87 4x4 ranger 2.9l (Sill looses RPM Code 31 also seems to exaust from intake) HELP!!

[vpcoded]

Here is the run down Started out as a 500 dollar purchase has now turned into one hell of a project.

Symptom-On start up the truck drives as it should. After driving 20 min or so I am able to reach less RPMs to the point I am shifting at 2 grand due to this being the rev limit. If i down shift or am going down hill and pushing gas it will back fire while trying to reach higher rpms. The truck seems to not be able to breath out (no cats or muffler) I get a exaust rumble in my air intake box when holding gas in neut to the limited RPM ie 2 grand and no more, full throttle. I have read threw alot of fourms and symptoms that sound alike are sometimes fuel filter others 02, some unknown, looking for some help here. I belived i caused this issues when putting the oil pump in some how due to the fact some things appear diffrent now then when i first took the air intake off such as soot/oil in cyl 2 and 3 almost as if a timing issue exaust instead of intake i dont know tho.


Items Replaced:
1. Oil pump / pressure sending unit - no more dummy light shinning.
2. MAP sensor (due to loss of RPM also cut cats off ) no help
3. Starter selonid
4. Cap, plugs, wires, Roter (cyl 2 and 3 plugs showed signs of soot/oil)
5. Pulled injectors and rail (New O-rings and caps on the injectors/same rail)
6. New air intake lower gasket (cyl 2 and 3 intake ports were black like exaust smoke/oil-was not like this when i purchased truck<--DID I CAUSE THIS by getting cap wires crossed some how)
7. I belive i have located and tightend all grounds.
8. I have followed alot of the wiring harnas down and replaced areas that had been chewed thew or in rough shape.
9. Vac lines have been replaced. as well as pvc valve gromet.(valve rattles)
10. I felt a possible cause for this lack of power could be due to the egr valve being stuck opened and it reciving more emmisions then air less combustion placed a folded piece of alum between erg valve and intake body and tighted bolts cutting off emmison to the air intake appeared to run a little better still lost rpms.

I ran the codes after all of this was complete and pulled the 31 again during KOEO and 31 13 and 77 KOER the 77 i know i errored it and will try again when i get home from work.

I also would like a pic if some one would be so kind of the rear of the air intake and how the hoses coming from there to the break boost ect are hooked up i belive i have something off due to high idle after i put it back lol.

Any help would be great ive sold my daily driver about a week ago to throw more money at this damn thing and getting to the same place with a better running motor that still looses RPM and is no where near able to drive to work lol before complete loss of power.

 

[low_five]

coolant temp sensor is the first and easiest thing I would try
fuel filter is next.

 

[vpcoded]

Thanks

Ok i have read about that as well but at that time didnt know there are two of these one to the dash another to the computer where can i locate the second one .

I am going to replace fuel filter ASAP

 

[Spitfire1975]

Ok i have read about that as well but at that time didnt know there are two of these one to the dash another to the computer where can i locate the second one .

I am going to replace fuel filter ASAP

Above the thermostat......one wired sensor on the right is the gauge sender. The two wired sensor on the left is the coolant temperature sensor. That is the one that the computer uses to help establish fuel mixtures.

Give a little more info for the tech gods that lurk in these pages.....1. What are your compression readings? 2. What are your vacuum readings? 3. Have you completely checked for vacuum leaks? 4. Are you completely without any exhaust components? Where is your O2 sensor?? 5. What is your fuel pressure?

I kept blowing egr codes and eventually replaced all egr. I had 3 components....the valve modulator, pressure feedback sensor and egr valve solenoid (on passenger side fender well). Yours may or may not have this setup.

 

[Spitfire1975]

You can test the Coolant temperature sensor with a multi-meter.
http://www.broncoii.org/techpages/eeciv/index.htm#TFI Timing: (11)

 

[Spitfire1975]

No exhaust components is going to screw up your back pressure.......sorry, I mean EXHAUST VELOCITY.

