Car won't run on HO firing order

Daggar · Dec 22, 2005

I don't understand why the right side would read rich and the left lean if the injector is firing in correct time with piston position and valve event. Assuming what's written on the website is correct, (not asuming at all that this is the case just trying to understand) then in the case of the original poster, he would need to have had a no-HO computer installed at some point?

Daggar · Dec 22, 2005

Daggar said:
I don't understand why the right side would read rich and the left lean if the injector is firing in correct time with piston position and valve event. Assuming what's written on the website is correct, (not asuming at all that this is the case just trying to understand) then in the case of the original poster, he would need to have had a no-HO computer installed at some point?

Nevermind... it just hit me that the computer still assumes that those injectors are on the other side and would in effect... be leaning out the wrong injectors.

95GTAODE · Dec 22, 2005

You could have a standard 86+ passcar engine in there. It would still have a roller cam, but would use the non-HO firing order. It will also have the crappy E6SE heads too. That wouldn't surprise me at all, especially if it's a parts store special.

Modular2v · Dec 22, 2005

make sure the company didnt send you a hyd flat tappet cam....this has happend to me in the last 24hrs and nearly cost me an engine

carbed87 · Dec 22, 2005

man, this is turning into quite the discovery... prepare to be bumped, because im doing it as hard as i can.

Michael Yount · Dec 23, 2005

You don't have to bother with valve cover or spark plug removal. If it runs fine on the 1-5 firing order (spark plug wires) then it's got a non-HO cam in it; if it's running on only 4 cylinders when you try the 1-3 firing order -- it's got the non-HO cam in it. I think he started off by saying this.

The engine stock was painted Ford grey -- so if it's black, it's likely the engine has been replaced as Smock said. Be interesting to see if it's a roller motor or a flat tappet....you'd have to pull the intake to see.

While a non-HO cammed car will run with an HO computer, it's not optimum. The injectors are sequentially fired -- so you've got fuel puddling in the ports for the 4 cylinders that fire at different times. To remedy that you can alter the wiring harness for the injectors to match the non-HO firing order.

You may want to check and see which computer is in the car....

Daggar · Dec 23, 2005

Michael Yount said:
While a non-HO cammed car will run with an HO computer, it's not optimum. The injectors are sequentially fired -- so you've got fuel puddling in the ports for the 4 cylinders that fire at different times. To remedy that you can alter the wiring harness for the injectors to match the non-HO firing order.

Heya Mike --

We were just talking about that last night and Hissin pointed out that that's probably not a good solution. Swapping the injector harness plugs around to match the non-HO firing order appearantly causes probems of its own. See His post in this thread. It took me a little bit of thinking on it to try and understand why but I think that I see their (Ford fuel injention's) point.

Michael Yount · Dec 23, 2005

Who's post 'this thread'?

Michael Yount · Dec 23, 2005

Got it --- well, I used to coach people with the same information; but I've come across others who insist the ecu DOES NOT use the O2 sensor signals independantly to alter pulse width so that they're different on the separate banks of the engine.

So - the dilemma continues....

Daggar · Dec 23, 2005

Michael Yount said:
Who's post 'this thread'?

Look at Hissin50's post in this thread. There is a link to Fordfuelinjection.com. They didn't do a great job of explaining the "why" but after thinking about it a bit, I can see where the trouble with swapping injector connectors around might case a problem. The EEC will leaning out injectors that it think is on one side of the car but would be caause a problem due their being moved over tothe other side. The harder the EEC tried to level out that cylinder bank, the worse it makes the problem.

It could be done but it appears to require some EEC tuning to make it happen or swapping the EEC out for a NON-HO.

Edit: Whoops.... it was jrichker not Hissin50

Here's the link: http://fordfuelinjection.com/index.php?p=92

Michael Yount · Dec 23, 2005

We're cross posting -- yeah, I was aware that some think rewiring poses an open loop feedback issue -- but others insist that controlling the injectors independantly bank to bank does not happen.....I remain......confused.

