Dang poppin noise!!Help me figure it out!

[Kdubslugga]

Ok so whenever i start my car up the idle at cold sucks!! Thats always been a problem. I have to give it gas to keep it runnin. If i give it to much gas it makes a pop noise, a sort of backfire i guess youd call it, more of a pop noise though, usually not to loud but enough to bother me. And every once and awhile when i floor it on the highway, never happens when i just launch from a stop, it wil backfire, or pop. Its only coming from the right side or passenger side. Sometimes it sounds like its coming from in the engine bay then other times it sounds like its coming out of the exhaust! Ive heard of lean pop, but i just had my car checked out and the guy said its running rich, so im clueless. Is this something to worry about???

 

[5spd GT]

I'm curious also...the other day I went to rev it up (some idiot was passing me way unsafely)...and I heard a pop? And I have to keep on the gas "in the cold" for about 20-30 seconds to keep it from dieing and then it is fine...

What would cause this for both of us? Bad timing?

 

[Daggar]

Wild ass guess only (I haven't heard this noise). But if the car is running well and pulls hard normally, I would guess that there might be a single bad injector that's causing a lean condition in one cylinder. It wouldn't explain your poor idling problems (although it may be contributing) but it could explain your other symptoms.

Edit: Oh... and it would also make sense that it did it more often when the engine was cold if that injector is not keeping up or is on the border.

 

[5spd GT]

Wild ass guess only (I haven't heard this noise). But if the car is running well and pulls hard normally, I would guess that there might be a single bad injector that's causing a lean condition in one cylinder. It wouldn't explain your poor idling problems (although it may be contributing) but it could explain your other symptoms.

Edit: Oh... and it would also make sense that it did it more often when the engine was cold if that injector is not keeping up or is on the border.

So going on this guess...what is a simple way to check the injectors to see if they are running properly...? My injectors are brand new...2 months old...

 

[Daggar]

That's a good question and I've got 1 and a half answers... Take them to NAPA (or any other parts store that has the equipment) and have them put on the cleaning machine. The machine will totally clean the injectors and is also able to check flow and duty cycles (so you can replace just the bad ones). The other half an answer would be to swap all the left ones with all the right ones and see if your symptoms change or go away. Us ethe half answer only if you if you can't find a place that can do the first.

 

[5spd GT]

That's a good question and I've got 1 and a half answers... Take them to NAPA (or any other parts store that has the equipment) and have them put on the cleaning machine. The machine will totally clean the injectors and is also able to check flow and duty cycles (so you can replace just the bad ones). The other half an answer would be to swap all the left ones with all the right ones and see if your symptoms change or go away. Us ethe half answer only if you if you can't find a place that can do the first.

Yeah I have a NAPA close by...so they could check my injectors right there in the parking lot without me having to take anything off?

My car runs fine most of the time...it popped that one time...what are the repruccsions if I go to the track with a bad injector?...

I might flip flop my injectors when I got to fix my valve cover leak here in two weeks...any bad things that might cause?

 

[Daggar]

Yeah I have a NAPA close by...so they could check my injectors right there in the parking lot without me having to take anything off?

My car runs fine most of the time...it popped that one time...what are the repruccsions if I go to the track with a bad injector?...

I might flip flop my injectors when I got to fix my valve cover leak here in two weeks...any bad things that might cause?

Unfortunately No. You'll have to take the injectors out to be put into the machine. You can clean the injectors without removing them but theat won't help you pinpoint a bad injector if there is one. The unit I referred to is about the size of a baby ATX computer case and does nothing but clean and check flow rates on injectors. Make sure you've found a place that has this machine before you go removing all your injectors. If nothing else, it will rule out my theory.

