Question about 1991 Volvo 240

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ECU appears to be dead

My 91 volvo240 has just failed on me. The coil and injectors are not being pulsed. The engine turns on cranking and the TDC sensor pulses so I assume the signal is getting to the ECU.
The diagnostic plug unit lights when you press the button but displays no codes. I get no response and all the fuse board fuses are OK.

Any ideas on how to confirm this before I commit to an expensive repair?

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About a year or so ago, my 1991 240 Volvo was experiencing similar symptoms. Has this been an intermittent problem? (Sometimes starts, sometimes not?)
I looked at my fuses, especially fuse #6 which powers my fuel injector relay. With a friend, who is a professional mechanic, we determined fuel was getting to the injectors, but my coil spark was weak and injectors were not being pulsed. I wasted 300 dollars having the injector relay replaced, by another mechanic. Two weeks later, my car failed once again to start! It turned out to be a pitted connection at fuse #6! I inially just looked at the fuses, which were not blown, but when I took #6 out, it and the associated connector were pitted. Burnishing the connector and replacing #6 fuse has corrected this issue! If you haven't, pull your fuses, and inspect and clean the contacts! Maybe it's just that simple. Good Luck!!

Posted on Dec 19, 2008

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2006 wrangler x no pulse on injector #3&4, others are fine. (name them? all?)


Cud b voltage issue. Unplug them and clean contacts. Also u cud unplug computr and clean pins . Older cars have corrosion

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1993 Geo tracker fuel injector is not working right. i have to pour fuel into it. any suggestions on what i should do?


Important to know if it's not working at all, or if it is working some, just not enough? If not at all, then you need to check the injector wiring circuit, it's pretty simple really, just a hot wire with key on, and a ground wire that goes into the engine computer. Test with a voltmeter, best practice.

You should probably first check fuel pressure. The injector won't work unless the fuel pressure inside it is at the specified pressure. If the fuel pressure is too low, you have a bad fuel pump or a clogged fuel filter. If the fuel pressure is correct, you could have a clogged injector. The best way to clean that is with the injector off the engine.

Dec 09, 2015 | Geo Cars & Trucks

1 Answer

2011 swift 1.5 no injector pulse no spark


blown fuse. ; is first, as per always.
2nd is scan it, did you scan it yet? that is always 2nd.
all efi engines, all ECU , all cut injectors for (noid lamp test dead?)
you said pulse,does that mean fuel pulse or electronic pulse to injector coil..... ? all injectors dead. or just 1. same for spark.
toss coin land, noid dead. all noids
loss of. NOID signals.!
1; spark
2: lose of CMP or CKP signals (cam or crank senders)
3: ecu sees wide open throttle it cuts fuel 100%
4: ecu bad, is CEL lamp dead key on? scan it.

Apr 01, 2015 | Suzuki Swift Cars & Trucks

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What will shut down the coil pulse from ecu but still have injector pulse,idle control module ??


Don't dismiss the coil pack completely. The hi voltage side of the pack is what usually fails.

Dec 14, 2014 | 2006 Hyundai Getz 1.6

1 Answer

Injector not fireing


you have a TBI 8valve engine. just like my 91
the injector , not firing, so by guy method.
1: it dont click? (sonic ,stethoscope)
2: the noid dont flash. (use a noid lamp and win)
3: it dont squirte, watching it with eyes, cranking,

if the noid fails, that means ECU is bad or one of 3 inputs to ECU are dead.
if noid works, that means, the injector is cogged, it has 10 micron screens that are easy to clean. or there is no 35 PSI fuel pressure.

here is the page just for that.
  1. THE ECU IS PROGRAMMED to cut fuel if there is no spark preventing TV like crashes and burns. (and other fire reasons)
  2. the tests are all easy. no order but #1 is #1
  3. fuel pressure at spec.
  4. injector coil reads 1.0 OHMS.
  5. injector clean. (there is only one, so all hope is just here)
  6. noid lamp fails , so is CMP dead? or TPS TP pin stuck high or , ecu throwing code 41./42s errors, BINGO!

http://www.fixkick.com/INJECTORS/injectors.html

or no starts

http://www.fixkick.com/INJECTORS/injectors.html

May 06, 2014 | 1992 Geo Tracker

1 Answer

1994 Geo Metro will not start


all spark plugs dead. and at the main coil?
in this case after fuse (test them , ones that look good can be bad)
these steps work or all EFI cars made.
first is the rotor spinning cranking, if not the cam belt snapped!
a 1 second check, do you try to run 60k mile belts 200k ?


  1. CEL lamp on? key on? no crank? y/n,, if no the ECU is dead. or lamp burned out, we fix this FIRST. for next tests.
  2. I insert the diagnostic jumper clip (paper clip)
  3. the CEL now flashes codes, write them all down.
  4. I then crank for 5 seconds. and release the key.
  5. The ECU then reports live codes. beyond above stored codes.
  6. The ECU is very good at finding bad crank or cam sensors dead or even missing pulses, 1 in 10 lost. trust it, on all cars ......
  7. if no sensor code errors or spark bad errors then do the next things.
  8. The ecu also reads back the Tacho signal and will report dead tacho, sig, the ECU creates this and is the COIL drive signal to the ignition coil via the IGNITOR device.
  9. If the ignitor dies, or the coil primary opens, (dead Ign.coil) then the ECU see this and gives you Spark fail codes, cranking only!
  10. if you get far with a dead ignition coil, the ignitor is bad or the coil assuming coil even has power 12vcd key on.
this is all in the FSM, if you read it.
as is the Ignitior tests, and the coil tests.
The FSM is an amazing thing if your read it.
buy one.