Daggar · Dec 23, 2005

Michael Yount said:
We're cross posting -- yeah, I was aware that some think rewiring poses an open loop feedback issue -- but others insist that controlling the injectors independantly bank to bank does not happen.....I remain......confused.

I'd always thought that swapping the injectors around to match the firing order was the solution as well. I'd talked with others that had done this to resolve the problem and don't recall any problems with running the fix that way. No clue as to whether these folks has ever run codes afterward, or if they were datalogging the AFR. Having never tried this myself, I can see the point that they are tryig to make on Fordfuelinjection.com though.

The EEC sees a lean condition on the left bank.
The EEC attempts to make corrections for that condition by richen up the injectors for that bank.
Problem is that those injectors are now on the right bank.
The right bank is now rich and the EEC attempt to correct for it by leaning out the injectors in the right bank.
Only now THOSE injectors are on the other side (left bank).
So the EEC ends up compounding the problem by trimming these injectors to it's max capabilty.

I don't know if that is what would actually occur but it does make sense.

Michael Yount · Dec 23, 2005

Understand the issue completely Daggar; I used to give folks the same warning -- the missing link is whether or not the computer actually controls each bank independantly w/regard to the O2 sensor signal and pulse width for that bank. Others whose opinion I regard indicate that the ecu DOESN'T control the injectors/banks independantly. So I don't know....

Daggar · Dec 23, 2005

Me either bro...

Numerous threads that I've gone through on EECTuning (the TwEECer forum) seem to indicate that the 88-93 MAF EECs are capable of adjusting individual banks but I don't know for sure. Later, I'll ask that question directly and see what kind of a response I get.

jrichker · Dec 23, 2005

The clue is that there is a error code for O2 sensors for each bank (code 41/91). The same fault (low voltage output from the O2 sensors) generates a separate code for each bank.

Michael Yount · Dec 23, 2005

richker - just because it monitors them separately doesn't necessarily mean it acts on or uses the signals separately. Some say the ecu averages the signals for purposes of making injector adjustments....that would not keep it from reporting a separate left or right side error code. In fact, it makes some sense that it wouldn't make separate bank adjustments so that one side of the engine doesn't get too far out of whack (power production-wise) from the other side. Monitoring the signals independantly, but using them averaged to make injector decisions would provide a warning to check out a problem which is going to be even bigger if left unchecked. And it might be unchecked for longer if the ecu 'adjusts' for the problem over time.

I'm still uncertain as to how it uses the signals....

Daggar · Dec 25, 2005

Here's what i've gotten so far from the TwEECer forum. There were two posts confirming independant bank control from the EEC. I post only this one so as not be redundant.

sailorbob from EECTuning.org said:
I don't know where there is any literature to confirm it you but looking at my ecu's code there are two adaptive fuel trim tables in the KAM (in my ecu they are at 0x0694 and 0x06EA respectively) and each KAMRF is taken from these tables. Both tables are used independantly for each bank unless there is a problem with one of the HEGO's in which case the KAMRF from the working side is used for both banks. If there is only one HEGO then only the first adaptive fuel table is used for both banks. (My ecu is actually for a 4 cylinder engine but all the code is still there).

jrichker · Dec 25, 2005

Daggar said:
Here's what i've gotten so far from the TwEECer forum. There were two posts confirming independant bank control from the EEC. I post only this one so as not be redundant.

Makes sense to me... Otherwise, why have two separate codes for the same type of O2 sensor fault?

Michael Yount · Dec 25, 2005

It makes sense to me also -- but there's a good reason to have 2 separate codes on the O2 sensor fault -- even if the computer is not controlling the banks separately. So you'll know which one to replace if only one goes bad...

86bluecobra · Dec 25, 2005

i guess to solve the problem you should just go buy a H.O. cam stick and install it. while you are at it replace the heads if you have the cash.

Car won't run on HO firing order

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