|
|
1998 jeep 4.0 turns over strong will not start
|
|
|
| |
|
|
multicore911
User
Dec 3, 2010, 5:22 PM
Post #1 of 18
(5372 views)
|
|
1998 jeep 4.0 turns over strong will not start
|
Sign In
|
|
no spark crank sensor replaced did run for a couple of weeks when running shes smooth as silk. im leaning to the ignition pickup wanted some advice please. seems to be intermitant i drove it home after sitting overnight. started and ran throughout the day, after temp outside dropped below 40 degrees started all over again turns over strong wont start no spark. seems to be getting fuel though. coil tested fine, new wires new plugs cap and rotor 1 year old, brand new optima gell cell batt. also k and n filter (filter only) 6 months old any info would greatly be appreciated =)
thanks,
jonathan
pewee valley, ky
|
|
| |
|
|
Sidom
Veteran
/ Moderator
Dec 3, 2010, 8:24 PM
Post #2 of 18
(5362 views)
|
|
Re: 1998 jeep 4.0 turns over strong will not start
|
Sign In
|
|
The thing with intermittents is parts have to be tested during the problem & on the car.
The only real accurate way to test the pick up would be with a scope. What you could do would be to backprobe the signal wire and check it with voltmeter, while cranking the reading should be jumping up and down between 0 & 5v, if it is while it's not 100% it does mean there is some kind of signal happening. You'll have to check a wiring diagram but I believe the signal wire is the gray one, it might have a black tracer on it. (my memory sux & I'm away from my database)
Also check for power at the coil & PCM. Wiggle the connecters on the PCM to see if that makes a difference especially the connector on the left (as you're looking at it). Try swapping the ASD relay. Test all the fuses with an ohm meter or test light.
With a no spark you have to find out what part is losing power or what sensor has a bad signal.....guessing can get expensive & frustrating...
(This post was edited by Sidom on Dec 3, 2010, 8:25 PM)
|
|
| |
|
|
multicore911
User
Dec 4, 2010, 10:27 AM
Post #3 of 18
(5352 views)
|
|
Re: 1998 jeep 4.0 turns over strong will not start
|
Sign In
|
|
ok im down to the pcm thats the large panel on the drivers side firewall? theres 3 harness pig tails that plug in? where or wich wire should be checked? i am going to replace the ignition module since its cheap $60 as i should have anyway while doing the crank sensor plus 195 thousand miles aint help n me any. she may go to the scales before its all over. thank you so much for your help sir your a great asset here i want you to know that.
jonathan
pewee valley, ky
(This post was edited by multicore911 on Dec 4, 2010, 12:05 PM)
|
|
| |
|
|
Hammer Time
Ultimate Carjunky
/ Moderator
Dec 4, 2010, 4:18 PM
Post #4 of 18
(5347 views)
|
|
Re: 1998 jeep 4.0 turns over strong will not start
|
Sign In
|
|
And why are you down to the PCM. What have you done that would indicate a bad PCM?
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
We offer help in answering questions, clarifying things or giving advice but we are not a substitute for an on-site inspection by a professional.
|
|
| |
|
|
multicore911
User
Dec 4, 2010, 10:58 PM
Post #5 of 18
(5339 views)
|
|
Re: 1998 jeep 4.0 turns over strong will not start
|
Sign In
|
|
i guess it wont matter much till i can get some help knowone here at my house wants to lend a hand it seems and no money for parts. checked the crank sensor today laying in the snow god i love that. all seems well its buttoned up snug no gaps still brand new. guess i will chance it and put on the ignition pickup module any guidence there? the distributor has to come out right?
thanks,
jonathan
|
|
| |
|
|
Sidom
Veteran
/ Moderator
Dec 5, 2010, 11:47 AM
Post #6 of 18
(5334 views)
|
|
Re: 1998 jeep 4.0 turns over strong will not start
|
Sign In
|
|
I'm guessing you are talking about the pickup coil (cmp sensor) when you say module. This has no ign control module. It's possible it might be bad.
Did you check it like I told you to? This is easy to do, just back probe (push a paper clip under the weather packing on the back of the connector) the connector and hook a voltmeter to it on the 20v scale, crank the engine and look for a volt reading jumping around between 5 & 0v. This is the gray/black wire on the connector.
Check all the fuses in the fuse box, it could simply be just a blown fuse.
Then check power at the PCM and grounds. You should have power on pin #2 & 22 of connector C1 (black) and pin #12 connector C3 (gray).
