hey all, i'm new to the forums here. i just bought an '89 formula 5.7 and she started giving me problems as soon as i parked her into the driveway. i finally got her started, but now she is running real rough. i was trying to check the injectors with a noid light and the engine will actually run a bit better with one of the injectors unpluged and will stall when i plug the wire harness back in. any suggestions?

 

Id start with the good ol tune up, just to eliminate annoying little issues creating a big problem, new plugs wires, cap and rotor button, fuel filter, and check fuel pressure, I believe you should be between 40 - 44 PSI, then see from there!

 

http://www.youtube.com/watch?v=lKKhYJd1gzg i think u have a bad injector. If so replace all 8 at the same time. 22lb/hr injectors.

 

stock fuel pressure is 43.5 psi also,but i doubt that is your problem.

 

thanks for the reply so far guys. the pressure from the shrader valve is like 40-42 psi. i actually tried checking the injectors with a cheap ohm meter i bought, but i cant figure out how to use the f-en thing. not sure if replacing the injectors is something i would try to do myself. i guess i should do the tune up sooner than later, was just hoping to wait for some warmer weather. what plugs do you guys recommend.

 

Did you watch the video i sent you? How did you check the fuel pressure? Should be checked with vehicle in park and running with the vacuum hose to the regulator plugged.

 

thanks for the reply ninety-one. i did watch the video, but still had trouble figuring this thing out for some reason. please bear with me because other than some routine maintnence i am pretty novice at this. the ohm reading from the injectors was not consistent and the one that i plug in and stall the car was a 7 i think. i re-tested the fuel pressure like you suggested and got 43.

the car seemend to run pretty good when i bought it, but with a slight miss, then went to no start at all. it finally started when i used a test light in the injector boot. i was thinking that there could be a ground problem and the test light grounded the FI wire or wires. i checked all the ground wires i could find.

so i guess i do need to replace the injectors, but do you think that the injector would fail fast enough to cause these problems all of a sudden?

 

Yes it would. All of your injectors should be up around 0.015 ohms or higher or at least close to that and all be consistent with each other. If u find one at like 0.011 ,then it is bad. Replace all 8 injectors at the same time too. This is a very common problem on these cars too.

 

Sounds like injectors. If the ohm reading of 7 is accurate, your coil is bad and that is something that cannot be repaired. Unfortunately, as ninetyone mentioned, the multecs are notorious for this type of problem. They should probably be replaced.
By the way, welcome to the forum. The members are great and they are extremely
knowledgable.
If we can help you in anyway please do not hesitate to contact us.

 

thanks again 91. thanks southbay, i am gonna try to get ahold of a quality meter and ohm the injectors again. i figured i would be giving you a call later today or monday, as i have seen your post on here before. i am on long island also, central suffolk.

when you say multecs, is that the stock injectors?

 

Yes, the multecs are the stock injectors.
Well, again, when you are ready, we will do whatever we can to help.

 

Originally the car would not start at all? Did you try starter fluid? What would happen? Did you check the timing?

 

hey bandit. when she did not start i tried starter fluid and she would start up, so i was thinking that the injectors were not firing gas into the cylinders. she started on her own when i took one of the fuel injector wire boots off and tried to use a test light on it. so she starts with the injector unpluged. that injector ohms real low, so i guess ts not functioning, maybe allowing too much gas into the cylinder and flooding it, not letting start. im gonna see about ordering some new injectors today. i hope that solves my problem.

i have not checked the timing, i did remove the distributor cap but did not loosen the distributor at all. i guess she wouldnt run if the timing is really off, but how bad could she run if the timing is off?

 

If you've got one inj with very low resistance, it's defective.

Replace them before trying to troublehsoot it further. Pretty tough to figure out anything, having to work around something fatal like that. A waste of time really.

Leave the timing alone for now. It doesn't just up and change all on its own. Unless somebody has already messed with it it's fine. People blame it WAY TOO MUCH for problems it cannot possibly cause, this being one such.

Tune-up stuff though, also a total no-brainer; do it right away; it's yerbasic "new to me" maintenance, just like replacing the fluids.

 

Injector season mine bad to runs 4 10mins dies won't start up till l8r and do it again

 

thanks guys, picking up the new injectors tomorow, will let you know how it goes. any pointers for installing them?

 

just picked up my fuel injectors from south bay fuel injectors this morning. i have to say, the NICEST person to do business with. very freindly, helpfull and answered all of my numerous questions. i wish i could buy all my auto parts from them. i would definately recomend giving them a call if you need injectors.

now just wish me luck in installing them.

 

How did it go

 

just getting to it now. have some issues at the house now too.

 

unfortunately i couldnt get outside today until about 1:45 and had to wrap it up at 4:30ish as it was getting dark quickly. so far so good, got the fuel rail ready to lift off, but left it on top as i was afraid to take it any further in the dark. expecting some rain tomorow so hopefully i can get a early start on friday.