Popping / Backfire?!

[skeptiq]

I am getting this popping sound that seems to be coming from the passenger side motor. Kind of sounds like a burst of backfires (like its carbed). I can have the car in park and run the motor for half an hour and it won't do it (even some revs during the half hour). It will only do this in the first couple miles of driving so only 'under load.'

Before winter I was having idle issues and this started right before it got cold out and I put her in the garage for winter. Since I got it, I have replaced the IAC, Plugs, Wires, Disp cap. I have properly set the timing and idle. Timing is at 12* advanced. Idle is at 750. I have run the scanner and I get EGR error (EGR is removed) so I expect that one. I also get 137 (rich condition HEGO). Could this be causing this? What is it that is going on? I am thinking o2 sensors should be replaced, but do you think this will fix it? Has anyone else ever experienced this?

Later.
Ben

[Kevin1989]

sounds like what my car was doing a while ago... sounds like a really hollow pop? its probably poping out of the intake because its running lean on start up.

[skeptiq]

Yep hollow and rapid. If I mash the gas it gets through it. What can be done to fix that? Planning a tune shortly after o2s are replaced. You think new o2s will fix it?

Ben

[Kevin1989]

I think its in the tune, but check the ignition box, do you have an MSD box or something?

[skeptiq]

Msd ignition coil. Have 6al to install this weekend.

Man I can't wait for the tune.

Ben

[Timido]

Did you remove the spout connector when you set your timing to 12deg? Is this a mass air car or speed density

[skeptiq]

Did you remove the spout connector when you set your timing to 12deg? Is this a mass air car or speed density

Spout out for timing. Disconnected IAC when idle was set. Only idle issue currently is a slight hang (less than 5 seconds). Flow tested stock 19# injectors put on when cobra intake went on. Cold air in fender, with clean filter. Stock MAF. Vac lines all replaced. EGR gone as well as smog.

Only thing I can think of is o2's throwing off the puter. So those are getting replaced for sure. My goal right now is to get the car ready for the tune. Hopefully these little 'quirks' will go away. Do you think driving it will harm it?

Ben

[Timido]

Unplug the air meter and see if it gets any better. Anouther one I have seen is fuel pressure regulator ruptured. Check to see if there is any fuel coming out of the vacumm side of the regulator when the car is running. You might want to have a fire extinguisher handy when you check this for saftey.

[INSANEBA]

Unplug the air meter and see if it gets any better. Anouther one I have seen is fuel pressure regulator ruptured. Check to see if there is any fuel coming out of the vacumm side of the regulator when the car is running. You might want to have a fire extinguisher handy when you check this for saftey.

You'll smell fuel in your oil after this one too...

[skeptiq]

Unplug the air meter and see if it gets any better. Anouther one I have seen is fuel pressure regulator ruptured. Check to see if there is any fuel coming out of the vacumm side of the regulator when the car is running. You might want to have a fire extinguisher handy when you check this for saftey.

Interesting about the regulator. I actually have an aeromotive afpr to install also. I'll take a look at that this weekend.

Thanks for the suggestions so for. If anyone else has anything feel free. Hoping to get most of these things worked out this weekend.

Later.
Ben

[skeptiq]

One more quick question. If I unplug the meter, is it ok to drive it??? It only pops when I am driving and only withing the first mile or two...

Later.
Ben

[bobtsgt]

Pull your plugs and check them as well. See if any are soaked or real white. Your 02s may cause a problem but it would throw a code indicating that your values are out of the normal. So if you got a code for that bank it would show that the sensor is seeing too much or not enough fuel.

[skeptiq]

Pull your plugs and check them as well. See if any are soaked or real white. Your 02s may cause a problem but it would throw a code indicating that your values are out of the normal. So if you got a code for that bank it would show that the sensor is seeing too much or not enough fuel.

Currently I am getting DTC 137 (HEGO rich condition), which is why I want to replace the o2's. Just need to get those things ordered so I can get that step done and see what happens. There are sooo many things interrelated, I forgot how taxing this stuff can when you want to get to the root.

Just not sure if 137 is causing to popping or if it's something else. One step at a time I guess.

For o2's, I have heard conflicting opinions. Some say Bosch is bad, some say Bosch is good... What do you guys think for o2 brand???

Later.
Ben

[Timido]

Most the time people put 02 sensors on when the problem is a vacuum leak or an over rich condition. Don't just throw parts at it

[bobtsgt]

I would have the 02s read by a scanner in real time to see how they are fluctuating. That would tell you in the sensor is flaking out or not. Also I think the 0137 means rear 02s and not the front. Do you have cats on the car or not? If not do you have it turned off in the computer or using manual bypass methods?

[bobtsgt]

If you removed the EGR stuff and didn't turn off the switches in the computer then the car is still thinking that its active and will try to make it work. Once it figures out that its not working correctly you will get a code. As soon as you get a check engine light your computer is put into a "safety" mode where it will add fuel and take away timing so you can drive it safely until you get it inspected.

