Question about BMW 325

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Bmw 1988 325 no power to fuel pump and no spark verified fuel pump relay good but ground from mcu cuts off when ignition is turn to start.

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PROBLEM COULD BE IN THE MOTRONIC CONTROL UNIT.WHEN IT MALFUNCTION IT HAS TO BE REPLACED.

Posted on Sep 12, 2009

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I've got a 2005 chrysler 300 and it won't start I have changed fuel pump, camshaft and the crankshaft sensor coils and spark plugs and i still wont start what could be causing it not to start?


Try to determine if it is fuel or ignition related.
Turn key to on, do you hear the fuel pump turn on for a couple of seconds? It should come on briefly to pressurize the lines and fuel rail on the engine. Do you have fuel at the engine under pressure? Easiest and preferred way is to check fuel pressure with a pressure gauge at the test port on the fuel rail. With key on, pressure on mpfi systems should be 40-50 psi.
If there is gas in the fuel rail, test ignition by checking for spark on the end of a plug wire, with the engine cranking over. If you have a blue snapping spark, then ignition is probably good-may want to check more than one plug wire. Hold the metal terminal end of plug wire 1/4 inch from a ground on the engine, the engine block or a bolt or metal bracket. Verify a blue snapping spark, repeatedly, as the engine cranks. An orange spark, intermittent spark, or no spark points to an ignition problem. One thing you haven't changed is the ignition control module. This module, when signaled by the pcm, is what cuts the primary current to the coils for spark to be generated.

If you have both gas and spark, check the fuel injector circuit. Post back if you need help with that. There should be an injector fuse that needs checked. Also a fuse for the fuel pump, if no pump action, besides the fuel pump relay.

Apr 04, 2014 | 2005 Chrysler 300

1 Answer

1988 Ford Ranger 2.9L A/T, 2wd, A/C. Won't Start. Fuel pump does not come on. Scan tool cannot connect to the ECM. Verified Fuel pump Relay good. Ground to STO Fuel pump pin will engage the fuel...


The engine computer must be working to get spark and fuel injector pulse. I would want to know if the computer has power and is functional. The computer grounds the EEC relay and the fuel pump relay as well as the injectors.

Aug 26, 2013 | 1988 Ford Ranger

1 Answer

99 dodge durango


Could be a problem in the ignition circuit. Check or test coil and ignition module-one of them may be shutting down or shorting out when they get hot.
Verify by checking for spark at a plug wire immediately after it shuts off: if no spark, it is an ignition problem. Besides the coil and ignition module, other possibilities are the crank position sensor, cam position sensor, ecu, the ASD relay (automatic shuit down relay-it's in the power distribution box under hood). If that relay fails, all power is cut to coil and fuel injectors, and maybe the fuel pump also.
Good luck.

Dec 20, 2012 | 1994 Oldsmobile 88

1 Answer

2003 Galant fuel pump ground problem


Power to the pump is provided by the relay for the first 3 or 5 seconds to build pressure back up to start. Once the 5 seconds are past, the relay is grounded by the computer IF it sees oil pressure or crank signals. This helps prevent a fire if the car is in a wreck.
If it still won't start with the pump relay bypassed, you would check for spark and see if the computer is getting a crank signal.

Aug 26, 2012 | 2003 Mitsubishi Galant

1 Answer

Fuel pump cuts in but car wont start


If you have to force the fuel pump on by the relay who is controling ignition? The fuel pump will come on thru the main relay which is next to the fuel pump relay this controls ignition,go back to the begining,on one of the coil leave a 1/4 between the sparkplugwire and the coil crank the engine there should be spark is there is no spark correct for spark and fuel will return when the ECM see a valid RPM signal.so test for spark first. The Main relay is what needs to be look at

Mar 20, 2012 | Cars & Trucks

1 Answer

Car is 00 skoda octavia 1.9 tdi when i turn on ignition the heater plug indicator light does not come on on full turn engine turns over as normal but will not start no error shown on diagnostics on further...


Hi,

I apologize for a delayed response as i was not at my desk.

