New 351w running rich and bad idle
 

Hello,
I have recently swapped in a 351w from an '89 f250 as well as the zf 5spd. I bored it .040 over and installed a crane cams 444232 cam and long tube headers. I also deleted the smog system.

The problem is it sucks down fuel and smells very rich while running. The idle quality is also very poor and surges slightly. On a cold start-up it will always run at about 1250 rpm's for around three to five seconds and die if no throttle is givin. After restarting it, it won't die until its completely cold again. As soon as i crack the throttle open at all, it'll jump up to 1500 rpm's. While driving i'll pull up to a stop and it idles smooth around 900 rpm's for around 30 seconds, then it will kick down so low it almost dies before catching itself and will idle rough around 600-750 rpm's.

Codes are
KOEO 34 and 85
CM 34 and 96
KOER 12, 41, 34, and 18 with 18 not always showing up.

I'm using a reman ECU for 1989 f250 and a wiring harness for a 302, not sure of year. I figure the code 96 is because they went to a single fuel pump in 1990 and code 85 because the wiring harness does not have a canister purge connector on it so i'm not running one. Could there be other differences in the computer causing it to run wrong? I have one coming for a 1990 that will be here in a few days.

The timing jumps around quite a bit while running and is around 20-30 deg at all throttle ranges.

The only thing that is not brand new is the IAC valve and fuel injectors.
The timing advance check comes out good.
I have replaced all vacuum lines.
The O2 sensor is located in only the right side header right after the collector. Does this location matter much? I had to weld in a bung myself.
I also hear that the throttle body wears out causing issues. Sometimes the throttle sticks slightly and I have to pump it to kick down all the way.

Any insight would be great. Fuel injection problems are starting to drive me crazy.

I'll give any more info needed, just ask.

So this deleted smog.. does that include the EGR? If so how did you block it off at the intake?

The code 18 is a concern and if it's intermittent that may suggest a wiring or connector problem.

The sticking TB is also a concern, I suggest swapping the whole assembly from another motor.. the 5.0 uses the exact same parts.

O2 sensor location is not a concern

Have you checked that the vacuum canister(juice can) on the passenger inner fender holds vacuum? These things always rust out on the bottom.

I had the exact same engine combo in my truck and it purred like a kitten.. just so you know this should work a lot better.

The vacuum is holding steady at 15-16 in/hg and both canisters were takin out and checked/painted during the swap. The egr is still intact with a new valve, position sensor and vacuum solenoid.

Is there a chance it's mechanical? leaking head gasket or something? It runs great while on throttle/driving. But doing research, just about any injection problem causes idle issues.

Thank you for the insight

OK.

Is the tube attached to the exhaust or is the valve open to atmosphere? There cannot be any fresh air entering the intake through this valve, it's has to be all exhaust or it has to be sealed up. You are getting an EGR code so something is wrong.

Anything is possible, have you done a compression/leakdown test?

Did the engine harness plug right into the chassis harness or did you have to modify it? With all the new parts the fact you are getting codes suggest something the isn't right with the wiring, a mismatch on several sensor would do that.. you may have to trace all the wires to ensure they go to the right places. Why didn't you use the original wiring harness from the truck? Was it hacked up badly?

The EGR tube is attached to the header like it should.

The wiring harness off the 5.8l was chopped up from the guy who pulled it. The harness from my truck was falling apart and I fought high idle problems previously with the 302. So I thought I would just get a fresh start. The harness in it now hooked up with no modification.

I haven't done any kind of compression or leak-down test yet.

Improvement,

I swapped out the computer with one for a 1990 (oddly they both had the exact same codes and part numbers marked on them, but the shape of the case was completely different). Now it is definitely running better but some of the idle issues are still there, just not as bad. It seems to be running much less rich as well.

Now the only codes i'm pulling are-

KOEO-34, 85
CM-34
KOER-12

Just to make sure i'm not just missing the plug, does the canister purge solenoid plug go into the engine wiring harness or the body? I thought that it separated from the harness around the TPS or IAC valve.

Also,

I just got a very very good book on ford fuel injection and it sounds like the code 34 could be the idle culprit. The way i'm understanding it, the code 34 is saying that there is not enough resistance at the EVP when it is closed allowing too much voltage to read back.

But I am getting some conflicting information. The fuel injection book says that the resistance should go from 5,500 ohms closed to 100 ohms open. My Haynes manual says it should be slightly less than 5,000 ohms (but no greater than) closed to slightly greater than (but no less than) 100 ohms.