 

[vpcoded]

I have not gotten a compression test tho i plan to in the morning.
I just got it put back togeather before i had to run to work.
I have not gotten vac readings ither due to lack of gauge. I have compeltely checked for vac leaks.
I am running headers only o2 still hooked up ran with it un hooked same issue. Will rehook up exaust soon ha ha pulled over by security on the lake the other night over sound lol.

I have kinda slacked on the compression check and fuel press due to the fact of how strong it runs for the first 20 or 30 mins of driving i get before loss of power. I am not a mechanic but struggle seeing compression as a factor unless you can loose compression due to the motor warming up.

Thanks for the responces. I get off in a few hours and will gather more intell to share ie compression,pressure, and coolant temp sensor.

I am thinking about pulling the TFI and taking it to get tested while i grab some gauges.

 

[dawson111299]

you most definatly can loose compression after warm up eg. blown head gasket , cracked head . The thing that gets me is you say the #2#3 cyl are black and sooty looking in the lower intake witch could be and idication that its loosing compression through the valves , the head gasket , or a crack in the head. Id definatly have the tfi checked though just to rule out a spark problem. When you do a compression check do it after the engine is hot and start with the #2 and #3 cyl If you do find low compression there pull the valve cover and check the valve spings Ive seen them break and cause problems like that.
The reason for loosing compression after warm up is if the enginge has ever overheated even just once the head can warp. When it cools down the head gasket is sealed or a crack is sealed. As the head warms up it starts to expand a warped head will expand unevenlly opening a crack or loosing pressure on a small part of the head gasket. It wont nessicarilly leak coolant depending on where its leaking.

 

[Big Jim M]

Dawson that may be..

you most definatly can loose compression after warm up eg. blown head gasket , cracked head . The thing that gets me is you say the #2#3 cyl are black and sooty looking in the lower intake witch could be and idication that its loosing compression through the valves , the head gasket , or a crack in the head. Id definatly have the tfi checked though just to rule out a spark problem. When you do a compression check do it after the engine is hot and start with the #2 and #3 cyl If you do find low compression there pull the valve cover and check the valve spings Ive seen them break and cause problems like that.
The reason for loosing compression after warm up is if the enginge has ever overheated even just once the head can warp. When it cools down the head gasket is sealed or a crack is sealed. As the head warms up it starts to expand a warped head will expand unevenlly opening a crack or loosing pressure on a small part of the head gasket. It wont nessicarilly leak coolant depending on where its leaking.

But it is rather rar fetched. The head bolts are there to HOLD the head tightly to the block. A warp in the head shows up after the head is taken OFF the block.

Backfire comes from a leaky intake valve.. or crossed plug wires... or low fuel pressure... or increased timing..
So first guess would be Xrossed wires... then low fuel pressure.. then timing set too much advanced and lastly one or more valves..

When the engine is cold the mixture is rich and the timing is retarded.. So the backfire might not be as noticeable. As the engine heats up the timing advances and the mixture leans out.. The combination of these causes the backfire to be seen more easily.

Big JIm

 

[vpcoded]

I have checked the cap and the wires were as show in my haynes. I changed the TFI module and in the process of changing the PIP in the Dizz but came to a round metal plate that i belive needs removed to change it. Any information on getting this off will help.

The compression gauge i have is cross threaded is why i have not posted compression the new pick up was only 17 bucks so i grabed it any ways the TFI did fail the test at autozone for threshhold.

 

[Big Jim M]

Answered

I have checked the cap and the wires were as show in my haynes. I changed the TFI module and in the process of changing the PIP in the Dizz but came to a round metal plate that i belive needs removed to change it. Any information on getting this off will help.

The compression gauge i have is cross threaded is why i have not posted compression the new pick up was only 17 bucks so i grabed it any ways the TFI did fail the test at autozone for threshhold.

Check your other post on this matter..
Big JIm