whats a good MPG for a 4.2L 5spd?
04-26-2015, 10:45 AM
#31
Yeah, I am not questioning what you are doing. Actually interested in how your truck runs after all you've done. I am all for ditching all this junk they put on the engine, and get it back to the basics. The only reason they have this junk on the engines is so they can make the engines pass some emission standard set by politicians.
I just didn't know if the engine computer would go nuts after these changes? Here in VT the check engine light on may mean no state inspection. I have seen some ways to trick the rear O2 sensors though.
I just didn't know if the engine computer would go nuts after these changes? Here in VT the check engine light on may mean no state inspection. I have seen some ways to trick the rear O2 sensors though.
I would't recommend doing what I'm doing to anyone that has state inspections. We don't have them here in Indiana "at least not yet". I will be finishing up the truck today and I may post a vid on my thread https://www.f150forum.com/f6/97-f150...4/#post4058733 of it running. and over the next few weeks I may be able to get some mpg figures after the engine is good and broken in.
04-26-2015, 04:41 PM
#32
Senior Member
Make sure you do that, - Good AND Bad results, - be honest and don't be shy with either.
A vid of it running and being brought up to speed. I want to see this lol.
Then I'll explain what you need to do now.
A vid of it running and being brought up to speed. I want to see this lol.
Then I'll explain what you need to do now.
Last edited by Jbrew; 04-26-2015 at 04:44 PM.
04-26-2015, 05:10 PM
#33
No problem...I'm not afraid to admit when I **** something up. I will let you know what to do or what not to do. I didn't get as far as I thought so maybe tomorrow night it will be finished up. All the little stuff really adds up.
04-27-2015, 11:15 AM
#34
Sorry I'm not sure I understand the question. How do I plan on making it run? It runs just fine. I hear people talk about the egr gasses are used to keep the exhaust temps down but that makes very little sense to me. The exhaust temps should not be overly high in the first place. These engines aren't running super hi compression or ran super lean from the factory. In fact the factory tune is on the richer side.
I kept the pcv system in place because it's needed to help control the pressure in the engine.
The IMRC valves are butterfly valves in an extra intake port for each cylinder. The idea behind them is sound but when they malfunction they can be a pain to deal with and you will get horrible mileage if they stay shut all the time. I may lose a small amount of low end torque but I would rather it breath easy and nt worry about if the valves are working properly.
The cats were removed because they were clogged bad. The 02 sensors that control most of the air fuel mix are the sensors in front of the cats. The ones behind the cats are to basically throw a code if there is very little variation between the front and back. They only sense a heat range which changes the voltage in the 02 sensor for a range of less than 1 volt. I can put in an adjustable resistor if I really would like to control my a/f ratio.
In the end to each his own. I don't knock anybody for being different or trying something new. I like my truck and if it works better then great and if it get horrible mpg then I can change things as needed. I'm a motorsport technician by trade graduated MMI in Orlando in 2004 so I may not know it all but I've had pretty decent success with past projects. I just like having conversations with people.
I kept the pcv system in place because it's needed to help control the pressure in the engine.
The IMRC valves are butterfly valves in an extra intake port for each cylinder. The idea behind them is sound but when they malfunction they can be a pain to deal with and you will get horrible mileage if they stay shut all the time. I may lose a small amount of low end torque but I would rather it breath easy and nt worry about if the valves are working properly.
The cats were removed because they were clogged bad. The 02 sensors that control most of the air fuel mix are the sensors in front of the cats. The ones behind the cats are to basically throw a code if there is very little variation between the front and back. They only sense a heat range which changes the voltage in the 02 sensor for a range of less than 1 volt. I can put in an adjustable resistor if I really would like to control my a/f ratio.
In the end to each his own. I don't knock anybody for being different or trying something new. I like my truck and if it works better then great and if it get horrible mpg then I can change things as needed. I'm a motorsport technician by trade graduated MMI in Orlando in 2004 so I may not know it all but I've had pretty decent success with past projects. I just like having conversations with people.
I enjoy having conversations as well. I myself graduated from Ford Fact in 2005 and recieved my Ford Masters cert in 2009.
04-27-2015, 12:01 PM
#35
Original programming was on the rich side when these trucks were new. At 14.2:1. Now that ethanol is added to fuels it is actually on the lean side. With the added air flow because of the IMRC delete you actually do have a possible issue of burning the tops of the pistons. Also by deleteing EGR you can cause a issue with it burning oil under high rpm closed throttle. Also the IMRC controls runner length in the intake. You will have slight loss of engine response along with a loss of torque from around 1800 to 2500.
I enjoy having conversations as well. I myself graduated from Ford Fact in 2005 and recieved my Ford Masters cert in 2009.
I enjoy having conversations as well. I myself graduated from Ford Fact in 2005 and recieved my Ford Masters cert in 2009.
Anyways I appreciate the feedback and agree with at least the theory in what your saying.
The things we were taught in tech schools are sometimes more of a blanket statement rather than fact for all cases. 2 stroke, diesel, gas etc all are different style engines and in those classes are more individual styles of engines. What works for one does not work for all.
Last edited by ametzker; 04-27-2015 at 12:06 PM.
04-27-2015, 01:08 PM
#36
EGR is activated anytime the manifold vacuum is over a certain value. As long as the rpms are above a certain programmed value. Hence the reason fueling while cruising is actually so lean. The added fuel is added from the exhaust. The problem lies when the pcm isnt reprogrammed for the removal of egr system. The fueling and timing table need slight adjustment. I have a 5.4 so I'm unsure how negatively it will effect the 4.2. I know on the my 5.4 that in the upper rpm range and I let off throttle, the manifold vacuum goes thru the roof, and pull oil out of the driver side valve cover breather. When I turn egr back on the issue goes away as it pulls exhaust thru the intake and relieves interal pressures via exhaust instead of thru the valve cover.
04-28-2015, 05:18 PM
#37
Senior Member
Sooo, - did yuh take her fer a drive yet ?
04-29-2015, 09:17 AM
#38
Yes I did drive her yesterday. I found out I don't have brakes so that is what I'm installing today. The rear metal line was so rusted it was leaking. Front rotors are toast so. As far as running and driving it was great for a truck that hasn't been on the road in over a year. No idling issues no misfires or hesitation. I will know better when I can take it for a longer drive after the brakes are done. I will post a vid of it running today.
04-29-2015, 10:02 AM
#39
Senior Member
Thread Starter
So you said you have no cats, did you run headers or stock manifolds with straight pipes? And did you run the exhaust dual or back to the single exhaust? Sounds like you're happy with how it runs so far! Thats always a plus!
05-06-2015, 07:24 PM
#40
I've been driving now for over a week. I still haven't put together a vid because I just last night finally cleaned the interior out. I drove to Indy yesterday which is about 160miles round trip and calculated my MPG. The engine isn't completely broke in yet and I did a ton of in town driving in Indianapolis so it was a fair mix of in town and country driving. It came out toe be 19.6mpg which I am happy with. The truck idles at 800rpm and never skips a beat. I can tell the factory fuel maping comes on stronger at around 2k rpms and it seems to really want to go at that and above. I also installed my Treadwright retread BFGs 245-75-16 before the trip and they did great. A little bigger and heavier than stock but I like them. Of course I have the check engine light on because I have no EGR and no cats and I also bypassed the rear abs when I did the brakes because it seemed to be acting up. But with all that the truck seems completely content on starting, idling, and running perfect. With almost 20 mpg I don't think I could be more happy with it.