Pin#3-C3 is the ground control for the ASD relay.
The PCM grounds are #31 & 32-C1
Also check power,ground & control of the ASD relay....this should help...
(This post was edited by Sidom on Dec 5, 2010, 11:50 AM)
|
|
| |
|
|
multicore911
User
Dec 5, 2010, 11:59 AM
Post #7 of 18
(5325 views)
|
|
Re: 1998 jeep 4.0 turns over strong will not start
|
Sign In
|
|
yea i will break out the meter and test tomorrow gotta work today till midnight. yes the pickup coil will be my next adventure i will test it first see what i get voltage wise. since the car does run well when it starts will that rule out the pcm as an issue? also any tricks to the pickup install it says distributor must come out.
thanks for your help,
jonathan
pewee valley, ky
|
|
| |
|
|
multicore911
User
Dec 12, 2010, 5:34 PM
Post #8 of 18
(5307 views)
|
Re: 1998 jeep 4.0 turns over strong will not start
|
Sign In
|
|
i tested the ignition pickup like you said with paper clip into housing i only got 0.0 to 0.5 volts. i replaced it tonight but no luck still. i had a thought about the crank sensor i replace about a month ago. when i replaced it i noticed a difference the old sensor had a backing of some sort like a piece of film that held something on. the new one had nothing like that on top of sensor? if a small piece was to have come of the old one could it be blocking this crank sensor or cause a problem? is there a gasket or anything like that i didnt have one on the sensor of any kind. is there a way you could get me a parts breakdown of that area if possible and of that sensor assembly?
thank you,
jonathan
|
|
| |
|
|
Sidom
Veteran
/ Moderator
Dec 13, 2010, 12:26 AM
Post #9 of 18
(5302 views)
|
|
Re: 1998 jeep 4.0 turns over strong will not start
|
Sign In
|
|
Just make sure you are getting a good connection when you backprobe, you can feel the probe (paper clip) when it hits the connector on the inside. Also try switching to the 10v scale and see if that makes a difference.
The paper on the bottom of the ckp sensor it just for setting the air gap. The older one would have it but I've noticed the newer ones don't any more and the mounting bolt hole is tighter. I haven't had any issues to day with installing them with out the paper shim.
You should check your 5v ref supply to both sensors and check the grounds as well. When checking the grounds be double, triple sure of which wire you are working with. PCMs don't like current and if you get the ref line by mistake when checking the ground you could damage your PCM.
I don't recall if there were any codes set. If you don't have a reader, just turn the key from the off position all the way to the on (without cranking the engine) 3 times (going all the way back to off) and if there is any codes, they will show in the odometer. If there are no codes and you did this right it will say "done"
|
|
| |
|
|
multicore911
User
Dec 14, 2010, 4:12 PM
Post #10 of 18
(5293 views)
|
Re: 1998 jeep 4.0 turns over strong will not start
|
Sign In
|
|
worked on it some tonight couldent get any codes in the odometer i followed your directions and tried fast slow medium really fast really slow and made sure it was starting out at off and to on but not engage the starter. no luck at all is it three times then back on to view or 3 times and stopping at off as normal? also all fuses check out whats the best way to check the relays?
thanks,
jonathan
(This post was edited by multicore911 on Dec 14, 2010, 7:28 PM)
|
|
| |
|
|
multicore911
User
Dec 18, 2010, 11:30 AM
Post #11 of 18
(5277 views)
|
|
Re: 1998 jeep 4.0 turns over strong will not start
|
Sign In
|
|
code reader shows camshaft sensor? not sure where it is knowone lists one on here. i read that its under the distributor? as i said i replaced the pickup already. any thoughts ?
jonathan
|
|
| |
|
|
Jeff Norfolk
Enthusiast
Dec 18, 2010, 12:16 PM
Post #12 of 18
(5274 views)
|
|
Re: 1998 jeep 4.0 turns over strong will not start
|
Sign In
|
|
Yep part of the distributor I believe. What is the code exactly? Crank sensor failiure is way more common on these.
Jeff
|
|
| |
|
|
Sidom
Veteran
/ Moderator
Dec 18, 2010, 12:21 PM
Post #13 of 18
(5273 views)
|
|
Re: 1998 jeep 4.0 turns over strong will not start
|
Sign In
|
|
A specific code # would help, like a P0340 or what ever it is. You have to understand that codes aren't telling you want part is bad, just what circuit is being affect.
