engine starts then it dies, mabe has somthing to do with anti theft alarm ?
Optional Information: 1993 Jeep grand cherokee 5.2Already Tried: hooked up my snap on scanner and ok to drive all sensers ok
What if you hold the gas pedal at 3/4 and crank, will it fire up and run?
How many miles are on this engine?
Any codes stored in memory?
Have you tried locking and unlocking the drivers door twice, with the Ignition key, to disarm the system?
-Rip
Reply to RIP's Post: I did the key in the door ,there is 144,000 miles on the motor.
Will the engine idle with the accelerator partially pressed?
How long do you estimate it fires for, is it just a second, or are you able to give it some gas?
Reply to RIP's Post: SORRY NO HELP
Sounds like you were looking for a magical answer? Unfortunalty, earnly Jeeps have a variety of faults which cause immediate stalls after firing, such as the CKP, PCM, Anti-theft, IAC, 5-volt Reference affecting CKP, CMP, VSS, and the famous fuel pump. All with different sysmptoms. So how am I supposed to know which one yours is, without asking questions? I hope you let your doctor ask you questions... You can relist for different opinon, or get your deposit refunded thru customer service. Thanks,
Reply to RIP's Post: ALL CODES CLEARED,Replaced map senser,throtle positioning senser,checked all fuses,New Batt, when it starts voltage meter go's up to 13.5 volts, checked all the relays,fuel presure is normal,it starts and 3 sec later it dies.
Thanks for the info. Will it immedialty restart, or does it need a cooldown period?
Have you been able to verify loss of spark (spark tester) or injection pulse (noid lamp) just shortly before it stalls?
When it does stall, does the Check Engine Lamp illuminate, as it should when the key is first turned On?
Do you know any history on the CMP (Camshaft) and CKP (Crankshaft) position sensors? These have an extermemly high failure rate, and often result in start and stalls or a no fire condition, at this milage it should have already been replaced at least once. Also, do you have access to a Vantage, or Lab Scope if it comes down to graphing the signals? On you Snap-On, does it show current CMP and CKP sync? If so monitor it just before the stall, if a second before one goes to "No," we'll know we're dealing with a possible faulty CKP. It's difficult to monitor sync on a condition which occurs so quickly, so this test may be inconclusive due to the slow transfer rate on the scan tool, but it may also show us an obvious sign.
Try spraying some Carburator cleaner into the intake, while an assistant fires it up, see if we can get it to momentarily run longer, verifying that this is fuel related.
Create a vacuum leak and see if it will idle than. Let me know the outcome of the tests and questions above, and we'll proceed from there. Thanks,
Experience: A.S.E. Master Technician, Advanced Level, Smog - European, Domestic, & Asian -- Car Category Mentor
Reply to RIP's Post: No loss of spark, I did spray carb cleaner and it ran until i stopped spraying,also i sync the scanner to graphing and could not find any problem,I dont think the ckp has ever been changed i think this is the next step,thanks for your help this is the first time that that i have used this site,thanks for your help.
So if it runs on carb cleaner, we know it's a fuel issue. But as you stated the pressure is Normal - correct? What about fuel flow, have you tested it? A faulty fuel pump or plugged filter can cause low flow. Also, we need to verify injector pulse with a noid lamp, while continuing to spray cleaner into the intake. If the noid lamp doesn't blink while the engine is running off the cleaner, we know it's a injector control issue. Don't replace the CKP just yet, it commonly causes a loss of spark, however the CMP and CKP circuit failing can cause a loss of injector pulse. A faulty PCM can also affect the injector pulsing, and the ASD (AutoShutdown Relay) can fail causing loss of power to the injectors. Let me know the outcome of the test.