mark kibort

Thanks John,

So, as i suspected, just reving the engine wont show me anything, however going to the dyno to simulate load and do a test would be kind of expensive. However, i do have a way to simulate load in my driveway. I can jack up the rear of the car, put the car in gear and run it at moderate to high rpms, and apply the emergency brake for a load. i can almost go WOT at 4krpm and check if flappy is working for example. i could do this quickly and pull the sensor and see what the timing changes too, or see if it changes. if half load is a valid test, then ill see what happens with the timing.

you mention that the knock sensor changes only the cylinder timing that is knocking, do you mean which bank or the actual cylinder, based on knowing if a knock is found, there are only a few cylinders that are in the ignition phase. why are there two knock sensors? is it front to rear sensitivity, or left to right?

I also noticed that the idle timing values were pretty low for all rpms. why is it that i found near 20degrees at 2-3000rpm and near 35-40degrees reving the engine up to 5000rpm? even when i just do constant rpm , (not reving the engine, which creates a load), i get some values over 35degrees?

I think the key thing here is to use the later computer box and see if we can get some error codes.

thanks again,

mk

Bill Ball

There it is, Mark. Also, you can't observe the effect of the WOT switch on timing - kinda hard to keep the pedal mashed for more than a fraction of a second with no load. It would be ideal to run the diagnostics. I have the Spanner cable for the early diagnostic plug. We just need to temporarily hook the GT brain or my 89 S4 brain into the Holbert car. We'll work out a time.

John, it's just the later LH that we need to install, right? Or do we need to hook up a later EZK as well?

John Speake

Hello Mark,
The knock system uses two knock sensors, front one measures knock on four pots 1.2.5.6, and the rear knock senor the other four 3,4,7,8. The Hall sensor combined with the firing order is enbougfh to tell the EZK which cylinder is knocking.....

There is a seperate map for closed throttle advance, I took the 10deg figure from that.

Hello Bill,
You will need to install an S4 EZK to read knock sensor and Hall sensor fault codes.

Alternatively Mark can retro fit MY88 EPROMS to both his LH and EZK to his 87 units, and then he is ready to go. I can supply, or anyone with a SHarkTuner can make a set of EPROMS for him.

Please note the igntion maps for S4, GT and GTS have signifiacant differences in their maps, which is why all three are available in the EZK SharkTuner

IcemanG17

MK
Yup....the best way to figure this out is to install 88+ EZK & LH brains then use the spanner or theo's hammer to trouble shoot......

My 1st thoughts are:

Hall sensor
WOT
Knock sensor or both

Or some combo of those....say the hall and WOT....that should be at least 20hp....

Since your compression #'s still look fine and just did a tune up....

mark kibort

John,

also more great info.

just for reference, my stock advance, but the idle is a little high (ie 1200rpm) is in the 12-3 degree range closed throttle.

you mention to bill that you need to "install" a S4 EZK, is that what i have since i have both the S4 boxes?

also, i was just looking at the dynos again. maybe the correction factor is just way off. if i can make 300rwhp on a 84 degree day 30.05 barometric, why on earth would the correction factor be "0"? on an earlier dyno last winter,(also shown on the dyno) there was a 3% lower than standard temp run (66F/29.80), yet it was altered 3% (SAE). 327rwhp actual, 318rwhp SAE. why would my hot dyno at 20%+ greater temp, show no correction???
Even if my dyno run with almost 10X the tempurature change, was to show the 3% SAE correction , i would be at 310rwhp corrected.

maybe thats the issue right there?

Another few questions.
1. as far as your eprom's go, would that solve my issue if the knock sensor is failing, or do they need to be addressed.

2. what do your new maps provide as far as WOT performance from 4-6.5k?

3. would there be any advantage of using a GT LH box? dont you need both to get the mixture maps as well as the spark advance changes?

4. based on my dyno runs and the possibility of the timing brought back 5-6 degrees for a failed Knock or Hall sensor, wouldnt the graph uneven as far as the losses to HP expected? especially at 6500rpm where im still down as much as i was at 3000rpm. This reduction in Hp looks like the correction factor is not matching conditions, OR, i have an e-brake issue (or as i metioned, strap down forces were way over normal)

Mk

mk

mark kibort

i guess the WOT switch is easy enough to check. Ill have to check the pin numbers and put a meter on it. what does the WOT switch do on the S4?
is it fuel enrichement like the older Ljets or does it tell the computer to change to a different advance map or something?

