Engine cranks but will not start?

Good evening,

Can you hear the pump run when you turn the key to on?

I attached a diagram for you. Can you check for power to the 2 wires I circled at the relay with the key on?

https://www.2carpros.com/articles/how-to-check-wiring

https://www.2carpros.com/articles/how-to-check-an-electrical-relay-and-wiring-control-circuit



Roy

While sitting in the vehicle I can’t hear it turn on. I will check on the wiring. I haven’t read a wiring diagram much at all. How do you know which wires to check based on where they are within the relay itself? If that is what you are wanting me to do.

If you hear it turning, then most likely it is getting power.

https://www.2carpros.com/articles/how-to-check-fuel-system-pressure-and-regulator

Most likely you will need to replace the pump.

https://www.2carpros.com/articles/how-to-replace-an-electric-fuel-pump

Roy

Engine cranks, but doesn't start. Battery and battery connection are good. Fuses and relays are good. Changed spark plugs, ignition wires, ignition coil, cap and rotor, fuel pump,and cps. The engine ran and i did a test drive. When i came back home the engine stop. And the same problem occurs. Could not start engine again. Found trouble codes 12 and 33.

If you have checked to see that it is getting fire, and it is, then may I suggest checking the fuel pump relay, this is located on the passenger side fender near the rear of the battery, there are two relays together I think the fuel pump relay is the one on the bottom, the other is the idle air control relay, it will not hurt if the idle air controle one is removed, I suggest you just switch them and it will tell you if that is the problem, if so you can get them for around 10-12 dollars and you will know which one it is, When you turn the key to the on position without cranking the engine over can you hear the fuel pump run in the tank for 5 seconds?

https://www.2carpros.com/articles/car-cranks-but-wont-start

Please run down this guide and report back.

thanks for the help. I did what you told and the same problem occurs. I double checked the ignition system and found out my ignition coil was not putting out its full capacity. i used a spark tester and saw spark, but it seem weak this time. I exchanged the bad coil with a new one and this time cleaned and check all my ground connections. Now, the engine running good. I'm assuming a defected part or a bad ground. Thanks again for the help. I appreciate it.

My car starts perfectly fine in the morning, but does not restart once even though the engine revolves fine but does not start.please advises

Disconnect a plug wire or 2 ground it to the engine and crank engine over-Do you have a snapping blue spark? if not troubleshoot the ignition system. If so check the fuel pressure, fuel pump might not be producing the correct fuel pressure.

Runs good while cold, but won't run when engine gets warmed up.

Good afternoon,

When it does not run, did you check for spark at the plugs?

https://www.2carpros.com/articles/how-to-test-an-ignition-system

Did you check the fuel pressure?

https://www.2carpros.com/articles/how-to-check-fuel-system-pressure-and-regulator

One of these will be missing. You can rent a pressure tester at a parts store.

https://www.2carpros.com/articles/car-cranks-but-wont-start

Roy

I hit a tree with my wrangler at about 15 mph. Had light front end damage. Engine cranks but will not fire. Is this vehicle equipped with a cut off switch for the fuel pump, in the event of a collision? If so is there a reset?? Thanks for any help!

Hey only
No inertia switch in that vehicle, sorry. I would recommend to check for spark and fuel pressure. Base further testing on what you find! Additionally, is there an alarm system in the vehicle possibly causing this? Let me know!

Chris

[quote:f2a5f5aff7="only1jp"]I hit a tree with my wrangler at about 15 mph. Had light front end damage. Engine cranks but will not fire. Is this vehicle equipped with a cut off switch for the fuel pump, in the event of a collision? If so is there a reset?? Thanks for any help![/quote:f2a5f5aff7]


If there's No spark and fuel pump don't come On-check your ASD relay thoroughly-comeback I still got some more to follow.

If this relay goes kaput-you're a sitting duck

HTH Good Luck comeback with the feedback.

