Bullitt problems

beebs90 · Mar 9, 2017

Hi,
So I have finished putting my engine back together with new cams, valves, valve springs and ported and polished heads. got it running and idling ok..... it was all working ok then I stated to lose vac to my air vents and a burning smell. so I got a vac pump and gauge and checked all the lines they are all fine. checked the entire loom for any burning cables and they were all fine. so today I fixed a leaky exhaust from the headers to the downpipe (stripped the threads on old bolts first time round). had it running for abit again and the idle settled but I noticed the drivers side exhaust and mostly cat was getting incredibly hot, a lot more then the passenger side. so much so that it had melted the paint off the underside and started melting the sound proofing and insulation inside. the car still has the EGR valve fitted. good news I found out there's no issues with the loom in the cabin and that I found the burning smell. the bad news I have no idea what's causing the drivers exhaust to get so hot. I have a compression tester on way so will do that in the next few days but is there any ideas out there what could be causing it? both sides of the engine stay at the same temperature and no overheating. the car has not been tuned yet, need to sort the issue before I can take it anywhere to tune it.

Thanks guys, really lost on this.

lwarrior1016 · Mar 9, 2017

How old are your cats and how many miles do they have on them? It sounds like they are in need of replacement.

07GtS197 · Mar 9, 2017

Correct me if Im wrong but doesnt that mean youre running lean? What size injectors are you running? Fuel pressure?

lwarrior is probably right though, cats can do that when they get old and/or clogged.

beebs90 · Mar 9, 2017

Thanks for the quick responses,
The cats are aftermarket race cats, not sure when they were fitted the history on the exhaust is vague, but they were working with no issues at all before I took it apart.
I'm currently running 19lbs but will be going to 29lbs when I get it tuned.
Not sure on fuel pressure can I measure it with an SCT X3 tuner?
Could the EGR valve having anything to do with the problem as I'm getting barely any vac and it fluctuates even then.

Thanks folks

lwarrior1016 · Mar 9, 2017

How did you time your cams?

The vacuum to the vents is a little bitty black hose that goes through the firewall on the passenger side.

I would also think that if it was running lean, it would show up at the head/header mating surface more than showing up at the cat.
I guess that side could be loading up with fuel and igniting inside the catalytic converter.

beebs90 · Mar 9, 2017

yeah ive checked all the lines they all hold pressure when the engines not running, I've checked all the lines relating to the air vents they are all okay and work. Only stops working when the engine is running. Timing was done by matching the end links of each chain with marks on the crank and cam gears. cant remember where we saw to do it that way. seems to run ok on that front

07GtS197 · Mar 9, 2017

Oh thats right I remember you from that other thread you posted about fuel injectors.

How quickly after you fixed the header leak did you notice it was getting really hot? If it was right afterwards then it could have been from the exhaust leak making it run rich.

When you say the vacuum fluctuates do you mean engine vacuum? What vacuum line did you tee into?

And yes there should be a pid for fuel rail pressure on the x3. I dont datalog with my tuner so Im not too familiar with doing so but I believe its a parameter you can monitor. I do know it can be monitered via sct's livewire software.

g36 monkey · Mar 10, 2017

Typically the cats getting hot, even to the point of glowing, is an over rich mix.

I've melted down a set because of it. Sometimes that happens from bad plugs, or bad wires, because fuel is dumping right into the cats.

beebs90 · Mar 12, 2017

Ok, so a quick update. I haven't had much chance to fiddle with the car the last few days. so I started it up to check the vacuum from the intake manifold, I tested the port that the air vents and EGR valve run off. I got it fluctuating between 0 and -3 psi. So there's definitely a problem there. I took the plugs out on the drivers side and there all black, I checked a passenger side plug and it was still golden, these are brand new motorcraft plugs. I decided to check if the intake manifold was tight, I got 1/2 to 3/4 a turn on them which is odd as they were torqued down though I admit that I didn't do the torque in the correct procedure. I have not started the car back up since doing that as I'm waiting to do a compression test on all the cylinders in a few days for peace of mind.

07GtS197 · Mar 12, 2017

If all the plugs on the drivers side are black then that proves that bank is over fueling. You might want to check cam timing because I have a suspicion its off on that bank.