A few questions (long)

[jasonv1013]

OK, I'm hoping you guys can help me out with a few questions here.

I have a 95 Cobra with 125,000 miles on it Before this car, I've never had another v8 (or anything big for that matter). It seems to me that it's running rough and having some problems with its age. It also takes a while to start up when I crank it, and I don't think its pulling as hard as it should (though I have nothing to compare it to and have never taken it to the track).

I've replaced the air filter with a K&N, the cap, rotor, and wires were replaced about 10K miles ago with the stock replacements from Schucks, and the plugs are Bosch Platinum +4's. It's got a 180 thermostat in it and I've checked the TPS voltage and cleaned out the throttle body and the IAB. Also a relatively new battery.

The fuel pump was shot, and I just replaced it with a Walbro 190 today. It seems to be starting and running a little better, but it still had to crank for a good 10 seconds or so to start one of the times that I did it. I also put a new fuel filter in there and a new stock replacement pressure regulator (FMS pump that I got at first was shot, tried everything to get it to work).

So, any ideas? Are there any tune-up type items that I've missed? I was thinking of doing a compression test, think that would help? I know the motor is old, and I do someday plan on doing heads, cam, full exhaust, but I'd like to get it running well before I start digging into it.

Thanks for any help that you guys can offer.

Jay
-------------------------
'95 white Cobra Coupe
- K&N (silencer removed)
- 180 stat
- Walbro 190 in-tank pump
- almost running right

 

[Ginsu]

My car was doing some of the same things as your and when I replaced the fuel pump, it corrected some of the problems with hard starts and other little fuel starvation issues I noticed. I have a MSD that I plan on putting in soon but currently trying to decide where I am going to put it if I do not relocate the battery.

A tired ignition will also be symptomatic of hard starts and lose of power. Another thing I am considering is going to Jiffy Lube or other similar place to have the injectors cleaned.

I am assuming you car is otherwise mostly stock so it is not perform up to your expectations. Ford was natorious for choking the 5L engines from the factory. Poor flowing heads and restrictive exhaust and the 94-95 Cobra's (as well as GT's) had a milder computer to save transmissions (old topic but Ford did this in response the numerous warranty claims from the fox body Stangs). My self and a couple other guys here are using the FMS Extender that has been modified for the Cobra to help cure that problem. There are many topics in this forum on the Extender so use the search feature.

 

[MARK C]

Jay,
Myself I would go ahead and get the injectors cleaned or replaced. With that kind of mileage and having replaced the other things that you menchened already. I'm sure you are no way close to 100% flow anymore. You really can't go wrong. You should be able to get a set of 24#'s for around $200.
Hope this helps.
Mark

 

[want-a-L]

Ginsu,

Where would I be able to get the RPM Extender from? I just purchased a 95 Cobra. I know that the ones you order from FRP is for the GT and you would have to get it modified for the Cobra. Where would I get that done, or order one that is already modified?

Thanks

Chris

 

[SVT X 2]

I believe Rob & I got the Extender from the same place...
Diversified Products Marketing in Plymouth MI. They take the order and then ship it to Sam Guido of General Systems Research in Dearborn MI (313) 755-4543. He then charges $50.00 to modify it for the Cobra's, then ships it to you.

Jason,
check your EGR valve for proper function, also it wouldn't hurt to replace the PCV valve. I would also look into having the injectors cleaned. I just took mine out and brang 'em to this shop with the right equipment to have them cleaned & flow tested. They first quoted me $107.00 to do all 8, and ended up putting in all new o-rings, filters & screens, and one new cap and ended up only charging me $73.00!! The crap in the gas today is not too injector friendly... so a bottle of cleaner at every oil change is a good idea.

Also, it wouldn't hurt to have your O2 sensors individually checked (or replaced).

I have heard of dirty wires in the MAF causing rough running problems... might wanna clean those to be safe.

Even though you have a new pump, I'd verify that the check valve is working. Borrow or buy a gauge for the schrader valve on the fuel rail and see if your pressure holds after you shut the car off.

A compression check is okay to do for current motor conditions info. I did this last weekend... good luck with the back plug on each bank... those are real fun
I came up with 140 on each cyl, with two being 145 (25k on the Cobra).

That's all I can think of right now... hope this helps!

 

[jasonv1013]

Thanks for all the tips guys, here's an update:

Lately, the car has taken to shutting itself off while driving down the road, it's real fun to bump start it going 80 mph down the highway.:uh oh: Also, a few years ago, I was getting a check engine light, so I took it to the dealer, and they ran the codes. They said that the MAF had to be replaced, they wanted $800 to do it, so I waited, and the light stopped, so I did nothing. (bad, I know :sad ).

So this week, I ordered a Pro-M 75mm bullet, a Mac CAI kit, an MSD 6AL box, MSD coil, cap, rotor, and FMS wires. I'll also pick up new plugs from the parts store. I figure that should cover the shutting off (if it's the MAF) and the rough idle, and lay a decent framework for some later mods.

I'm also changing the oil this weekend, so I'll pick up a PCV valve too. Haven't changed that in a while. I was also looking at the O2 sensors, but Schucks wanted $90 each for them. Does anyone know where I can get them cheaper, or is that just what they cost? I'll also run through another can of injector cleaner, and if all of this doesn't help, I'll look at new injectors, or getting the ones I have refurbished.

Any other tips would be greatly appreciated, and thanks for all of the help guys.

Jay
-----------------------
'95 white Cobra Coupe
- K&N (silencer removed)
- 180 stat
- Walbro 190 in-tank pump
- almost running right

 

[jasonv1013]

Also, can I get to the injectors without taking off the upper intake, or should I get an upper to lower gasket before I start messing around with them?

Thanks.

 

[SVT X 2]

OMG! Thankfully you were smart enough not to go ahead and have the dealer replace your MAF!! That's a completely OUTRAGEOUS price for a MAF replacement!

Unfortuneately the upper plenum has to come off for injector removal... but it's not really a tough job to do yourself. You probably won't need any gaskets either, as long as you don't mung it up while removing the upper. I didn't need a new gasket, and it was off/on a couple times. Re-install of the plenum is best done with a torque-wrench. Starting with the inner bolts out, tighten in three, ft-lb sequences... with the last one ending in 24 ft-lbs.
I started with like 15lbs and hit all the bolts, then went to 20, then 24.

The O2 sensors aren't cheap are they? :cryying:
I just found out yesturday that BOTH mine are shot! I've been trying to figure out what's been wrong forever. I finally had a recent buddy that works at a dealer grab a Gen Star checker on his day off (Friday) and we went for a ride and the O2's were just doing whatever they pleased... including ZEROING out while driving! Tried finding a pair, but no luck. Found one dealer waaaay over here that had one, then another dealer waaay over there that had one, with not enough time left to get both where we were by quittin' time.
He's having the parts guy get 'em both there Monday (he's off then too) and he's gonna sneak a hoist real quick so he can put 'em in. Dealer retail per sensor is $100! Luckily he's gonna get 'em on his discount... which is 10% above cost, so $50.00 ea. (whew!), then whatever he wants me to flip 'em for time. He kids around and says he'll charge per 10th dropped in the quarter

Morral... get to be friends w/a dealer mechanic!! lol...