Fuel Possible fuel issue.

olmstead.jim.w

New Member
Mar 21, 2019
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Hello, I have an 87 Mustang 5.0 that has been converted over to Mass Air by the previous owner. I have checked the wiring and it appears to all be done correctly. When it’s cold it runs perfectly, after it’s up to temp for s bit it starts fluctuating in idle and I also start noticing a strange smell from time to time that I’m not sure if it is some sort of exhaust smell or burning too much fuel.

It has a cold air filter on it but it is positioned right by the engine so I’m wondering if it’s pulling hot air if that might be causing a problem? Idk what it has for injectors currently but could I be pumping too much/not enough fuel?

Any advice, tips, thoughts would be greatly appreciated. I am always open to learning something new.

Thank you...
 
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General karthief

wonder how much it would cost to ship you a pair
Mod Dude
Aug 25, 2016
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This checklist will help you resolve your issues, just read the directions step by step.
Let us know if you get stuck on anything. Post some pics of your stang and include the engine compartment and future plans.
 

c's90GT

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Oct 30, 2018
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I had a similar issue on my 90 gt. I used this checklist and got a few codes. Its actually easier to do than I thought. I kind of cheated and bought the OBD1 scanner for around $20.
 

olmstead.jim.w

New Member
Mar 21, 2019
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Warren Center, PA
General karthief thank you for that information. I had seen that once a while back but I couldn't remember where and was having trouble finding it. It has a lot more information there than I remembered. I believe it will be quite helpful. I am actually planning on cleaning the car up a little tomorrow so I will try to get a couple pictures and post them after.

c's90GT I decided to do the same and ordered an OBD1 scanner. Hopefully with both that list and the scanner I will be able to get it all worked out and running smooth.
 

olmstead.jim.w

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Mar 21, 2019
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Hello again. Here are a couple pictures of the car from over the weekend. Our town did our yearly fireman field days and the actual picture of the car was taken during the parade. The engine pictures were taken the day before when I was replacing the heater hoses that both cracked that day while I was driving home from town.

In the picture you can see where the air filter is located, which in the surging check list says do not do that with the mas air conversion. SO I thnk that is the first thing that I am going to change this week. I already had planned to do plugs, wires, cap, rotor and thermostat Wednesday this week so I will add that to the list of things to do. I found a factory airbox for it and also have the kit to make the hood functional for ram air. The kit basically replaces the cover for the air filter and puts the cone style k&n filter inside the box while getting the air directly from the hood vents. (not really trying to explain how the ram air works because im assuming you already know that just trying to say what I have and plan to do). My question here is do you think this will help get me back to getting cooler air rather than the hot air that I would assume its getting being right next to the engine at t he moment?...

Also I thought I would mention, other than the Mass Air conversion, it has had long tube headers put on it and I don't believe it has the Cats on it.

During the parade going at slow speeds for longer than I have ever had it at slow speeds like that, it was deffinatelt overloading on fuel. A coule times when the few of us mustangs that were in the parade would rev it up for the amusements of the interested kids (and some adults lol) It was quite noticeable that I was getting some black smoke out the tailpipe. My cousin who was watching the parade said a couple time it looked like I was driving a diesel. In the article with the check list it mentioned that could also be a bad fuel pressure regulator. so there's something else that I am going to have to look into from the look of it.

First thing I am going to do this week however is run the codes with that new code reader that I have. I didn't realize until I was reading the manual what its a 2 person operation unless you have the extension cord to hook it up and be able to do it yourself from inside the car. I ordered that and plan to have it Tuesday so I think Wednesday will be a busy day diagnosing some problems.

One last thing that I have been thinking about that I am curious if anyone would know. Another thing that the list says is that the speed sensor being bad can cause the surging also. I replaced the speed sensor about 2 months ago because my speedometer wasn't working so I replaced the speed sensor and gear. My speedometer worked for about 2 weeks and quit working again. Well once in a while it will work but only for a few mins and quits again. The old gear when I took it out was stripped on the inside where is goes on the shaft of the speed sensor. I am assuming that this gear that I installed is doing the same thing with the new speed sensoe making me think that the cable has an issue. Either way what I'm wondering is even if I have a good speed sensor but the gear is no good, would that cause the same effect?

Thanks again for any help and time...
 

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