Engine running horribly / CEL Knock Flash even with knock sensor disconnected

[krut]

Hello,
I have been having an issue with the electrical system on my 89 Daytona. Currently, the motor is running horribly and even flashing the CEL when the knock sensor is disconnected. From reading information here, the CEL flash technically flashes only when the timing is being retarded.
At any rate, even the slightest throttle creates this condition. The motor is not detonating.

I have set up mptune to data log, but I have not yet logged any length of data to be worthwhile to study.
So far I have verified the timing belt marks and verified the timing is set at 12 BTDC, and have put on my backup map sensor as the ECM threw a code 13. I have used a spare HEP to test as well. The distributor does not have a worn pickup. Overall the car idles fine, but when driving it (even 1st gear, and low speed) you can feel the timing change -- this is leading to the engine feeling like it is bucking (and backfiring). I currently have a custom boostbutton cal in it.

I am curious if anyone has had any experience with such an issue, and what I should look into next. Any input would be helpful!

Thanks!

[trannybuster]

So whats been done to it....nothing besides a cal? Sounds like you might still have the map issue, best check all vacuum lines...bypass the solenoid that the map attaches to and hook the vacuum line right to the map sensor.

[tryingbe]

Have you checked all ground cables?

[bamman]

Erase the codes and check to see if 13 comes back. The engine speed will be limited to 2000 RPM with a code 13, which may explain the "bucking" that you are experiencing.

[krut]

I erased the codes. The boost control is manual, and all vacuum lines are good and have been replaced. The motor has been warmed up a bit, with a hybrid turbo and a ported head. If I remember correctly, the codes were cleared. I'll check when I get home. The motor does rev over 2000 rpm, and the CEL lamp is flashing any time the throttle is touched.

As for the ground cables, the ground next to the battery is fine. I checked the ground to the computer while it was running, and it is at 100mV. Are there any other ground locations that I should be looking at?

Thanks.

[speedfreek500]

Check the ground at the fuel rail also

[Vigo]

Maybe i'll eat my words on this one but given that you have strong clues that the computer thinks it is seeing knock even with the sensor unplugged, i would personally disconnect the battery, pull the 60way connector off the computer, and back the terminal for the knock sense circuit out of the connector with a pick and then reconnect it and run the car without that wire hooked up. If it still does it, i would put a stock computer back (if you still have one) and see what happens. If that were to fix it it would come down to something on the chip being messed up, or something on the rest of the board.

[trannybuster]

Do the timing again, right by the book.....#1 tdc(timing mark on crank @0 through timing hole or crank mark), pull distributor make sure its pointed in the right direction, check wiring(wires) order (1342...I think lol))ensure cam gear slot is in right position. Whats your idle rpm and vacuum reading? Popping is pretty much a timing issue, but.....

[krut]

I had retimed the motor Wednesday, and the markings are right. The light reads 12 on the timing light, and idles fine. Once the throttle is hit the engine stumbles.

I plan to check the knock sensor pin, the timing, and the other computer tomorrow. Ill post any results I may find. Upon a quick inspection this evening, I found that a couple pins on the 60 way could be a little out of round. Hopefully something simple is the issue....

[krut]

Okay. I triple checked the timing, and at 0 on the flywheel, the camshaft is aligned properly, and so is the slot for the distributor. Everything is right there.
I tried a reburn of the same prom to ensure there were no errors there, and also pulled the pin for the knock sensor.
The car was still difficult to crank, but I was able to run it long enough to set timing. The ECM reports no codes currently, and will not rev well. When the motor is revved, it stalls out upon dropping back to idle. The CEL light is still flashing with the slightest blip of the throttle. I plan to check the sync wires and the HEP pickup wires tomorrow, as I've also ran into an intermittent no spark condition.

Vigo - If I use the old computer, should I swap in a 2bar map as well? - Presently I'm running +40's and a 3bar. I'm beginning to suspect it may be the computer.

[Vigo]

I would think something is going on in the computer board at this point. If you do put the stock computer back on it i would hook up the 2bar map as well for testing purposes. I wouldnt bother bolting it down, just lay it next to the 3 bar and move the connector and hose to it.

The stock computer is also going to run like crap with +40s but it will probably run well enough to give you an idea of whether that was the issue or not.

[bakes]

for testing only leave the 3 bar map and injectors and put the 2 bar ecm in it should run and not be over fueling
I know of a 2 car that ran at the track on this combo this is dangous only because the timing map will not pull the timing back but safe enough for a low boost test drive

[Vigo]

A 2-bar cal reading a 3-bar map is going to underfuel. But at full idle vacuum their signal voltage should be pretty similar so there wouldn't be a whole lot of difference at idle.

[tryingbe]

Don't do the 3 bar map sensor with 2 bar map calibration.

[Vigo]

It's way too easy to just plug a 2bar back in assuming you didnt cut the factory plug off to run a different plug.

[krut]

Well, thanks everyone for the help. I found the problem, and speedfreak was the person to guess it. I finally had a day off work today so I could focus on working on the car instead of working on it 30 minutes a day. It turns out the eyelet for the fuel rail was shot. A new eyelet on the grounds and tightened back down, and I'm good to go! Thanks everyone for the help! I feel stupid for not noticing it. I need to learn to tug harder on wires :P.

[turbovanman²]

A 2-bar cal reading a 3-bar map is going to underfuel. But at full idle vacuum their signal voltage should be pretty similar so there wouldn't be a whole lot of difference at idle.

WRONG WRONG WRONG. I've done it many times, and as Bakes said, the timing isn't great but the fuel is ok, hence he is commenting on me,

A stock computer using the 3 bar map, +40's act like stock injectors due to the 3 bar map scaling. Don't believe it, try it your self.

[krut]

I may give it a try sometime for grins. So the idle timing will be approximately correct, but it won't pull enough timing because the slope for the map scale is less on the 2 bar?

[knepppipes]

map issue.check for vaccum at map.if u do bypass selonoid don't keep as a perm fix as u will detonate the map.

[Vigo]

Well, what i said is still correct. My statement did not include 'bandaiding how far off it will be with +40 injectors'. But if the guy wants to try it, im not really against it. It's still going to overfuel roughly 40% at idle.