Low economy at citi???

[javi2001]

Hi guys my F150, 1995, 4.9L + E4OD is runing very nice on highway but driving by town it actually "Drink" fuel.

This truck is totally stock, good service, all the tuning and maintenance stuff is recent, even brand new Ford injectors. The only thing modified is a restrictor plate installed at EGR valve.

I was wondering, the EGR helps to reduce fuel used?? isn't it? Way people install that restrictor plate at EGR???

Thanks in advance, any input will be appreciated.


Upss I forgot, right now there is no knocking sensor installed, I'm using 95 octane gasoline I can't feel any knock noise.

[Silver Streak]

The missing knock sensor could be your problem. Without it the PCM retards timing to protect the engine and that can kill mileage.

[lordoflivernois]

This is pretty much the same problem that im haveing.. Does it foul out plugs?

[javi2001]

Ok tahnks I'll install sensor this weekend, then will see. Any extra comments?

[hoxiii]

what kind of bad economy are you actually getting? black smoke out tailpipe? heavy fuel smell?

Justin

[javi2001]

Originally Posted by hoxiii

what kind of bad economy are you actually getting? black smoke out tailpipe? heavy fuel smell?

Justin

Ok let me explain, there is no black smoke, no fuel smell, no nothing, just the truck is using a lot of fuel on city. It is giving me around 9 - 10 MPG, on highway gives around 15 - 17.

There are no fuel leaks, apparently...

[hoxiii]

Is that 10 per US gallon or imperial (i see you're in venezuela, i don't know what you go by). If it's 10 per US that really isn't that bad for that truck. If you're getting 10 imperial i would agree that there is something majorly wrong.

When was the last time it had a tune up? have you tried some basics like checking the timing,fuel filter, and aircleaner?

Justin

[javi2001]

Thanks Justin, here in Venezuela we use liter, I did make simple conversion to US gallon, so you can help me.

Basic tune up including Sparks plugs, all filters, oil, cables, timing was performed just 2 months ago.

That same engine was running previously on my old F150, 1986 using a carburetor and was giving me 11.5 - 12 on town and 15 - 16 at highway I guess same engine running with EFI setup MUST run with less fuel, isn't it???

[fmc400]

I'd guess it's the EGR valve block-off plate causing problems. It's the only thing on your engine that isn't in perfect order. Engines with EGR are calibrated to run leaner with more advance than engines without EGR - without your EGR valve you are changing the ratio of inert exhaust gas to combustible air\fuel, and it is throwing off the computer and disrupting your timing curve. You need to hook the EGR valve back up; that's what's wrong. There is no reason to block off the EGR valve anyway - it's actually to your benefit. Inert exhaust gasses reintroduced into the combustion chamber help to lower combustion temperature. There are absolutely zero performance gains from losing the EGR setup no matter what people say. It is a common misconception that it hurts performance because people think it is just "smog junk." That assumption could not be any farther from the truth.

[javi2001]

Ok I'll remove the restrition plate, is not dificult and could take just 5 minutes, then will see

Now I'm taking new readings since presvious number was not using A/C, now it is working and I'm specting even worse readings...

[Silver Streak]

Originally Posted by javi2001

That same engine was running previously on my old F150, 1986 using a carburetor and was giving me 11.5 - 12 on town and 15 - 16 at highway I guess same engine running with EFI setup MUST run with less fuel, isn't it???

Your problem may lie in that statement. The carb engines use a different combustion chamber that requires more timing to run efficiently. If you're using that engine with a stock EFI system it probably doesn't have anywhere near the timing it should have. You could try bumping the base timing up 8-10 degrees from stock and see if that helps, but that's a bandaid fix for a much larger issue.

[javi2001]

Ok let me explain a bit...

MY truck originally was F150 1986, 5 years ago I got in yard a "used almost new" 300 engine coming from a EFI Econolione 1991. I just took that engine, removed all EFI stuff and installed the stuck carby.

Last year, my truck was roll over and I lost the passenger cab, the fast and cheap solution in my country was buy in yard "half" F150 1995. I did remove everything over main frame then installed all the "new" parts coming from the 1995 truck, including all EFI stuff, so the engine is running EFI again.

My truck is basically a 1995 F150 on a 1986 frame, 1991 L6 engine and 1995 E4OD tranny updated to 2000, a little Frankenstein someone said...

[javi2001]

Hey guys, I did remove the restrictive plate from EGR, but until now I can't tell the difference, no more no less power but fuel used seems to me is same.

I did not install the knock sensor yet, engine block need some threat job

[javi2001]

Hi all, after several weeks trying to find my Low Economy problem, I notice this:

1° Problem is getting worse and now truck is using too much fuel even driving on highway.
2° Sometimes there is a bad odor from exhaust pipe, no black smoke.
3° Knock sensor is not installed yet since the engine block needs a new thread to install it

I dont have to much experience on this kind of problems, so I guess any info about the troubleshooting procedure will help.

[Silver Streak]

The first two symptoms sound like you might have a plugged up exhaust.