Cruise hesitation/misfire & cant rev past 6500

[Jungy]

I just got the car running for the first time and wanted to do some tuning but I am running into an issue with major hesitation and what seems like misfires while cruising and slowly accelerating. What I've noticed is that when the car is under load and can get into a little bit of boost is smooths out. When I try to free rev the motor I can not get it to go past 6500 rpm. I've tried new plugs, new wires, swapped coils, and swapped transistors. I'm going to try and add a couple more grounds from my batt neg to the sensor ground and to the block because the car is wire tucked and running a pc680 in the trunk hopefully that takes care of it but I'm also curious if it could be the CAS? Any input would be appreciated.

 

[DSM98GSX]

This might sound like a dumb question, but are there any engine codes being thrown?

 

[throwedgsx]

Hey dude, i was thinking, that day we were f***ing around with it your BOV sounded like the set screw was really loose. Is it leaking at all?

 

[Jungy]

No codes being thrown, and the BOV isn't leaking. I tried running is SD and still had the same hesitation as running on the 2g MAF. The CAS isn't 180 out and its timed at 5 deg BTDC.

 

[Jungy]

I added the ground wires running from the battery last night and went and checked it out today and still the same issues.

 

[Jungy]

I borrowed a different CAS to see if that was the cause of my hesitation. No change ... so I narrowed it down to be a fuel injector issue now and went down the line unplugging injectors one by one while idling and everyone i'd unplug would make the car stumble until I got to the last one and there was no change. I ohm'ed all the injectors out and all tested 5 ohms (Bosch 1600's), I don't suspect it to be injectors because they are new, now I am going to see if I'm getting any signal at the injector from the ecu.

Edit: No dice went out and tested it I'm getting about 3v at every injector connector at idle. I do hear a slight change in idle when I disconnect the #4 injector but not as much as the rest. Dead/clogged injector?

 

[turboglenn]

What are your AFR's at? I had an issue very similar a couple years back where i couldn't get past 7200 RPM. I tried everything i could think of and even consulted some other friends that have tuner shops to see if i could bounce some ideas around and nothing seemed to work untill one day i leaned the AFR's out to the higher 11's range (11.8:1 or so) and that halfway fixed it, then i gapped my plugs down smaller (.020) and that fixed a LOT of it too. Then the addition of an MSD DIS-II cleaned up the rest with no issues since.

I changed the CAS, re-wired and grounded it and most other major connections and more when all it really needed was to be leaned out and to have the plug gap tightened up. THe MSD box wasn't really needed untill i was running the boost at 30psi constantly

Might wanna try a few of those things before swapping expensive parts since a tune is free (if you can do it yourself) and plugs are only 2 bucks a pop start with those

BTW, what areyour wideband readings when this happens?

 

[Jungy]

I'm running br7es' for plugs gapped at .026. I'll try tightening the gap some more and see if it changes

You must be logged in to view this image or video.

Wow well you cant really see that very well but my afr's are around 15 cruising on e85

 

[Artago]

^^ Isn't e85 stoichiometric 9.765 ??

E85 in standard engines - Wikipedia, the free encyclopedia

 

[Jungy]

Just tried gapping my plugs .020 and .034 no change still the same problems with both.

The wideband calculates afr off the lambda value, e85 lambda value of 1 = 9.765 and the lambda value of 1 on gasoline = 14.7. The zt-2 is setup to calculate gas afrs from lambda values so you tune for similar displayed values even though its a different fuel.

 

[Artago]

The wideband calculates afr off the lambda value, e85 lambda value of 1 = 9.765 and the lambda value of 1 on gasoline = 14.7. The zt-2 is setup to calculate gas afrs from lambda values so you tune for similar displayed values even though its a different fuel.

Gotcha.

 

[Jungy]

Tested the CAS wiring and I'm getting 12v between the red and black wires, 5v between the blue/white and black wires, and 5v between the blue/black and black wires. This was all tested with the key on and the connector disconnected from the CAS and probing the pins inside it. Are all there readings correct?

I moved the car from my parking spot to my garage and at about 2200 the car was bucking and the tach had an electrical jitter to it. My wideband is pulling its power and ground from the ecu (pin 12 & 26) so I wonder if the heater circuit for it is drawing too much current from the ecu and causing these issues. I'm gunna rewire it to the cig lighter power and chassis ground it and if that doesn't take care of it I'm all out of ideas.