98 Cobra Family Cruiser

[jfisher]

New guy to the forums here. I've had my 1998 Cobra for about a year now and figured I'd start a thread to help diagnose a couple issues and document the build.

I flew to St. Louis last April and drove the car home to Cincinnati. It was nicer in some areas than I was expecting, but had a couple issues that I wasn't told about so it all evened out

I put about 4k miles on the car last year and did several changes during that time.

-Removed the Eibach Sportline springs and installed a set of H&R Super Sports specifically for convertibles.
-Replaced the worn out stock struts and shocks with a set of Bilstein HD's
-Replaced the no name CC plates with a set of 4 bolt MM's
-Traded the Cobra R hood for an OEM 96-98 Hood (some may call me crazy, but I think the hoods are what make these 96-98 cars)
-Replaced the Flowmaster catback with a Borla S Type
-Added an MGW Short Shifter
-Replaced the BBK CAI with a JLT CAI
-Replaced the SR performance clutch quadrant with an MM (have the MM OEM Ford Cable that I need to install as well still)
-Swapped the FR500's that were on the car for a set of Aodhan 18x9.5 and 18x10.5 +22

As of now I've got the following parts sitting in the garage awaiting install
-FRPP 4.10 gear kit
-Team Z K member and A Arms
-12" 200lb coilovers
-Pacesetter Long tubes
-Pacesetter X pipe
-MMR IMRC deletes
-Mcleod Clutch and Alum Flywheel
-All new FRPP clutch related parts (fork, tob, pivot, etc)
-Other misc things I'm sure I'm forgetting

I am having two major issues with the car.
1) The car doesn't idle well at all. Once it gets warmed up I can't get it to come down past 1800rpm in neutral. The ECU is trying to add 24% fuel at idle which is also very odd. I suspected vacuum leak, but I've used an automotive smoke tester on the car and I see no visible leaks besides a little coming out of the IAC vent
2) When the car is under 1/2 tank of fuel the car will straight cut out completely going around any kind of turn. At first I was thinking this was just a bastard 98 fuel system bucket issue, but I posted up elsewhere and lot's of folks are able to run their car to empty without issue. I ordered up a new TI Auto 255lph fuel pump system off LMR and am just going to replace everything to eliminate that.

That's all I can think of for now. Here's a couple pics:

 

[RAU03MACH]

Welcome
Nice looking cobra
The vac. Leaks check for sure that creates hang idle

 

[RAU03MACH]

On the deleted plates you will check engine light
You might wanna get a tune for it

 

[jfisher]

On the deleted plates you will check engine light
You might wanna get a tune for it

Yep, I am going to be sending the car down to Blankenship Performance to have them tune the car. I am thinking some of my idling issues may be tune related as my car was "tuned" prior when all of the emissions parts were removed.

 

[RAU03MACH]

Possible

 

[07GtS197]

Your fuel issue might be that the sock came off the fuel pump. Fuel is sloshing away from the pump and is starving it.

The issue with it adding fuel, I’m willing to bet that’s a tuning issue. It probably had a blower on it before you bought it and is still running that tune.

 

[jfisher]

Your fuel issue might be that the sock came off the fuel pump. Fuel is sloshing away from the pump and is starving it.

The issue with it adding fuel, I’m willing to bet that’s a tuning issue. It probably had a blower on it before you bought it and is still running that tune.

That is very much a possibility. I do now have a generic X4 tune on the car that is off the X4 and I still have the weird idle issue. I am dropping the tank this weekend and hope to find something obvious.

 

[07GtS197]

That is very much a possibility. I do now have a generic X4 tune on the car that is off the X4 and I still have the weird idle issue. I am dropping the tank this weekend and hope to find something obvious.

Even with the tune it’s still adding fuel? I had a bunch of strange issues on my 00 gt recently. I never figured it out before I sold it but I did find someone had tapped into one of the O2 sensor grounds for something. When I pulled it out it ran much better. The fuel trims were still screwy but it ran much better. I think the ecu had some bad traces because of that. I ruled out pretty much everything else and it still pulled a lot of fuel from bank 2. And the reference voltage for a few sensors was low. I think there was a common issue somewhere but short of going through every inch of wiring in that car I wasn’t going to find the issue. Anyway, I hope your issue isn’t as bad as mine was.

