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Topic Review (Newest First)
12-23-2010 05:52 PM
drewcipher88 Good to know!
12-23-2010 04:41 PM
chadsti I fixed it. It turned out to be the o-rings where cracked in the 1st and 2nd cyclinder injectors. the cracks where letting air leak into the intake.
12-21-2010 09:43 AM
chadsti I bought it at a sketchy place but for a good price, i think it was done there and just took a while to make its way through the fuel sock and such, but if someone did do it to me, i cant change. i gotta tell um like it is, not my fault they dont like it lol.
12-15-2010 03:36 AM
ALASKA99TJ sorry couldnt resist, pretty much after you have sugar in your tank your screwed, start all over and um yeah start all over.... just my experience...
12-15-2010 03:33 AM
ALASKA99TJ maybe dont make people mad so they pour sugar in your tank? haha jkjk
12-14-2010 11:23 PM
chadsti a little update, i dropped it off at a dealer on Sunday for them to troubleshoot. They looked at is a bit monday. they are also stumped. I will update again when i hear more from them.
12-10-2010 02:27 PM
jeepjones Sorry I can't be of more help, good luck, if I think of something you haven't already done I'll let you know.
12-10-2010 01:36 PM
jasonwrangler check PCM
12-10-2010 12:20 PM
chadsti the mechanic put a new one on it. I just tested it with a multimeter and it reads in spec. thanks for your input tho. :-)
12-10-2010 05:46 AM
jeepjones I'm sorry that your mechanic has taken you for a ride, I hope you find your problem soon. Have you tested the ignition coil? When a coil is going bad it will idle ok but when a load is put on it it will fire intermittently.
12-10-2010 12:25 AM
chadsti I put the oem plugs in. They had no positive or negative effect on the condition. I now think it is either the distributor is out of sync a tiny bit or the pcm is programed wrong.
12-08-2010 11:18 PM
rrich Well?

Did you put the right plugs in it?
12-06-2010 02:47 PM
chadsti I hope they do the trick too. i am in my final year at Vermont Technical College. they have a automotive technology program here. i am going to meet with the head of the program this afternoon to see if he can take a look at it with the schools scopes. I will let every one know what he thinks is going on with it.

I run e3's in my subaru. they made a big difference with engine knocking, when i am forced to get sub-par quality fuel. But the performance mods i have in that car is a little different then my stock jeep.
12-06-2010 02:16 PM
rrich Sounds like most everything is new already.

Hopefully using the plugs the engineers designed the head around will do the trick. I have no experience with the E3's, but from I've read they are most likely in the category of "advertising hype."

If it doesn't, try finding someone that has and understands how to use an ignition scope. A performance dyno shop probably has technicians that can.

A good tech with a scope and a bottle of propane should be able to find the trouble in just minutes. Computer scanners won't do much to help.

Sounds to me the required voltage to fire the plugs is more than the ignition can provide. But that doesn't mean the coil is bad. We'll see.

Let us know!
12-06-2010 01:52 PM
chadsti I was wrong. the Bosch's where in when the PCM died. the mecanic put in a set of motorcraft, then i tried a set of those e3 plugs. i ordered up a set of oem champion's. ill give them a try
12-06-2010 01:26 AM
rrich Bosch? Do a search on here - there are many many threads about how Bosch plugs do that exact symptom!

Or better yet, just put in the right ones.


Please, Let us know how it turns out.
12-05-2010 11:05 PM
chadsti
Quote:
Originally Posted by rrich View Post
I'll ask one more time because it's exhibiting the typical common symptoms -

Are the spark plugs the same ones the underhood label calls out?

Not what the parts idiot says works better, not what your neighbor says, not advertising hype says, not what fits a Yugo, not Bosch - but the EXACT SAME ONES THE FACTORY SUGGESTS?

im not sure. i know i did replace them 3500 miles ago. it ran fine till the day it wouldn't start. then once the pcm was replaced and it would start. it would do it with those plugs. the mechanic put a set Bosch plugs in. then when i got it back i tried a set of those e3 plugs. ill take a look and see what jeep recommends and try them. i hope its just my plugs.
12-05-2010 10:04 PM
chadsti
Quote:
Originally Posted by jasonwrangler View Post
maybe you can try swap it back in see if it works
Ive never hear PCM failures unless you burn it up.

Ill have to see if the mechanic still has it, go figure its the only thing i didn't get back. Maybe ill take it out and bring to to a jeep dealer to see if they can confirm the fitment.
12-05-2010 09:55 PM
jasonwrangler
Quote:
Originally Posted by chadsti View Post
it was replaced. I do know for a fact in the week i parked it it failed some how. my code reader would not read the old PCM at all, and the jeep would not start.
maybe you can try swap it back in see if it works
Ive never hear PCM failures unless you burn it up.
12-05-2010 08:44 PM
chadsti
Quote:
Originally Posted by rrich View Post
Was OK, parked a week - now the PCM is the wrong one? Santa's elves needed the PCM but left the wrong one it it's place?

it was replaced. I do know for a fact in the week i parked it it failed some how. my code reader would not read the old PCM at all, and the jeep would not start.
12-05-2010 08:42 PM
chadsti
Quote:
Originally Posted by jasonwrangler View Post
did you check if the PCM is the right one? just a thought. seem like the Fuel Injection map is totally off and the rev limiter is wrong too.

