foild

woops

foild

thats hard to read aint it... well, here are the captions from LEfT to RIGHT

2000 RPM
13.8AFR
14.5 AFR
3000 RPM
12.7AFR
13.4AFR
16.2AFR
15.5AFR
14.5AFR
1467 RPM
5200RPM
average of 14 AFR with drop at end to 13.4
6600 RPM

HAILERS

I'm no 'pert. But the 13.4 stuff would not worry me with a non turbo.

It's what a half dozen people after this post will take note of. That's the obvious lean condition around 3500 rpm where it gets real, real lean that is the most troubling. The 16 afr.

Does your car hesitate at 3500 when the secondarys come online. From looking at that chart it seems it must be hesitating caused by the secondarys coming on a tad late?? or??

The 14's don't scare me all that much either. It's the 15 stuff that would bug me. If I were you I'd richen up the area around 3000 to 4500 quite a bit and go for a drive to see what happens. I don't think you'll blow anything up. Say go a plus 10 in that range and see what happens. Sorry, I don't have a wideband on my 86. I just remember it running especially rich around 5000 when I did have the wideband on the car, and when I leaned it out to the 13's it ran MUCH better. Your car seems to be the opposite. It could be the air flow meter doing this. You can overcome that using the safc.

I am no 'pert. Done.

foild

thanks hailers.
exactly whata i am gonna do..
but i do notice a little hesitation... what would this be from?

HAILERS

When under load, the secondary injectors come on line at 3500 rpm on a series four. Sometimes it seems they come on a little late. My 87 had that slight bump/hesitation at 3500rpm. I fixed mine by splicing an extra ground wire to the ground wires coming off the ECU plugs and attaching the other end of that ground to the the chassis or bracket that holds the ECU in place. That worked for me. If I remove that ground wire I'll get the hesitation again. Put it back on and the hesitation goes away.

That said, this fix does NOT work for everyone. For instance, NZCONVERTIBLE has tried this and it did not work for him. He seems competent, so his problem must be another thing.

On early sevens, there is/was a factory service bulletin that addressed this hesitation. Their fix was to add an additional wire to the brown/black wire at the boost/pressure sensor and ground that wire to the filler neck. This problem should have been fixed at the factory for eighty eight cars on on, I suppose.

If you watched with a meter the primary and the secondary injectors as you drive the car under full throttle, you'd see the voltage on the primaries steadily drop from 11vdc or so, down to as low as maybe 4volts , while the secondary voltage would stay around 12vdc, UNTIL you reach 3500rpm whereupon both the voltage for the primary and secondary immediatley go to the same voltage which would be something like 6-7 vdc, and then gradually both drop down as the pedal is held to the floor. Note: the voltages are apporox in the above. Anyway, the hesitation I guess is due to the secondaries coming on just a hair late or the primary's reacting just a hair late. I've no idea which.

If you elect to add an additional wire to the brown/black wire at the boost/pressure sensor, beware. If you accidentally ground the brown/white wire....you'll fry your ECU and the car will not ever start again until you put a new ECU in. It kills the reference voltage output in the ECU if you accidentaly do that.