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Forward Some Money
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5,054 Posts
Discussion Starter #1
Yes, I did a search.

I am in the final phase of completing my resto. After some test driving, it's kicking out a Code 41. (Lean condition) Check engine light comes on after run on the freeway for 5-10 minutes. There were NO code issues with the old engine. The engine (long block) was rebuild professionally and I reinstalled the upper intake and peripherals. Timing is at 10 BTDC and vacuum at idle is 16. FPR is new(er) and front fuel pump is NOS. Idle is a little lumpy but it may be the new cam profile. Fuel injectors are new from Ford and are purple vs the old orange.

EGR sensor and controller are new. EGR seems to be working fine. I think I read somewhere that the lean condition could be caused by the EGR sticking open. I assume it's ok b/c I put vacuum on it at idle and the engine faultered.

I havent spent a lot of time on it - but was looking for some guidance (shortcut) on what typically goes wrong to cause this code on Broncos.

Thanks
 

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Forward Some Money
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Discussion Starter #2
It's pretty much a stock 1989 351. +.030. over (no stroker)

cam is a Lunati 61001 LK
Advertised Duration : 256°/262°
Duration @ .050 IN/EX : 213°/219°
Gross Valve lift IN/EX .483''/.499''
LSA and ICL 112/108
RPM Range: 1000-5500

Heads are stock (refurbished) with SD EFI induction feeding it.
New Ford fuel injectors (19 lb I assume) FOTZ9F593DA
- I havent checked the fuel pressure at the rail - lost gauge. I only replaced the front pump b/c I broke it. There were no issues with the fuel system before, so I made some assumptions here.

The old stuff, (intake, distributor, front bolt-ons) was just returned to the bebuilt long block.

Vacuum reads 16 and steady at 850 rpm. I cant find any obvious leaks.
Timing was set to 10BTDC with the SPOUT disconnected. I didnt alter the ignition. Total advance looks to be aout 32

I didnt check compression - here again I made an assumption that since the engine rebuilder is a top fuel engine builder he probably did put it back together right. He did clean up the block and head mating surface so I may have picked up a few compression points.

I was kinda hoping :twak there was a "common" i.e. quick and dirty... reason why it might be throwing that code. What threw me was the translation by my scanner. It is worded such that it had me chasing down EGR stuff. If I get the chance today, I'll get out the compression gauge and check some cylinders.
 

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aka: kemicalburns
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7,874 Posts
well the cam is your first problem. you need a lob seperation of 114* or more for speed density to function. you need to know what injectors your using, if they are anything other then 19lbers then you have more issues.
 

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Crusher Mike
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6,111 Posts
well the cam is your first problem. you need a lob seperation of 114* or more for speed density to function. you need to know what injectors your using, if they are anything other then 19lbers then you have more issues.
I was just thinking the same thing you need to convert it to mass air if you want to run those aplications.
 

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Forward Some Money
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Discussion Starter #5
OK, looks like the cam is somewhat of the issue. ;) Not what I wanted to hear. Now I need to decide how to correct it. I really dont want to pull the front off the truck to change the cam. This thing has been down for 2 years and I need to get it rolling. :doh0715:

So it looks like the easy fix it to convert to mass air. I did a search and I find threads addressing some of the issues......but maybe my search terms arent pulling up what I need. I dont mind spending the money to "update" it to MAF but I want to avoid any nightmares with linkage. I dont want to loose my cruise or any other function.
What research I did here looks like the original SD computer can be retained. It has a C-6 so the trans shouldnt be a problem.

I have an FIPK kit and Summit shorty headers....so some performance mods have been made.


Thanks....sorry to be such a "newbie", but I am behind the curve on EFI stuff as most of mine has been carb-ed.
 

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The Anti Yam!
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22,674 Posts
112* LSA is too low 90% of the time. But a few have gotten away with it on S.D. setups in the past. How did you come to choose that cam?

Before doing anything else test the fuel pressure at the rail and make sure it is within spec.

However, you injectors are wrong. 19lb/hr injectors from Ford are orange.
(unless they are some form of goofy outsourced replacement part sold under Fords name)
 

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Registered
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897 Posts
I bet you have a intake leak. Maybe it did not seal well?
 

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Forward Some Money
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Discussion Starter #8
112* LSA is too low 90% of the time. But a few have gotten away with it on S.D. setups in the past. How did you come to choose that cam?

Before doing anything else test the fuel pressure at the rail and make sure it is within spec.

However, you injectors are wrong. 19lb/hr injectors from Ford are orange.
(unless they are some form of goofy outsourced replacement part sold under Fords name)

The cam was recommended by the engine builder. He was a little embarassed when I told him. They build mostly high-end racing engines and dont do much with street stuff or EFI.

Agreed I need to get a fuel pressure gauge. I am pretty confident it is "ok" as I changed the pump with an NOS one. (not that those never fail)

The purple injectors came directly from Ford. I was a little curious about their non-orange condition. He double checked and said that's what they were super-ed by. He's ordering me a new O2 sensor so I'll have him triple check them next week.

Nothing is ever easy.....this would have been a lot easier if I hadn't been born in the age of carbs. stupid EFI ....stupid computers :cry :histerica

makes me manic depressive.........

but on a nicer note..... it drives like a new one...........crap......
 