Check to see if the fuel pump relay clicks when you turn the key on. If it doesnt click verify one terminal has constant ground if not you will need to run a new ground wire. If ground is good access pin 46 on connector 1 of the pcm to check for voltage if no voltage replace pcm if it has voltage replace green/white wire between pcm and relay. You can also first try to swap the relay with another one to see if that helps. If relay clicks then check the 15 amp fuel pump fuse and if blown replace. If fuse is good verify one terminal on the relay has voltage at all times and gray wire has voltage leaving relay when key is in crank position for for a few seconds when turned into on position. If gray wire leaving relay has voltage but not gray wire at fuel pump replace the wire.

Let me know,once you check the above.

Thanks and Regards
taran_2005

Nov 13, 2011 | Cars & Trucks

3 Answers

1989 astro van turns over will not start seems not getting fuil gas tank full


#1 NEED TO VERIFY SPARK AT SPARK PLUGS # 2 CK FUEL PRESSURE AT SCHRADER VALVE ON FUEL RAIL ,,PRESSURE DEPENDS ON TYPE ENGINE ....IF NO SPARK AT SPARK PLUGS CHECK SPARK FROM COIL WIRE , IF NO SPARK AT COIL ,CHECK VOLTAGE TO IGNITION COIL SHOULD BE 12 VOLTS, IF NO VOLTAGE AT COIL ( KEY ON ) CHECK FUSES THEN IGHITION SWITCH. IF NO FUEL PRESSURE AND FUEL PUMP RUNS REPLACE PUMP .. CK VOLTAGE TO FUEL PUMP WHILE CRANKING . CK USING PUMP GROUND WIRE AT THE PUMP CONNECTOR THIS WILL PROVE GROUND ALSO. USE TEST LIGHT TO VERIFY

Aug 07, 2010 | 1989 Chevrolet Astro Cargo

2 Answers

My car wont start


a) Do you have crank no start? (see entire write up)
b)No crank no start ,No dash lights?, ( battery, battery cables, ignition switch,,starter relay)

If you have symptom A then the affected items are , ignition switch, battery, battery cables, starter, starter relay ,coil, coil pack, ignition module ,Distributor cap ,rotor, (if applicable) spark plugs and wires.
The best thing to do is to first make sure your timing belt didn't break. As long as the engine cranks you can do this. Give the battery a 3 min charge . Then have a helper crank the vehicle while you observe the rotation of all the pulley's and belts. They must rotate together. If the vehicle has a distributor remove the cap, ground the coil wire and remove fuel pump relay ( to disconnect the pump for testing)and watch the rotor as the engine is cranked. it should spin. If this is a-ok your worse nightmare is over.
Now we have eliminated the timing belt as being a cause. We now have to charged the battery again for three min and load test it( this is best done by a repair shop a load tester is expensive .If the battery if more than 5yrs old you may want to replace it.
If battery does not pass load test replace it.
Whatever you decide the rest of the items can NOT be checked out without a fully charged battery.
Check ignition switch and starter relay for B+ going to them and leaving them. Check starter circuit. Make sure B+ is making it to starter ( use a digital voltmeter). If B+ (12 volts) is making it to the starter and it doesn't crank then the starter is defective. Verify this by removing the starter and have it bench tested.
If starter cranks now your into coil testing . First thing reconnect the distributor.
Pull a spark plug, hook it up to a spark tester and ground it, now crank the engine if you get spark coil is ok and in all likelihood so is module.
If you don't get spark test for spark at the coil wire.
If you get spark here and don't get it at the spark plug wire problem is at distributor cap , rotor or spark plug wire. If plugs look bad use a fresh plug to do testing and naturally replace them.
If all of the above are a-ok.
Next is fuel checks. Reinstall fuel pump relay
Easiest fuel check is to put key into ignition cylinder and turn to on position. Lister for pump to buzz or hum. if it doesn't then check fuel pump relay for B+ going to it and leaving it and going to the pump. If B+ making it to pump and it doesn't turn on the pump is your problem. If B+ not making it to pump either the relay or the ignition switch is defective.
Naturally if the pump is defective have a repair shop do the repair . Its dangerous and a real pain.
Good Luck
Now the cutting out after running fora whilrcoild have caused by the coil, ignition module, fuel pump.
We kinda have to get the car to start first to be conclusiveas to why it cuts out.

May 20, 2010 | 1994 Buick Park Avenue

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