Ok, so hears my story. I did an engine/tranny swap last winter. I had a donor truck, 1989 F 250 2wd. Engine had been rebuilt with RV cam. so I'm told. This engine sat on my shop floor for a few years. This engine was installed into my 1989 F250 4x4 that had a 5.0 and mazda 5 speed. After a lot of mod's and finding a C6 auto, I finally had engine in and started. I needed new injectors, and a few other parts. I just looped the air pump, I swapped computers, used existing wiring harness. I scrapped the exhaust system as it was rusted out on the donor truck, But Installed New 02 sensor. but no cat, muffler tail pipe. As I said Truck did run ok but ran rich and very poor mileage. 4-4.5. So Its just a farm truck. Well my Son started driving it a lot this summer and it finally wouldn't Idle, and hardly run. I did find one vacuum leak. Still not running right or Idling. replaced distributor cap wires. Compression tests are 145-150 on a cold engine. Vacuum is at 10hg. with it running at 800 rpm. Do I have another leak? I removed the EGR, it was clean and movable, same with Idle control bypass valve. I've looked at most of the vacuum lines. Not sure where to look next. Any Ideas?

 

Poor mileage, running rich and no idle sounds like you are running in limp mode.
You guessed it, it is time to see what codes you have in KOEO and CM.
This will tell us why it is limp mode.

 

You have, as you are aware, 7 vacuum take off's from the intake manifold.

5 behind the upper intake manifold.

Your vac. reading sounds low.

As an in-shop test, would you consider capping off all except to pcv valve and fuel pressure reg?

And I mean cap off at the vac. tree's.

 

Those two items in bold are your problem. What are the specifications on that "RV cam"?

10 inches of vacuum at idle is causing the PCM to add fuel because it thinks the engine is under load. Low idle vacuum can also be triggered by retarded base timing.

 

I have done the KOEO and KOER test. but I'm confused as I've read pre 91 trucks use a 2 digit code and later used 3. I have video taped the test maybe I can post here? Yes I can block off all vac lines not needed. I have had the passengers Vac can off. looks good. maybe have to take drivers side off and check. Also the Cruse control is not hooked up to throttle body, different fitting. I see a big vac line goes to the cruse and then around back of intake, Also I crawled under and see that my new vac line to trans is pinched, or got hot. I also have a ticking sound coming form the left bank, sounds like exhaust gasket leak? rear most spark plug is sooty on the outside. Can't really work on it today, just getting ready for the next go around. This has turned into Man vs Machine. With it running so rich, I need to find exhaust hose and vent out the shop. I didn't know it had a limp home mode. I've also had the ECM out and looked inside for burnt diodes, ect. It looked clean. there is a wiring plug coming out of the trans C6, I assumed it was a neutral switch, my manual harness didn't have the same plug. I'm ready to remove all the pollution crap on this truck. It needs to run but will probably never see over 1000 miles a year. Truck body only has 82k.Thanks for the Help.

No specs on the cam. just bought truck that way. It has been overhauled as I had the pan off to straighten it. looked like a rod bearing went out and was nicking block. What do I do about cam specs?
timing I set to specs but will recheck. Maybe I set to wrong specs?
Donor Truck was 460 with C6 2wd so ECM should be the same.??

 

If the PCM Computer is for a 89 460 with an E4OD it may very well have 3 digit codes.
2 digit codes were used though 1994 for the 4.9L with a standard transmission.

You may need to replace the PCM Computer with one for a 1989 460 with a C6 or standard transmission.

As noted above the low vacuum to the MAP sensor may be a big factor.

 

Without a cam card you are pretty much screwed without pulling the cam out to see if it has any markings or send out to be verified.

Did you pull the SPOUT plug when you set the base timing? If not..there is your retarded timing.......

 

The '89 460 E4OD trucks have a two digit fault code for sure as I have two trucks that are in that category.

If your using the method to count fault code flashes on the dash, that may be confusing.

If the engine supplier called the cam an "RV" cam, maybe you'll be ok, because regarding "speed density" trucks of that year, it's pretty common knowledge that only one tame "RV" cam below a certain lift and duration is all that works with the computer, and hopefully that motor was rebuilt to run in the '89 donor truck.

Was there any difficulty with the injectors install?

I only ask because a problem with an O-ring on the intake manifold side of the injector would be a source for a vac. leak.

 

I said you may have a PCM Computer for a 89 460 with an E4OD that may very well have 3 digit codes.

I have ran into at least two 1989 F53 chassis with the 460 and E4OD that had 3 digit codes.
All of the Ford F53 chassis I have worked with from 1989-1997 had the 3 digit codes. They all had the 460 E4OD with a 5.13:1 rear end.
I do not know if any 1989 PU trucks got the 3 digit codes but they could have if the F53 had them.

 

Yes the injectors were a Pain in the *** to get the fuel rail on, don't remember the install into the manifold. How would I detect that type of leak?
Yes the Engine out of the donor 89 F250HD with C6 auto was its original.

 

Is it possible that the updated 4 hole injectors were over 19lb injectors and its over fueling?

 

Bill, that's very interesting and good to know. Thanks!

Blue, there's a few different procedures.

I'm not up on them enough to give you details on them.

One involves a harmless smoke pumped into the manifold to see where it exits.

Another involves something like starting fluid introduced to the suspect area while the engine is running, looking for a response in RPM.

If you are able to look into each bore that the injector is installed into, you should be able to verify that none of the o-rings are pinched, twisted.

The method I've settled on for the fuel rail install in these trucks is, currently...

Lightly oil the new o-rings on the injectors, upper and lower.

Clean and lightly oil the bores in the intake.

Snap the injectors into the fuel rail by orbiting back and forth gently.

Lower the fuel rail, with the injectors intact, hanging, into the bores, just moving to get the plastic nozzles to essentially feed into the bore with little resistance.

Then tighten the bolts on the rail in 4 steps in a cross pattern.

Don't force the injectors into the manifold.

Have the injectors in the rail already facing their factory orientation for the power plug, so they hardly have to be rotated.

 

A 460 should have 24 lb. injectors.

 

Setting here think about it I never seen the numbers on either PCM Computer so it is possible that both PCM Computer were changed out with newer PCM Computers.

 

I'll try and post the photo of the ECM that is in the truck. Donor truck was the same year, 460 w C6 auto 2wd and that is the ecm I'm using. But I have no Idea if it was changed..