Mazda 6 Forums banner
1 - 20 of 24 Posts

·
Registered
Joined
·
19 Posts
Discussion Starter · #1 ·
The car was misfiring and front pre-cat broke and pieces went into the downstream cat. I took them apart and cleared out the debris from the downstream cat. The front pre-cat is empty. But when I started it again the misfiring persisted and there was an exhaust leak from the front manifold. I re-tightened the manifold bolts and the leak seemed to decrease but the car only idled for a few seconds and engine stopped. Now it cranks and seems to fire and then stops immediately. A rapid clicking sound continues till I remove the keys. The car was low on fuel so I put a gallon in. I can hear the fuel pump when I put in the keys. What could be the issue? There was a code related to heated O2 sensor circuit open but I assumed that was old since I started the car once with O2 sensor unplugged. I cleared that code and there are no more codes. How to I diagnose this no start?
 

·
Registered
Joined
·
798 Posts
Not sure how you think making two identical threads is going to help you better.

It is usually nice for newbies to say "hi", "please help" and other common courtesy verbiage and not just dump a long list of issues and then expect people to jump in and help.

All I'll say is that you have a misfire and you do not say that you fixed it. Do that first, replace all coils and plugs before anything else.
 

·
Registered
Joined
·
19 Posts
Discussion Starter · #3 ·
Not sure how you think making two identical threads is going to help you better.

It is usually nice for newbies to say "hi", "please help" and other common courtesy verbiage and not just dump a long list of issues and then expect people to jump in and help.

All I'll say is that you have a misfire and you do not say that you fixed it. Do that first, replace all coils and plugs before anything else.
I couldn't find the original thread I created so I thought it must not have entered it correctly. So I re-typed it. I will delete the duplicate thread if I can. Thanks. I have removed the front spark plugs and they seem fine. I had installed all new spark plugs and one of the coils 5K miles ago. I will check the back spark plugs next after removing the intake manifold.
 

·
Registered
Joined
·
798 Posts
Don't rely on doing just the front. Replace all plugs and coils to fix that misfire.
 

·
Registered
Joined
·
19 Posts
Discussion Starter · #5 ·
Don't rely on doing just the front. Replace all plugs and coils to fix that misfire.
Yes, I will check the back coils and plugs next. I fear there is something else that broke though since the car had been idling rough for a while but always started on first try. Its also weird that it makes that rapid fire click sound till I remove the keys after a failed start.
 

·
Rally Racer
2004 Mazda 6s Wagon ATX
Joined
·
3,729 Posts
Replace all coils and plugs. Clear out all four cats or replace them (preferred). If you only cleared one upstream cat because it was killed by a mis-fire, the other is also dead or clogged. All that debris has clogged the downstream cats. Oxygen sensors last about 100,000miles but will give you a code before they stop working.
@vkapoor
 

·
Registered
Joined
·
19 Posts
Discussion Starter · #7 ·
I never got any cat code from the rear cylinders bank and can see through the main cat of the rear bank. So I think the rear bank pre-cat and main cat are fine. I cleared out the debris from the main cat of front bank and the pre-cat is hollow. I will do a back pressure test if the car starts again but not sure I want to purchase new catalytic converters till I can get it to start again as the problem might be elsewhere.
 

·
Registered
Joined
·
19 Posts
Discussion Starter · #8 ·
I never got any cat code from the rear cylinders bank and can see through the main cat of the rear bank. So I think the rear bank pre-cat and main cat are fine. I cleared out the debris from the main cat of front bank and the pre-cat is hollow. I will do a back pressure test if the car starts again but not sure I want to purchase new catalytic converters till I can get it to start again as the problem might be elsewhere.
I was afraid the engine is blown so I tested compression on one of the cylinders today (front bank passenger side end) and it is 150 psi. Is this in the right range?
 

·
Registered
Joined
·
164 Posts
Depending on how you did the compression test that could be OK. If the throttle body wasn't held open you'll get a number in the 150's. If the intake manifold is off or throttle body physically held open it should be in the 170-180's. At least that's what I got on mine when it had 160k on it.

The clicking you're getting sounds like a low battery or bad grounds. If you're in the rust belt these cars tend to have ground issues.
 

·
Registered
Joined
·
19 Posts
Discussion Starter · #10 ·
Yes, low battery could be the cause as I haven't been driving it much but the battery itself is only a few months old.
 

·
Registered
Joined
·
19 Posts
Discussion Starter · #11 ·
Depending on how you did the compression test that could be OK. If the throttle body wasn't held open you'll get a number in the 150's. If the intake manifold is off or throttle body physically held open it should be in the 170-180's. At least that's what I got on mine when it had 160k on it.

The clicking you're getting sounds like a low battery or bad grounds. If you're in the rust belt these cars tend to have ground issues.
Unfortunately I get between 140 and 150 on all front cylinders with throttle body open and intake manifold loosened. The car has 95K miles on it. What to do now?
 

