Got another problem

[Mr Wiggl3s]

Ok, so, ill set cruise on 65, and ill go all the way home (20 mi), the gas needle wont move at all, thats about about ~21 MPG. But then i get in a hour later and the needle drops 1/8 tank just going down the street (~8-11 MPG). I don't think this is a gauge problem. I think the EGR is at fault here, but i don't know. I seems like theres an exhaust problem here, i think I'm just going to replace the EGR anyway

NEW: Plugs, wires, cap, rotor, fuel filter, air filter, oil, oil filter, cleaned the IAC recently

[v8_dave]

You think the EGR is stuck open all the time? You can troubleshoot this without throwing parts at it.

[Mr Wiggl3s]

I just had some codes ran, and there wasn't anything wrong with it at the time

[v8_dave]

Yea but you can still troubleshoot by disconnecting and plugging vacuum lines, etc....I dont know a 5.0 but these guys can tell ya.

[Mr Wiggl3s]

Not for the EGR i don't think. All i know is on later models you can check the diaphragm and see what that feels lol

[Tman70]

That great a variance in mileage is not normal. There are plenty of tests for the EGR on an 88. I'm leaning toward reality here. The gauge is supplied with voltage from the instrument cluster. If the voltage when cruising is high, the gauge will read higher. Around town lower voltages (due to lower rpm), will cause a lower reading. Put a voltmeter on the car as you're driving around and see what I mean. If you have the message center (tripminder), use that to check it in both areas. Not perfect, but it can give you some indication. Also possible is a faulty ECT sensor (Engine Coolant Temperature).

[Elemino]

If you suspect the EGR try a new sensor. Keep in mind these cars get waaaaaay better gas mileage at highway speeds than on city streets.

[Taran]

If you suspect the EGR try a new sensor. Keep in mind these cars get waaaaaay better gas mileage at highway speeds than on city streets.

:eek:

this is a kiddy answer.. faulty communication beetween the gauge and gas tank? :p

come to think of it.. the EGR did give some trouble to dads car..


i agree wiggs :p.. change the egr

[gadget73]

Make sure its working first, don't toss parts at it. The EGR system on these cars are pretty simple to troubleshoot. Remove the valve and make sure the passages in the intake are clean. Use a hand vacuum pump to check if the diaphram holds vacuum. Check the voltage on the position sensor to see if its working properly. EGR position sensor values can be found here:
http://fordfuelinjection.com/index.php?p=35
Plumb a vacuum guage into the feed line and observe under what conditions you have vacuum. It should only open when the engine is warm and you are running at a steady speed, which roughly translates to mostly highway usage. Around town it should seldom open. Quite honestly the egr valves themselves do not go bad that often. I'm running a 20 year old one, and I've seen a lot of old boxes, and none of them have needed a new egr valve. A few have needed new position sensors, but the valves themselves seldom actually fail. Coolant temp sensors can and will fail, but they're easy to check too. All the info you could ever want on the sensors, and thier expected values under specific conditions is found here:

http://fordfuelinjection.com/?p=10

[Mr Wiggl3s]

So if there is, what would be the proper way to clean a sensor like this? Rubbing alcohol?

[LuxuryLiner]

Mr Wiggs-
My 99 will do about 12-14 in the city and then jump to 26-27 on the highway...me and my partner drive the car, he gets 26.8 normally on the hiway and I get 24-25 on trips...I drive harder to speed than he does, but on average the car takes a dump in the city driving!! :achoo:

[Mr Wiggl3s]

I dont drive in the city, i do 40 miles a day, at 65

If i do go anywhere, like out or anything, thats when i see a huge drop almost right away

[87 town]

I dont drive in the city, i do 40 miles a day, at 65

If i do go anywhere, like out or anything, thats when i see a huge drop almost right away

My two cents on EGR's. I was failing my emmissions test a few years ago and replacing mine got me to pass. Other than that, my undedrstanding is that even though the valve is still working, there could be large carbon/laquer like build up within the valve which is hard to get at to clean and maybe easier to just replace. I paid about $70. for the part at the time and it is an easy install. Maybe my imagination....but I felt that she ran a little smoother afterwards.

[Elemino]

So if there is, what would be the proper way to clean a sensor like this? Rubbing alcohol?The sensor should be sealed, meaning you can't clean it as far as I know. But it definately improved gas mileage and pick up on my car. The vavle I just pulled and cleaned. Not sure if that ever did anything, but I know it works.