 

[jfisher]

I am wayyy behind on updates here...

I ended up replacing my fuel pump back in March with a new TI Auto / Walbro 255lph drop in replacement 98 pump. What I found is that the car had a On3 340lph pump in the car which I believe all are non-variable voltage pumps. I had seen where a non-variable voltage pump will get burnt up fairly quickly if you don't have that functionality turned off in the ECU or by manually adding a jumper to the wiring to bypass that. After I got the 255lph pump installed the car idled much better (not perfect though), but most importantly it eliminated my cutting out issue around turns completely.

After that was fixed I started tearing into the car to put in the new Mcleod Super Street Pro clutch, Pacesetter long tubes and Team Z front suspension. That is where I really started running into a bunch of issues.

1) One of the first fun things I ran into was that the previous owner or the shop the previous owner used to work on the car pinched the knock sensor harness in between the block and bellhousing. This is what I believe caused the high rpm clutch slip and funky clutch pedal vibration and feel. I think that the trans wasn't squarely mounted up to the block causing misalignment issues everywhere else.

2) Additionally whoever did the clutch job (car ended up having a newer Clutch Max clutch and Flywheel in the car) probably was running in the upper right hand bellhousing bolt into the knock sensor harness and instead of backing it out and finding out why it wasn't threading in just cranked on it until it snapped off in the block.

3) I have no idea how this even happened, but as I was working on another area of the car noticed this lovely ground cable going from the battery to engine mount was completely severed in half and a horrible attempt at soldering and electrical taping it back together took place.

4) This is also the time I was noticing that the engine itself just seemed really crusty, leaky and nasty compared to how clean the rest of the car was. At 71k miles it just seemed odd. Low and behold the 6 bolt crank At this point I was really upset and decided to contact the previous owner. I wasn't expecting any money or anything like that, rather just some information on wth I was working with. Not sure why I even tried as the PO didn't know anything about it and pointed me towards the shop that worked on the car which I'm not going to name. So now I have a brand new Fidanza Aluminum flywheel I can't use.

 

[jfisher]

At this point I just decided it would be much easier to pull the engine as I now wanted to regasket everything and check inside the engine for any surprises. My guess is this car was probably boosted at some point and a PO hurt the stock engine.

Now onto the fun stuff. Got the entire engine regasketed besides the head gaskets. Got the coolant crossover pipe and upper intake lid coated and got the engine back in the car.

 

[jfisher]

At this point more fun began. I can't really point the blame at any one thing, but I can say my combination of aftermarket parts just didn't really work well together. I've had two Team Z K members in the past with zero issues, but for whatever reason this one just did not fit well at all. The stock oil pan hit the k member using Prothane engine mounts (which sit higher than another set of ES engine mounts I still have). The steering rack was way too far to the passenger side forcing me to barely get the toe in spec (the out tie rod on that side was threaded on as far as it would physically go). The driver side had plenty of thread on the tie rod remaining. If I turned the rack the other direction it just shifted the problem to the other side. And the passenger side header didn't fit well at all. I just seemed like everything was shifted to the passenger side too much.

What I eventually ended up doing is slotting the Prothane mounts to move the engine back about 3/8" which gave me just enough clearance for the pan to clear.

 

[jfisher]

Once I got that lined up I started tackling the suspension.

Went with UPR front coilovers with 250lb 12" springs.

ATS caliper conversion using the S&S Engineering mount kit.

 

[jfisher]

Got the 4.10's installed, engine buttoned up and had the car aligned last week. Thankfully everything aligned good except for the caster on the driver side. My dude got it to 4.8 I believe, which was the best he could get it. Dropped the car off last night for some exhaust work. The "matching" Pacesetter X pipe does not work on the 96-98 cars due to their unique trans cross member.

 

[07GtS197]

I’m curious whether that’s the stock teksid block with different internals or the whole bottom end was swapped. Looks like you’re making good progress even with all the setbacks.