Interesting story there! i pulled one out out of another 1997 wrangler se that was exactly the same as mine in every way. the mechanic told me the one i had for an auto and the jeep dealer could not program. so he got me one off ebay. i do know he took it to a jeep dealer and they programed it for him. he had them bill me.
12-05-2010 08:19 PM
jasonwrangler
Quote:
Originally Posted by rrich View Post
Was OK, parked a week - now the PCM is the wrong one? Santa's elves needed the PCM but left the wrong one it it's place?


OP said """""it will immediately buck and start to backfire"""""

How will backfiring in the exhaust make it buck?

Backfiring in the intake will.
he replaced PCM once.
12-05-2010 07:44 PM
rrich Was OK, parked a week - now the PCM is the wrong one? Santa's elves needed the PCM but left the wrong one it it's place?


OP said """""it will immediately buck and start to backfire"""""

How will backfiring in the exhaust make it buck?

Backfiring in the intake will.
12-05-2010 02:30 PM
jasonwrangler did you check if the PCM is the right one? just a thought. seem like the Fuel Injection map is totally off and the rev limiter is wrong too.
12-05-2010 02:23 PM
jasonwrangler
Quote:
Originally Posted by mholloway1809 View Post
Its sounds to me like the timing belt may be worn or have missing teeth, Pull the cover and check the condition of the belt and for residue on the cam position sensor.

Second, its not unusual for mechanics to keep faulty sensors from other jobs laying around to cover there ass when they start swapping parts because they cant diagnose the problem.

I ran my own repair shop for 10 years and i never charged a customer if i swapped a part and it didnt fix the problem, to have that many sensors go bad at once ?
Aint no way, get your money back, sue if you have to. PUT EM OUT OF BUSINESS !
the 2.5 has no timing belt.
12-05-2010 02:21 PM
JD Adams The backfiring is due to excessive raw fuel being in the exhaust tubes; the cats will ignite it when conditions are right and there is oxygen to burn. On a PCM-controlled engine, this should not happen.

If someone did sugar the fuel tank, something in the fuel system may have been damaged and overlooked. I'd take it to another mechanic who specializes in Jeeps and get another opinion. It could be something as simple as a damaged fuel pressure regulator, an emission-related sensor or even a simple intake air leak. Hooking up a code scanner and comparing o2 sensor voltages should confirm fuel system problems, while other simple tests will pinpoint any air leaks if present.
12-05-2010 02:14 PM
rrich I'll ask one more time because it's exhibiting the typical common symptoms -

Are the spark plugs the same ones the underhood label calls out?

Not what the parts idiot says works better, not what your neighbor says, not advertising hype says, not what fits a Yugo, not Bosch - but the EXACT SAME ONES THE FACTORY SUGGESTS?
12-05-2010 01:59 PM
mholloway1809 Its sounds to me like the timing belt may be worn or have missing teeth, Pull the cover and check the condition of the belt and for residue on the cam position sensor.

Second, its not unusual for mechanics to keep faulty sensors from other jobs laying around to cover there ass when they start swapping parts because they cant diagnose the problem.

I ran my own repair shop for 10 years and i never charged a customer if i swapped a part and it didnt fix the problem, to have that many sensors go bad at once ?
Aint no way, get your money back, sue if you have to. PUT EM OUT OF BUSINESS !
12-05-2010 01:34 PM
chadsti this morning I went to the parts store and picked up a distributor pickup. it was only 20 bucks so i figured i would try it. It did not help.

i had a new upstream o2s from another jeep. i also installed that to see if that would help, it didn't also.

i plugged my code reader in to see if there was any pending codes. there was one it was p0500. Vehicle Speed Sensor Malfunction. So i looked at mine, the shaft that goes into the transfer case wouldn't spin easily. so i replaced it with a new Vehicle speed sensor. this did not help the backfiring issue however.


I took a video with my phone. this is exactly what it is doing.

http://www.youtube.com/watch?v=3nzXnDXgU4U

1st time i slowly push the gas to WOT

2nd time i push the gas right to WOT

3rd time i slowly push the has to about half then i quickly push it the rest of the way to WOT

4th time i slowly push the gas to WOT again
12-05-2010 09:21 AM
chadsti
Quote:
Originally Posted by s3nt3nc3d View Post
One mistake I think some of you guys are making is you're throwing parts at it left and right. While yes, you may eventually figure out the cause, you're shelling out a lot of money in the process. Try to work on eliminating obviously dumb ideas...read up on other stuff to see if it would even cause that problem...and if you don't know, take it to a mechanic and make sure they fix it right the first time (or only charge you for what the actual cause of the problem is...so they're not just throwing parts at it either). To the original poster...that last part really applies to you. It sounds like your shop is throwing parts at it...and instead of saying, 'We screwed up and that didn't fix it afterall'...they're finding ways to justify you spending money on the unnecessary parts. IMO, you should take it back to them and demand they fix it right like you've already paid them...too much...to do or you'll take your business elsewhere as well as submit a complaint with the Better Business Bureau and if necessary, write a letter to the editor of the local newspaper about how they're taking all your money and not fixing the problem you're paying them to fix. Often times, that will make a local business take action...negative press = biiiiiig trouble for small businesses. They can't just shrug it off as a few customers lost.
i thought he was doing this too.he gave me all the old sensors so i went on motor all data, and looked up the specs and testing procedure for every sensor that failed to meet spec. they had problems. hard part is all there problems never followed a pattern. one was shorted to power. the injectors where indeed cloged, the tps read out of range. the fuel pump was slow.
when he had it the condition would improve a little after the sensor was change, tho it is still not driveable in realworld conditions. I put the new MAP on just because i had received two for another jeep i had. i figured it couldnt hurt. However he is telling me know if i run it it will go away on its own, and ya he just doesnt wanna lok at it any more all that it.
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