[quote:3cb1340362="carundell"]Hey only
No inertia switch in that vehicle, sorry. I would recommend to check for spark and fuel pressure. Base further testing on what you find! Additionally, is there an alarm system in the vehicle possibly causing this? Let me know!

Chris[/quote:3cb1340362]

Yes I do have an alarm system, a Viper to be exact. Could this be disabling the fuel pump? Any ideas on how do I override it? Never have had a collision with the vehicle before, so not sure....... Thanks guys!

I need to know whether you have spark and the fuel pump comes On.

I do have a Viper alarm installed in this vehicle. Do you think it could be disabling the fuel pump? If so any ideas on how to reset it? Thanks guys!

[quote:7eb6a181d1="only1jp"]I do have a Viper alarm installed in this vehicle. Do you think it could be disabling the fuel pump? If so any ideas on how to reset it? Thanks guys![/quote:7eb6a181d1]

So much of electronic security/conveniences-get rid of the aftermarket stuff-remove all the wires attached to it and throw the remote away-its giving you problems now-someday out from no where it decides not to start. What's next-Tow truck

Do you hear the pump for 2sec when key is in On position

My jeep has a no start condition, engine cranks but no power to the coil and no check engine light. I have checked the fuses, electrical connectors and the ignition switch along with the auto shutdown relay. Any ideas before i spend the big bucks for the ECU?? Thanks

