Auction Bought Cobra - Running Very Poorly

[foofinator]

All,

I have a 2001 Cobra convertible that I purchased at auction through Copart. It was a repossession, and it has 145,000 miles.

I've just now gotten it to run. The car was (and still is) a total mess. See the picture below for some of the things I've been dealing with -- that's JB Weld fixing a fuel leak. There was also a quart of gear oil spilled in the passenger compartment, the engine bay, hood, and fenders were painted black with flex seal, amongst other tragedies.

The next issue I have is that the car doesn't run well. At idle, it burbles like it has a miss, and the car shakes. Driving at low throttle inputs seems to work well, but, if you try to increase throttle, the car sounds strange and wont accelerate. It's hard to explain, but it reminds me of how my 75 Nova runs when the carb settings are off. The car also stumbles when you give it gas off idle.

I've researched this a lot, but it seems like these issues can be caused by a variety of items. I have made a few attempts at fixing my problem.

1. Brand new fuel injectors (from eBay, supposed to be an exact replacement for factory)
2. New alternator
3. New battery
4. Replaced IAC
5. Replaced TPS
6. Replaced PCV
7. Fixed vacuum lines and checked for leaks using cigar smoke (I actually found one)
8. Cleaned throttle body
9. Checked coils and found one that looked a little rough and replaced it

I pulled the coils off of the plugs while the engine was running, and each of them was indeed providing spark (could hear the arcing). I also pulled the injectors one at a time, in each instance, the idle got worse and recovered when the injector was plugged back in. I've been hoping that the car will throw me a bone and give me a check engine light, but no such luck.

My next plan was to replace the fuel filter, then the EGR, but at this point, I'm just throwing parts at the car. I have a datalogger, if there's anything I can look at to help figure this out.

It's important to keep in mind that this car is a total unknown, and it was severely mistreated. It doesn't however, seem to be burning oil, nor was there coolant in the oil. I think it's safe to assume that anything I haven't touched hasn't ever been serviced (why I am looking forward to changing the fuel filter).

Any thoughts on what I shoul do next?

 

[foofinator]

As a quick follow-up, I should mention that I replaced the MAF also. It had been hit with a hammer.

 

[COBRA90GT]

JB Weld for a fuel leak fix & flex seal, can you say "yikes?" LOL

The OEM fuel injectors were 24 lb if that helps any w/ your Ebay injectors (flow rate adequate enough?); sure sounds like it's starving for proper fuel but who knows for sure with all of the neglect/problems you have to sift through on that ride man.

FWIW - Cooling system tip, if you did not already know the proper way to refill/burp coolant on these 4v motors. it is done via the 1/4 plug from the top of the coolant crossover tube (the black metal pipe located directly in front of the alternator). There's a whole specific process on "burping" these engines, can search/google for it...

G'luck !

 

[Dark04GT]

I’d assume with all of those issues that the car has been sitting for a while. Assuming the motor is in good shape it is probably a fuel, ignition, or engine control system issue.

Simple things first-
1) clean your air filter (or replace it)
2) change out the fuel filter (pour out the tank side fuel - it should be clean - if it looks nasty i’d be worried about old gas / gas tank corrosion)
3) get new spark plugs and gap them appropriately (now your entire ignition system is new)
4) new EGR valve (not sure about your model year on this one)
5) siphon off what ever fuel you have in the tank and put in fresh fuel if you haven’t done this already (any fuel that came with it is likely ancient)
6) double check you have the right oem fuel injector size
7) change the engine oil and inspect for any metal / strange fluids / signs of trouble
8) pull engine codes and correct any error codes

Next steps-
1) new fuel pump & inspect inside of fuel tank to see if you need a new tank
2) inspect fuel lines all the way to the front of the car to make sure you don’t have any other damage / issues

If the above doesn’t work it is probably time for a cylinder compression check / inspection of timing chains / time to consider a more serious issue.

 

[wmburns]

The next issue I have is that the car doesn't run well. At idle, it burbles like it has a miss, and the car shakes. Driving at low throttle inputs seems to work well, but, if you try to increase throttle, the car sounds strange and wont accelerate.

Any thoughts on what I should do next?

Yes. Run a compression test and a cylinder leak down test.

You may not want to hear this. But I have helped several people that initially reported poor running and a "burble" sound. In several cases it turned out to be leaking intake valves.

+1 on above. The 4V DOHC motors can be very difficult to remove all of the air from the coolant jacket. The procedure is hard enough where many people will say that the only way it can be done is with a vacuum refilling kit.

+1 on checking the oil filter for debris. Also consider replacing the timing chains and guides if doing any major engine work. 150K miles is about the "magic" number for how long the guides last. If any debris is found in the oil filter, replace the timing chains/guide right away.

Good luck.

 

[foofinator]

Ok, so just did the compression test. I idled the car until the radiator was hot to the touch and then disconnected the coil packs and the injectors. I didn't add any oil to the cylinders.