As far as swapping out injectors: I would suggest that you be delicate at first. Detonation caused by a lean condition is not a good thing. Even if it's just one cylinder. The only thing that this method would prove is that you do have a bad injector somewhere but it won't pinpoint that injector. The idea is that you're swapping injectors from cylinders that are normally a little lean anyway (driver's side) to the cylinders that normally wouldn't be. If your symptoms change then all you will know for sure is that ONE or more of your injectors needs replacing. The first method is waaaaay better. It completely rules out or confirms the existance of a bad injector where the second method only assists in shade tree diagnosis.

 

[5spd GT]

Unfortunately No. You'll have to take the injectors out to be put into the machine. You can clean the injectors without removing them but theat won't help you pinpoint a bad injector if there is one. The unit I referred to is about the size of a baby ATX computer case and does nothing but clean and check flow rates on injectors. Make sure you've found a place that has this machine before you go removing all your injectors. If nothing else, it will rule out my theory.

As far as swapping out injectors: I would suggest that you be delicate at first. Detonation caused by a lean condition is not a good thing. Even if it's just one cylinder. The only thing that this method would prove is that you do have a bad injector somewhere but it won't pinpoint that injector. The idea is that you're swapping injectors from cylinders that are normally a little lean anyway (driver's side) to the cylinders that normally wouldn't be. If your symptoms change then all you will know for sure is that ONE or more of your injectors needs replacing. The first method is waaaaay better. It completely rules out or confirms the existance of a bad injector where the second method only assists in shade tree diagnosis.

Dang that is what I was afraid of...hmm...I'll have to find a time to do that sometime...when I got money...

The only time I ever heard that pop was when I went to rev it up suddenly...

I don't notice anything when I'm going WOT besides my slipping clutch

 

[Daggar]

Dang that is what I was afraid of...hmm...I'll have to find a time to do that sometime...when I got money...

The only time I ever heard that pop was when I went to rev it up suddenly...

I don't notice anything when I'm going WOT besides my slipping clutch

Money shouldn't be a huge issue. It's not very expensive at all (I think I had all 8 of mine cleaned and checked for $16 / $2 per injector). If you have to replace a single injector it'll be what... $30? The fact that your car is acting silly during acceleration still leads me to believe that my theory may be correct. I see that Michael Yount... I'll try to get him in here to see if he has a different theory.

 

[blackstangt]

check your intake gaskets by spraying some intake cleaner around it, if it stops, bad gasket, happened to me. also, check timing and spark plugs.

 

[Michael Yount]

Popping/backfiring through the intake is usually a timing issue - ignition or cam.

But, have either of you pulled the codes?

 

[5spd GT]

Popping/backfiring through the intake is usually a timing issue - ignition or cam.

But, have either of you pulled the codes?

Haven't pulled any codes...does NAPA do them?

My timing is at 16* and spark plugs gapped at .045 (Autolite 3924's)...

 

[jrichker]

So going on this guess...what is a simple way to check the injectors to see if they are running properly...? My injectors are brand new...2 months old...

Do a cylinder balance test to find clogged injectors or injectors that aren't firing. Warm the car's engine up to normal operating temperature. Use a jumper wire or paper clip to put the computer into test mode. Start the engine and let it go through the normal diagnostic tests, then quickly press the throttle to the floor. The engine RPM should exceed 2500 RPM's for a brief second. The engine will shut off power to each injector, one at a time. When it has sequenced through all 8 injectors, it will flash 99 or the number of the failing cylinder such as 22 for cylinder #2. Quickly pressing the throttle again up to 2500 RPM’s will cause the test to re-run with smaller qualifying figures. Do it a third time, and if the same cylinder shows up, the cylinder is weak and isn’t putting out power like it should. See the Chilton’s Shop manual for the complete test procedure.

To do a cylinder balance test, you have to put the computer into test mode. Here's the links on how to do that...

Here's the link to dump the computer codes with only a jumper wire or paper clip and the check engine light, or test light or voltmeter. I’ve used it for years, and it works great.