·
Registered
Joined
·
19 Posts
Discussion Starter · #12 ·
The pressure increases if I crank longer. On 6th cylinder I got 170 psi. Went back and checked cylinder 5 and cracked longer. I got 160 psi where as previously I got 145 psi
 

·
Registered
Joined
·
164 Posts
It might have hopped the timing chain. Mileage seems low for that but these cars are all pretty old at this point and things can just fail with age.
 

·
Registered
Joined
·
19 Posts
Discussion Starter · #15 ·
Did you already changed the coils and plugs?...
Not yet. The spark plugs look perfect since I had put double platinums few thousand miles ago. Is there a good way to test the coils? I will check the resistance with a digital multimeter. If it is ok do they still need to be replaced? I had replaced one of the coils few thousand miles ago but it didn't make a difference. I found one of the fuel injection wires was exposed. Not sure how that happened there. See picture. I have wrapped it in
electrical tape.
Tire Automotive tire Wheel Motor vehicle Tread

It might have hopped the timing chain. Mileage seems low for that but these cars are all pretty old at this point and things can just fail with age.
When timing is off then the compression in ALL cylinders should be low. I put a teaspoon of oil in one of the cylinders and compression jumped to 190 PSI from 130 PSI. I think this points to bad pistons but I am doing the test on a cold engine so not sure.
 

·
Registered
Joined
·
19 Posts
Discussion Starter · #16 · (Edited)
Resistance on all the 6 coils is 0.7 ohms in primary winding and 5.4K ohms in secondary winding. This matches the spec so I can't conclude there is something wrong with the coils yet. I will do a spark test on each and if it fails I will replace. This video shows the coil tester I am planning to use.
It has an adjustable screw that can test if the coil can produce 40 KV. Lisle Coil-On Plug Spark Tester-LIS20700 - The Home Depot Is this a good test?
 

·
Registered
Joined
·
164 Posts
I was thinking of suggesting the oil in the cylinder compression check. Figured the mileage was to low for it be down on compression from wear. It seems like you have confirmed that though.

Unfortunately it seems like if you want to keep the car going the engine will need to be replaced. Not sure if it is worth it or not to you. One thing I recently discovered is the 2011 Ford Escape motor is an almost direct replacement. Many people have swapped the slightly older fusion motors but I hadn't heard of the alternate escape motor. Prices on the Escape engines are DIRT cheap. I can get one locally with 70k on it for $350. The fusion motors seems to start around $750.
 

·
Registered
Joined
·
19 Posts
Discussion Starter · #18 ·
I was thinking of suggesting the oil in the cylinder compression check. Figured the mileage was to low for it be down on compression from wear. It seems like you have confirmed that though.

Unfortunately it seems like if you want to keep the car going the engine will need to be replaced. Not sure if it is worth it or not to you. One thing I recently discovered is the 2011 Ford Escape motor is an almost direct replacement. Many people have swapped the slightly older fusion motors but I hadn't heard of the alternate escape motor. Prices on the Escape engines are DIRT cheap. I can get one locally with 70k on it for $350. The fusion motors seems to start around $750.
I haven't changed the oil in the car for couple of years since it wasn't driven through Covid but it was having some misfires before that. May be the compression will improve with oil change and warm engine. I will put it back together after testing the coils in couple of weeks and go from there. Thanks
 

·
Registered
Joined
·
2 Posts
192.168.100.1 192.168.1.1
I was thinking of suggesting the oil in the cylinder compression check. Figured the mileage was to low for it be down on compression from wear. It seems like you have confirmed that though.
Unfortunately it seems like if you want to keep the car going the engine will need to be replaced. Not sure if it is worth it or not to you. One thing I recently discovered is the 2011 Ford Escape motor is an almost direct replacement. Many people have swapped the slightly older fusion motors but I hadn't heard of the alternate escape motor. Prices on the Escape engines are DIRT cheap. I can get one locally with 70k on it for $350. The fusion motors seems to start around $750.
that's what I was thinking of , anyways If you want it solved you have to take it to a garage , get a professional help run a full analysis this is the fastest way, surely not the cheapest
 

·
Registered
Joined
·
19 Posts
Discussion Starter · #20 ·
that's what I was thinking of , anyways If you want it solved you have to take it to a garage , get a professional help run a full analysis this is the fastest way, surely not the cheapest
I had taken it to a garage who are supposed to be the best around here. They couldn't figure it out even though I told them I suspected front pre-cat. They normally rely on codes and the car wasn't throwing any. They didn't charge me anything and drove the car to Midas. Midas said it was the catalytic converters and charged me $165 for the diagnosis. Their repair estimate was $3000 to replace couple of catalytic converters. I have already unclogged the cats myself at this point but the car was low on power even with cats removed. Not sure who to take it to next.
 
1 - 20 of 24 Posts
Top