93 Cobra hesitation, misfire, backfiring, etc.

[93_SVT_Cobra]

Thanks again for the great advice, Mark! I did replace the TFI about a month ago and nothing changed. The bogging under load remains. The coil has been changed as well along with plugs, wires, Cap and rotor. The gauge I have should reach to the cowl as it has about 3' of line. If you could, please advise on what I should be seeing as far as pressure is concerned under load, idle, etc. As said before I'm getting 32 psi at idle with vacuum connected to the reg, and throttling it with the throttle body, it jumps to 38 and quickly down to 28. That's why I'm thinking replace the pump. I really feel I've installed an 88 lph and it just won't keep up with the 24 lb injectors. Again the regulator is a new stock replacement. Next I'm thinking if the pump isn't the issue, may be a leaky injector ? Again it started becoming hard to start about two weeks ago like its losing pressure through the pump or an injector. Thanks again for your time and advice!

 

[fivestangs]

Dropping down to 28 or so on the guage wouldn't concern me..it could just be a fluctuation in the pressure or maybe the guage is a little off. When you're getting on it, and it's starting to bog, it should be reading at least 32psi, and realistically, it should be rising as the vacuum goes down. If it starts to DROP, like down in the mid to low 20's, I would have to believe there's some fuel delivery issue (insufficient pump capacity, insufficient voltage to the pump, perhaps a kinked/crushed supply line).

 

[JoeRacer]

I had some starting/driving problems in my 93 Cobra that were baffling me. I went through this article:

How to Solve an EFI No Start

There is a lot of really good info in there, and it helped me sort out my problems. Maybe you'll find something in there you haven't looked at yet. Good luck!

 

[93_SVT_Cobra]

Thank you for the great article. There's some good info in there indeed. So today I installed a Walbro 255 lph pump and that has solved the issue! After a year now and finally the car is fixed! It screams now. I haven't had this car run as good in a very long time. So long in fact, I had forgotten just how much fun my Cobra is to drive. Thank you all for the great advice and info. I hope my explanations and solution here will help somebody else.