Coke Car running lean...
09-12-2015, 06:36 PM
#61
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Did you just type that backwards? If your car is an '86.5 it should have 24 lb injectors...in fact, even if it were an '87, I THINK the Porken chips require 24 lb injectors...
09-12-2015, 06:55 PM
#62
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Bosch 0 280 150 706 is listed at 20.35 lbs/hr at 2.5 bar 36 psi. Not sure what that translates to at 48 psi (unless the relationship is linear....)
How does the MAF ohm out?
How does the MAF ohm out?
09-12-2015, 08:59 PM
#63
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He had similar lean troubles with an S3 (the one he put headers on).
Just for kicks, check the resistance of the WOT input at the LH.
Although only a slider switch is used, both S3 and S4 have a variable input for WOT.
If there is too much resistance it won't pass the threshold for 'true' in the code.
Both 19# and 24# are the same color for whatever reason.
09-12-2015, 10:06 PM
#64
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I had a Euro engine come from Texas with a bad "rebuilt" MAF....running 16.0 to 17.0. The upper couple of inches of the cylinders, where the pistons got super hot and expanded were really ugly....this hurt the engine in a huge way. This was a non-oxygen sensor controlled engine, so there was no "feedback loop" continously attempting to enrichen the mixture...so it ran 16.0 to 17.0 the entire way.
Granted, a short period of time running this lean of a mixture may not hurt anything and Texas to California is a long drive....but the reality is that engine damage can and does occur in engines run this lean.
The more modern engines running in "lean burn" have very active computers reading many different variables to keep engines from being damaged. When damaging heat goes up, the injection systems are smart enough to make appropriate changes to keep the engine from overheating the pistons.
A 1980 design injection system doesn't have anything to detect conditions below about 15 to 1.....nor can it do anything once the feedback loop is maxed out....if there is a feedback loop.
09-12-2015, 10:09 PM
#65
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Thanks all.
Forgot the mention, MAF is set at 300ohm.
For WOT, should i measure ohms between WOT pin (12 I think) and ground while engaged?
Just measured.
WOT closed = 1270
WOT engaged = 1315
That doesn't seem right. Does it?
Forgot the mention, MAF is set at 300ohm.
For WOT, should i measure ohms between WOT pin (12 I think) and ground while engaged?
Just measured.
WOT closed = 1270
WOT engaged = 1315
That doesn't seem right. Does it?
Last edited by AO; 09-12-2015 at 10:28 PM.
09-12-2015, 10:28 PM
#66
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OK boys... Things are still not fixed. The car is still too lean for WOT operation. Here's what I've done.
* I replaced the FPR with the 87. FP at the rail at idle is ~48 PSI.
* I (open-air) calibrated the Innovate Wide-band.
* I tested the WOT Switch at the LH, at it clearly is working.
I took this video so you can see what's happening. After I shout this, I tried the stock chips as I was thinking that maybe the stock chips would cause it to run pig-rich with the higher fuel pressure, but it didn't - it ran almost exactly the same... maybe a tad better at WOT.
Any thoughts?
* I replaced the FPR with the 87. FP at the rail at idle is ~48 PSI.
* I (open-air) calibrated the Innovate Wide-band.
* I tested the WOT Switch at the LH, at it clearly is working.
I took this video so you can see what's happening. After I shout this, I tried the stock chips as I was thinking that maybe the stock chips would cause it to run pig-rich with the higher fuel pressure, but it didn't - it ran almost exactly the same... maybe a tad better at WOT.
Any thoughts?
I've had so many of the "US rebuilt" MAFs not perform properly, that I almost automatically suspect them as being a potential issue, when I have a car with an injection problem and one of these MAFs are present.
My belief is that the "rebuilding and/or calibration" method is flawed....and while these MAFs may work adequately when the engines are run in closed loop, the flaws show up when engines are run in open loop. (Our injection systems totally rely on the signal from the MAF, when in open loop.)
I have no idea of how many of these "US rebuilt" MAFs I've sent to England to have them correctly repaired....but it is certainly enough that I'm very suspicious whenever I see one!
If you have a MAF like the one I had in my post #64, it is going to run at 16.0 to 17.0, regardless of what else you do. I completely traced and checked every single injection component, "rang" the entire wiring loom, and tried a different set of computers before figuring out that the MAF was the issue.....and the only reason I did not try the MAF first was because the customer told me the rebuilt MAF was an "English rebuilt unit" and not a "US rebuilt unit".
