3.0 swap issue

[Foxbody96]

Hey guys first time posting long time follower. I killed the original engine in the truck so picked up the same one from the local junk yard from the same year of truck. I got it all together and she runs great. But have an issue with lack of power. The only difference from my old engine to the new one is the injectors, thought I'd just leave it and try it out. Would anyone know if my computer would be the problem now with this setup? Or should I put the original harness and injectors on there. Thanks !

 

[stmitch]

If the injectors are different sizes, you should use the size that goes with the PCM. So, if you're still using the original PCM, use your original injectors, or at least injectors the same size as the originals.

 

[RonD]

Welcome to TRS

The computer should adjust to injector size difference after first warmup and Closed Loop.
If injectors are too large or too small computer will set a code and turn on the CEL(check engine light).
CEL should come on when key is turned on, and then go off after engine starts.
Is your CEL working?

Since it is a used engine, I would do a compression test.
Cold engine
Remove all spark plugs
Test each cylinder with screw in type pressure gauge
Crank engine until you hear 4 or 5 "hits", you will know what that means when you do it
Write down results

3.0l will have 160psi or higher, usually closer to 170psi, in each cylinder

If compression is good then you can investigate other issues, if there is a problem with compression then you will just be chasing your tail until you do the test.

A gasoline engine needs 3 things to work
1. Fuel, in the correct mix with air
2. Spark, at the right time, 1994 also has distributor
3. Compression

Fuel and spark have several variables
Compression is the only "it's good" or "it's bad" thing, so once tested it can be taken off the table, and because it's a used engine it should be tested.

 

[Foxbody96]

thanks for the responses guys, RonD the engine light came up for first start up but went away after that. and no egr on this on i will do a compression test tonight. i tried looking up to see if there were any different injectors for that year but didnt come across a thing. figured id give it a try first. thanks again

 

[Foxbody96]

So did the compression test and the one half of the engine is a little lower then I would like but should do, the spark plugs were white as a ghost though

 

[Foxbody96]

Just checked the injector part number that is installed on my truck and they acuatally match my originals. So I don't believe that's my issue anymore

 

[RonD]

1/2 is lower?

The numbers aren't as important as the difference in the numbers.

Are you hitting 165psi on one bank and 130psi on the other?

 

[Foxbody96]

Yes

 

[RonD]

Than that is your loss of power.

You will need to find out why.

 

[Foxbody96]

Think it could just be a worn out engine ?

 

[JP02XLT]

Worn piston rings, bad valves / valve seat, cracked head, the list continues, if all 3 cylinders on the same side are 130 psi, I would be looking at doing a leakdown test on that side and then go forward

JP02XLT

 

[Foxbody96]

Okay thanks, I will look into it. Now for it running too rich is there a way to find out how to make it right? Or a way to test the Air flow sensor or o2 sensors?

 

[Foxbody96]

Did a leak down test and everything seems to be good, after it I decieded to check to see if any engine codes were available even without an engine light. Seem to be getting 1,3,6,5,3,6 I'm guessing those are 2 digit codes? 13,65,36? Thanks again.

 

[Foxbody96]

And I'll add that the truck is missing and losing power but gaining it back randomly having energy burst

 

[RonD]

1994 will be 3 digit codes

Seen here: http://www.therangerstation.com/tech_library/3digitcodes.shtml

136 is Left bank O2 sensor showing low volts, and not changing when computer adds more fuel, so possible lean condition.

O2 sensors generate their own voltage based on Oxygen content in exhaust.
.10volt = high Oxygen level, Lean
.90volt = low Oxygen level, Rich

.45 is what computer aims for, it adjusts fuel injector "open time", pulse width, to add or reduce fuel to stay around .45.
The code means computer is adding more fuel but O2 sensor is still showing low volts and computer has reached its "pre-set" limit, based on MAF sensor air flow, so it set a code.

Could be vacuum leak(most likely cause), or exhaust manifold leak on that side, sucks in extra air.

536 is a Brake test code, it means you didn't step on the brake pedal during the BOO test, so forget that one.