My son drives a 89 Turas with a 3.0. It was running rough with now power so he gave it a tune up which helped for a day or two. The plugs fouled out quick. Was going to check timing and found the vibration damper outer section was loose from the inter section, it was replaced with no help. Checked the fuel pressure regulator and it is working good with no leaks. I have not checked the injectors yet to see if they are getting a singal to fire but since the plugs are fouled I would think they should be. The only way to get it to start is and run is with starting fluid. It has 40 psi of fuel pressure so its getting gas and spark. If you spray enough to keep it running it sounds good but to little it will backfire back out the intake. Its got 165,000 on it and the compression is starting to get wide, 100 to 150. He hopes to be able to run this a few more months until he can afford something else. Does anyone have any ideal as what needs to be checked next. Thanks for any help that you can give.

 

One possibility is that it's not getting the proper amount of fuel despite the pressure reading and the regulator checking out OK. I would continue to focus on the fuel delivery system, especially the injectors, in that regard.

As for timing, what does the distributer look like? On older 3.0Ls, sometimes the gears on the synchronizer can wear out and fail.

 

I've not pulled the distributer to look at the gears. I have watched it with the cap off and it looks as if it is turning good. I may need to pull the injectors and see what they look like. If iI can borrow a scope from work I may check the signal to the injectors to see what they look like. I just get a couple of hours on the weekend to look at it so its slow going. I guess I also need to remove the connection on each injector and ohm it out to make sure that one or more is not open and cannot fire causing the problem. I made him leave it outside so I could park inside so I hope the weather is good. Thanks for the help, I'll let post what I find.

 

I used a scope to check out the firing of the injectors. They are getting a pulse of about 10.3 volts for about 20 milliseconds (on time) and are off for about 440 milliseconds for a total of about 460 milliseconds per pulse. The lowest I saw on the battery voltage was 9.92 and fuel pressure was 36 psi. I did pull the injectors and clean them, also replaced the o rings and caps. I also put about 30 psi od air pressure on them and cycled them several time each and they all were workin, this was using a charger so the voltage was a little higher. I gapped a old plug to .055 to see how good of a spark it was getting and it looked good. Does anyone have any ideal what it could be?

 

I finally had a chance to work on it and it was the map sensor. The output was between 88 and 33 hz and should have been between 162 and 92. Its easy to check if you have a meter that will read hz and can cause a lot of problems since its used to set the timing. You could see ruff idle to poor gas milage. If you need more info on how to check just do a search online for Ford map sensor amd you can find some web sites on checking it out.

 

Thanks for the update. Good to hear you fixed it.