[skeptiq]

Throwing parts at is not what I want to do. I have replaced the Vac lines. I guess I can hook up a Vac tester. What should it read?

I just assumed since I replaced the Vac lines they were ok. Just seeing if there was anything else I could rule out before replacing the oxygen sensors. car has 114k and the guy I bought it from owned it for several years and he said he didn't ever replace them so I doubt they have ever been replaced so I was thinking it should be done anyway.

Thanks for the suggestions!

Ben

[Timido]

Make sure the cainister purge is not hooked up to straight vacuum that would cause a very rich condition. Is the egr valve still on the car? I know you said was nit hooked up.

[skeptiq]

Hmmm... I thought the 95 5.0's had only two o2 sensors and it was the 6 cyl's that had 4... I haven't been under there to look... so I'll check that out tomorrow.

EGR is removed and plugged. All vac lines were plugged and the rest of the vac lines were untouched except to replace with new lines. I don't have a tune yet, so the puter still things EGR and smog are still active.

If I am picking up what you are laying down, the fact that the egr hasn't been removed from the puter could be causing the 137 dtc. So basically since the puter still thinks it's there, but doesn't get readings, it goes into safety mode and dumps fuel... which could be causing the o2 sensors to be reading rich, thus causing the popping? Or is the popping caused by something else (will need to check the afpr as suggested above), and vac lines for proper pressure. Sounds like I just need to install the 6al (last thing on my list for now) and get a tune and see where she's at. I just wanted to get most of these little things wrapped up before the tune, but sounds like I need the tune so that can take care of what's going on.

Thanks to everyone who has been posing here! I really appreciate it. I have been running around trying to fix the issues and have exhausted searching and trying stuff I find online. Nice to know that you guys step up and give some good solid help!

Later.
Ben

[skeptiq]

Make sure the cainister purge is not hooked up to straight vacuum that would cause a very rich condition.

Where is the canister located? I haven't messed with vac lines other than to plug the egr lines and replace the vac lines that were left like the lines that run to the upper intake, fuel vapor, etc.

Thanks,
Ben

[Steves LX]

I had a motor that would do this same thing to a T. Once I bought a sct chip and had it tuned all the problems went away. I have this old set up in my wifes coupe and its not tuned. And guess what? It does the same thing as it did when it was in my car before I bought the chip and had it tuned.

[skeptiq]

No cats on the car... shorties to prochamber midpipe to mac dumps

[bobtsgt]

check to see if you have rear 02s. I don't know if the 94/95 did. Usually if a rear code comes up after the cat then the cat could be clogged and throwing the values out of its limits. But if you only have 2 02s then the one bank is seeing more fuel or the sensor is messing up. I would still get someone to scan the sensors even with you driving to make sure they match eachother and are acting right.

[skeptiq]

Will see if I can get my buddy to bring his scanner over to see... He just lives down the street, might be able to hook that up tomorrow and see...

So, am I doing harm to the car by driving it???

Thanks!
Ben

[Timido]

I looked up 137 Heated oxygen sensor indicates rich condition, left side

If you had a code that indicated that both banks were rich I would have been looking for somthing that would effect the whole engine. Now that I see the code is one bank. If you swith the 02 sensors side to side and get a rich code on the rt side after that the o2 sensor is bad.

[skeptiq]

I looked up 137 Heated oxygen sensor indicates rich condition, left side

If you had a code that indicated that both banks were rich I would have been looking for somthing that would effect the whole engine. Now that I see the code is one bank. If you swith the 02 sensors side to side and get a rich code on the rt side after that the o2 sensor is bad.

Good call, will try that tomorrow and see if the code follows the sensor.

Thanks again!
Ben

[skeptiq]

UPDATE!

Installed the 6al. After that I ran codes again and now I get dtc 136. The manual for the reader just says hego sensor fault, always lean. Which is the opposite of the 137 (always rich) according to manual. Is this the right text for that code? If so I don't think the o2's are bad.

Next step tune for sure.

Thanks
Ben

[Kevin1989]

i say get a tune haha and it should solve it all!

[babiixoxbritty]

cant say this is your issue but ive had the same symptoms in the past a couple times and it was in the distributor. try spraying some pb blaster on the mechanical parts inside there. this has worked for me.

[skeptiq]

Tune scheduled!

Thanks for all the help guys, I really appreciate it. We'll see where she stands after the tune. Going to be a long 26 days until tune gets done though!

Later.
Ben

[Kevin1989]

Tune scheduled!

Thanks for all the help guys, I really appreciate it. We'll see where she stands after the tune. Going to be a long 26 days until tune gets done though!

Later.
Ben

Nice where you taking it??

[skeptiq]

Decided on Adam at S&M.