Hey All,

My real love is the '78/'79 Ford Broncos but I made a deal today and aquired myself a 1990 2wd F150 shortbed with the 351W and (I think) the E40D overdrive trans. Problem is, the newest Ford I've ever really worked on in the past was an '83. I get the basics of what parts are what as far as EFI... but have to admit that I know NOTHING about actually working on / tuning / troubleshooting one! Other than the obvious (read, learn, buy a manual, and absorb info) any tips on any good online reading on this stuff? Betting between this site and the Mustangs sites out there... there's a lot of good info out there?

Thanks in advance!

 

Welcome to the site.
You might want to check out this site also.
http://fordfuelinjection.com/?p=1

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Thanks Subford! Wow that site has a ton of info! About all I know as of yesterday is what the basic parts are (intake, throttle valve, injectors, etc). Tuning / troubleshooting is ALL new to me. Yesterday's issue was that when I started it the fast idle (if you even call it that on an EFI) only lasted about 4 or 5 seconds and then it dropped right down to about 500rpm. Figured I'd do some reading before I start posting here with prob's and how-do-I-fix-it posts. This is all a new learning experience for me.

 

Lots of info here on tuning "etc". These trucks seem to run best on MotorCraft plugs.......MSD Cap, Rotor and Coil and Ford Racing 9mm wire is a nice upgrade for them too. Wire routing is BIG. Lots of crossfire/miss if you don't route correctly. Here's a post for that....use the "bobcf" 1-3 and 1-5 for the best pics.

https://www.ford-trucks.com/forums/6...e-routing.html

Troubleshooting is reading your codes when you have a CEL. I bought an OBD1 reader at Advance that makes it easier for me....$30. Your "fast idle" sounds like it's working ok if you aren't having any stalling issues.. EFI isn't like a carb at all.....computer controls it completely.

Ask and you'll get answers........and we love pics too. Show it off........

Good Luck
Bob

 

I've been outside messing with it in the garage today. Will definitely have to check out the wiring situation! I did pull off the coil wire and the contact was completely rusted up so I replaced that wire with another 8mm coil wire I had in the garage.

Problem is that it will run but it won't idle without dieing unless I keep giving it some gas. It has a tach on the dash and it wants to idle (in park) at 500 rpms. Not even sure about Drive yet because it definitely won't idle in Drive without dieing.

On the other hand... I think I am probably running this on what could be some very old gas... fortunately the front tank is almost on empty and I need to get some new stuff in there. Seems to be a lot of clues that this thing has sat for a long time. Hoping that new gas will really make a difference. Got this from my neighbor who is a mechanic and this was payment towards labor on a job that he did for someone. It's something that was known would be needing some work but basically runs.

Thanks for all the input here, I really appreciate it!

 

Sounds like the IAC valve may be stuck.

 

Spent at least a good hour or more just searching this forum this afternoon.... the IAC is EXACTLY what I suspect! Maybe tomorrow after work... it was kinda cold drizzly and blah here all day long (except for the new toy) but I finally just called it a weekend.

Funny part... I had to print out the "Abbreviations" page from fordfuelinjection.com to keep up with what you guys were talking about while searching threads... LOL! Gotta start somewhere I guess.

 

The stuck/sluggish IAC problem is VERY common on these motors, this valve need routing cleaning. You'll do a better job of it if you remove the valve from the intake, remove the actuator and then use carb cleaner and a small brush on the valve. When it moves freely you are done.

 

Today's update... messed /messing with it after work. Had it running for a while until I could get it to stay running while idling at it's usual (since I've had it) 500 RPMs. Pulled the plug to the IAC and it died. That's what it's supposed to do. Sidenote... when I first start the engine cold, it does run at about 1200 RPMs, but only for about 5 seconds. Wondering if I should try getting the codes. I'm new to this but I'm wondering why, if the valve is stuck, I do get those few seconds of 1200 RPM's. (Hmmm... unless maybe that's just the ECM advancing the timing)?


BTW- this 500 RPM idle is a very steady 500, not up or down, tach stays right at 500. Think I'm going to get at this IAC and see what's up with that before I go any further!

Back out to the garage.....

 

I would think the IAC is OK if it dies when you pull the plug.
My 95 is idling at 600 RPM in gear, I was watching it today when I stopped at some stoplights.

 

You will have a very good truck after you get the engine in good tune. I had one equiped just like yours except mine had the long bed. That was a great truck! Traded after it had 100K for a 1995 4X4 F150. Made a mistake of buying the 95 with a 302. Sounds like you are on track on what to try first. These folks will keep you working until you find the problem.

 

Took the air tubes off last night (throttle valve to airbox). Pulled the IAC and it really wasn't that bad at all. Maybe a little bit oily but not gunked up. Replaced the IAC anyways with one off of a 5.0L I picked up yesterday at the junkyard (ID numbers were the same). Started it up. With the air hoses off now I can definitely hear the IAC cycling when it gets 'stumbley' and it does pick the idle back up. Disconnected the battery cable for awhile thinking that maybe it'd give the ECM a fresh start... (don't know if that actually works but it made me feel better)! It idles at 600 RPMs now and didn't die when I put it in gear (still stayed at 600 RPMs)... but by that point this was with the engine pretty well warmed up.

Ya' know... I had the re-realization last night that I never did put any new gas in the truck. I've ran some old carbed vehicles in the past with old gas and the exhaust was WICKED. This one's not so bad. But then again I'm thinking most of the old gas vehicles also had screwed up carbs too. This is a whole new ballgame here and I am wondering if most of my problem here might just be as simple as really old gas.

Unfortunately I don't have much history on this truck. As far as papers laying around the inside when I got it, one was a proof of insurance card that expired in Nov 2001. I got to thinking about it.... the possibility exists that I may be running this on INSANELY OLD gas. Maybe I should be glad that it runs at all?! Figured no new 'troubleshooting' until I get new gas in there!!