ECU = engine brain, or EFI brain
EFI = eletronic fuel injection
CEL is the check engine light also called SES or MIL.
your ECU is OBD1 and no scan tool works .
only the winky blinky light.

Mar 04, 2014 | 1994 Geo Metro

1 Answer

Autoshutdown keeps turning on


which engine???????????????????????????
ASD is tricky on jeeps.
The Auto shutdown,relay.
what is it , how does it works is covered in the fsm. read it.
http://www.jeep4x4center.com/knowledge-base/index.htm?utm_source=cj#service
The ECU runs this RELAY, and if the ECU sees a gross error
it shuts this down, and the schematic there is clear as to what.
both spark and fueling.
here is what can drop it out.
1: crank sensor.
2: cam sensors or TDC ,etc.
3: sees spark dead or weak.
4: Immobilizer active. (failed)

as the book says , make sure spark is good for the 2 seconds cranking. (not after the 2seconds)
the ECU is programmed like this.
user cranks.
ECU creates spark,, using the crank/cam sensors at the time base
for 2 seconds
if the spark read back fails or the 2 sensors fail, the ecu shuts DOWN.
this is for fire prevention.
most other cars just cut the injectors, but not jeep
the drop the MAIN ASD relay.

using the check engine light flash codes, you can see which of the
3 failed, cranking for 5 second and releasing the key on all cars.
1996 and newer a scan tool is use to same effects.

now the 64,000 dollar qustion,
see page 8w-30-4
why does the ASD KILL THE IGNITION coil. easy.
1: it only guess it 2 seconds to make spark
2: if it cant,. it then drops the relay. killing fuel too.
3: this prevents the the crash and burn you see on TV.

so its 2 second permissive system. (or 3?) i forget exact seconds, its in then book and is short.
many dont know this. but is a fact.


now the flash codes.
crank for 5 seconds while in flash code mode
see emmisions page for how.

flash code 11 drops the ASD ! (cam or crank sensor dead)
code 54 cam signal dead?
code 43, spark bad.

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1 Answer

Jaguar xj sport 3.2 no spark or injector pulse


If ECU has crank signal and engine turns over, ECU should give injectors a pulse and trigger the ignition. If not ECU might be bad. You should check power and grounds going to ECU. There are usually multiple power and grounds going into ECU

Jan 06, 2014 | Cars & Trucks

1 Answer

Suzuki wagon r wont start


all fuses good, using ohm meter tests in hand. or better
12v on both ends of fuse key on?
K12a, 16valves, DOHC, chain cam motor.)
well you are on track, no spark, that be real. huh>
the immo (slang for UK immobilizer) for other readers.
so not TDC codes, but that is not all there is, you can attach
a scan tool and see if you have CMP/CKP sigs, and RPM cranking.
crank for 5 seconds to see if these critical to spark parts are in fact working.
single distrib? (the 2 forms of k12a ) a= real japan engine not china.
new cap, new rotor, , no china rotors that mount backwards allowed.?
do you have schematic of your engine EFI?
you really need that, or finding problems can be very hard.
in usa we have 3 major sources here , all on line, to get that fast.
do you? have that in UK? do you have a suz, dealer? with shop man?
we have mitchells,alldata, and chiltons all on line for this.
we also have the for free in public libs here...
diagnosis. (ill assume its flooding) prevents fire and ring damage.
1: i cut the fuel pump by pulling FP relay.
2: then check spark,,if spark is bad to all 4 spark plugs, that's right 4.
then check spark directly at the COIL, some cars have hidden coil.and can be checked, ask.
if spark is bad at coil, HV terminal. then check for Ignitor drive
pulses. if good then coils is bad. (good input, bad output, bad coil)
if the ignitor is dead, check its input, if input bad , ECU is not
sending inputs. this can happen for only few reasons. in no order.
1: bad ecu
2: no cmp or ckp signals.
3: lost power to ECU, fuses,
IF car has dash tachometer, is it dead, cranking , no 300 rpm cranking?
scan too.
RPM dead. cranking.
no CMP /CKP errors cranking from ECU DTC, ERRORS ON SAME.?
That is how i do this, and never fail.
better is:
1: compression good?
2: spark good and timed
3: good fueling?
you fail #2 (lets work that)

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1 Answer

1999 volkswagon jetta v6 cranks but wont start


I'm having a similar issue with my '97 Golf K2 with a 2.0 I checked the resistance to the crank sensor and it was almost 900ohms with the replacement one being 500 ohms. Changed it, didn't work.


Mine was running fine driving 70MPH on the highway and just shut off. Now it cranks, fuel pump runs and it seems to be getting fuel but still no spark. I have a coil/module on order and will try it tomorrow.


UPDATE

Replaced the coil. Coil sparks once when you first turn the key on, that's it. crank sensor has already been replaced yesterday.
Injectors seem to fire (I smell fuel if I crank it a while) but still no spark.
I have 12V to the coil and 12V when cranking.

I see tons of posts with this issue but no resolutions. Come on somebody has to have been here before....

UPDATE #2

I do NOT have an injector pulse or a pulsed signal to the coil. When I crank the car the oil pressure light blinks on and off (just noticed this not sure if it is relevant)

I do get a check engine light when I turn the key on and when cranking, thought this meant ECU was good?

Any other way to test the ECU?

Could the pick up in the distributor be bad? Doesn't the pick up signal the ECU to fire the coil and injectors, I thought the crank sensor was just a TDC reference point?

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Mar 15, 2013 | Cars & Trucks

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