Driver's Side (from front of car): 171 (lowest), 180, 174, and 176.
Passenger's Side (from front of car): 189 (highest), 189, 185, and 172.

These numbers seem to be acceptable, with the lowest being within 10% of the highest. Good news?

 

[foofinator]

And, just to provide a little more information:


1) clean your air filter (or replace it) - Replaced with hand-me-down (but freshly cleaned and oiled, K&N)
2) change out the fuel filter (pour out the tank side fuel - it should be clean - if it looks nasty i’d be worried about old gas / gas tank corrosion) - Got the new filter, still need to install.
3) get new spark plugs and gap them appropriately (now your entire ignition system is new) - Replaced with Motorcraft plugs, with gap set per the Haynes manual.
4) new EGR valve (not sure about your model year on this one) - Need to purchase.
5) siphon off what ever fuel you have in the tank and put in fresh fuel if you haven’t done this already (any fuel that came with it is likely ancient) - Put 5 gallons of fresh fuel in. Seemed like the tank was empty (though read a little under a quarter full).
6) double check you have the right oem fuel injector size - I included a picture of one below; according to the internet, they are 24 pounders.

7) change the engine oil and inspect for any metal / strange fluids / signs of trouble - Changed (and discarded) oil and oil filter when the car arrived.
8) pull engine codes and correct any error codes - Car has not thrown any codes.

Next steps-
1) new fuel pump & inspect inside of fuel tank to see if you need a new tank - Next on the list, after the EGR. I bet you fuel system is where my problem lies.
2) inspect fuel lines all the way to the front of the car to make sure you don’t have any other damage / issues - This is a great idea, will do with the fuel filter and fuel pump work.

 

[foofinator]

Last update of 2017. I got bored and threw in the new fuel filter; that was fun -- lots of room to work between the IRS and gas tank. The old fuel filter was backwards, its inlet (really, its outlet) was bent by at least 30 degrees, and the line from the tank was contorted. I've never had to work like that to disconnect fuel lines - the new one snapped right in as it should. Also, black stuff poured out. I won't know if this fixes the problem until later, because I still have to reassemble everything I took apart during the compression test.

 

[Dark04GT]

Hopefully it is just the fuel system from what you have found so far -black stuff pouring out sounds like fuel tank nastiness. Backwards fuel filter placement -yikes!

If that car was sitting for a while that fuel pump and tank might be in rough shape. I’d drop that tank -take the fuel hat off and take a look inside.

 

[foofinator]

Alright, the car finally threw me a bone in the form of three codes:

P0358: I understand to be the coil on cylinder 8 not firing.
P1504: A high idle code (but this could be due to me using a hand-me-down throttle body from my 04 Cobra, which had the idle screw set very high).
P0193: An issue potentially with the fuel rail pressure sensor.

The P0193 could be because I unplugged the FRPS during testing a few times.

Could all of this just be a bum coil, after all?

I had a weak moment and ordered 8 new Motorcraft coils. The mix of various coils in the car right now and this code pushed me over the edge. Hopefully this helps; oh well, it was something I was going to do eventually, anyway.

 

[foofinator]

So, the idle is still high, but I am a believer in Motorcraft coils. The car runs much better and will spin the tires, as it should. One thing I noticed was the green ring that's supposed to seal the coil pack connectors got pushed into the connector and thereby acted like a spring that tried to separate the coil pack connections -- something that others having problems that are similar to mine should check.

Now I'm on to the radio. Just learned the PO replaced the Mach 460 with a base headunit. No sound from the front/rear lower speakers. And, a butchered harness. This should be fun.

 

[Neuron]

So, the idle is still high, but I am a believer in Motorcraft coils. The car runs much better and will spin the tires, as it should. One thing I noticed was the green ring that's supposed to seal the coil pack connectors got pushed into the connector and thereby acted like a spring that tried to separate the coil pack connections -- something that others having problems that are similar to mine should check.

Now I'm on to the radio. Just learned the PO replaced the Mach 460 with a base headunit. No sound from the front/rear lower speakers. And, a butchered harness. This should be fun.

Crutchfield was a big help with my Mach 460 debacle by the PO.

 

[foofinator]

Ended up buying a decent JVC unit and the associated wiring from Crutchfield. Got everything hooked up, replaced a busted amp, and everything seems to be working well.

I dropped the glovebox to route the USB cord and found an old syringe and pills hidden behind it.

 

[rancorkeeper]

I dropped the glovebox to route the USB cord and found an old syringe and pills hidden behind it.

You sure you didn't buy a Camaro?

 

[foofinator]

I knew something was strange.

I've since learned that the transmission is busted (new TR3650 is on the way). Just added 04 cobra wheels (2 from my 04 Cobra and 2 10.5's) and am experiencing rubbing on the IRS bolts. One adventure after another. Going to drop it on its nuts this weekend with some H&R springs - it'll at least look good.