The seller was very dubious of my diagnosis....so I "swapped" this MAF back and forth multiple times....to confirm it was the source of the problem.
Before anyone gets their panties in a wad and gets all defensive, I'm not trying to rub anyone the wrong way. I actually don't care what other people use for parts. I use what I use, for my own reasons.
In reality, I'm just trying to relate my experiences and pointing to a potential source of the problem, for the OP.
Last edited by GregBBRD; 09-12-2015 at 10:44 PM.
09-13-2015, 03:03 AM
#67
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12 and 25.
Forgot to mention that you must disconnect the EZF plug when measuring this as it shares the WOT input.
I don't recall what it is normally. I will check my '86.5 tomorrow.
09-13-2015, 10:26 AM
#69
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Just checked WOT (with EZF unplugged) between 12 and 25, and I get pretty consistent 3.4-3.6 ohms (open loop when not engaged). Does that seem right? Maybe I need to build myself that WOT POT?
As for the MAF. That was the first thing we suspected. We swapped in a known-good MAF. The original (that came with the car) and the known-good MAF were both rebuilt by Injection Labs and both seem to perform equally.
AS to Greg's experiences, I too have had similar experiences with "rebuilt" MAF not working properly, but in my experience it was exactly opposite. The English ones were inconsistent, while the US were more reliable. Perhaps the pendulum has shifted?
As for the MAF. That was the first thing we suspected. We swapped in a known-good MAF. The original (that came with the car) and the known-good MAF were both rebuilt by Injection Labs and both seem to perform equally.
AS to Greg's experiences, I too have had similar experiences with "rebuilt" MAF not working properly, but in my experience it was exactly opposite. The English ones were inconsistent, while the US were more reliable. Perhaps the pendulum has shifted?
09-13-2015, 10:50 AM
#71
Here is something for you to try, set up a jumper where you plugged in that harness at the front of the motor grounding the WOT circuit and compare the ohms between 12-25 on the LH. If it goes to 0 test drive the car with the jumper installed and see if it changes the AFR. If it improves you need a new TPS.
09-13-2015, 11:28 AM
#72
Race Car
Been chasing A/F and drivability issues with an inj labs Maf, replaced with John Speaks and all is well. Long story with this but I have another friend with a IL rebuilt and they have drivability issues. I would look into substituting an English rebuilt and see what happens.
09-13-2015, 12:26 PM
#73
Actually, what you really need to do is get the FPR for the 1988-1995 application, with the 16mm x 1.5 threads. I make a custom line that goes from this regulator to the "early" fuel cooler (instead of that two piece hose set-up with one hose rubber, the other hose plastic, and that crazy adaptor on the back of the block....what the hell were they thinking?) This is what I do for "early" 1987 street cars and 1985-1986 cars with Porken's chips.
If someone has a race car and is not running the fuel cooler (no A/C, so it's not necessary), I also make a line that goes from the 1998-1995 regulator directly to the junction block on the firewall, eliminating another couple places for leaks to occur.
"Race cars" need to be kept simple and have as few fuel connections as possible. Every connection is another place for a leak to occur.....and adds complexity that not only isn't needed but is also completely undesirable.
If someone has a race car and is not running the fuel cooler (no A/C, so it's not necessary), I also make a line that goes from the 1998-1995 regulator directly to the junction block on the firewall, eliminating another couple places for leaks to occur.
"Race cars" need to be kept simple and have as few fuel connections as possible. Every connection is another place for a leak to occur.....and adds complexity that not only isn't needed but is also completely undesirable.
There you go. And I think those fpr years are cheaper!
09-13-2015, 12:33 PM
#74
Where does the wide band sit? Has it been calibrated? (Didn't see that mentioned)
09-13-2015, 12:34 PM
#75
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Here is something for you to try, set up a jumper where you plugged in that harness at the front of the motor grounding the WOT circuit and compare the ohms between 12-25 on the LH. If it goes to 0 test drive the car with the jumper installed and see if it changes the AFR. If it improves you need a new TPS.
Maybe it is the MAF? I think one of my homos here has European re-built MAF, or at least one known to work well under WOT with the S300 4.0 chips.
If this doesn't work, I may need to do my own Shark Tune and ditch the S300's.
. That's a lot of time and effort!