possible fuel problem

[joshbaker]

hey all, new here. i just got my stroker built and in. its a 1990 with 4.2 rods and crank, new everything, lunati cam (63501)ported head. when i pulled the engine i found that 3 injectors had no tips so i pulled the ho injectors from my buddies spare engine. now for the problem, when i'm running down the highway and get of the gas and then get back on it it sputters and pops but eventually gets going again. does the same from a stoplight. any help would be great. thanks

[Muad'Dib]

Sounds like your running lean, and i would expect that you are since your running stock replacement injectors. Try some 24 pounders, and you should be good to go.

[joshbaker]

thanks. will the ford orange injectors work? i believe they are 19#, what are stock renix and stock ho injector sizes?

[Muad'Dib]

I forget when the actual split was, but stockers are 19# and something like 21# for later models...

The mustang 5.0 injectors are stock replacements for the two peice 19#ers that tend to break and leak. You need 24# injectors.

[eliv1]

i would check the vehicle speed sensor. i guess its the one to blame.

[joshbaker]

so i finally got some new 24#ers. better throttle response, better high rpms, but still the same thing down low. also when cruisin down the road ( at any speed) you can just feel it like lose power all the sudden. friend of mine thinks its a flat cam. any thoughts on that? thanks

[dwg86]

Are you having valve noise? That would be the first sign of a flat cam.

[joshbaker]

no valve noise. when it pops, its through the intake. i have a fuel pressure gauge.where should i put it and what numbers should i be looking for?

[Muad'Dib]

When i had popping through my intake it was from running lean. It was a combination of fuel rail o-rings being leaky, and my fuel pump not working properly. When i took pressure readings at the rail all was good... but the fuel pump was still on its way out.

If i were you i would get a junkyard fuel pump and swap it in. See what happens. I did just that, and i am still running on the same junkyard pump for the past 3 years.

[joshbaker]

thanks man. that was going to be my next guess cause it doesnt come on everytime i turn the key on. i thought it would still have good pressure tho when on.

[gradon]

So I've been having an issue with the coil input connector connection(the snap thingy is broken, so I have it zipped) and every now and then it'll skip a sequence and then when it fires the next, there's a nice big backfire in the exhaust. A backfire in the intake sounds like the cam sensor in the dizzy isn't sync'd correctly, so fuel is being ignited at the wrong time. Go read Bratcop's project build to find the article.pdf to index the dizzy correctly.

[joshbaker]

so think i got the dizzy indexed right. now my cam sensor is straight down, 6 oclock, so i put the rotor at about 7 oclock. the guide says it should be at about 5 oclock. it also seems that the stuttering is when its warmed up. its fine when cold. so far now since the problems started its got new coil, icm, crank sensor, tps, new cap, rotor. would the knock sensor cause some of these symptoms? map sensor? will try the fuel pump when i get back from vacation. thanks guys

[joshbaker]

sorry guys, foergot to inform you that i got it fixed. its was the fuel pump.i took the old one out and ran a hose down inplace of the pump. i then put an inline pump in. works awsome. thanks for all the help

[Muad'Dib]

Glad you got it sorted.

[joshbaker]

new problems. so the fuel pump i put in is a in-line pump from summit i had laying around. new fuel filter. now new fpr. the jeep runs rich as hell. smell it bad in the exhaust and in the oil. i put the stock injectors back in and it wouldnt run again. so back to the 24'ers. what do i replace next? thsi thing is a never ending money pit.