I have a 94 xlt 4X4 with a 5.0L, 5 speed, 56,000 miles. The truck pings while accelerating and climbing hills. The problem goes away using 93 octane fuel (expensive!) Since I've had the truck I haven't gotten more than 15 mpg. I've found out it has nothing to do with the timing. I've heard everything else from ignition, O2 sensors, intake problem. Any ideas will help, I'm stuck. I would hate to have to take it to the shop, there is no check engine light. Thanks

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1994 F-150 4X4 Regular Cab, 302 EFI, 5 spd. K&N Filter, Gibson Super Truck Split Rear Exhaust

 

Could be a number of things! Tune up lately, with plugs, wires, etc? There is all kinds of running maintenance with cleaning the throttle bores, IAC valve, checking sensors like your 02 or temperature coolant. The truck is designed to run on 87 octane, so it is just a matter of making it run more efficient. I have found that every little detail matters with these EFI systems, so just make sure ALL your features, such as your ignition, filters are performing well. A slight vacuum leak, can cause one of your sensors to read something and pass the wrong info back to your computer, which could advance your timing. You could change brands of gas too. Could be the same octane rating, but all are not created equal..Hope this helps you out some..

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1993 F-150 4x4 5.0L EFI 5spd. Silver Shortbed..Kelly Safari AWR tires,K&N Air filter,Cat-Back Exhaust.

 

Doesn't the little things irritate you! His/your truck is Mass Air, and I am not sure if you can manually adjust the timing. I set my timing advance way ahead to about 15 BTDC one time, and it pinged horribly. I would suggest resetting your timing back to original, says on the underhood sticker on the drivers side.

 

yep, had the same problem.try seperating your plug wires really good,maybe you have some bleed over.

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91 long box,302,auto,bosch plugs,accel wires,steelhorse steps,31x10.50 tires

 

Ok Pastmaster, you didn't start that pitcher with out me did you? Lol! I think my truck is the speed density and not mass air. If I've done my homework, MAF was started in a partial of trucks for 94' and the same partial for 95' and 96' was all? MAF's. I don't know what pacat1 has, he'll have to look.

 

From the Factory, it would be Speed Density. At least my 93 is, and most are. Your in luck if it is Mass Air. another member here has a 1995 F-150 with a 300, and his is Speed Density. So I think just the v-8's got MA. I don't think I've ever seen A speed Density EFI on a 94 or newer F-150, any v-8, but I may be wrong.

 

Would one of you mind explaining the difference in speed density and mass air. How can I tell what I have on my 1996 f150 w/302. One large tube leaves my air box and splits into two about a foot later. There is a small sensor in the in the back of the air box that twists in and out. Thanks for your answers. I have no idea. -- Martin

 

You posted the same question under the "help" topic by jim-mc and it was answered there. But it sounds like you've got the MAF, which will allow more notiable mod's for performance improvements...Hope this helps..........Les

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1993 F-150 4x4 5.0L EFI 5spd. Silver Shortbed..Kelly Safari AWR tires,K&N Air filter,Cat-Back Exhaust.

 

The MAF sensor is located right next to your air box, in line with your hose hook up. It will be a 3" box x about 1 1/2" thick, with a cluster of wires going into it. The sensor is the go between your air box and the throttle bores. Speed Density will just have the throttle bore hoses hooking directly up to your air box. Hope this helps......Les

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1993 F-150 4x4 5.0L EFI 5spd. Silver Shortbed..Kelly Safari AWR tires,K&N Air filter,Cat-Back Exhaust.



[This message has been edited by JOHNNY MC (edited 04-17-2000).]

 

Sorry for the same question. I knew that I had asked it but forgot where it was, I spent a long time one day last week looking for it. I quess I'll go read it now.

 

Hey, no problem ...If you forget or have a question, just go up to the search mode and type in the subject. It'll search the archive's for about any subject or answer that has already been discussed. Enjoy!!

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1993 F-150 4x4 5.0L EFI 5spd. Silver Shortbed..Kelly Safari AWR tires,K&N Air filter,Cat-Back Exhaust.

 

I have two tubes leading from my air filter, is this mass air or speed density? Where is the sensor located on this setup?

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1994 F-150 4X4 Regular Cab, 302 EFI, 5 spd. K&N Filter, Gibson Super Truck Split Rear Exhaust

 

I checked under the hood, I have speed density on my 302. I'm in the process of changing the PCV valve and checking the EGR valve. How difficult is it to replace the O2 sensors and the IAC valve? I was also wandering what a fipk would do on this setup? Would that take the O2 sensors out of the loop?
Thanks

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1994 F-150 4X4 Regular Cab, 302 EFI, 5 spd. K&N Filter, Gibson Super Truck Split Rear Exhaust

 

It's not real hard to change your 02 sensor, just getting the right tool to remove it. You can get this at about any auto parts store. I know some of these sensors are pretty $$. Are you replacing the IAC valve because you know it is bad or just replacing it? No, with the FIPK system, you'll leave in your 02 sensor. If you don't have a repair book or service manual, I recommend getting one. Not only will it save you money in self tests, but you'll learn more from the book and here asking question about your truck. No such thing as a dumb question here on this board! I know it gets real frustrating trying to trouble shoot and not knowing alot about the truck. Sensor this, sensor that, but after reading about the tests and asking questions, you'll learn how the EFI system works. Still having the problems?.....Les

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1993 F-150 4x4 5.0L EFI 5spd. Silver Shortbed..Kelly Safari AWR tires,K&N Air filter,Cat-Back Exhaust.




[This message has been edited by JOHNNY MC (edited 04-18-2000).]

 

pacat1. You might want to wait on yout FIPK system as some are expensive and I personally don't think you gain alot with some types. The key is to get fresh air into the motor. You've probably got the same set up as mine, with the air box and an air intake tube that plugs into the bottom, with the opening mounted to the top of the rail over your radiator. Slowly close your hood and you'll notice that the inside bulge of your hood sets right in front of the inlet tube opening!! No fresh air here! Some of the kits will have a tube coming off of your throttle bores and then a big cone filter mounted to that, That'll be breathing heated engine compartment air! No fresh air here! Either look into using a newer model set up with the fender air or using some type of ram air system like the old muscle cars had. With the Speed Density, you can make "minor" improvements like spark and air, but the MAF systems, you can make cam, manifolds, etc. and the EFI system will still run. You also can "chip" your computer, which will allow for any mod's or just to make your current system run ALOT better..Sorry this is long, but there is alot to consider here...Hope this helps..........Les

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1993 F-150 4x4 5.0L EFI 5spd. Silver Shortbed..Kelly Safari AWR tires,K&N Air filter,Cat-Back Exhaust.