Jeep Grand Cherokee 95 Problems (Not Wanting to Start)

Why a new timing chain? Is it really a chain? Are the timing marks on cam and crank lined up?

Are both valves closed when the distributor rotor is aligned with #1 terminal?

Does it backfire? Are you a competent mechanic, or like me, a tinkerer?

the timing chain was bad and had to be replaced because it had been backfiring, so bad that it had blown the muffler apart. as far as the rest of your questions, the answer is yes. no it does not backfire now that i have worked on it. in fact it turns over just fine.yes i am a competent tinkerer.

Timing chains are good or they are bad, there is no in between. Meaning, if it runs the chain can be worn and still the engine will function ok. You will typically not see anything until it jumps a tooth and then its over, it will not run! It sounds to me that there is other items going on with the unit. You don't say what engine you have in the unit. The inline 6 is a good engine. the big V-6 not so good. I would look at the following items.

1. is the cam timing correct (from replacement).

2. Are the fuel injectors working (you will need node tester for this) I think if my memory severs me well, the injectors are of a all or none (my description) style like earlier GM's.

3. Fuel pressure

4. Cylinder compression (bent or burnt valve)

5. take to shop for proper dia.

Good Luck

You can try disconnecting again and re- connect the minus of the battery last. In neutral, switch on off 3 times (not the whole way to start) Check your codes again. I became member of alldata and there I found what to do. Your PCM might find its data back. Otherwise check for autocomputerexchange. They can help you.

Or go to a dealer to re-program your PCM. Need you engine type, year, odometer setting.

Check to see if the immobiliser has been activated, the same would happen if the radio was disconnected

the system see this as attempt to steal.

http://en.allexperts.com/q/Chrysler-Repair-807/Voyager-Immobiliser.htm

link taken from below link

http://www.google.co.uk/search?q=jeep+grand+cherokee+immobiliser&sourceid=ie7&rls=com.microsoft:en-gb:IE-SearchBox&ie=&oe=&rlz=1I7GGLT_en&redir_esc=&ei=B-nfTNnSAY-5hAfmgr25DQ

Hello.I monitor these threads intermittently and i am accustomed to seeing problems solved quickly due to the high level of experience and knowledge of the paticipants.I do not as yet see a reply that you have solved the problem.If i am reading your words correctly,the vehicle started and ran before you worked on it,but now it turns over but will not start.This usually indicates that the work you have done is in error,most likely not getting the timing marks lined up correctly.Another thing is your question on the computer's memory.Disconnecting the battery will clear the codes out of memory on most computers and clear adaptive strategy which is learned through driving but will not prevent it from starting.Backfiring can be the result of timing but not neccessarily the chain.A rule of thumb i use is to rock the crankshaft for freeplay in the chain and if it exceeds 12 degrees i replace.If your distributor runs off the camshaft checking valve and distributor position will not tell you if the chain is lined up properly.Hope this helps.

the jeep that i am working on is a 5.2 lt. or a 318 cubic in. if you prefer. the jeep had stopped running as a result of the backfiring, after which i first checked for spark, all was good there, compression checked out pretty close to specks in chiltons repair manual. i then decided to look at the distributor, but the distributor can not be moved in any way, because of factory preset notch built into the hold-down fork, which prevents the distributor from being moved. i then went to the timing chain, took everything apart, and sure enough the timing chain was the problem,the chain had more than 2 in. of deflection on one side, and the other side was tight. after removing the chain and replacing with new set, that brings me to wondering how to test or to find out if something is going on with the pcm. i have done everything i can think of, except for throwing holy water on it, and i am starting to run out of foul words to yell at it.

Did you have to remove the distributor when changing the timing chain? Could it have been replaced incorrectly?

Hi,

Tinkerers can get themselves in a lot of trouble if they don't stick to the basics and get a book on thier vehicle. Take a digital picture of everything before you touch it. This saves money and embarrising moments. You have spark, and fuel pump is on but check this list.

1. Remove the spark plugs after trying to start and check for gas smell, this means your computer is spraying the injectors.

2.If you have spark and fuel all you need is compression and timing.You did double check all your work and the timing is on the marks on the compression stroke.Timing on the wrong stroke could also cause the engine damage. Cars now have interference engines so if a timing belt that is not changed on schedule breaks the engine pistons break all the valves.(I Learned this on an 82 escort)

3.Check that the compression is good using a compression testor. Follow the instructions.

4. you may have removed something like a vacumm hose that could cause the engine to not spray the injectors.

5. If the ancient 95 you are working on is a high milage vehicle then the compression may be the backfiring issue.

Backfire through the muffler is caused by unburnt gas exploding due to faulty spark plugs or lack of spark, lack of air fuel mixture, bad timing or lack of compression.

Good Luck

Philliro wrote: "Cars now have interference engines so if a timing belt that is not changed on schedule breaks the engine pistons break all the valves.(I Learned this on an 82 escort)"

I think you've answered (most of) the question I wanted to ask, that being: are most (or all?) modern engines "interference". The followup being: the reason?

I'm guessing it has to do with getting a higher compression ratio? Is there any alternative to get the high(er) compression ratio without an interference engine?