I will try to make this short but still involve all necessary information. I was driving on the highway last Wednesday when my cruise control went out and i couldnt drive over 25-30 mph, my check engine light did not come on when this happened. I managed to limp the car very slowly about 2 miles down the highway as that was the nearest exit. I took the exit and when i went to “accelerate” at the light i got a loud whooshing sound from under the hood. I pulled into an auto repair shop and found the EGR Valve had a hole blown in side.
Several hundred dollars and several hours later the shop put on a new EGR Valve and had cut the lower cat converter of the car and run a straight pipe where it had been. They said they believed the cat got clogged and built up enough pressure to blow the side out of the EGR. The car ran fine like this for a few days while i waited on my brother in law to gut the cat so we could replace the cat shell as to be within the law, as it is illegal where i live to remove the cat. We gutted the cat and cut out the section it was originally and put the shell back on. The car ran ok for a few hours but then i stopped at a gas station and the check engine light started to blink and the rpms would run way low. When i say low i mean around 1000 at 55mph and would idle around 250, if i put the car in neutral it would idle around 500 but that is still low.
Does anyone have any ideas as to what i could look into as the cause of this issue? Any help would be greatly appreciated.
If the vehicle has the 3.0L V6 there’s two catalytic converters.
Usually when the cat fails at the manifold it sends debris to the second cat under the vehicle restricting it. This causes excess back-pressure so the engine isn’t able get rid of the exhaust gases which can cause a misfire.
You could try crawling under the vehicle and hitting the cat with a rubber mallet to see if a rattling noise comes from the cat. If there’s a rattling noise the substrate in the cat has broken up and causing a restriction in the exhaust.
Or you can have a shop perform an exhaust back-pressure test to see if the cat is restricted.
Tester
We gutted the 2nd cat so i know there is no build up in it, it is essential just the shell for show to avoid legal issues from not having it.
My guess (having had the same problem in an Escape I flipped):
You have a misfire…at least intermittantly…on one cylinder. THAT misfire is what 1. melted your pre-cat, leading to 2. your down-stream cat being clogged. The fact that you have a flashing CEL indicates you STILL have a misfire that is STILL melting down (what’s left of) one of the two pre-cats.
You need to find out which one of six COPs is acting up (per the OBDII codes) and fix it. Given that a big reason COPs burn out is working too hard with worn plugs, I’d replace the plugs if it has been > 60,000 mi since the last time. This is a PITA on this car, as you have to remove the intake to access the reak bank: deal with it!
P.S. It blew out the EGR on mine, too. Find an Escape/Mazda Tribute and take the fastener off of it.
I have seen alot of issues on the Escapes starting with a blown EGR that turn into a money sink, is this car worth dumping money into or should i just chalk it up as a loss.
IIRC, the COP is like $60, and 6X iridiums are maybe $40? I’d like to think even an older CUV is worth throwing a Benjamin at and seeing if it sticks!
I just threw almost 400 at it, just dont want it to be the start of a trend.
If you’re telling us that BOTH cats have been gutted out and there’s a misfire, there’s NOT enough back-pressure.
The engine is tuned to have certain amount of back-pressure. Without this back-pressure the EGR circuit won’t operate properly and the cylinders can be over-scavenged causing a misfire.
If you want to know what over-scavenging is without back-pressure on an engine, enter into a search engine.
Tester
My friend ran low flow muffler. He had so little back pressure that the headers were glowing cherry red.
No only the rear cat was gutted, im sorry if my comments were confusing or i misunderstood or misread something.
Sorry if you posted this already, but is the check engine light on? Have you had the computer’s diagnostic trouble codes read out?
Agreed that since the ‘check engine’ light is flashing, you have a misfire problem. This will quickly damage your remaining catalytic converter(s). If you read the stored malfunction codes, hopefully it will point you towards a specific cylinder misfire. As a side note, since you have gutted them, your CEL will never go out, as the system will always detect that the emissions system is malfunctioning. Maybe not that big of a deal if you don’t need to get the car inspected. The lack of back pressure from the gutted cat(s) may cause drivability problems too, such as stumbling, surging, and poor fuel economy, since the system was designed for and is expecting the converters to be present and working.
If you don’t understand how the car’s electronics and emissions systems work, you are likely going to end up with a worse-running vehicle than you started with. Any vehicle that is over 10 years old is going to start costing you a bit of money.
Pretty sure this is the same problem I had…it certainly is presenting the exact same symptoms. I bought the car in non-running status, with the exhaust plugged and the EGR blown out. Hacking off the rear cat confirmed the obstruction; all that remained was to do the plugs, replace the bad COP, and slap on a universal cat.
I made a nice return, flipping that car!
I think you should fix the converter or converters properly to get the expected back pressure and then address any remaining misfires (quickly before damaging the converters).
Unless you plan to junk the car yourself, selling or trading in a car with illegal emissions could come back to bite you, so you might as well fix it correctly now.
The pricing I have found on the converters is about 200 for the rear and about 300-500 for the front. I have also recently found that oil is leaking into the spark plugs which Im guessing, im not super knowledgeable in car repairs, is the cause of the misfire. This means that i will now have to tear deep into the engine to replace seals/gaskets to fix that. The pricing i have found for COP is 75-150 for all 6, which i assume all will need replaced along with the plugs after fixing the oil leak issue.
I dont have alot of money to throw into this car so before i start this i want to make sure im not getting in to deep money wise.
You only need to replace the bad coil. The code will tell you which cylinder has the missfire.