billgates

Can anyone help I just bought a 1989 mustang gt with a lot of unknown mods on car. The mods i can see are a elbrock performer intake,a massive ford racing fan,ford racing plugs and wires,headers,h pipe,and it deffently has a aftermarket cam from the sound of the car but it has more mods that i cant see and dont even know if its a 302 or not. The car was sold at a auction it belonged too a guy who was killed in irac the only info on car was a lot of money put in to engine and car i also can tell it has low gears in it as well. The car is extreamly fast it smokes my 2010 camaro ss. But it seems to be running really really rich as i smell a lot of unburnt fuel and at idle it surges bad sometimes so bad it dies and it puffs a lot of black smoke when surging. Any ideas as to how to fix the surging or rich running. I know i cant tell ya all thats been done to car becuse i dont know with out taking engine apart.

dawson1112

any codes stored in the computer?
http://www.dfwmustangs.net/forums/showthread.php?t=7908

billgates

None the car scans no codes. But also i have noticed when it surges the fuel pump surges as well with the engine. I dont know what thats about. From the sound of the pump i know its not factory at all its one of the loudest fuel pumps i have ever herd. Its like the pump matches the rpms more rpms more noise from the pump. But when the engine starts to surge the pump starts surging as well

94redGTConv

could you maybe have too big of a pump? it might be a dumb ? but hey gotta learn somewhere I'm almost positive I'm wrong


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dawson1112

I was wondering the same thing if maybe the fuel pressure regulator is bad or if its adjustable maybe set to high.

billgates

Ill check out the pump. This is the first mustang i have ever bought. I am a mechanic but not for ford so dont hate me lol. The pump does sound like over kill to me but once agin i dont know ford cars very well. I will tell ya once its out of idle it runs fine and dosnt seem to be over fueled once the car is going. When at idle it dosnt start surging right away it takes about a min to start the surging so mabe it is getting loaded up on fuel.

dawson1112

Pull the vacuum line off the fuel pressure reg and see if it has fuel in it . If there is fuel in the vacuum side of the reg its bad.
and just another thought while im sitting here. Does it still have the egr valve on it ? if so it may not be closing all the way. When its at idle there should be no egr. If the egr is stuck open at idle it will stumble and load up.
Oh and as far as fuel pump is concernd a larger pump isnt necissarally make it run rich . The fpr controls the amount of fuel the injectors can have , if the fpr is set properly and working like it should any excess fuel from a bigger pump will be sent back to the tank via the return line.
Get a fuel pressure tester and check your fuel pressure. You should be at 30-45 psi engine idling and 35-40 koeo . If some one installed a larger pump it would make sence to install an adj. fpr it may be set to high.

billgates

Also when i was looking at the engine today. The fuel rail looks way differnt from other 5.0 i have seen before it has some strange adaptors and capped off lines coming off it. Mabe had nos on it at some point or i just could be crazy. But from other 5.0 i have seen it looks differnt and larger size fuel rail. Its hard to work on a car or know what to check when you have no idea what has been done to car. A lot of parts on this car look like over kill like this huge high pitched fan on this car i bet the wind off this thing could power the car like a plane. But once agin what do iknow im just a heavy equipment mechanic.

billgates

Good idea man i didnt think about that ill check that out. Thanks man

billgates

I didnt see a egr valve. Ill get some gauges from work and see what the fuel pressure is. I did see a ajustable regulator but im gonna check the pressure before i change any settings.. could it also be a stuck injector.