ENGINE SENSORS & SWITCHES SENSORS & SWITCHES Camshaft Position Sensor (Synchronization Signal Generator) 1. Use an analog voltmeter. DO NOT remove distributor connector from distributor. Insert voltmeter leads into backside of distributor wiring harness connector to make contact with terminals. Ensure that connector is not damaged when inserting test probes. 2. Insert positive voltmeter lead into synchronization signal output Tan/Yellow wire on Cherokee and Comanche (Gray/Black wire on Wrangler) at distributor wiring harness connector. 3. Insert negative voltmeter lead into ground Black/Blue wire (Brown/Red wire on Wrangler) at distributor wiring harness connector. Set voltmeter to 15-volt DC scale. 4. With distributor cap removed, manually rotate engine until pulse ring enters sync signal generator. Turn ignition switch to ON position. With pulse positioned in the sync generator, reading should be about 5 volts. 5. If no voltage is indicated, check voltmeter leads for good connections If connections are okay and there is still no voltage, check for voltage at Orange supply wire on Cherokee and Comanche (White/Black wire on Wrangler). 6. If no voltage is indicated at supply wire, remove engine controller and check voltage at pin No. 7. Engine controller is located on left side of engine compartment. If there is no voltage at engine controller, see appropriate synchronization sensor/circuit tests in the appropriate TESTS W/CODES article. 7. If voltage is indicated at engine controller pin No. 7, but not at supply wire, check continuity of supply wire between the distributor connector and the engine controller. If no continuity exists, repair wiring harness as necessary. 8. If supply wire is okay, check continuity between sync signal output wire at the distributor connector and pin No. 44 at engine controller. If no continuity exists, repair wiring harness as necessary. 9. If sync signal output wire is okay, check continuity between ground circuit wire at the distributor connector and ground. If no continuity exists, repair wiring harness as necessary. If ground wire is okay, go to next step. 10. While observing voltmeter, crank engine. Voltmeter needle should fluctuate from 0-5 volts while the engine is cranking. This verifies that stator in distributor is operating properly and that a sync (pulse) signal is being generated. If voltmeter does not fluctuate, replace synch sensor stator. Coolant Temperature Sensor 1. Disconnect coolant temperature sensor. Using a DVOM, check the sensor resistance. Resistance should be as specified in the COOLANT TEMP SENSOR & MANIFOLD AIR TEMP SENSOR RESISTANCE table. Replace sensor if necessary. 2. Check continuity between engine controller wiring harness terminal No. 2 and sensor connector terminal. Also check continuity between engine controller wiring harness terminal No. 4 and sensor connector terminal. Repair wiring if an open circuit is indicated. Crankshaft Position Sensor 1. Disconnect crankshaft position sensor. On Cherokee and Comanche, connect ohmmeter across sensor terminal "A" (Orange/Dark Blue wire) and terminal "B" (Black/Light Blue wire). On Wrangler, connect ohmmeter across sensor terminal "A" (Brown/Red wire) and terminal "B" (Red/Green wire). 2. Ohmmeter should read 125-275 ohms with engine hot. Replace sensor if reading is not as specified. Also see appropriate crankshaft position sensor tests in TESTS W/CODES article in this section. Manifold Absolute Pressure (MAP) Sensor 1. Inspect MAP sensor vacuum hose connections at throttle body and sensor. Replace or repair vacuum hose if necessary. 2. Turn ignition on, engine off. Using DVOM, check MAP sensor output voltage. On Cherokee and Comanche, connect DVOM to MAP sensor terminal "B" (Dark Green/Red wire). On Wrangler, connect DVOM to MAP sensor terminal "B" (Red/White wire). 3. Output voltage should be 4-5 volts. Voltage should drop to 1.5-2.1 volts with a hot engine operating in Neutral and at idle speed. Also check for output voltage at engine controller wiring harness terminal No. 1. If voltage is not as specified in step 2), repair wiring harness if necessary. 4. With ignition on, check MAP sensor supply voltage at sensor connector terminal "C" (Violet wire on Cherokee and Comanche or Brown/Yellow wire on Wrangler). Supply voltage should be 4.5-5.5 volts. Also check for supply voltage at engine controller wiring harness terminal No. 6. If supply voltage is not as specified, repair wiring harness if necessary. Check continuity of MAP sensor ground circuit at sensor connector terminal "A" (Black/Light Blue wire on Cherokee and Comanche or Brown/Red wire on Wrangler) and engine controller wiring harness terminal No. 4. Repair wiring harness if necessary. Check continuity of MAP sensor ground circuit at engine controller wiring harness terminal No. 4 and engine controller wiring harness terminal No. 11. If ohmmeter indicates an open circuit, go to next step. If ground connection is okay, replace the engine controller. Check for defective sensor ground connection. Connection is located on right side of engine block, at oil dipstick tube mounting block. Repair connection as necessary. Manifold Air Temperature (MAT) Sensor Disconnect coolant temperature sensor. Using a DVOM, check the sensor resistance. Resistance should be as specified in the COOLANT TEMP SENSOR & MANIFOLD AIR TEMP SENSOR RESISTANCE table. If resistance is not as specified, replace sensor. Check resistance between engine controller wiring harness terminal No. 21 and sensor connector terminal. Also check resistance between engine controller wiring harness terminal No. 4 and sensor connector terminal. Repair wiring if resistance is greater than 1 ohm. Oxygen (O2) Sensor (Heating Element) Disconnect oxygen sensor connector. Using an ohmmeter, check sensor heating element resistance. On Comanche and Cherokee, connect ohmmeter to Black/Tan and Dark Green/Black sensor wires. On Wrangler, connect ohmmeter to Black and Dark Green/Black sensor wires. Heating element resistance should be 5-7 ohms. Replace oxygen sensor if ohmmeter reads infinity. Park/Neutral Switch (AW-4 Auto. Trans.) Disconnect park/neutral switch. Ensure continuity exists between terminals "B" and "C" with transmission in Park or Neutral. See Fig. 1 . Ensure continuity exists between terminals "A" and "E" with transmission in Reverse. See Fig. 1 . Ensure continuity exists between terminals "A" and "G" with transmission in 3rd gear. Ensure continuity exists between terminals "A" and "H" with transmission in 1st or 2nd gear. See Fig. 1 . If switch fails continuity tests, replace park/neutral switch. 1: Testing Park/Neutral Switch Continuity (AW-4 Auto. Trans.) NOTE: If terminal No. 4 has a short circuit to 12 volts, correct this condition before replacing engine controller. If necessary, perform appropriate MAP sensor tests in TESTS W/CODES article in this section.Park/Neutral Switch (32RH Auto. Trans.) 1. Disconnect park/neutral switch. Check continuity between switch center terminal and transmission case. Continuity should exist only when transmission is in Park or Neutral. 2. Shift transmission into Reverse. Check continuity between the 2 outside terminals on switch. Continuity should exist only when transmission is in Reverse. Check continuity between each outer terminal and transmission case. 3. Continuity should not exist between either terminal and case while in Reverse. If switch continuity tests are okay, check gearshift adjustment or back-up light circuit. If switch fails continuity tests, replace park/neutral switch. Throttle Position Sensor (TPS) 1. Turn ignition on. Check TPS output voltage at sensor wiring harness center terminal. At idle, output voltage should be greater than 200 millivolts. 2. Gradually open throttle plate. Output voltage should gradually increase as throttle plate is opened. At wide open throttle, output voltage must be less than 4.8 volts. W/CODES article in this section. NOTE: Also see appropriate throttle position sensor tests in TESTS W/CODES article in this section.