 

[jfisher]

I’m curious whether that’s the stock teksid block with different internals or the whole bottom end was swapped. Looks like you’re making good progress even with all the setbacks.

My guess is the whole long block was swapped out. I believe even the mark viii engines were teksid blocks? That's what I'm thinking this engine is out of, but I haven't confirmed. I did look up the cylinder head part numbers and they are also the same as Cobra B head castings so it's tough to say what is actually going on.

I did pick the car up yesterday from the exhaust shop. I always like the look of the Magnaflow tailpipes, but never liked the Magnaflow sound. I found a Borla S Type catback for a 99-04 car a while back and put it on in place of the jank Flowmaster catback that was on the car. I always hated the big 4.5" tips that were on this catback though so I had them swapped out for some Magnaflow style 3", 18" long tips. I think it looks a lot better and flows with the rear bumper a lot better. The only thing I'm not super happy about is how quiet the car is now. It was way louder with the stock exhaust manifolds and offroad h pipe. The pacesetter long tubes and offroad x pipe really quieted this thing down. Just wasn't expecting that

 

[07GtS197]

Didn’t even think of that, I’m sure you’re right. If the po didn’t swap cams, the stock mark 8 intake cams are a little less aggressive than the stock cobra cams.

 

[cobrajeff96]

When I saw your post concerning the 6-bolt crank in a Teskid block I thought oh by the previous owner left out some pertinent details. Then again, they might've not even known what they got when they bought it from someone else before. Either way, yikes. Good on ya though for sticking with 'er.

The mentioning of the IAC leak earlier makes sense, too. That's going to be un-metered air coming in. And that is a gasketed interface. Might just be old and worn in need of replacement. Should still be plentiful supply out there, I'd think.

I agree on the 96-98 Cobra hood. To me, it's iconic for the SN95 and I've always loved it even though it's largely non-functional.

FWIW, in 98.5 Ford went returnless fuel. Everything before is return.

 

[jfisher]

Didn’t even think of that, I’m sure you’re right. If the po didn’t swap cams, the stock mark 8 intake cams are a little less aggressive than the stock cobra cams.

At this point I'm just assuming they did not swap the cams. I believe it is just the intake cams that are different and that the exhaust cams are the same. From what I've seen we're talking about 10hp difference.

 

[jfisher]

When I saw your post concerning the 6-bolt crank in a Teskid block I thought oh by the previous owner left out some pertinent details. Then again, they might've not even known what they got when they bought it from someone else before. Either way, yikes. Good on ya though for sticking with 'er.

The mentioning of the IAC leak earlier makes sense, too. That's going to be un-metered air coming in. And that is a gasketed interface. Might just be old and worn in need of replacement. Should still be plentiful supply out there, I'd think.

I agree on the 96-98 Cobra hood. To me, it's iconic for the SN95 and I've always loved it even though it's largely non-functional.

FWIW, in 98.5 Ford went returnless fuel. Everything before is return.

Yep, it's tough to say. The previous owner had the car for 10 years though so I would be really surprised if he didn't have any knowledge. Previous owner also told me the car had SFC's, that the car shifted good and that it rode great. It was probably one of the worst riding vehicles I've ever been in when I picked it up, you can see the trans issues above and the SFC's were cut out about half way back (I flew to STL from Cincinnati to buy the car). If the car itself wasn't as clean as it is I would be a lot more bitter.

The owner before that was the original owner and had the car for 12 years so I'm 3rd owner.

I really don't think the IAC was ever the issue. Once I replaced the fuel pump my idling issues resolved for the most part. I think it still needs a bit of fine tuning, but that is coming soon.

I am swapping to an SCT BA5000 slot style MAF this week. I hate the placement of the stock MAF with this JLT intake and there's already a provision on the intake tube to add a slot style MAF. Should really help smooth things out as it's in a portion of the intake tube that is nice and straight.

 

[apsmith49921]

Very Nice car. sucks to see that 6 bolt in there that's definitely an oddity. I too found out a few dirty little secrets about my car too just have to accept it/fix it and move on. Really excited to see the progress on it!

Quick question did you notice anything by swapping to the H&R vert springs? I've got so called coupe springs on my car.