I tested the one I just installed and it was 4,600 to 350 ohms. I put more faith in the EFI book than haynes so I picked up another. I haven't even run the truck with it yet because its reading 4200 to 370 ohms. Even going off Haynes, that seems like much more than slightly less than 5,000 ohms and slightly more than 100 ohms. Did I get two bad sensors or are these readings good?

Thank you.

Also, the reference voltage at the connector is right at 5.0 volts like it should be.

Perfect example of why I do not like resistance values, measure the EVP signal output VOLTAGE. The PCM is expecting a certain voltage range, so measure the voltage.

Some great EVP info here: Fuel Injection Technical Library » EGR Valve Position sensor (EVP)

When back probing the evp and sig rtn I get .75 volts. If it makes a difference it's the black EVP sensor.

The closed EGR signal limit is 0.67 VDC. So your 0.75 VDC is too high. I recall my old 1992 F350 w/5.8L engine had a gray EVP sensor.

Not sure what yours should be.

I've got some updates since I was last on here.

I discovered coolant leaking from the drivers side head gasket down the block. So after pulling the engine and heads I found that the rear cylinders on both sides were definitely burning coolant and a few others may have been as well. The lower intake manifold also had a number of bolts that were not even finger tight and most all didn't seem to have the proper torque still on them which I would guess cause a vacuum leak and or burning oil. So after fixing these and re-installing the engine it definitely ran much smoother. But the idle was still acting up and doing strange things.

After pulling codes I received KOER codes 12,13,34,41. Since I still hadn't replaced the Idle air control yet, I picked up a new one. Now the engine is going almost perfect, but will still die when started cold, lope during idle on occasion, and hesitates while getting on the throttle from idle. As well as a very light rich smell from the exhaust. Pulling codes again I get -

CM-34
KOEO-34 and 85
KOER- 34 and 41

I pulled and blocked every non essential vacuum line one by one and reran the test with same results. At this point I don't think there is any way it is a vacuum leak. I also blocked the egr line to ensure the egr valve wasn't leaking or opening at the wrong time causing bad idle and came up with the same results. I tried a new O'2 sensor as well with no change.

The truck is almost good enough now but I've spent too much time and money on this swap now to just call it good. So what else would cause these lean and egr codes? I'm starting to lean towards the throttle body or fuel injectors. The fuel pressure is at around 32 psi while idling (minimum is 30). Could even the simple mods I did require more fuel pressure?

I'm starting to dream of the day it comes back code 11.

If the closed EGR value is still above 0.67 VDC that would account for the continued EGR code 34. Remove and cap off the vacuum line to the EGR. That will ensure the EGR is supposed to be closed. If the EVP signal is still too high then either the EGR valve is stuck partially open or the EVP sensor is bad.

I do not recall seeing a truck of this vintage with a black EVP sensor, only gray. Their signal output values are different.

Alright here's where I'm at now. I took the injectors from the original 302 and put them in the 351w (they had different part numbers). That gave some improvement But a very low idle (500 rpm's). I was throwing a code 12, 13 and 18, 34 and 42 KOER. I adjusted the throttle body stop by the book and got rid of the 12,13, and 18. During adjustment I noticed the 18 is always there with the code 12 or 13 which didn't make any sense to me but it's gone now. I then checked every inch of the EGR system electrically and mechanically. It was all spot on with the exception of the signal coming from the EVP sensor. Sense I had tried 3 different sensors with no luck, I decided to get another EGR valve (despite already having a new one). That worked, getting rid of all code 34's. But that turned the code 42 to a 41.

So here's where I'm at now- after driving for a couple days engine runs almost perfect with only a slight miss at idle and what feels like a slight lack in overall power. The exhaust still smells pretty rich, just not as much as before.
Codes are
KOEO-85
CM-11 (woo hoo!)
KOER-41

Yet again, I feel the 85 Isn't causing any troubles since it's just disconnected completely (no line from vapor canister to throttle body, nipples capped on throttle body). So it's just the matter of the sensor reading lean, when it smells rich.

Any ideas?

This might be one of times I would suggest to pull a battery lead to completely reset to computer. You have replaced a lot of sensors and changed the operating characteristics of the engine.

I assume there are no exhaust leaks upstream of the O2 sensor?

How old is the O2 sensor?

Odd the EGR valve fixed Code 34 and then one would think a closed EGR would be just that...closed. If it has some other internal defect, closed but leaking that could account for the idle change and now lean code issue. Sorry, just had to throw that out there.

If you were burning excessive oil when your head and intake manifold gaskets were bad, your O2 sensor may be fouled. If so, it could be falsely reading lean, and the EEC is trying to compensate by fattening things up.

I'd at least pull the O2 sensor to see what it looks like.