More daytona help needed

[douglas87]

Rough idle, worse when coming to a stop. Not a miss, feels like an older carbuated car loading up. Give a little gas and it clears up.It's fine when driving down the road. Tried to set base timing but when I do it doesn't work. I did the vacuum leak waited then unlpug the ais, replug the vacuum leak. When I move the screw it doent change idle. If I screw it in all the way it will stall. It's not idleling high, adjusting the screw just doesn't change idle I can't find any vacuum leaks everything apears to be routed correctly. 87 daytona turbo 1 auto.

[NAJ]

Sounds like a vacuum issue.
First, are there any fault codes?
What is manifold vacuum reading? 16-20" HG?
Are you reading the same at the baro solenoid and from the baro solenoid to the map sensor?
When checking vacuum supply to the baro and map "tee" the vacuum gauge inline.

[douglas87]

No fault codes vacuum is 16 hg at baro and 16 from baro to map. If I take vacuum away from the map it clears up a little. I have signal voltage at the map and at the logic module on the map circuit. 7.5 volts. I had the map sensor checked at autozone showed ok.I will check the vacuum lines again. Also it gets worse after it warms up, opposite of what I think a vacuum leak would be.

[4Daytonas]

I'd be checking for a leaking injector.

[woodrow Z]

Quote:

Originally Posted by 4Daytonas I'd be checking for a leaking injector.

+1 on that. Mine blew the seal right out of #1 injector causing all of your symptoms.

[douglas87]

Thanks, I will check the injectors tonight what am I looking for, to know if they are leaking? A flooded cylinder, wet spark plug? Torn seal?

[NAJ]

First was "7.5 volts" on the MAP signal line a typo?
Do you have a fuel pressure gauge or are you going to remove the fuel rail?

[douglas87]

No it was 7.5 volts at the map senser and 7.5 volts at logic module.

[NAJ]

Map sensor works on a 5 volt reference so all output on the signal line will be below that.
If the output read 5 volts that would indicate a open on the signal return line and the controller would set a code 14, map circuit electrical, voltage high.

[douglas87]

Vacuum is good, found that the 02 sensor was stuck lean. Put an 02sensor in it and now it is running rich????????? But the idle is smooth and sounds better. Now when you drive it and give it about 3/4 throttle it misses bad back fires. Yes the timing is correct and timing belt is on right. I double checked(did not do this before) Please help !!!!!!!!!!

[NAJ]

The O2 only reads air in the exhaust.
First be sure none of the wiring on the O2 is damaged, they have a tendency to ride on the manifold and melt.
Any fault codes?
If not then back to where you were originally with the MAP circuit which is dominant fuel control.

[douglas87]

Wires appear ok not melted of damaged. There are no codes. is there a test I can do on the map to test it?

[NAJ]

Start by checking vacuum.
Be sure engine vacuum is ok at a manifold source(16-20"HG).
Then be sure you have the same reading at the baro solenoid and from the baro solenoid to the map sensor.
You will have to "tee" the vacuum gauge inline when checking to the baro and map.
Be sure all the lines are tight and secure and not cracked.
If vacuum falls off the map see's the increase in pressure as more air entering the engine and increases injector pulse width.