See http://www.troublecodes.net/Ford/
OR
See http://www.dalidesign.com/hbook/eectest.html for more descriptive help
OR
See http://www.mustangworks.com/article...c-iv_codes.html

IF your car is an 88 stang, you'll have to use the test lamp or voltmeter method. There is no functional check engine light on the 88's except possibly the Cali Mass Air cars.

Codes have different answers if the engine is running from the answers that it has when the engine isn't running. It helps a lot to know if you had the engine running when you ran the test.

Trouble codes are either 2 digit or 3 digit, there are no cars that use both 2 digit codes and 3 digit codes.

For those who are intimidated by all the wires & connections, see http://www.actron.com/product_detail.php?pid=16153 for what a typical hand scanner looks like. Normal retail price is about $30 or so at AutoZone or Walmart .

 

[5spd GT]

What I'll do is take my injectors off when I redo the valve covers and adjust the valves again and just get them tested at NAPA...would just a regular "code reading" from a parts store tell me if I have bad injectors also...

 

[AJBlackGT]

Leans pops?... OR Are all of your plug wires wired correctly?

 

[87'GTstang]

Do a cylinder balance test to find clogged injectors or injectors that aren't firing. Warm the car's engine up to normal operating temperature. Use a jumper wire or paper clip to put the computer into test mode. Start the engine and let it go through the normal diagnostic tests, then quickly press the throttle to the floor. The engine RPM should exceed 2500 RPM's for a brief second. The engine will shut off power to each injector, one at a time. When it has sequenced through all 8 injectors, it will flash 99 or the number of the failing cylinder such as 22 for cylinder #2. Quickly pressing the throttle again up to 2500 RPM’s will cause the test to re-run with smaller qualifying figures. Do it a third time, and if the same cylinder shows up, the cylinder is weak and isn’t putting out power like it should. See the Chilton’s Shop manual for the complete test procedure.

To do a cylinder balance test, you have to put the computer into test mode. Here's the links on how to do that...

Here's the link to dump the computer codes with only a jumper wire or paper clip and the check engine light, or test light or voltmeter. I’ve used it for years, and it works great.

See http://www.troublecodes.net/Ford/
OR
See http://www.dalidesign.com/hbook/eectest.html for more descriptive help
OR
See http://www.mustangworks.com/article...c-iv_codes.html

IF your car is an 88 stang, you'll have to use the test lamp or voltmeter method. There is no functional check engine light on the 88's except possibly the Cali Mass Air cars.

Codes have different answers if the engine is running from the answers that it has when the engine isn't running. It helps a lot to know if you had the engine running when you ran the test.

Trouble codes are either 2 digit or 3 digit, there are no cars that use both 2 digit codes and 3 digit codes.

For those who are intimidated by all the wires & connections, see http://www.actron.com/product_detail.php?pid=16153 for what a typical hand scanner looks like. Normal retail price is about $30 or so at AutoZone or Walmart .

Ah you beat me to it. Another way is to pull the plug for that injector and if the idle doesn't change, then there's your faulty injector. Also there is specific equipment if you have it that will measure fuel injection quantity by means of a pulse signal to the injector. Pretty slick piece and is foolproof if you have access to one.

 

[5spd GT]

Wires are on correctly...

The only time I actually heard the pop was when I went to rev it up real quick...almost like I "shocked" the motor before it could keep up

Well I don't actually have to pull the spark plug itself...just the wire to that spark plug because then it will no longer emit a spark and will be more like a plug...right?

 

[Kdubslugga]

Well i just bumped my timing from 10 degrees to 15 and the popping stopped, so go figure!! Thanks for the replies everyone!!

 

[5spd GT]

So does that popping on my car possibly mean I don't have enough timing? It is at 16*...

Sorry I stole your thread Kdub...atleast you got it fixed...

 

[Daggar]

So does that popping on my car possibly mean I don't have enough timing? It is at 16*...

Sorry I stole your thread Kdub...atleast you got it fixed...

Could also mean that you have too much.