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Forward Some Money
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Discussion Starter #9
I bet you have a intake leak. Maybe it did not seal well?
I was VERY careful when I put it back on. (Upper to lower) I made special alignment pins to keep the gasket in place while I installed the upper. I torqued it all down to specs. I tentatively ruled out vacuum leak b/c I didnt hear anything, the engine idled correctly and the emissions stuff wasnt throwing codes. I'm not sure if a computer controlled engine will keep the engine from idling higher with an intake leak.
:scratchhe
BUT - I wont discount anything at this point.
 

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Registered
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Try spraying some brake cleaner around the intake, if you have a vac. leak it'll be sucked in and the idle will change... noticeably. Just an idea.
 

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Registered
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It's probably not a vacuum leak, it's the cam's lobe separation at 112. SD really doesn't like anything below 114*, and thus, you're getting a lean condition.

Your easiest fix, IMO, is pulling the cam for one with a 114* LSA... but converting to MAF really isn't all that bad as some make it out to be. You could use a kit, or you can do it the more time consuming way with a Mustang A9L EEC, and rebuilding your harness for sequential injection.

Search for MAF conversion/swap and you'll find a ton of information on it.
 

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Forward Some Money
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Discussion Starter #12
It's probably not a vacuum leak, it's the cam's lobe separation at 112. SD really doesn't like anything below 114*, and thus, you're getting a lean condition.

Your easiest fix, IMO, is pulling the cam for one with a 114* LSA... but converting to MAF really isn't all that bad as some make it out to be. You could use a kit, or you can do it the more time consuming way with a Mustang A9L EEC, and rebuilding your harness for sequential injection.

Search for MAF conversion/swap and you'll find a ton of information on it.
It wouldnt be like this to have an easy fix. I REALLY dont want to pull the nose off this. Maybe I'm being lazy but it seems like a MAF swap would be easier. I will only pull the engine down if the swap is too costly or it means I lose accessories

Iwillsearchforswapthread ....thanks!
 

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aka: kemicalburns
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7,874 Posts
perhaps asking the engine builder to fix it, they are the ones that installed the wrong cam in there. im sure you can come to some agreement on getting it taken care of.
 

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Forward Some Money
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Discussion Starter #14
Well I took the easy way out. Not the cheapest but it was easier than chasin' parts. I did the Ford racing conversion.
I was mistaken..I thought the whole upper intake and throttle body had to be swapped (to a Mustang configuration), which is why I was concerned about the Speed Density to MAF swap. I assumed it was going to change the configuration and I was going to loose my cruise control etc.

The kit made it pretty easy. The worst part was switching back to the original air filter box (base) after doing the K&N swap. The only part I wasnt happy about was the adapter that goes between the new processor and the old engine harness (engine side). It extends the depth and hits the inner fender. I had to loosen the back half of the inner fender to connect it.

The mistake I made was connecting the old MAP sensor back into the system. The check engine light came back on (which the directions say is normal for about 3 miles on cold startup)) The idle was a little lumpy. I connected my code reader but it was till set for the old '89 351 processor so it kicked out some codes. Realizing my mistake, I disconnected the MAP and plugged the vacuum source, but it didnt seem to help.

It sure does have better throttle response. I took it for a 5 mile cruise. It still isnt idling any better. Leter I decided to take it for a longer cruise (10 miles one way) The check engine light was off initially but came on at the end of the return trip. I didnt pull the codes b/c I wasnt sure what configuration to use on my reader. So I disconnected the battery and am going to try it again tomorrow. More then. ........

BTW, I did contact the engine builder. I asked for some $$$ consideration toward the MAF swap. It was going to cost them $200 for the SD cam and labor to install it. Thusfar.....no offer
 

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The only question I've got for all this. did you and the engine builder use O2 safe sealants through out the build? You have chased all over the engine except the one sensor that is giving the lean condition...O2 sensor. Just another thing to check out.

It sounds like once the 'puter decides to go closed loop, it kicks the code. which is when it starts looking at the O2 sensor.

Cheers

Steve
 

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Forward Some Money
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Discussion Starter #16
The only question I've got for all this. did you and the engine builder use O2 safe sealants through out the build? You have chased all over the engine except the one sensor that is giving the lean condition...O2 sensor. Just another thing to check out.

It sounds like once the 'puter decides to go closed loop, it kicks the code. which is when it starts looking at the O2 sensor.

Cheers

Steve
I dont know if THEY did or not. I only installed the upper intake and WP. I have replaced the O2. I'm going out now to reintall the battery cable and reboot the system. thanks for the suggestions.
 

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Forward Some Money
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Discussion Starter #17
I am/was still chasing this down but needed to get away from it. Tonight I revisited it. I found no ground at the O2 (HEGO). Actually didnt find anything.

After searching and tracing I found the O2 harness disconnected near the battery.

Now my question, the HEGO has 2 white and 1 black wire. I'm not sure it's wired to correspond to the harness.
Currently wired:

HEGO black wire - Harness DG/P (returns about 4 volts.
HEGO white - Harness Grey/yellow (or yellow grey)12 volts
HEGO white - harness ground.

Any suggestions? It was a Ford HEGO so I would think it's wired for my harness. It is still showing KOER Code 41. I cleared them with the reader but didnt disconnect the battery. Shouldnt the codes clear out once the problem goes away or do I need to disconnect the battery? I havent taken it out yet so I dont know if the CEL is on, but running the code reader again showed the 41/91 error.

Thanks
J R
 
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