New and Stumped...

[tooluser98]

Hello all. I'm fairly new to the modular 4.6l/ford world in general. I recently bought a 2001 cobra with 800 miles on a freshly rebuilt motor with '03-'04 internals. It currently has a JLT cai, ported DB cast 9 thread heads, and custom tuned. The main issue I'm having with it is cylinders 5-8(driver's side) are running pig rich for no apparent reason, and it's producing a pretty rough idle/smell of raw fuel. I recently switched out the driver's side upstream o2 sensor, which produced no change. I also changed plugs on all 8 cyl.s with same outcome. It is also misfiring in number 5 cyl and producing grey/blue smoke out the driver's side tailpipe at startup. Any ideas as to what's causing these issues? I've already spark-checked the cop in the #5 cyl and it's producing spark. I will also add that I compression tested all 8 cylinders; cylinders 1-4 were between 201 psi and 206 psi, while cylinders 5-8 were between 230 psi and 236 psi. I appreciate any help/answers to this nightmare.

 

[shurur]

I know this is a basic question and probably not helpful..I see you replaced the DS B2S1 O2 sensor...
Do you have at least a OBD2 reader (like torque with elm wireless adapter) to read codes?
And are you getting any codes?

 

[tooluser98]

It’s all good, I appreciate the response. Yeah I have a reader. Unfortunately, no CELs and no stored codes either. I’m pretty sure it could be attributed to the tune that’s on there as well.

 

[shurur]

probably a tune..others who know that stuff will post no doubt.

 

[tooluser98]

probably a tune..others who know that stuff will post no doubt.

Yeah for sure. I just wanted bounce ideas before screwing around with the ecu. Not my area of expertise at all.

 

[FIREBALL]

Blue/grey smoke is usually burnt oil----possible broken or misinstalled oil rings. Black smoke is fuel, white smoke is coolant. For a fresh built motor the compression should be more uniform.

 

[tooluser98]

Blue/grey smoke is usually burnt oil----possible broken or misinstalled oil rings. Black smoke is fuel, white smoke is coolant. For a fresh built motor the compression should be more uniform.

Yeah I was considering that as a possibility too. It just seems kind of suspect that something like that would be happening on the bank with higher compression. Wouldn't the compression numbers be significantly less on that side if one of the pistons had bad rings?

 

[FIREBALL]

Usually not with a bad oil control ring only. If its the compression rings then there will be lower compression.

Compression needs to be checked with engine cold and hot.

 

[01yellercobra]

I'd say your cam timing is way off. And I'd look into a bore scope. A poorly running engine with that few miles on a rebuild just screams issues to me. Do you have receipts or pictures of the parts being installed? Did it run right when you bought it and it got worse or was it like this from the beginning?

What's the rest of the set up? Fuel system, MAF, exhaust, etc. If it still has the stock MAF and injectors I'd put the tune back to stock and see how it acts. How did the plugs look when they came out? Black? Wet?

 

[tooluser98]

Yeah out of whack cam timing would make sense. I did go into it knowing there were a couple of issues, I just didn’t know quite how deep they went. I got a pretty good deal on it. As far as maf and injectors, I couldn’t say to be honest. If I had to guess, they could be stock. As far as exhaust, it has stock manifolds going to true duals with high flow cats and glass packs. All weld. As far as plugs, the plugs from cylinders 6-8 were wet with gas, all plugs from the 5-8 cylinders were fuel fouled.

 

[tooluser98]

I'd say your cam timing is way off. And I'd look into a bore scope. A poorly running engine with that few miles on a rebuild just screams issues to me. Do you have receipts or pictures of the parts being installed? Did it run right when you bought it and it got worse or was it like this from the beginning?

What's the rest of the set up? Fuel system, MAF, exhaust, etc. If it still has the stock MAF and injectors I'd put the tune back to stock and see how it acts. How did the plugs look when they came out? Black? Wet?

Also, unfortunately I don’t have receipts or pictures of the parts being installed.

 

[01yellercobra]

Stock injectors are black. But that doesn't help too much as 60lb and 80lb injections are black as well. I can't see that set up needing that much injector though. If the MAF is stock it'll say Ford on it. Can you post some pics? We might be able to help identify the parts.

The fact that the compression numbers are high would leave me to believe the rings are good. You said the heads are ported and you have blue smoke so I'm thinking valve seals or guides. But a leak down might not be a bad idea.

With this issue plus the possible cam timing I think the best thing is to pull the engine and give it a good once over. Pull the pan and check the rotating assembly. With it out you can retime the cams as well. Plus verify everything in the engine.

 

[tooluser98]

For some reason the picture sizes are too big for the server to process. What I did find out also was that I couldn’t take past 3000 rpms... after cold start.

 

[01yellercobra]

That could be a tune issue. Do you know who tuned it?

 

[tooluser98]

He used a sct x4 to tune it. Not really sure if he used a canned tune or had a custom tune put in using that. I overwrote that tune using my Hypertech just to see what would happen. It was pretty stable until it got up to operating temp. Then it just started hesitating and bucking when I’d try to get on it.

 

[01yellercobra]

He used a sct x4 to tune it. Not really sure if he used a canned tune or had a custom tune put in using that. I overwrote that tune using my Hypertech just to see what would happen. It was pretty stable until it got up to operating temp. Then it just started hesitating and bucking when I’d try to get on it.

Sounds like the second tune was off too. I'd put a stock tune back in it and see what happens.

 

[tooluser98]

That’s not a bad idea. Something else I found out was that it has pretty low fuel pressure. Like 12 psi at startup/ idle, dropping down to 6 psi while accelerating. Not normal at all.

 

[01yellercobra]

That’s not a bad idea. Something else I found out was that it has pretty low fuel pressure. Like 12 psi at startup/ idle, dropping down to 6 psi while accelerating. Not normal at all.

That's not a good thing. But that could be an issue with a sensor. If the ECU is thinking it has plenty of pressure it'll keep dropping the FPDC. But then I don't know if I've ever seen it that low.

 

[tooluser98]

That's not a good thing. But that could be an issue with a sensor. If the ECU is thinking it has plenty of pressure it'll keep dropping the FPDC. But then I don't know if I've ever seen it that low.

Yeah I’ve never seen fuel pressure that low on anything. It especially shouldn’t be decreasing during acceleration. So I’m going to cross reference that with an old fashioned fuel pressure test a little later on and see what that shows. The sensor would probably be the first on the list to get swapped out. Hopefully I don’t have to drop the tank lol.

 

[BigFatMatt]

Dropping the tank isn't all that bad as long as it's less than half a tank of gas. You'll want an extra set of hands to help lower it down.

One of the bolts on the strap is tough to access. I used a stubby wrench but it took me like an hour to get it out. That was the hardest part but it could have been avoided.

None of the write-ups mention it but get a SWIVEL SOCKET for the bolt I think it is 13mm if I remember correctly. Not a swivel attached to a socket but an actual "swivel socket"... I didn't have a set but I would have bought one had I known. Regardless, I had the tank out and back in after maybe 5 hours total over the weekend.

Sounds like you might have a fuel pump issue so dropping the tank may very well be in your future...