Mk

Bill Ball

Mark:

We need to install both of the 88 or later LH and EZK boxes or modify your current boxes with the updated EPROMS John mentioned that he or Sharktuner owners can provide. This is because the earlier box's EPROMS had no diagnostic code storing.

Doing these swaps will not fix any bad sensors but will help us determine if they are bad. Then they would have to be replaced.

Also, I'm going to guess that your WOT switch is fine. If it were bad, I think you would have gone lean at WOT during the dyno. The WOT switch takes the fuel off closed loop and retards the timing, actually quite a bit (I think down to 28 advanced from 40). You did not trip WOT in your driveway testing, but you would have on the dyno.

Anyway, the WOT switch function can be checked easily now with a muiltimeter at the LH or EZK plugs. I have found a lot of bad ones on cars, and another thread provides a failure mode that can be fixed with some solder (once the switch is off the car).

Check the WOT switch as follows:
Disconnct both LH and EZK plug
- EZK plug: Connect ohm meter across pins 26 and 18. It should read infinite ohms at idle, <10 ohms at WOT.
- LH plug: Connect ohm meter across pins 17 and 3. It should read infinite ohms at idle, <10 ohms at WOT.

John Speake

Thanks Bill, you have nicely covered all the points that Mark raises...... :-)

I would not recommend a GT EZK as the igntion is retarded in mid to high range as the GT breaths better with their different cams. (This is why a GT EZK EPROM can be used in a "knocking" GTS as one way of fixing the knocks)

PorKen

It sounds like maybe your TempII sensor is out on the EZK side, and maybe the IAC is bad, or you have a vacuum leak. When the EZ sees the engine is cold, it advances the timing by 3°. Hot it should be 10° at idle.

I was thinking that maybe he should use a GT map with the modified 86 cams he put in, which have comparable lift and duration of a GT?

Mrmerlin

Mark since you have already noticed that the insulation on the knock sensor wires is bad why dont you just figure that its time to replace them, there is no doin only one if you remove the intake then you should at a minimum replace the flappy actuator unless your going to disconnect it, both knock sensors, the hall sensor, the crank position sensor, the TPS, the ICV and every soft line under the intake as well as the oil filler seal , and the intake gaskets and not knowing what the fuelinjection system is remove the injectors have them tested to see what they flow and at best replace them with the newer 4 pintle injectors, and also replace the fuel pressure regulator and both of the fuel dampers. Have you had enogh yet? Dont forget to replace the fuel lines. Sorry but this is what the intake covers and if its removed there is no reason to delete any of the things i have mentioned, goodluck, Stan

mark kibort

Thanks for the info. as far as the knock sensors go, you are probably right. time for them to be replaced. However, i dont want to dig into the intake if im going to be pulling the engine after this season anyway.

flappy doesnt need to be replaced, as it works fint, its just disconnected and pegged open. (perminantely at high rpm setting) this is because i never need any performance below 4000rpm, ever!

the hall sensor is behind the cam, and i guess we can check to see if it is working, and the car doesnt run unless the crank position sensor is good so that is probably ok. on the 6.5Liter rebuild, i will consider replacing them both though.

rising rate fuel regulator seems to be working fine and i dont thing its worth replacing the dampers, as i have the vacuum removed from them anyway, as well as fuel being controled very well.

mk

Mrmerlin

Mark the reason i am advising on replacing all of these parts is that if one is bad chances are they are all bad, just to be clear, trying to use parts that have been in position where others are starting to degrade means that they all need replacement otherwise you will be on this board trying to find other problems, when the real culprit is a cost cutting mentality. i know you like to save your cash for tires but think about this when your on your last lap and in first place and the crank position sensor shorts out you might then remember this advise. usually all of the connectors will be disintegrating and you will find this out when you remove the harness from the engine. Spend a little dime up front to insure continued performance
Also if you have a different fuel pressure regulator then that may save you some cash for a new set of injectors,if you need them. the fuel dampers being disconnected should also be plugged ,if they are not and they develop a leak then the leak will be on your engine, goodluck, Stan

mark kibort

good points! especially the part about the dampers. even though they are connected on the vacuum lines, their is a leak to not pull back pressure on idle or off throttle. that could be a nasty firery problem if not plugged back into the vacuum system. maybe ill plug it back into the air box or just on top of the throttle plate, just in case. good point!

mk

heinrich

Will the later EZK/LH fit Mark's harness? I doubt it.

SwayBar

Yes.