[Mr Wiggl3s]

Does anyone have a suggestion? Im getting 5mpg now

No leaks or anything

[87 town]

Does anyone have a suggestion? Im getting 5mpg now

No leaks or anything

she has got to be running "terrible" then... seems that upon acceleration you are sucking in way too much fuel right off the bat.
HOW does it run? fuel injectors spitting out too much fuel, maybe? vacume leak somewhere? drawing too much air? are you sure your mileage is that bad?

[joedogg]

Long shot, but it is shifting into overdrive right? I lost 4th and eventually 3rd on my old transmission, with gas milage being shot right to hell.

[Mr Wiggl3s]

Ya, i just got all the vacuum's tested

I'm thinking valves, but that doesn't make since still

Maybe the air intake? OR Some MAF sensor or something?

I think ill run some Seafoam in there, its got like 1 gallon in it, so thats enough to get me to the end of the street :mad:

[87 town]

Ya, i just got all the vacuum's tested

I'm thinking valves, but that doesn't make since still

Maybe the air intake? OR Some MAF sensor or something?

I think ill run some Seafoam in there, its got like 1 gallon in it, so thats enough to get me to the end of the street :mad:

i dont think valves have anything to do with this. air/fuel mixture and possible sensors that would have to do with that regulation. did you see what Haynes said as troubleshoot. i think there are suggestions to trouble shoot bad mileage? dont have my book with me.

[Tman70]

My thought is still the ECT sensor. It's responsible for shutting off the fuel enrichment circuit. Try disconnecting it and see what that does for you. It's the sensor in the heater line coming out from the top of the manifold by the thermostat housing.

[Shrewsbury]

I agree with Tman. The ECT sensor controls the EGR. It's a cheap & easy replacement.
Also, how are you calculating mileage?

[Mr Wiggl3s]

I do it by 1/4 tanks

What is a ECT and what does it do?

[Shrewsbury]

I do it by 1/4 tanks

What is a ECT and what does it do?

All quarters aren't equal. Calculate it over a few full tanks.

ECT = Engine Coolant Temperature sensor
It allows the EGR valve to open once the engine gets to a high enough operating temperature. If it fails, the EGR never opens, the engine runs rich and wasteful. It can make more power running rich, but NOx emissions are higher and economy drops. The same thing will happen if your thermostat fails open in the winter. Do you have good heat? That's another possibility.

[Mr Wiggl3s]

Its worth a shot, ill check my Haynes

[gadget73]

You can clean the EGR valve and the intake area where it fits up with a wire brush and carb cleaner.

Check the ECT before you replace it. It can be checked with a voltmeter. Warm engine temp should be 190-210 fully warmed up, if you dont have a temperature guage to get a more accurate fix on it. Values are here:

http://fordfuelinjection.com/index.php?p=28

How much vacuum does the engine hold at idle? If its under 16", you probably have a leak. If its a valve problem, it might be low, but valves don't go bad over 2 weeks, they deteriorate slowly over many years. If it had one specific valve bad, the vacuum guage would show a distinct twitch. If the guage is low, start pinching off vacuum lines that connect right to the intake manifold to see if the guage changes.

Also, another thought, are you leaking fuel? Common leak point is just forward of the driver's door.

[worldkeepsakes]

:faint::wheee::faint:

[Mr Wiggl3s]

34 - EGR Value position sensor or pressure feedback EGR voltage hight or sensor fault

Awesome

So it looks like that means new EGR + sensor for me

[gadget73]

The valves don't go bad often, and are very easy to test with a hand vacuum pump. Pump it to about 10" of vacuum and see if it moves and holds. if it holds vacuum, the valve is fine, and either the sensor is bad or it is not recieving proper vacuum signal to open it. Make sure the plastic lines feeding over to the fender are not cracked or leaking as this is often the issue.

[Mr Wiggl3s]

ok i got a new EGR and i got 2 seals. one i know where it goes, and a o-ring thats rather thick

I'm just wondering where that o-ring goes

if anyone can give me a quick response that would be great

[gadget73]

There should be only one flat gasket with two holes for the EGR valve. Never seen an O ring for the EGR, unless you got a PCV grommet? Was the EGR valve actually bad? Did you get a new sensor with it?

[Mr Wiggl3s]

Ya i got a new sensor with it, it must have just got thrown in there for no reason. I swapped it out ran it, ran codes, and its purring like new man i love this car