I've posted schematics and what to check 1st. Once again you need to check your 5v ref, ground and signal wire. On both the cam and crank. The cmp sensor is in the dist the ckp sensor is in the bell housing on the the back of the engine on the drivers side but the connector should be on the passenger side below # 5 & 6.
Some of this stuff you can check with a voltmeter other things you really need a scope.
I'm not really sure at this point if you are checking and doing everything I have been suggesting........ I really hope you've already check the fuses and other basics I previously suggested....
|
|
| |
|
|
multicore911
User
Dec 18, 2010, 11:28 PM
Post #14 of 18
(5267 views)
|
|
Re: 1998 jeep 4.0 turns over strong will not start
|
Sign In
|
|
today after the camshaft sensor code unknown on the number i checked the harness coming from the pickup outside of the distributor and the jeep fired right up drove it around the block, shut it off. started fine! 2nd time drove it to work shut it off, sat for 8 hours. started fine 3rd time drove it a few miles on interstate no problems there. shut it off and when i went into the gas station for 5 mins came out would not start. i pushed the CMP connector and it started. the pig tail from the CMP is very hard to get together for some reason just friction it all lines up. tomorrow im going to un hook it and try some dielectric grease around the inside mate surfaces see if that will help me get it seated better.
wild card here: do you all think the coolant temperature sensor could do any of this?
yes i have checked everything just as you asked me to. MINUS the ECM due to not wanting to f anything up and MINUS the CKP since i changed it as a new part a month ago. i really am glad you all have helped me thus far and i know that a tech needs to see what there working on and more so even in this kind of deal. the weather has been in single digits and ice and snow so its very slow going. i will check back later today with an update.
thank you,
jonathan
|
|
| |
|
|
Tom Greenleaf
Ultimate Carjunky
/ Moderator
Dec 19, 2010, 9:36 AM
Post #15 of 18
(5259 views)
|
|
Re: 1998 jeep 4.0 turns over strong will not start
|
Sign In
|
|
jonathan:
TMK the coolant temp sensor wouldn't stop spark but rather tells how much fuel to deliver based on actual engine temp.
Intermittent crap really stinks. You said pushing on a connector allowed it to start! Does touching that while it's working kill the engine?
Suggestion - keep battery charged up. Easy on starter with any testing or add that the troubles.
Good luck,
T
|
|
| |
|
|
multicore911
User
Dec 19, 2010, 10:35 AM
Post #16 of 18
(5252 views)
|
|
Re: 1998 jeep 4.0 turns over strong will not start
|
Sign In
|
|
thanks for everyones help i put some dielectric grease on that connector it slid in and clicked all systems are go. that connector was so tight that even after pushing fairly hard last time and thinking it was in, it still was not connected fully. and it cant be be out even a smidge or wont start right i guess the engine heat and cold expands and contracts. should be good from here thanks to everyone for your help. u do a great thing by vol your time here. egg nog on me happy holidays!
jonathan
louisville, ky
|
|
| |
|
|
Sidom
Veteran
/ Moderator
Dec 19, 2010, 11:00 AM
Post #17 of 18
(5251 views)
|
|
Re: 1998 jeep 4.0 turns over strong will not start
|
Sign In
|
|
I'm glad to hear you got it going. looks like persistence paid off.
With connectors sometimes the pins get weak and don't make good contact. If I remember right that is more of a "bullet (round)" type connector which is actually better for holding it's tightness. Still if you keep having trouble I would be tempted to change out the connector.
It's hard to find OE harness connector (unless RT wants to help ya out  ) so you may have to go to the wrecking yard. It's critical that it's sealed properly. uninsulated butt connectors and heat shrink tubing for the harness, leave nothing exposed. Under no circumstance should you use scotch loks or the butt connectors with plastic on them (blue & red ones) that is guaranteeing problems down the road...
|
|
| |
|
|
multicore911
User
Dec 19, 2010, 11:49 AM
Post #18 of 18
(5247 views)
|
|
Re: 1998 jeep 4.0 turns over strong will not start
|
Sign In
|
|
cool, good to know on the connector and wiring. yes persistant you are but its a real good thing keeps people motivated. i looked around on here some people need the help way worse than me so i am glad to be off the list. you all get back to it. talk at ya later fun i hope not business
|
|
| |
|
Auto Repair Home
SEARCH
WHO'S 
LOG 
mdma pills for sale : WhatsApp +33758633852
Drive Shaft Repair
2006 Toyoto Camry XLE Driver Side Electric Window Trouble
equipment