my 91 jeep wrangler won't start

What is it doing cranking over and w/n start or just won't crank at all/nothing when you turn key to cranking position-let me know

These guides can help us

https://www.2carpros.com/articles/car-cranks-but-wont-start

Please run down these guides and report back.

it's cranking over but won't start,i repalced the battery,spark plugs and cables,distributer cap and button,and ignition coil.and still nothing.

i haven't tried testing the spark plug yet,so i just unplug one of the spark plug boots and hold it close to the engine block and have someone crank the engine and look and listen for spark and sound? i also bought an ignition control module but for the life of me can' t find it in the engine compartment to replace it.

I see Ras Hasn't found you again,

I will not attempt a Corporate takeover---I will just try to help you along to make up some idle time

This Site is being Re-Vamped as we communicate, things aren't working as they should, and its difficult to RE-LOCATE a post with a reply...especially for RAS!....He's probably got hundreds of answers to reply back to (I may have half-a-dozen, and its hard on me!)

If I am wrong about this, RAS might pop back in and correct me (so watch for that!)

With the Plug wire test--stick (wedge) a nail or like Object in the plugs boot opening sorta between the actual metal plug connector and the rubber (as if you are extending the metal slightly out of the boot. (Don't pokey a hole in your rubber boot!)

Hold this 3/16 from the engine block or similar metallic, grounded engine component....and roll the engine over a few times....while either you hold the wire with insulated pliers ETC----Or just let your Buddy hold it barehanded!, insure someone is watching for the QUALITY of the spark, being as RAS Described...your Pal may not see it, he may feel it!...But that will not tell you whether it was BLUE and SNAPPING!

OK, disregard the Buddy Boinking! Just kidding, no sense in him being mad at the both of us!

I did have my Sister do that once--she will not assist me in a car repair anymore!

The IGNITION MODULE IS PROBABLY IN YOUR DISTRIBUTOR

If the old one lays flat in there, with some sorta grease between it and the metal distributor housing----Thats how it DISSIPATES HEAT---this will extend its life too....so don't install it dry.

You can usually obtain that HEAT DISSIPATING Grease in sorta a small Condiment packet at the parts house without having to buy a big container!

YOUR TURN OR RASMATAZ's TURN

KEEP US POSTED on your progress

The Medic.....Merry Chrismas from "WILLY"

Engine Mechanical problem
1990 Jeep Wrangler

engine will turn over but will not start

Hope this late post helps. Not much info in your question but ill try and give you some help. Cranks ok but does not start.. First ensure you have fuel, On a 90 i believe you have a fuel rail and you can check vor pressure on the schrader valve, be careful its under pressure and will spray out whatch your eyes. If you have fuel then check for spark when cranking by using a spark tester or by holding a spark plug close to ground and observing the spark. Try this and get back to me and let me know. Thanks Curt