[Arian5.0]

hey guys im trying to figure out wth is going on with my car it has 10 pounds of vacuum and compression on the 8th cylinder was dead and i brought it back up to 110. PISTONS AND RINGS ARE GOOD, THIS IS WHAT THE MECHANIC TELLS ME. car is not running how it should.. it has a miss at 1500 rpm 2500 rpm. ive posted a topic about this not too long ago and i havent gotten answers.. this all started happening when i changed the fuel pump which was a walbro 255 i beleive it was outside for sometime, im not sure if the fuel injector are dirty or clogged but ive checked the fuel pressure and its good its around 45. the only this is that pressure drops when the car is hot but not while im driving. when im at a stop.. the car has been in the shop for about a month and they cant figure out wtf!! is wrong with the car and its already gettign frustation.. sorry for the (wtf) PLEASE ANY ANSWERS WOULD HELP

[93hatch]

change your plugs

[haywood11]

i dont know about you but ive had hands on expierence with buying a used fuel pump and the results were irratating. have you checked the injector pulse on that cylinder?

[haywood11]

plugs may be the problem but i dont know how that would go hand in hand with fuel pressure dropping when it gets hot.

[grnstang]

change fuel filter and fuel pump

[1slo5.0]

Originally Posted by Arian5.0 hey guys im trying to figure out wth is going on with my car it has 10 pounds of vacuum and compression on the 8th cylinder was dead and i brought it back up to 110. PISTONS AND RINGS ARE GOOD, THIS IS WHAT THE MECHANIC TELLS ME. car is not running how it should.. it has a miss at 1500 rpm 2500 rpm. ive posted a topic about this not too long ago and i havent gotten answers.. this all started happening when i changed the fuel pump which was a walbro 255 i beleive it was outside for sometime, im not sure if the fuel injector are dirty or clogged but ive checked the fuel pressure and its good its around 45. the only this is that pressure drops when the car is hot but not while im driving. when im at a stop.. the car has been in the shop for about a month and they cant figure out wtf!! is wrong with the car and its already gettign frustation.. sorry for the (wtf) PLEASE ANY ANSWERS WOULD HELP

How did you "fix" the dead cylinder???? I'd throw that fuel pump out and get a new one. Using a fuel pump that you don't know the history of or one that is not known to be working is just asking for trouble. There should have been a light bulb going off in your head the minute you suspected it sat outside for a period of time.

Oh, and find a different shop because the one you are dealing with is obviously filled with idiots. These places get paid to fix vehicles, if they can't properly diagnose and fix a problem then they shouldn't be in business. Especially on something as simple as a fox body Mustang.

[haywood11]

+1 right on man

[Arian5.0]

well the dead cylinder was at 45.. the heads had some bent valves, but the problem is still there.. compression is at 110 or more not sure of the correct reading.. mechanic saids its electrical and i would take it somewhere else but i have credit with them so im not paying for anything.. either way they have to fix it. and the fuel pump has been out of the tank, i cleaned out the tank and put back the old one.. the guys saids its not the piston or the rings.. any suggestions?

[88Saleen]

get your car out of that shop. you can do what they have done for you... nothing. find a better shop

[GoodOleBoyzRacin]

Originally Posted by Arian5.0 well the dead cylinder was at 45.. the heads had some bent valves, but the problem is still there.. compression is at 110 or more not sure of the correct reading.. mechanic saids its electrical and i would take it somewhere else but i have credit with them so im not paying for anything.. either way they have to fix it. and the fuel pump has been out of the tank, i cleaned out the tank and put back the old one.. the guys saids its not the piston or the rings.. any suggestions?

find out what bent the valves. they just dont bend for no reason. but if they are bent yes compression will be low. check the pcm also for the fuel problem. i know theres been a few times ive seen a computer go bad and the car do the exact same thing

[1slo5.0]

Originally Posted by Arian5.0 well the dead cylinder was at 45.. the heads had some bent valves, but the problem is still there.. compression is at 110 or more not sure of the correct reading.. mechanic saids its electrical and i would take it somewhere else but i have credit with them so im not paying for anything.. either way they have to fix it. and the fuel pump has been out of the tank, i cleaned out the tank and put back the old one.. the guys saids its not the piston or the rings.. any suggestions?

How do you know you have bent valves? If valves are bent you will not fix any compression issues until you pull the heads and fix the valves. The only for sure way to tell if valves are bent and which ones is to have the heads off so if someone had the heads off to look at valves, why didn't they fix the valves???

[Arian5.0]

Originally Posted by Darrell How do you know you have bent valves? If valves are bent you will not fix any compression issues until you pull the heads and fix the valves. The only for sure way to tell if valves are bent and which ones is to have the heads off so if someone had the heads off to look at valves, why didn't they fix the valves???

ok this guy is telling its an electrical problem because my valves are good piston and rings are good.. he changed the coil whic h was going bad, fixed all of my exhaust leaks..the only things is taht my vacuum is at 10, but i do have a mild cam, not sure which one i have...anyways he told me he pulled out the valve cover and did an air test to see if the air escapes from somewhere but it doesnt..he changed the valves and springs that were bad.. the guy is good from what ppl tell me because hes done a couple of my friends stangs that were worst than mine.. and hes taken care of them. i think its the fuel injector.. because the problem started happenning the day i changed my fuel pump but i put back the old one..