Technical => Engine Tech => Topic started by: jpc647 on August 09, 2010, 08:58:36 PM
Title: Fuel Pressure on a 1987 5.0 SO
Post by: jpc647 on August 09, 2010, 08:58:36 PM
If one were to test the fuel pressure on a 1987 Thunderbird 5.0 SO, at the little nipple valve on the fuel rail, what should it be? I tested it with the car running. I'm trying to figure out if i'm not getting enough fuel into the injectors, hence the injector clicking noise. And I did get a code relating to a fuel pump problem.
Anyone know? I tried looking in the book, but I didn't seem to find it.
Title: Fuel Pressure on a 1987 5.0 SO
Post by: Kitz Kat on August 09, 2010, 11:27:33 PM
Maybe you should ask a mechanic, You seriously got a lot of ??'s, How messed up are you making that car? All the ??'s you asked were answered , try searching a little harder.
Title: Fuel Pressure on a 1987 5.0 SO
Post by: hypostang on August 09, 2010, 11:48:04 PM
It should be close to 39psi
Title: Fuel Pressure on a 1987 5.0 SO
Post by: BogusSVO on August 10, 2010, 10:21:31 AM
39-43 psi with the vac line to the FPR disconnected
the roller over reset switch can also go semi-bad and that will in turn cause a low voltage to the fuel pump, and that will give low fuel pressure
Title: Fuel Pressure on a 1987 5.0 SO
Post by: jpc647 on August 10, 2010, 04:43:44 PM
Quote from: Kitz Kat;331342
Maybe you should ask a mechanic, You seriously got a lot of ??'s, How messed up are you making that car? All the ??'s you asked were answered , try searching a little harder.
What do you mean all the questions I asked were answered? I'm not messing up the car, I'm trying to fix it. They aren't worth a whole heck of a lot mint, so its not worth taking it to a shop and getting a $500 bill if I can ask a few questions here, make a few friends, and learn to work on my own car.
My 1972 Cutlass 442, I don't have to ask how to fix it, there are no sensors, check engine lights, everything is mechanical and one can see how it works. Although, that is probably why I never have a problem with that car.
Thanks for the replies though guys. If I'm getting 41ish, with the Fuel pressure regulator plugged in, is that normal?
Title: Fuel Pressure on a 1987 5.0 SO
Post by: TurboCoupe50 on August 10, 2010, 08:40:04 PM
Should be 39-41psi with the vac line disconnected and 30-33psi with vac, BUT a extra few psi of pressure will not cause the injector(s) to click, neither will low pressure...
To determine if it is a injector, disconnect each one's electrical connector(one at a time) and running the engine with it disconnected... It'll skip just as if a plug wire is off but won't hurt anything...
Title: Fuel Pressure on a 1987 5.0 SO
Post by: Bob on August 10, 2010, 10:12:15 PM
Quote from: jpc647;331385
What do you mean all the questions I asked were answered? I'm not messing up the car, I'm trying to fix it. They aren't worth a whole heck of a lot mint, so its not worth taking it to a shop and getting a $500 bill if I can ask a few questions here, make a few friends, and learn to work on my own car.
My 1972 Cutlass 442, I don't have to ask how to fix it, there are no sensors, check engine lights, everything is mechanical and one can see how it works. Although, that is probably why I never have a problem with that car.
Thanks for the replies though guys. If I'm getting 41ish, with the Fuel pressure regulator plugged in, is that normal?
Okay I get it, the 40 year old car is easy to fix but the 22 year old car isn't.
Pick up this book: http://www.amazon.com/Ford-Racing-M1832Z1-Electronic-Injection/dp/0837603013/ref=sr_1_1?ie=UTF8&s=books&qid=1281492197&sr=8-1
I read it about 15 years ago and after reading it (makes a good bathroom book) you will understand what all the sensors do, why they do it, EEC-IV error codes, and what tests will help you diagnose your problems.
In the meantime the search feature works great here. After searching and your at wits end than post a question. Thats all, I search stuff on this board at least 2 times a week and I've been messing with the same car for 15 years. Yesterday I wanted to know what size tire I could run on a 15x8 weld draglite and all I had to do was plug it in the search and my question was answered like 3 years ago and I even found pics of what it would look like. Now I could have had started a new thread and asked someone to take a picture of there wheels and post it but why? It was already asked and posted I just had to find it.
Title: Fuel Pressure on a 1987 5.0 SO
Post by: jpc647 on August 11, 2010, 08:43:53 AM
Quote from: Bob;331411
In the meantime the search feature works great here. After searching and your at wits end than post a question. Thats all, I search stuff on this board at least 2 times a week and I've been messing with the same car for 15 years. Yesterday I wanted to know what size tire I could run on a 15x8 weld draglite and all I had to do was plug it in the search and my question was answered like 3 years ago and I even found pics of what it would look like. Now I could have had started a new thread and asked someone to take a picture of there wheels and post it but why? It was already asked and posted I just had to find it.
Let me ask then. What did you type into the search bar to bring up exactly what you are looking for? Maybe my wording and so forth wasn't close. But my fuel pressure search pulled up all kinds of threads, but nothing close to what I was looking for.
