1992 Lacks Power

[sean_carole]

Hi guys, i've got a 1992 Allegro Bay class c motorhome e-350 chassis with the 460 efi motor. It's lacking power anytime i'm under acceleration, and is having a very hard time climbing any type of incline to the point i would almost have to pull over and let all traffic behind me pass. The "check engine" light comes on, then will go out through out the trip. Any ideas what the problem might be would be greatly appreciated!
Thanks.
Sean.

[subford]

Why don't you ask the RV what the problem is?
If you do not know how to ask it, go to the link below:
Fuel Injection Technical Library » How To Run a Self-Test

Get paper and a pen before you start and write down what it says and then post what it says back here. Then we will interpret the codes for you.
Also let us know if each code is KOEO, CM or KOER.

[Jagtech]

Ditto on checking the codes. It might be as simple as a blocked converter or muffler, or any number of other faults.

[Rludtke]

... and a compression test will either give you peace of mind that the engine is capible of making power, or indicate that you have leaking valves or rings.

A compression tester is about a $20 investment. Test only on a fully warm engine by removing the spark plugs and observe the needle reading on the guage as someone cranks the engine over. I apologize for not remembering what kind of value a good cylinder will generate, but the tester will no doubt come with instructions.

Potentially you will find one or two cylinders with noteably lower values than others. If air can be heard puffing through the engine crankcase breather, the problem is leaking cylinder rings. If air can be heard puffing through the the exhaust, then it is an exhaust valve(s) leaking. If heard through the intake (with butterfly open on the throttle body), then it is leaking intake valve(s).

A compression test might be appropriate if the code test does not reveal any solutions.

Cheers,
Rick

[sean_carole]

Okay, thanks guys i will do some code reading and also take a peek into the converter to see if its plugged. Will keep you posted.
Thanks again. Sean.

[sean_carole]

I just picked up a Ford obd-1 code reader at the local auto parts store for $15.00 so hopefully it works for me.

[TXiceman]

Check the codes and get a tune up. A bad catalytic converter will make the thing suffer.

ken

[sean_carole]

Ya, i thought of that, i'm going to gut the converter, and take the beast out for a drive and see if it makes a difference. If that fixes the problem i'll replace the single converter with a dual exhaust setup(will sound better too).

[subford]

Originally Posted by sean_carole

I just picked up a Ford obd-1 code reader at the local auto parts store for $15.00 so hopefully it works for me.

Take it back, that one will only have an led and maybe a buzzer.
You all ready have the same light on your dash so that one is a rip off. They sold you something that you already have.

I cannot believe that anyplace is still trying to sell that led reader. That one came out when they did not have a CEL (MIL) on the cluster as in the 1985-1986 Ford trucks.

Get one that has a digital read out if you are going to get one so you do not have to count the flashes.
Here is one that is sold at most auto part stores and also on amazon.


The one at Amazon for $24.99:
Equus 3145 Ford Digital Code Reader : Amazon.com : Automotive

And at O'Reilly Auto Parts for $31.99:
Equus Innova 3145 - Digital Code Reader | O'Reilly Auto Parts
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[sean_carole]

Thanks Subford, will do. I'm kinda leaning towards a plugged converter, so it'll be interesting to see what code or codes show up.

[Dwight]

The Ford OBD I that Subford shows is what is also needed for the Ford chassis F53 460, 7.5 L engine for 1996 & 1997 and F53 chassis motorhomes built with the 460, 7.5 L before the V10 chassis. The code book came with my Ford OBD I code reader.

Problem: The OBD I connection is under the engine cover on the F53 chassis and hard to excess without the Ford OBD I extension cord that sells for an additional $25- and is shown below the OBD I picture. What do others think? Is the extension cord necessary?

[subford]

I have used the Equus 3145 with and without the Ford OBD I extension cord. So it can be done but it is a lot easier to use the Ford OBD I extension cord while setting in the seat and push on the brake, push the button on the end of the stalk and do the WOT at the right time.

The bottom line is you do not need OBD I extension cord to do the KOEO electrical self-test and read the CM codes but to do the KOER it sure make it a lot easier.

I have even left the OBD I extension cord on while on a trip with the doghouse cover on so I could check codes and nail down what was going on. Turned out the bug was in the wrong place on my header install so I had to move the bungs location and weld a new bung on to get rid of the code and keep the CEL off.

[WOMD]

If it's that old, could also be a worn out o2 sensor throwing codes while under load and hence the lack of power.

[subford]

Originally Posted by WOMD

If it's that old, could also be a worn out o2 sensor throwing codes while under load and hence the lack of power.

If you are talking about the bung above everybody that has installed that brand of headers have the same problem and code.