to me as I recall the trouble with my mother-in-law's '92 940.
The trouble with that pump, as you read, was the broken brush wire, such that the pump's current must go through the brush spring - a flimsier version of a ball-point pen spring. The current would fluctuate, depending on how long the pump was running, as the spring became hot.
I could observe that fluctuation, even while driving, because I made an extender like Lucid's, to bring the relay out where I could get at it. The amount of time the current looked adequate to me convinced me I could nurse the car 45 miles from Mom's house to mine. I never made it. I wound up doing the job in my daughter's driveway, about half-way home from the last spot I made it safely off the highway.
Try to get a pressure gauge on the rail. I used an ordinary pen-style bicycle tire gauge. Be careful about the bit of fuel that will spurt as you're on and off the Schrader valve.
Current is not so easy to measure accurately and repeatably in a situation like this. That's why I took the time to make that extender - knowing I couldn't hold the tire gauge on the rail while driving.
I'll check in here some while Bruce is traveling.
--
Art Benstein near Baltimore
Dad: Someone who hopes his sons will turn out to be just like him, and who is afraid his daughters will meet someone who did.
|
|
-
|
|
|
Hi Art,
To measure the current with the extender do you pull the relay and put your ammeter probes between 2 pins in the socket? My reading was done at fuse 11 and was very stable as the engine was rev'd. Close enough to call 4 amps. It was nothing like the varation on the one you had a problem with. The actual symptom is like a "bog". If you bring the rpm up slow it seems to run ok. If you punch it down quick it bogs and hesistates before getting up to rpm. I guess to really check the fuel pump I need to measure the pressure. I still have hope that maybe its a bad sensor even though the fuel pump is suspect. I'm thinking maybe MAP sensor as it runs similiar to a car with a bad AMM. Even read one post about a bad knock sensor. Any ideas welcome.
Thanks,
Al
|
|
-
|
|
|
This was a few years ago, so I'm not sure of my specific strategy, but the objective was to measure the current and run the car at the same time, so I believe I would have unpinned fuel pump circuit at the socket of my extender, to insert the ammeter. I used this meter. Its leads are directly terminated with 1/4" fastons - the alligator clips are convenience items.
Even so, the "fluctuation" I mention was intermittent. Sometimes I had steady, but low readings, as you can imagine might happen with a flaky electrical contact passing current.
In general, a bog is consistent with very lean mixture, a condition that could just as easily arise from unmeasured air (vacuum leak) as from low fuel pressure. AMM failures present the same way (unmeasured air).
Do the easiest things. If you have a spare MAP sensor, it is even easier than swapping an AMM. If you can put a tire gauge on the fuel rail without setting the neighborhood on fire...
--
Art Benstein near Baltimore
"Body work is just like drywall. Frame it right, hang it right, use less mud. Don't paint until its perfect." -AB
|
|
-
|
|
|
"Any ideas welcome"
Well......my idea would be to check all of the vacuum lines on the engine and also look at the big bellows that feeds the air into the intake....look for holes.
As always.....look for the simple things first.
Just a few ideas
steve
|
|
-
|
|
|
"I'm measuring 3.8A at fuse 11. Is this a good reading?"
I'd say no -- my new pump measured about 7.2A. And that's with the Fuel relay on an extender (below) which probably added a bit of resistance).
P.S. I'm away till Sunday PM. Good luck with it.
|
|
-
|
|
|
Hi Al:
If the fuel pump doesn't turn out to be the culprit, perhaps the throttle position sensor (TPS) is at fault. I am not certain that this can cause hesitation on a Regina car but it may be worth a look.
Just a thought - good luck with your search.
Andrew S.
'91 744 Regina
|
|
|
|
|