Title: Fuel Pressure on a 1987 5.0 SO
Post by: Bob on August 11, 2010, 09:05:53 AM
I'm not sure what your trying to do, if your trying to test fuel pressure because of one injector that clicks (they always make a clicking sound btw) than your barking up the wrong tree. From my experiences fuel pressure will effect all the injectors not just one. If it was my car I would clear all my codes, drive it briefly and do the engine running test and a cylinder balance test and than take that data and look for a fix. If you don't know what those tests are than either read your scan tool book, buy that ford fuel injection book i recommended, search this forum, or google search it. Write down all your codes and use the links provided to you in the other thread and see what codes could possibly be related and handle each one, one by one... till you have no codes. Than if your car still runs funny its more than likely a mechanical problem I would think.
Title: Fuel Pressure on a 1987 5.0 SO
Post by: jpc647 on August 11, 2010, 09:48:59 AM
Yes, I was trying to test fuel pressure, to see if maybe there was a fluctuation in it, leading to the injector click. One, possibly two injectors are clicking all of a sudden. The clicking started after I changed the intake gasket, I don't understand why, the injectors weren't removed from the intake.
Title: Fuel Pressure on a 1987 5.0 SO
Post by: mcb82gt on August 11, 2010, 07:50:34 PM
Sounds like your pressure is fine. How are you sure it is injector noise and not a rocker arm or exhaust leak tick....etc?
Just thinking out loud.
Title: Fuel Pressure on a 1987 5.0 SO
Post by: jpc647 on August 12, 2010, 10:11:13 AM
Quote from: mcb82gt;331522
Sounds like your pressure is fine. How are you sure it is injector noise and not a rocker arm or exhaust leak tick....etc?
Just thinking out loud.
I thought about the rocker arm possibility. My thought on that though, is it only does it when there is a load on the car, and it will never do it in park or neutral no matter how high the rpms go. Wouldn't a rocker arm make noise regardless? Secondly, its not exhaust related, I've checked and rechecked the system. Nothing on the exhaust was touched when I did the intake swap. It started after that.
Knowing that the pressure is fine, it takes one more thing off the table. Trying to narrow it down here.
Title: Fuel Pressure on a 1987 5.0 SO
Post by: TurboCoupe50 on August 12, 2010, 08:36:12 PM
Are you sure the timing is correct and you're not hearing spark knock???
Rockers are going to make the same noise regardless of load on engine...
Title: Fuel Pressure on a 1987 5.0 SO
Post by: Beau on August 14, 2010, 04:07:33 PM
And if you play with timing, make sure you unplug the SPOUT connector, otherwise it'll be way off.
Title: Fuel Pressure on a 1987 5.0 SO
Post by: thunderjet302 on August 14, 2010, 07:43:33 PM
Quote from: TurboCoupe50;331642
Are you sure the timing is correct and you're not hearing spark knock???
Rockers are going to make the same noise regardless of load on engine...
At this point I swear it has to be spark knock......
Title: Fuel Pressure on a 1987 5.0 SO
Post by: jpc647 on August 16, 2010, 09:30:00 AM
Quote from: thunderjet302;331908
At this point I swear it has to be spark knock......
How can I tell? Is spark knock going to hurt the motor? I hate to sound dumb here, I've just never heard of it. I know the plugs and wires are a couple years old, I tried swapping a couple plugs around just to see if it changed, and I didn't notice a difference. I've seen a lot of threads where people have similiar problems, they do a complete tune-up and its still there, lol. I don't want to be one of those people, lol.
How can I tell the difference between spark knock and an injector click? Would spark knock be something that touching the valve covers or intake and such would allow you to feel something? I tried looking at the motor running at night for sparks or an arc, as someone else suggested, I didn't see anything.
Title: Fuel Pressure on a 1987 5.0 SO
Post by: Beau on August 16, 2010, 12:47:22 PM
Yes, spark knock, aka detonation is NOT good for an engine. I'd look into the timing, make sure it's set to factory specs for the engine itself, (i know you've swapped that v8 in there, right?) and get that sorted out first.
Spark knock usually only occurs under a load, or else with a higher compression engine on low octane gas, or really py timing/or timing advance not functioning correctly. Do you have a timing light, and know how to use it? How's the gas? Although in a stock 5.0 I wouldn't suspect that to be so much the cause, but you never know.
Is the Spout connector plugged in? It has to be unhooked to set timing, then plugged back in to run correctly...
If you're not sure where it is, you can google it, or I can snap a pic of mine. It should be on the harness that connects into the distributor, about 6-10 inches away. It's a square little thing with 2 wires, and it pulls out, to take the timing advance function out of the system.
Title: Fuel Pressure on a 1987 5.0 SO
Post by: jpc647 on August 16, 2010, 02:07:03 PM
The Timing was set, it is currently at about 12 degrees. It was set with a timing light, the spout connecter was u plugged to do it. I have tried running premium gas, with an octane booster, just to see. There was no difference. The plugs look okay, they could maybe stand to be replaced, but again, this didn't happen before the intake gasket was swapped in. The spout connected is back in place. I didn't check the gap in the plugs when I took them out, but I feel like that wouldn't have changed from putting the gasket in.
Would you be able to feel spark knock, near the cylinder? Also, when creating a situation where the sound is present, the timing can be changed +/- up to ten degrees retard and advance and the noise does not change. One way the engine dies, I forget which way, but the noise can not be "timed" out.
Title: Fuel Pressure on a 1987 5.0 SO
Post by: thunderjet302 on August 17, 2010, 12:49:26 AM
I know you pulled the distributor already but I'd do it again. Set the #1 cylinder to TDC again and make sure the distributor is pointed at the #1 cylinder and stab it in again. I keep getting the feeling that it is still off because the issues you've been having came up after you pulled the distributor.